Category: Precision Oncology

EGFR Exon 20 Insertion Mutations – These Are NOT Your Common EGFR Mutations

RR


 

 


Written By: David M. Waterhouse, MD, MPH & Anita Koshy, MD
This promotional educational activity is brought to you by Janssen Biotech, Inc., and is not certified for continuing medical education.
Dr. Waterhouse is a paid consultant writing on behalf of Janssen Biotech, Inc., and must present this information in compliance with FDA requirements applicable to Janssen Biotech, Inc.

It is estimated that approximately 237,000 people in the US will be diagnosed with lung cancer in 2022. Despite advancements in standard-of-care treatments for lung cancer, this disease remains the leading cause of cancer death in both males and females.1 Nonetheless, the burgeoning number of targeted therapies for some types of lung cancer, particularly non-small cell lung cancer (NSCLC), have allowed for improvements in mortality and survival.2 As of 2022, there are ~20 targeted therapies for ~9 actionable driver mutations in stage IV NSCLC.3,4 In order to determine optimal targeted therapies, the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) recommend comprehensive biomarker testing, like next-generation sequencing (NGS), for all eligible patients at diagnosis of advanced NSCLC.5

Common EGFR Mutations (Exon 19 deletion and Exon 21 [L858R] mutations)

Epidermal growth factor receptor (EGFR) is a potent oncogene commonly altered in NSCLC, and EGFR driver mutations may be found in as many as 28% of metastatic NSCLC patients.6 Tyrosine kinase inhibitors (TKIs) directed against EGFR were among the first molecular targeted agents used for treatment of advanced NSCLC.7 Initial studies of EGFR TKIs showed that patient characteristics associated with EGFR mutations, such as non-smoking status, female gender, East Asian origin, and adenocarcinoma histology suggested a greater benefit from EGFR TKIs compared with first-line chemotherapy.8 Later studies identified gene mutations that could target the kinase domain of EGFR and predicted response to such inhibitors. The variable deletions of at least 3 amino acid residues in exon 19, as well as the single point mutation leucine-858 to arginine (L858R) in exon 21, are often referred to as “common” activating EGFR mutations and represent the vast majority (90%) of all observed EGFR kinase domain mutations in NSCLC.8 (Figure 1)EGFR-Mutations

EGFR Exon 20 Insertion Mutations

Exon 20 insertion mutations are the third most prevalent type of activating EGFR mutations in NSCLC and are associated with a poor prognosis.9-11 These mutations are also enriched in women, non-smokers, Asian populations, and those with adenocarcinoma. Exon 20 insertion mutations, however, lack the key structural features that confer sensitivity of L858R and exon19 deletion mutations to first-and second-generation EGFR inhibitors. In-frame base pair insertions in exon 20 result in activation of EGFR, but, unlike the common activating EGFR mutations, they are associated with reduced affinity to most clinically available EGFR TKIs indicated for common EGFR mutations. Data are limited and variable, but multiple studies found that patients with EGFR exon 20 insertion mutations had an overall response rate of 0% to 8.7% when treated with first-, second-, or third-generation EGFR TKIs.12-16 (Figure 2)

Median-PFS-First-Second-Generation_TKI

*These data were taken from a retrospective observational study.16
†Common mutations include L858R, L861Q, and exon 19 deletions.16
‡These data were taken from multiple sources: a cohort study, a prospective post hoc analysis of phase 2 and phase 3 trials, a single-center retrospective analysis, and a systematic literature review and meta-analysis.12-14
HR, hazard ratio; ORR, overall response rate; PFS, progression-free survival.

Study results also demonstrate limited efficacy of immuno-oncology (IO) monotherapy in this patient population compared to patients with wild-type EGFR. In a retrospective study using real-world data, patients with EGFR exon 20 insertion mutation-positive NSCLC were associated with a 58% increased risk of shorter time to next-line therapy after first-line IO monotherapy compared to patients with wild-type NSCLC.17

The NCCN Guidelines® do not recommend most TKIs or IO monotherapy for treating patients with mNSCLC and EGFR exon 20 insertion mutations in the first- or second-line setting. Instead, the Guidelines recommend platinum-based chemotherapy as the standard first-line treatment for NSCLC with EGFR exon 20 insertion mutations.5§

§Exceptions include p.A763_Y764insFQEA and p.A763_Y764insLQEA.5

EGFR Testing

The NCCN Guidelines recommend comprehensive biomarker testing, like NGS, prior to the initiation of first-line therapy, if clinically feasible.5 Despite that recommendation, rates of broad biomarker testing remain low, according to real-world evidence.18,19 In a retrospective observational chart review study among 3,474 patients with advanced NSCLC receiving first-line therapy in the US Oncology Network, the EGFR testing rate was found to be 70%, but comprehensive NGS testing was completed in only 42% of patients.20 Failure to order comprehensive NGS testing is particularly problematic when it comes to identifying EGFR exon 20 insertions. There are over 100 unique EGFR exon 20 insertion variants, and polymerase chain reaction (PCR) testing can miss approximately 50% of the insertions identified by NGS.21 (Figure 3)

EGFR-Mutations-Foundation-Medicine

||Analysis from mutation profiles of 36,465 lung adenocarcinomas from Foundation Medicine (Cambridge, MA) FoundationInsights database, which is a database of 315,688 patient genomic profiles across 150 cancer types.
¶Commercially available qPCR methods were Roche cobas® EGFR mutation test v2 and Qiagen therascreen EGFR RGQ PCR kit.

Another notable issue is the accurate application of NGS data to clinical care. In multiple retrospective, observational cohort studies, approximately 17% to 24% of treatment-naive and 14% to 22% of second-line patients with EGFR exon 20 insertions received EGFR TKIs.11,17,22** Studies also found that approximately 7% to 40% of treatment-naive and 26% to 41% of second-line patients received IO monotherapy.17,22,23 These therapies (ie, most TKIs indicated for common mutations†† and IO monotherapies) are not recommended for first- or second-line therapy for EGFR exon 20 insertion mutations.5

**EGFR TKIs included first-, second- and third-generations.
††Exceptions include p.A763_Y764insFQEA and p.A763_Y764insLQEA.

Current Treatment Strategies for Patients With Exon 20 Insertion Mutations
Chemotherapy with a platinum doublet remains the recommended treatment option for the first-line treatment of patients with an EGFR exon 20 insertion mutation.5 When many of these patients progress, subsequent treatment options are needed. The NCCN Guidelines recommend amivantamab-vmjw or mobocertinib as subsequent therapy options for patients with EGFR exon 20 insertion mutations who have progressed on or after initial systemic therapy.5

Conclusion:

  • Advances made in the treatment of NSCLC have improved patient mortality and survival,2 and these advancements are due in part to the discovery of actionable mutations, like common EGFR mutations, and targeted therapies3,4,7,8
  • Multiple studies have found, however, that patients with EGFR exon 20 insertion mutations had a poor overall response when treated with first-, second-, or third-generation EGFR TKIs,11-15,17 and that IO monotherapies provide little benefit as a first-line treatment in patients with EGFR mutations, including exon 20 insertions17
  • The NCCN Guidelines recommend:
    • Testing eligible patients with mNSCLC for targetable genetic alterations to both identify potentially appropriate targeted therapies and avoid therapies unlikely to provide clinical benefit5
    • Treating patients who harbor a common EGFR mutation (exon 19 deletion and exon 21 [L858R] mutations) with an EGFR TKI in the first line of treatment, whereas those with an EGFR exon 20 insertion mutation are best treated with a regimen containing a platinum doublet5
    • Amivantamab-vmjw or mobocertinib as subsequent therapy options for patients with EGFR+ mNSCLC with exon 20 insertion mutations who have progressed on or after initial systemic therapy per the NCCN Guidelines5

References
1. National Cancer Institute. Cancer stat facts: common cancer sites. Accessed September 30, 2022. https://seer.cancer.gov/statfacts/html/common.html
2. Siegel RL, Miller KD, Fuchs HE, Jemal A. Cancer statistics, 2021.CA Cancer J Clin. 2021;71:7-33.
3. Benjamin DJ, Haslam A, Gill J, Prasad V. Targeted therapy in lung cancer: Are we closing the gap in years of life lost? Cancer Med. 2022;11(18):3417-3424.
4. Targeted Therapy in Metastatic Non–Small Cell Lung Cancer: Recent Updates and Controversies. Angel Qin. ASCO Daily News. Published January 19, 2022. Accessed November 14, 2022. https://dailynews.ascopubs.org/do/10.1200/ADN.22.200810/
5. Referenced with permission from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Non-Small Cell Lung Cancer V.6.2022. © National Comprehensive Cancer Network, Inc. 2022. All rights reserved. Accessed December 2, 2022. To view the most recent and complete version of the guideline, go online to NCCN.org. NCCN makes no warranties of any kind whatsoever regarding their content, use or application and disclaims any responsibility for their application or use in anyway.
6. Jordan EJ, Kim HR, Arcila ME, et al. Prospective comprehensive molecular characterization of lung adenocarcinomas for efficient patient matching to approved and emerging therapies. Cancer Discov. 2017;7(6):596-609.
7. Luo SY, Lam DC. Oncogenic driver mutations in lung cancer. Transl Respir Med. 2013;1(1):6.
8. Gazdar AF. Activating and resistance mutations of EGFR in non-small-cell lung cancer: role in clinical response to EGFR tyrosine kinase inhibitors. Oncogene. 2009;28 (Suppl 1):S24-S31.
9. Arcila ME, Nafa K, Chaft JE, et al. EGFR exon20 insertion mutations in lung adenocarcinomas: prevalence, molecular heterogeneity, and clinicopathologic characteristics. Mol Cancer Ther. 2013;12(2):220-229.
10. Leal JL, Alexander M, Itchins M, et al. EGFR exon 20 insertion mutations: clinicopathological characteristics and treatment outcomes in advanced non-small cell lung cancer. Clin Lung Cancer. 2021;22(6):e859-e869.
11. Bazhenova L, Minchom A, Viteri S, et al. Comparative clinical outcomes for patients with advanced NSCLC harboring EGFR exon 20 insertion mutations and common EGFR mutations. Lung Cancer. 2021;162:154-161.
12. Wu JY, Yu CJ, Shih JY. Effectiveness of treatments for advanced non-small-cell lung cancer with exon 20 insertion epidermal growth factor receptor mutations. Clin Lung Cancer. 2019;20:e620-e630.
13. Yang JC, Sequist LV, Geater SL, et al. Clinical activity of afatinib in patients with advanced non-small-cell lung cancer harbouring uncommon EGFR mutations: a combined post-hoc analysis of LUX-Lung 2, LUX-Lung 3, and LUX-Lung 6.Lancet Oncol. 2015;16(7):830-838.
14. Kate S, Chougule A, JoshiA, et al. Outcome of uncommon EGFR mutation positive newly diagnosed advanced non-small cell lung cancer patients: a single center retrospective analysis. Lung Cancer (Auckl). 2019;10:1-10.
15. Kwon CS, Lin HM, Crossland V, et al. Non-small cell lung cancer with EGFR exon 20 insertion mutation: a systematic literature review and meta-analysis of patient outcomes. Curr Med Res Opin. 2022;38(8):1341-1350.
16. Robichaux JP, Elamin YY, Tan Z, et al. Mechanisms and clinical activity of an EGFR and HER2 exon 20-selective kinase inhibitor in non-small cell lung cancer. Nat Med. 2018;24:638-646.
17. Girard N, Minchom A, Ou SI, et al. Comparative clinical outcomes between EGFR ex20 ins and wild type NSCLC treated with immune checkpoint inhibitors. Clin Lung Cancer. 2022;23(7):571-577.
18. Paz-Ares L, Gondos A, Saldana D, et al. Genomic testing among patients with newly diagnosed advanced non-small cell lung cancer in the United States: A contemporary clinical practice patterns study. Lung Cancer. 2022;167:41-48.
19. Waterhouse DM, Tseng WY, Espirito JL, Robert NJ. Understanding contemporary molecular biomarker testing rates and trends for metastatic NSCLC among community oncologists. Clin Lung Cancer. 2021;22(6):e901-e910.
20. Robert N, Chen L, Espirito J, et al. Trends in molecular testing for metastatic non-small cell lung cancer in the US Oncology Network community practices. J Thorac Oncol. 2021;16(10) (suppl):S1169.
21. Bauml J, Viteri S, Minchom A, et al. Underdiagnosis of EGFR exon 20 insertion mutation variants: estimates from NGS-based real-world datasets. Presented at: the IASLC 2020 World Conference on Lung Cancer; January 28-31, 2021;Singapore.
22. He J, Pericone CD, Vanderpoel J. Real-world patient characteristics, treatment patterns, and mutation testing patterns among US patients with advanced non-small cell lung cancer harboring EGFR mutations. Adv Ther. 2022;39(7):3347-3360.
23. Choudhury NJ, Schoenfeld AJ, Flynn J, et al. Response to standard therapies and comprehensive genomic analysis for patients with lung adenocarcinoma with EGFR exon 20 insertions. Clin Cancer Res. 2021;27(10):2920-2927.

© Janssen Biotech, Inc. 2022 12/22 cp-345345v1

FDA Approves ORSERDU® for ESR-1 Mutated Advanced Breast Cancer

RR

SUMMARY: The FDA on January 27, 2023, approved ORSERDU® (Elacestrant) for postmenopausal women or adult men with ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer, with disease progression following at least one line of endocrine therapy. FDA also approved the Guardant360 CDx assay as a companion diagnostic device to identify patients with breast cancer for treatment with ORSERDU®.

Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. It is estimated that approximately 300,590 new cases of breast cancer will be diagnosed in 2023 and about 43,700 individuals will die of the disease, largely due to metastatic recurrence. Approximately 70% of breast tumors express Estrogen Receptors and/or Progesterone Receptors. The most common subtype of metastatic breast cancer is Hormone Receptor-positive (HR-positive), HER2-negative breast cancer (65% of all metastatic breast tumors), and these patients are often treated with anti-estrogen therapy as first line treatment. However, resistance to hormonal therapy occurs in a majority of the patients, with a median Overall Survival (OS) of 36 months. With the development of Cyclin Dependent Kinases (CDK) 4/6 inhibitors, endocrine therapy plus a CDK4/6 inhibitor is the mainstay, for the management of ER+/HER2-negative metastatic breast cancer, as first line therapy. Even with this therapeutic combination, most patients will eventually experience disease progression, including the development of ESR1 (Estrogen Receptor gene alpha) mutations.

ESR1 (Estrogen Receptor 1) gene mutation is the most common acquired mutation noted in breast tumors as they progress from primary to metastatic setting. These mutations promote ligand independent Estrogen Receptor activation and have been shown to promote resistance to estrogen deprivation therapy. It appears that ESR1 mutations are harbored in metastatic ER-positive breast cancers with prior Aromatase Inhibitor (AI) therapy, but not in primary breast cancers, suggesting that ESR1 mutations may be selected by prior therapy with an AI in advanced breast cancer. In a previously published study (JAMA Oncol.2016;2:1310-1315), ESR1 mutations Y537S and D538G mutations detected in baseline plasma samples from ER+/HER- advanced breast cancer patients, was associated with shorter Overall Survival. In this study it was noted that there was a three-fold increase in the prevalence of these mutations in patients who had failed first line hormonal therapy for metastatic disease, compared with those who were initiating first line therapy for advanced breast cancer (33% versus 11%). It is estimated that 40% of ER-positive, HER2-negative advanced or metastatic breast cancer patients have tumors that harbor ESR1 mutations.

Fulvestrant (FASLODEX®) is a parenteral, Selective Estrogen Receptor Degrader (SERD) and is the only SERD approved for the treatment of postmenopausal women with HR-positive metastatic breast cancer. However, acquired ESR1 mutations can also occur following Fulvestrant treatment, possibly because of poor bioavailability and incomplete ER blockade when administered intramuscularly. There is therefore an urgent unmet need for an alternate SERD that has activity in tumors harboring ESR1 mutations, and has improved bioavailability allowing oral administration.

ORSERDU® (Elacestrant) is an oral, nonsteroidal, Selective Estrogen Receptor Degrader (SERD) that degrades the Estrogen Receptor (ER) in a dose-dependent manner and inhibits estradiol-dependent functions of ER target gene transcription induction and breast cancer cell proliferation. Estradiol-stimulated tumor growth was diminished by ORSERDU® in the HR-positive xenograft models derived from heavily pretreated patients, including models resistant to CDK 4/6 inhibitors, Fulvestrant and those harboring ESR1 mutations Y537S and D538G. In an early Phase I trial, ORSERDU® was noted to have an acceptable safety profile and demonstrated single-agent activity with confirmed Partial Responses in heavily pretreated patients with HR-positive metastatic breast cancer.

The present FDA approval was based on the EMERALD trial, which is a multicenter, International, randomized, open-label, Phase III study, designed to evaluate the benefit of ORSERDU® in patients with ER+/HER2- advanced or metastatic breast cancer. In this study, 478 postmenopausal women with ER+/HER2- metastatic breast cancer were randomly assigned 1:1 to receive either ORSERDU® 400 mg orally daily (N=239) or the Standard of Care which included investigator’s choice of Fulvestrant or an Aromatase Inhibitor including Anastrozole, Letrozole, or Exemestane (N=239). Treatment was given until disease progression. Both treatment groups were well balanced. The median patient age was 63 years, and patients must have progressed or relapsed on or after 1 or 2 lines of endocrine therapy for advanced disease, one of which was given in combination with a CDK4/6 inhibitor, had 1 or fewer lines of chemotherapy for advanced disease, and had an ECOG performance status of 0 or 1. ESR1 mutational status was determined by blood circulating tumor deoxyribonucleic acid (ctDNA) using the Guardant360 CDx assay and was limited to ESR1 missense mutations in the ligand binding domain. In the study, 48% (N=228) had tumors with mutated ESR1 and 43% received two prior endocrine therapies. These patients were evenly distributed in both treatment groups. Patients were stratified by ESR1-mutation status, prior treatment with Fulvestrant, and visceral metastases. The co-Primary end points were Progression Free Survival (PFS) in the overall population, and in those with ESR1 mutations. Overall Survival (OS) was a Secondary end point.

This study met both co-Primary endpoints and treatment with ORSERDU® resulted in a statistically significant and clinically meaningful improvement in PFS, compared with Standard of Care treatment. In the group of patients whose tumors had ESR1 mutations, the median PFS was 3.8 months in the ORSERDU® group and 1.9 months in the Standard of Care group (HR=0.55; P=0.0005), reducing the risk of progression or death by 45%. A post-hoc analysis of the PFS results based on the duration of prior CDK4/6 inhibitors usage was presented at San Antonio Breast Cancer Symposium (SABCS) in December 2022. The median PFS was 8.6 months in the ORSERDU® group versus 1.9 months in the Standard of Care group, in those patients whose tumors harbored ESR1 mutations and had been treated with a CDK4/6 inhibitors for at least 12 months.

It can be concluded from this study that ORSERDU® is the first oral Selective Estrogen Receptor Degrader for ER-positive, HER2-negative advanced breast cancer patients with ESR1 mutations, and offers a novel therapeutic option for this patient group.

Elacestrant (oral selective estrogen receptor degrader) Versus Standard Endocrine Therapy for Estrogen Receptor–Positive, Human Epidermal Growth Factor Receptor 2–Negative Advanced Breast Cancer: Results From the Randomized Phase III EMERALD Trial. Bidard F-C, Kaklamani VG, Neven P, et al. DOI: 10.1200/JCO.22.00338 Journal of Clinical Oncology. Published online May 18, 2022.

FDA Approves Tucatinib with Trastuzumab for Colorectal Cancer

RR

SUMMARY: The FDA on January 19, 2023, granted accelerated approval to Tucatinib (TUKYSA®) in combination with Trastuzumab for RAS wild-type HER2-positive unresectable or metastatic colorectal cancer that has progressed following Fluoropyrimidine, Oxaliplatin, and Irinotecan-based chemotherapy. ColoRectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 153,020 new cases of CRC will be diagnosed in the United States in 2023 and about 52,550 patients are expected to die of the disease. The lifetime risk of developing CRC is about 1 in 23.

Approximately 15-25% of the patients with CRC present with metastatic disease at the time of diagnosis (synchronous metastases) and 50-60% of the patients with CRC will develop metastatic disease during the course of their illness. First line treatment of metastatic CRC include Oxaliplatin or Irinotecan, in combination with a Fluoropyrimidine and Leucovorin (FOLFOX or FOLFIRI), along with a VEGF targeting agent such as Bevacizumab or EGFR targeting agents such as Cetuximab and Panitumumab. Patients with Stage IV colorectal cancer are now routinely analyzed for extended RAS and BRAF mutations. KRAS mutations are predictive of resistance to EGFR targeted therapy.

Human Epidermal Growth Factor Receptor 2 (HER2) is overexpressed in 3-5% of patients with RAS wild-type metastatic colorectal cancer. HER2-positive tumors are IHC3+ by Immunohistochemistry or IHC2+/FISH [Fluorescence in Situ Hybridization] amplified. There are currently no FDA-approved therapies that specifically target HER2 in colorectal cancer. Previously published studies have indicated that patients with HER2-positive CRC have less benefit from EGFR targeted therapies. In the HERACLES trial, a combination of two HER2 targeted therapies prolonged Overall Survival (OS) in RAS wild-type metastatic colorectal cancer.

Tucatinib (TUKYSA®) is an oral Tyrosine Kinase Inhibitor that is highly selective for the kinase domain of HER2, with minimal inhibition of Epidermal Growth Factor Receptor. Trastuzumab (HERCEPTIN®) is a humanized monoclonal antibody targeting HER2/neu oncogene.

MOUNTAINEER is a U.S. and European multicenter, open-label, randomized, prospective, Phase II study, conducted among patients with previously treated HER2-positive metastatic colorectal cancer. This U.S. investigator-sponsored trial initially consisted of a single cohort (Cohort A) of patients who received Tucatinib 300 mg orally BID in combination with Trastuzumab 8 mg/kg IV given as a loading dose on Cycle 1, Day 1, followed by maintenance dose of Trastuzumab 6 mg/kg IV on Day 1 every three weeks thereafter. Patients were treated until disease progression or unacceptable toxicity. This trial was subsequently expanded globally to include patients who were randomized to receive Tucatinib plus Trastuzumab (Cohort B) or Tucatinib monotherapy (Cohort C). Enrolled patients were required to have HER2-positive, RAS wild-type, unresectable or metastatic colorectal cancer and prior treatment with Fluoropyrimidine, Oxaliplatin, Irinotecan, and an anti-Vascular Endothelial Growth Factor (VEGF) monoclonal antibody. Patients whose tumors were MisMatch Repair (dMMR) deficient or were MicroSatellite Instability-High (MSI-H) must also have received an anti PD-1 monoclonal antibody. Patients who received prior anti-HER2 targeted therapy were excluded. Over two thirds of the patients had liver or lung metastases and had received a median of 3 prior lines of systemic therapy. The Primary endpoint was Objective Response Rate (ORR) as assessed by blinded Independent Central Review (ICR) in patients receiving the combination of Tucatinib and Trastuzumab (Cohorts A and B). Secondary endpoints included Duration of Response, Progression Free Survival (PFS), Overall Survival (OS) and safety and tolerability of the combination regimen.

At a median follow up of 20.7 months, the ORR among patients treated with a combination of Tucatinib and Trastuzumab (N=84) was 38.1% and the median Duration of Response was 12.4 months. The Disease Control Rate was 71.4%. The median Progression Free Survival was 8.2 months and median Overall Survival was 24.1 months. In the Cohort C patients who received Tucatinib monotherapy (N=30), the ORR by 12 weeks was 3.3% and the Disease Control Rate was 80%. Participants who did not respond to Tucatinib monotherapy by 12 weeks or had disease progressed at any time had the option to receive the combination of Tucatinib and Trastuzumab. Tucatinib in combination with Trastuzumab was well tolerated. Grade 1 or 2 diarrhea was the most common adverse event, followed by fatigue and nausea. Treatment discontinuation due to adverse events was low at 5.8%.

It was concluded that in this largest prospective trial to date among patients with chemotherapy-refractory HER2-positive metastatic colorectal cancer, Tucatinib in combination with Trastuzumab demonstrated durable and clinically meaningful antitumor activity and is a new chemotherapy-free treatment option for this group of patients. Studies are underway investigating Tucatinib plus Trastuzumab in earlier lines of therapy

MOUNTAINEER: Open-label, phase 2 study of tucatinib in combination with trastuzumab for HER2-positive metastatic colorectal cancer. Strickler JH, Cercek A, Siena S, et al: ESMO World Congress on Gastrointestinal Cancers 2022. Abstract LBA-2. Presented July 2, 2022.

TAILORx Long Term Update for Patients with Early Stage Breast Cancer

RR

SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. It is estimated that approximately 300,590 new cases of breast cancer will be diagnosed in 2023 and about 43,700 individuals will die of the disease, largely due to metastatic recurrence.

Approximately 50% of all breast cancers are Estrogen Receptor (ER) positive, HER2-negative, axillary node-negative tumors. Patients with early-stage breast cancer often receive adjuvant chemotherapy. The Oncotype DX breast cancer assay, is a multigene genomic test that analyzes the activity of a group of 21 genes and is able to predict the risk of breast cancer recurrence and likelihood of benefit from systemic chemotherapy, following surgery, in women with early-stage breast cancer. Chemotherapy recommendations for Hormone Receptor positive, HER negative, early-stage breast cancer patients, are often made based on tumor size, grade, ImmunoHistoChemical (IHC) markers such as Ki-67, nodal status and Oncotype DX Recurrence Score (RS) assay. Oncotype Dx assay categorizes patients based on Recurrence Scores into Low risk (0-10), Intermediate risk (11-25), and High risk (26-100). It has been unclear whether patients in the Intermediate risk group benefited from the addition of chemotherapy to endocrine therapy. TAILORx was specifically designed to address this question and provide a very definitive answer.

TAILORx ((Trial Assigning Individualized Options for Treatment) is a phase III, randomized, prospective, non-inferiority trial, and is the largest breast cancer treatment trial ever conducted, and the first precision medicine trial ever done, according to the authors. In this study, 10,273 women, 18-75 years of age, with hormone receptor-positive, HER2-negative, T1b-T2N0 early-stage axillary node-negative breast cancer were enrolled. Patients had tumors 1.1-5.0 cm in size (or 0.6-1.0 cm and intermediate/high grade). Patients were divided into three groups based on their Recurrence Score. Women with a Low Recurrence Score of 0-10 received endocrine therapy alone and those with a High Recurrence Score of 26-100 received endocrine therapy in combination with standard adjuvant chemotherapy. Patient with Intermediate Recurrence Score of 11-25 (N=6711) were randomly assigned to receive endocrine therapy alone (N=3399) or endocrine therapy and adjuvant chemotherapy (N=3312). The Primary endpoint was invasive Disease-Free Survival, defined as recurrence of cancer in the breast, regional lymph nodes, and/or distant organs, a second primary cancer in the opposite breast or another organ, or death from any cause. The researchers conducted an updated analysis, in which patients were followed for an additional 3.5 years, for an average of 11 years. The Primary endpoint in the updated analysis was invasive Disease-Free Survival (DFS) at a median follow-up of 11.0 years in the randomized population and 10.4 years in the overall population.

The previous TAILORx study conclusions remain unchanged. Among patients with a Recurrence Score of 11-25, endocrine therapy alone was non-inferior to chemotherapy plus endocrine therapy. The 5-year invasive DFS with endocrine therapy alone was 92.8% versus 93.1% with chemotherapy plus endocrine (HR=1.08; P=0.26). The 12-year invasive DFS with endocrine therapy alone was 76.8% versus 77.4% with chemotherapy plus endocrine therapy (HR =1.08). Although among those patients with a Recurrence Score of 0-25, less than 10% of patients had disease recurrence by 12 years, late recurrence events beyond 5 years exceeded earlier recurrence, regardless of treatment. There was also a higher risk of early recurrence in Black women.

It was concluded that with longer follow-up, the main TAILORx study findings remain unchanged, and clinicians should continue to use the 21-gene recurrence score results to guide decisions about the use of chemotherapy.

Trial Assigning Individualized Options for Treatment (TAILORx): An update including 12-year event rates. Sparano J, Gray RJ, Makower D, et al. Presented at SABCS 2022. December 6-10, 2022. Abstract GS1-05.

TUKYSA® Combination in HER2-Positive Metastatic Breast Cancer Patients with Brain Metastases

RR

SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. Approximately 290,560 new cases of breast cancer will be diagnosed in 2022 and about 43,780 individuals will die of the disease, largely due to metastatic recurrence.

The HER or erbB family of receptors consist of HER1, HER2, HER3 and HER4. Approximately 15-20% of invasive breast cancers overexpress HER2/neu oncogene, which is a negative predictor of outcomes without systemic therapy. Patients with HER2-positive metastatic breast cancer are often treated with anti-HER2 targeted therapy along with chemotherapy, irrespective of hormone receptor status, and this has resulted in significantly improved treatment outcomes. HER2-targeted therapies include HERCEPTIN® (Trastuzumab), TYKERB® (Lapatinib), PERJETA® (Pertuzumab), KADCYLA® (ado-Trastuzumab emtansine), ENHERTU® (Trastuzumab deruxtecan) and MARGENZA® (Margetuximab). Dual HER2 blockade with HERCEPTIN® and PERJETA®, given along with chemotherapy (with or without endocrine therapy), as first line treatment, in HER2-positive metastatic breast cancer patients, was shown to significantly improve Progression Free Survival (PFS) as well as Overall Survival (OS). The superior benefit with dual HER2 blockade has been attributed to differing mechanisms of action and synergistic interaction between HER2 targeted therapies. Patients progressing on Dual HER2 blockade often receive KADCYLA® which results in an Objective Response Rate (ORR) of 44% and a median PFS of 9.6 months, when administered after HERCEPTIN® and a taxane. There is however no standard treatment option for this patient population following progression on KADCYLA®.

With advances in systemic therapies for this patient population, the incidence of brain metastases as a sanctuary site has increased. Approximately 50% of patients with HER2-positive metastatic breast cancer develop brain metastases. However, systemic HER2-targeted agents, including Tyrosine Kinase Inhibitors, as well as chemotherapy have limited antitumor activity in the brain. Local therapeutic interventions for brain metastases include neurosurgical resection and Stereotactic or Whole-Brain Radiation Therapy. There is a high unmet need for systemic treatment options to treat established brain metastases and reduce the risk for progression in the Central Nervous System (CNS).

TUKYSA® (Tucatinib) is an oral Tyrosine Kinase Inhibitor that is highly selective for the kinase domain of HER2 with minimal inhibition of Epidermal Growth Factor Receptor. In a Phase 1b dose-escalation trial, TUKYSA® in combination with HERCEPTIN® and XELODA® (Capecitabine) showed encouraging antitumor activity in patients with HER2-positive metastatic breast cancer, including those with brain metastases.

HER2CLIMB is an international, randomized, double-blind, placebo-controlled trial in which the combination of TUKYSA® plus HERCEPTIN® and XELODA® was compared with placebo plus HERCEPTIN® and XELODA®. A total of 612 patients with unresectable locally advanced or metastatic HER2-positive breast cancer, who were previously treated with HERCEPTIN®, PERJETA® (Pertuzumab) and KADCYLA® (ado-Trastuzumab emtansine) were enrolled. Patients were randomly assigned in a 2:1 ratio to receive either TUKYSA® 300 mg orally twice daily throughout the treatment period (N=410) or placebo orally twice daily (N=201), in combination with HERCEPTIN® 6 mg/kg IV once every 21 days, following an initial loading dose of 8 mg/kg, and XELODA® 1000 mg/m2 orally twice daily on days 1 to 14 of each 21-day cycle. Stratification factors included presence or absence of brain metastases, ECOG Performance Status and geographic region. The median patient age was 52 years and patient demographics as well as disease characteristics at baseline were well balanced between the two treatment groups. In the total treatment population, 47.5% had brain metastases at baseline, 48.3% in the TUKYSA® combination group and 46% in the placebo combination group. The Primary endpoint was Progression Free Survival (PFS). Secondary end points included Overall Survival (OS), PFS among patients with brain metastases, confirmed Objective Response Rate (ORR), and Safety.

At median follow-up of 29.6 months, median OS in all patients with brain metastases at baseline was 9.1 months longer in the TUKYSA® combination group compared to the placebo combination group (21.6 versus 12.5 months, HR=0.60; P<0.001), with a 40% reduction in the risk of death with the TUKYSA® combination. The estimated 1-year OS was 70.0% for the TUKYSA® combination group and 50.6% for the placebo combination group and the estimated 2-year OS was 48.5% and 25.1% respectively.

The researchers in this exploratory subgroup analyses reported efficacy outcomes for patients with brain metastases, as well as time to new brain lesion(s) as the site of first progression or death, in all patients enrolled in HER2CLIMB trial, at a median follow up of 29.6 months.

There was greater CNS Progression Free Survival in the TUKYSA® combination group compared with the placebo combination group and was 5.7 months longer (9.9 versus 4.2 months, HR=0.39; P<0.001), with a 61% reduction in the risk of CNS progression with the TUKYSA® combination. The estimated 1 and 2-year CNS Progression Free Survivals were 38.4% versus 7.9% and 19.3% versus 0%, respectively.

Among those with active brain metastases and measurable disease at baseline, the intracranial Objective Response Rates for the TUKYSA® combination group were 47.3% versus 20.0% for the placebo combination group, with a median duration of intra cranial response of 8.6 versus 3.0 months, respectively.

The risk of developing new brain lesions as the site of first progression or death was reduced by 45% in the TUKYSA® combination group versus the placebo-combination group (HR=0.55; P =0.006).

The authors concluded that in this exploratory subgroup analysis, TUKYSA® in combination with HERCEPTIN® and XELODA® provided a clinically meaningful survival benefit, while reducing the risk of developing new brain lesions. The authors added that HER2CLIMB is currently the only double-blind, randomized, controlled clinical trial for patients with HER2-positive metastatic breast cancer, that prospectively included patients with both active and stable brain metastases.

Tucatinib vs Placebo, Both in Combination with Trastuzumab and Capecitabine, for Previously Treated ERBB2 (HER2)-Positive Metastatic Breast Cancer in Patients With Brain Metastases: Updated Exploratory Analysis of the HER2CLIMB Randomized Clinical Trial. Lin NU, Murthy RK, Abramson V, et al. JAMA Oncol. Published online December 1, 2022. doi:10.1001/jamaoncol.2022.5610

FDA Grants Accelerated Approval to KRAZATI® for KRAS G12C-mutated NSCLC

RR

SUMMARY: The FDA on December 12, 2022, granted accelerated approval to KRAZATI® (Adagrasib), a RAS GTPase family inhibitor, for adult patients with KRAS G12C-mutated locally advanced or metastatic Non-Small Cell Lung Cancer (NSCLC), as determined by an FDA-approved test, who have received at least one prior systemic therapy. FDA also approved the QIAGEN therascreen KRAS RGQ PCR kit (tissue) and the Agilent Resolution ctDx FIRST Assay (plasma) as companion diagnostics for KRAZATI®. If no mutation is detected in a plasma specimen, the tumor tissue should be tested.

The American Cancer Society estimates that for 2022, about 236,740 new cases of lung cancer will be diagnosed and 135,360 patients will die of the disease. Lung cancer is the leading cause of cancer-related mortality in the United States. Non-Small Cell Lung Cancer (NSCLC) accounts for approximately 85% of all lung cancers. Of the three main subtypes of NSCLC, 30% are Squamous Cell Carcinomas (SCC), 40% are Adenocarcinomas and 10% are Large Cell Carcinomas. With changes in the cigarette composition and decline in tobacco consumption over the past several decades, Adenocarcinoma now is the most frequent histologic subtype of lung cancer.

The KRAS (kirsten rat sarcoma viral oncogene homologue) proto-oncogene encodes a protein that is a member of the small GTPase super family. The KRAS gene provides instructions for making the KRAS protein, which is a part of a signaling pathway known as the RAS/MAPK pathway. By relaying signals from outside the cell to the cell nucleus, the protein instructs the cell to grow, divide and differentiate. The KRAS protein is a GTPase and converts GTP into GDP. To transmit signals, the KRAS protein must be turned on by binding to a molecule of GTP. When GTP is converted to GDP, the KRAS protein is turned off or inactivated, and when the KRAS protein is bound to GDP, it does not relay signals to the cell nucleus. The KRAS gene is in the Ras family of oncogenes, which also includes two other genes, HRAS and NRAS. When mutated, oncogenes have the potential to change normal cells cancerous.

KRAS is the most frequently mutated oncogene in human cancers and are often associated with resistance to targeted therapies and poor outcomes. The KRAS G12C mutation occurs in approximately 25% of Non-Small Cell Lung Cancers (NSCLC) and in 3-5% of colorectal cancers and other solid cancers. KRAS G12C is one of the most prevalent driver mutations in NSCLC and accounts for a greater number of patients than those with ALK, ROS1, RET, and TRK 1/2/3 mutations combined. KRAS G12C cancers are genomically more heterogeneous and occur more frequently in current or former smokers and are likely to be more complex genomically than EGFR mutant or ALK rearranged cancers. G12C is a single point mutation with a Glycine-to-Cysteine substitution at codon 12. This substitution favors the activated state of KRAS, resulting in a predominantly GTP-bound KRAS oncoprotein, amplifying signaling pathways that lead to oncogenesis.

KRAZATI® (Adagrasib) is a potent, orally available, small molecule covalent inhibitor of KRAS G12C. This drug irreversibly and selectively binds KRAS G12C in its inactive, GDP-bound state. Unlike LUMAKRAS® (Sotorasib), which is also a selective covalent inhibitor of KRAS G12C, KRAZATI® has a longer drug half-life of 23 hours, as compared to 5 hours for LUMAKRAS®, has dose-dependent extended exposure, and can penetrate the CNS. Approximately, 27-42% of patients with NSCLC harboring KRAS G12C mutations have CNS metastases, with poor outcomes. KRYSTAL-1 is a Phase I/II multiple expansion cohort trial involving patients with advanced solid tumors harboring a KRAS G12C mutation. KRAZATI® demonstrated clinical activity in patients with KRAS G12C-mutated solid tumors, including colorectal, pancreatic, and biliary tract cancers. Further, preliminary data from two patients with untreated CNS metastases from a Phase 1b cohort showed antitumor activity against CNS metastases, with satisfactory concentrations of KRAZATI® in the CSF.

The present FDA approval was based on the results from Cohort A, a Phase 2 cohort of the KRYSTAL-1 study in which KRAZATI® at a dose of 600 mg orally twice daily was evaluated in patients with KRAS G12C-mutated NSCLC, previously treated with chemotherapy and anti-Programmed Death 1 (PD-1) or Programmed Death Ligand 1 (PD-L1) therapy. This registration study included a total of 116 unresectable or metastatic NSCLC patients, with histologically confirmed diagnosis, with KRAS G12C mutation (detected in tumor tissue at a local or central laboratory), who had previously received treatment with at least one platinum-containing chemotherapy regimen and checkpoint inhibitor therapy (in sequence or concurrently), and who had measurable tumor lesions. Enrolled patients received KRAZATI® 600 mg capsule twice daily, and treatment was continued until disease progression or unacceptable toxicities. The median patient age was 64 years, 97% had adenocarcinoma histology, 98% had both platinum-based therapy and checkpoint inhibitor therapy, and 21% of patients had CNS metastases. Key exclusion criteria included active CNS metastases (patients were eligible if CNS metastases were adequately treated and neurologically stable), carcinomatous meningitis, and previous treatment with a KRAS G12C inhibitor. Exploratory Biomarker Analyses included candidate biomarkers (PD-L1 Tumor Proportion Score and mutational status of STK11, KEAP1, TP53, and CDKN2A on tumor-tissue specimens, blood specimens, or both, for their association with tumor response. The Primary end point was Objective Response Rate as assessed by blinded Independent Central Review. Secondary end points included the Duration of Response, Progression Free Survival, Overall Survival, and safety. The median follow up was 12.9 months and the median duration of treatment was 5.7 months.

Of 112 patients with measurable disease at baseline, the confirmed Objective Response Rate was 42.9% and the median Duration of Response was 8.5 months. The median Progression Free Survival was 6.5 months, and the median Overall Survival was 12.6 months, at a median follow up of 15.6 months. Among 33 patients with previously treated, stable CNS metastases, the intracranial confirmed Objective Response Rate was 33.3%. Treatment-related adverse events occurred in 97.4% of the patients and 53% were Grade 1 or 2 toxicities. KRAZATI® was discontinued in 6.9% of patients due to adverse events.

It was concluded that among patients with previously treated KRAS G12C-mutated NSCLC, KRAZATI® showed significant clinical efficacy without new safety signals and encouraging intracranial activity. The researchers added that these are the first clinical data demonstrating CNS-specific activity of a KRAS G12C inhibitor in this patient population.

Adagrasib in Non–Small-Cell Lung Cancer Harboring a KRASG12C Mutation. Jänne PA, Riely GJ, Gadgeel SM, et al. N Engl J Med 2022; 387:1238-1239

FDA Approves REZLIDHIA® for Acute Myeloid Leukemia

RR

SUMMARY: The FDA on December 1, 2022, approved REZLIDHIA® (Olutasidenib) capsules for adult patients with Relapsed or Refractory Acute Myeloid Leukemia (AML) with a susceptible IDH1 mutation, as detected by an FDA-approved test. The FDA on the same day also approved the Abbott RealTime IDH1 Assay to select patients for REZLIDHIA®.

The American Cancer Society estimates that for 2022, about 20,050 new cases of Acute Myeloid Leukemia (AML) will be diagnosed in the United States and 11,540 patients will die of the disease. AML can be considered as a group of heterogeneous diseases with different clinical behavior and outcomes. Cytogenetic analysis has been part of routine evaluation when caring for patients with AML. By predicting resistance to therapy, tumor cytogenetics will stratify patients, based on risk and help manage them accordingly. Even though cytotoxic chemotherapy may lead to long term remission and cure in a minority of patients with favorable cytogenetics, patients with high risk features such as unfavorable cytogenetics, molecular abnormalities, prior Myelodysplasia and advanced age, have poor outcomes with conventional chemotherapy alone. AML mainly affects older adults and the median age at diagnosis is 68 years. A significant majority of patients with AML are unable to receive intensive induction chemotherapy due to comorbidities and therefore receive less intensive, noncurative regimens, with poor outcomes.

Isocitrate DeHydrogenase (IDH) is a metabolic enzyme that helps generate energy from glucose and other metabolites, by catalyzing the conversion of Isocitrate to Alpha-Ketoglutarate. Alpha-ketoglutarate is required to properly regulate DNA and histone methylation, which in turn is important for gene expression and cellular differentiation. IDH mutations lead to aberrant DNA methylation and altered gene expression, thereby preventing cellular differentiation, with resulting immature undifferentiated cells. IDH mutations can thus promote leukemogenesis in Acute Myeloid Leukemia and tumorigenesis in solid tumors and can result in inferior outcomes. There are three isoforms of IDH. IDH1 is mainly found in the cytoplasm, as well as in peroxisomes, whereas IDH2 and IDH3 are found in the mitochondria, and are a part of the Krebs cycle.

Approximately 20-25% of patients with AML, 70% of patients with Low-grade Glioma and secondary Glioblastoma, 50% of patients with Chondrosarcoma, 20% of patients with Intrahepatic Cholangiocarcinoma, 30% of patients with Angioimmunoblastic T-Cell Lymphoma and 8% of patients with Myelodysplastic syndromes/Myeloproliferative neoplasms, are associated with IDH mutations. IDH2 mutations are more common than IDH1 mutations, occurring in approximately 15% to 20% of patients with AML. The presence of IDH mutations has both prognostic and predictive value. Patients with an IDH mutation and a Nucleo¬phosmin (NPM1) mutation usually have a better prognosis whereas patients with mutations in IDH and FMS-like tyrosine kinase 3 (FLT3) do not. Further IDH mutations predict response to specific IDH1 and IDH2 inhibitors in the Relapsed and Refractory setting. The presence of an IDH mutation is therefore not only prognostic, but also predictive of response to certain therapies.

The two IDH inhibitors presently available in the US include IDHIFA® (Enasidenib), approved for the treatment of patients with Relapsed or Refractory AML with IDH2 mutation and TIBSOVO® (Ivosidenib), approved for AML patients with the IDH1 mutation who have Relapsed/Refractory disease, as well as monotherapy for newly diagnosed AML patients 75 years or older with comorbidities that preclude the use of intensive induction chemotherapy. IDHIFA® can be associated with indirect hyperbilirubinemia, which is of no clinical consequence, whereas with TIBSOVO® there is a small risk of QT interval prolongation. Both agents can lead to Differentiation Syndrome in 10-15% of patients which requires systemic steroids and hemodynamic monitoring for at least 3 days.

REZLIDHIA® is a potent, selective, oral, brain-penetrant, small molecule inhibitor of mutant IDH1, that has exhibited favorable tolerability and clinical activity in high-risk AML patients in a Phase 1 trial (Watts JM, et al. Blood 2019). The present FDA approval was based on the Phase 1/2 Study 2102-HEM-101 trial (NCT02719574), which included 147 adult patients with Relapsed or Refractory AML with an IDH1 mutation, confirmed using the above now approved assay. Enrolled patients had pathologically proven AML, except those with Acute Promyelocytic Leukemia with the t(15;17) translocation, or intermediate high, or very high-risk MDS as defined by the WHO criteria or Revised International Prognostic Scoring System. REZLIDHIA® 150 mg was given orally, twice daily, until disease progression, unacceptable toxicity, or Hematopoietic Stem Cell Transplantation. The median treatment duration was 4.7 months. Sixteen (11%) patients underwent Hematopoietic Stem Cell Transplantation following treatment with REZLIDHIA®. The Primary end points included the rate of Complete Remission (CR) plus Complete Remission with partial hematologic recovery (CRh). Secondary end points included time to response, Duration of Response, Event-Free Survival, Overall Survival, and Relapse-Free Survival.

The Complete Remission plus Complete Remission with partial hematologic recovery rate with REZLIDHIA® was 35%, with 32% CR and 2.7% CRh. The median time to CR+CRh was 1.9 months and the median duration of CR+CRh was 25.9 months. Among the 86 patients who were Red Blood Cell (RBC) and/or platelet transfusions dependent at baseline, 34% became RBC and platelet transfusion independent during any 56-day post-baseline period. Of the 61 patients who were RBC and platelet transfusions independent at baseline, 64% remained transfusion independent during any 56-day post-baseline period. The most common adverse reactions were nausea, diarrhea, constipation, mucositis, fatigue/malaise, arthralgia, fever, rash, leukocytosis, dyspnea, and transaminitis. Health care professionals and patients should be aware of the risk of Differentiation Syndrome, which can be fatal.

REZLIDHIA® is the third IDH inhibitor currently approved for the treatment of Acute Myeloid Leukemia.

https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-olutasidenib-relapsed-or-refractory-acute-myeloid-leukemia-susceptible-idh1-mutation.

FDA Approves Biomarker-Driven ELAHERE® for Platinum-Resistant Ovarian Cancer

RR

SUMMARY: The FDA on November 14, 2022, granted accelerated approval to ELAHERE® (mirvetuximab soravtansine-gynx) for adult patients with Folate Receptor alpha (FR alpha) positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have received one to three prior systemic treatment regimens. The FDA also on the same day approved the VENTANA FOLR1 (FOLR-2.1) RxDx Assay (Ventana Medical Systems, Inc.), as a companion diagnostic device to select patients for the above indication.

It is estimated that in the United States, approximately 19,880 women will be diagnosed with ovarian cancer in 2022, and 12,810 women will die of the disease. Ovarian cancer ranks fifth in cancer deaths among women, and accounts for more deaths than any other cancer of the female reproductive system. Approximately 75% of the ovarian cancer patients are diagnosed with advanced disease. Approximately 85% of all ovarian cancers are epithelial in origin, and approximately 70% of all epithelial ovarian cancers are High-Grade Serous adenocarcinomas. Patients with newly diagnosed advanced ovarian cancer are often treated with platinum-based chemotherapy following primary surgical cytoreduction. Approximately 70% of these patients will relapse within the subsequent 3 years and are incurable, with a 5-year Overall Survival rate of about 20-30%. Treatment options for patients with platinum-resistant ovarian cancer are limited, and patients are often treated with single-agent chemotherapy, with an Overall Response Rate of between 4% and 13%, short duration of response, and significant toxicities.

Approximately 35-40% of ovarian cancer patients express high levels of Folate Receptor alpha, and this expression correlates with advanced stages of disease and more malignant phenotypes. There is limited expression of Folate Receptor alpha in normal tissues and is limited to the choroid plexus, proximal renal tubules, placenta, and endometrium. Testing for Folate Receptor alpha can be performed on fresh or archived tissue.

ELAHERE® (mirvetuximab soravtansine-gynx) is a first-in-class Antibody Drug Conjugate (ADC), directed against FR alpha, a cell-surface protein highly expressed in ovarian cancer. It is comprised of a Folate Receptor alpha-binding antibody, cleavable linker, and the maytansinoid payload DM4, which is a potent tubulin inhibitor, disrupting microtubule formation, and thereby designed to kill the targeted cancer cells. Microtubules are major components of the cytoskeleton that give shape and structure to cells. ELAHERE® is the first FDA approved ADC for platinum-resistant disease.

The FDA approval was based on the pivotal SORAYA trial, which is a single-arm study in 106 patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, whose tumors expressed high levels of Folate Receptor alpha, and who had been treated with 1-3 prior lines of systemic treatment regimens. All patients were required to have received prior treatment with AVASTIN® (Bevacizumab). Enrolled patient’s tumors were positive for FR alpha expression as determined by the above-mentioned FDA approved assay. Patients were eligible for the study if at least 75% of cells had 2+ staining intensity or greater, based on immunohistochemistry-based scoring. Patients were excluded if they had corneal disorders, ocular conditions requiring ongoing treatment, more than Grade 1 peripheral neuropathy, or noninfectious interstitial lung disease. Patients received ELAHERE® 6 mg/kg (based on adjusted ideal body weight) IV infusion every three weeks, until disease progression or unacceptable toxicity. Assessments were made for tumor response every six weeks for the first 36 weeks, and every 12 weeks thereafter. The Primary endpoint was investigator-assessed Overall Response Rate (ORR), and key Secondary endpoint was Duration of Response (DOR).

The confirmed ORR was 31.7% including five Complete Responses, and the median Duration of Response was 6.9 months. Response rates were consistently seen regardless of the number of prior therapies or the use of a prior PARP inhibitor. The most common adverse reactions including laboratory abnormalities, were vision impairment, keratopathy, fatigue, nausea, peripheral neuropathy, increase in ALT and AST and cytopenias. Product labeling includes a boxed warning for ocular toxicity. The authors reported that the ocular events were reversible and primarily included low-grade blurred vision and keratopathy, which were managed with protocol-defined dose modifications. Approximately 60% of patients with symptoms had resolution prior to their next cycle of treatment, and less than 1% of patients discontinued therapy due to an ocular event.

It was concluded that ELAHERE® had impressive anti-tumor activity, durability of response, and overall tolerability, and may be a new therapeutic option for patients with Folate Receptor alpha-positive platinum-resistant ovarian cancer.

Efficacy and safety of mirvetuximab soravtansine in patients with platinum-resistant ovarian cancer with high folate receptor alpha expression: Results from the SORAYA study. Matulonis UA, Lorusso D, Oaknin A, et al: 2022 SGO Annual Meeting on Women’s Cancer. Abstract 242. Presented March 19, 2022.

TAFINLAR® and MEKINIST® versus OPDIVO® plus YERVOY® for Patients with Advanced BRAF-Mutant Melanoma: The DREAMseq Trial

RR

SUMMARY: The American Cancer Society estimates that for 2022, about 99,780 new cases of melanoma of the skin will be diagnosed in the United States and 7,650 people are expected to die of the disease. The rates of melanoma have been rising rapidly over the past few decades, but this has varied by age.

The Mitogen-Activated Protein Kinase pathway (MAPK pathway) is an important signaling pathway which enables the cell to respond to external stimuli. This pathway plays a dual role, regulating cytokine production and participating in cytokine dependent signaling cascade. The MAPK pathway of interest is the RAS-RAF-MEK-ERK pathway. The RAF family of kinases includes ARAF, BRAF and CRAF signaling molecules. BRAF is a very important intermediary of the RAS-RAF-MEK-ERK pathway. BRAF mutations have been detected in 6-8% of all malignancies. The most common BRAF mutation in melanoma is at the V600E/K site and is detected in approximately 50% of melanomas, and results in constitutive activation of the MAPK pathway.

Immunotherapy with Immune Checkpoint Inhibitors (ICIs) has revolutionized cancer care and has become one of the most effective treatment options by improving Overall Response Rate (ORR) and prolongation of survival across multiple tumor types. These agents target Programmed cell Death protein-1 (PD-1), Programmed cell Death Ligand-1 (PD-L1), Cytotoxic T-Lymphocyte-Associated protein-4 (CTLA-4), and many other important regulators of the immune system. Over 50% of patients treated with a combination of PD-1 and CTLA-4 inhibitors are alive after five years.

TAFINLAR® (Dabrafenib), is a selective oral BRAF inhibitor and MEKINIST® (Trametinib) is a potent and selective inhibitor of MEK gene, which is downstream from RAF in the MAPK pathway. TAFINLAR® plus MEKINIST® led to long-term survival benefit in approximately one third of the patients who had unresectable or metastatic melanoma with a BRAF V600E or V600K mutation, from two randomized Phase III COMBI-d and COMBI-v trials.

A combination of OPDIVO® (Nivolumab) plus YERVOY® (Ipilimumab) showed durable improved outcomes among patients with unresectable or metastatic melanoma and approximately 50% of patients were alive at 6.5 years (J Clin Oncol 39, 2021. suppl 15; abstr 9506). The FDA granted approval for this combination in 2015 for the treatment of patients with metastatic melanoma, regardless of tumor BRAF mutation status.

It has been noted that BRAF/MEK inhibitor therapy tends to produce high tumor response rates and prolonged median Progression Free Survival (PFS), whereas OPDIVO® /YERVOY® tends to have its major impact on Duration of Response. However, the optimal treatment sequence for patients with treatment-naive BRAFV600-mutant metastatic melanoma, between combination OPDIVO®/YERVOY® checkpoint inhibitor immunotherapy and combination TAFINLAR® plus MEKINIST® molecularly targeted therapy, has remained unclear. Recently published tumor biology studies have suggested that resistance to BRAF/MEK-inhibitor therapy results in an immunosuppressive tumor microenvironment that is void of functional CD103+ dendritic cells, preventing effective antigen presentation to the immune system, and that immunotherapy may enhance BRAF-mutated melanoma responsiveness to targeted therapy.

DREAMseq (EA6134) is a two-arm, two-step, open-label, randomized Phase III trial, which investigated the anti PD-1/CLTA-4 immunotherapy combination of OPDIVO® plus YERVOY® followed by the anti-BRAF/MEK targeted therapy combination of TAFINLAR® plus MEKINIST®, versus the reverse sequence, in patients with advanced BRAF V600-mutant melanoma. This study was conducted to determine which treatment sequence produced the best efficacy.

In this study, 265 patients with treatment-naive BRAF V600-mutant metastatic melanoma were randomly assigned to receive either combination OPDIVO® plus YERVOY® (arm A=133) or TAFINLAR® plus MEKINIST® (arm B=132) in step 1, and at disease progression were enrolled in step 2 to receive the alternate therapy, TAFINLAR® plus MEKINIST® (arm C=27) or OPDIVO® plus YERVOY® (arm D=46). The two initial treatment arms were balanced and more patients on arm B had BRAF V600K-mutant tumors than those on arm A (25.2% versus 12.1%). The median patient age was 61 years and eligible patients had histologically confirmed, BRAF V600-mutant unresectable Stage III or IV melanoma with measurable disease. The Primary end point was 2-year Overall Survival (OS). Secondary end points included 3-year OS, Objective Response Rate (ORR), Duration of Response, Progression Free Survival (PFS), crossover feasibility, and Safety.

The study was stopped early by the Independent Data Safety Monitoring Committee because statistical significance was achieved for the Primary endpoint. The 2-year OS for those starting on arm A was 71.8% and arm B was 51.5% (P=0.01). Step 1 Progression Free Survival favored arm A (P=0.054). The Objective Response Rates were arm A: 46%, arm B: 43%, arm C: 47.8%, and arm D: 29.6%. The median Duration of Response was not reached for arm A, and 12.7 months for arm B (P<0.001). Crossover occurred in 52% of patients following documented disease progression. Grade 3 or more toxicities occurred with similar frequency between treatment groups and adverse events related to regimens were as expected.

It was concluded from this study that for patients with advanced BRAF V600-mutant metastatic melanoma, the treatment sequence beginning with the immune checkpoint inhibitor combination of OPDIVO® plus YERVOY® resulted in superior Overall Survival and longer Duration of Response, compared with the treatment sequence beginning with TAFINLAR® plus MEKINIST®, and should therefore be the preferred treatment sequence for most of these patients.

Combination Dabrafenib and Trametinib Versus Combination Nivolumab and Ipilimumab for Patients with Advanced BRAF-Mutant Melanoma: The DREAMseq Trial—ECOG-ACRIN EA6134. Atkins MB, Lee SJ, Chmielowski B, et al. J Clin Oncol. Published online September 27, 2022. doi:10.1200/JCO.22.01763

RNF43 Mutations Predict Response to Anti-BRAF/EGFR Combination Therapy in BRAF V600E Metastatic Colorectal Cancer

RR

SUMMARY: ColoRectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 151,030 new cases of CRC will be diagnosed in the United States in 2022 and about 52,580 patients are expected to die of the disease. The lifetime risk of developing CRC is about 1 in 23.

Approximately 15-25% of the patients with CRC present with metastatic disease at the time of diagnosis (synchronous metastases) and 50-60% of the patients with CRC will develop metastatic disease during the course of their illness. Advanced colon cancer is often incurable and standard chemotherapy when combined with anti EGFR (Epidermal Growth Factor Receptor) targeted monoclonal antibodies such as VECTIBIX® (Panitumumab) and ERBITUX® (Cetuximab) as well as anti VEGF agent AVASTIN® (Bevacizumab), have demonstrated improvement in Progression Free Survival (PFS) and Overall Survival (OS). The benefit with anti EGFR agents however is only demonstrable in patients with metastatic CRC (mCRC) whose tumors do not harbor KRAS mutations in codons 12 and 13 of exon 2 (KRAS Wild Type). It is now also clear that even among the KRAS Wild Type patient group about 15-20% have other rare mutations such as NRAS and BRAF mutations, which confer resistance to anti EGFR agents. Patients with Stage IV CRC are now routinely analyzed for extended RAS and BRAF mutations. KRAS mutations are predictive of resistance to EGFR targeted therapy.

Approximately 8-15% of all metastatic CRC tumors present with BRAF V600E mutations, which is recognized as a marker of poor prognosis in this patient group. These patients predominantly present with right-sided proximal tumors, tend to have aggressive disease with a higher rate of peritoneal metastasis, and do not respond well to standard treatment intervention. Approximately 30% of the BRAF-mutated population in the metastatic setting has MSI-High tumors, but MSI-High status does not confer protection to this patient group. Further, in striking contrast to patients with melanoma harboring BRAF V600E mutations in whom there is a 70% Objective Response Rate with BRAF inhibitor monotherapy, there is little or no clinical benefit with the same treatment among BRAF V600E mutant CRC patients.

Preclinical studies have shown that inhibiting BRAF in colorectal tumors can transiently reduce Mitogen-Activated Protein (MAP) kinase signaling. However, this can result in feedback upregulation of EGFR signaling pathway, which can then reactivate the MAP kinase pathway. This aberrant signaling can be blocked by dual inhibition of both BRAF and EGFR. In the Phase III BEACON Colorectal Cancer study, a combination of BRAF inhibitor BRAFTOVI® (Encorafenib) and EGFR antagonist ERBITUX® (Cetuximab), with or without concomitant MEK inhibition improved Response Rates, Overall Survival and Progression Free Survival in patients with metastatic CRC with a BRAF V600E mutation. The FDA approved this doublet therapy in 2020 for this patient group. Despite this improved efficacy, a significant percentage of patients do not respond this therapy and among those who respond, the responses noted in CRC are still not as robust as has been in BRAF-mutant metastatic melanomas treated with anti-BRAF therapy. This suggests that there may be other factors modulating treatment response, including molecular determinants, that need to be identified, to optimize clinical management of these patients.

BRAF V600E mutated tumors in CRC are also associated with specific molecular features, including a low frequency of APC mutations and a high rate of mutations in the tumor suppressor gene RNF43 (Ring Finger Protein 43). RNF43 is a E3 ubiquitin ligase which negatively regulates Wnt signaling by inducing degradation of the Wnt receptors. It has been postulated that the a cross-talk between the MAPK and WNT signaling pathways may modulate the antitumor activity of anti-BRAF/EGFR therapy.

The researchers in this study sought to explore which genes were enriched for somatic mutations in responder and non-responder groups, among patients with BRAF V600E mutant CRC, treated with anti-BRAF/EGFR combination therapy. This study included 166 patients (N=166) with BRAF V600E mutant CRC of whom 98 patients received treatment with anti-BRAF/EGFR combination therapy (N=46 in the Discovery cohort and N=52 in the Validation cohort). The Control cohort (N=68) consisted of BRAF V600E mutant CRC patients treated with chemotherapy with or without antiangiogenic therapy, and were not exposed to anti-BRAF therapy. Whole-Exome Sequencing (WES) and/or targeted gene sequencing was performed on baseline tumor and/or plasma cell-free DNA (cfDNA) samples of all included patients, and over 20,000 genes were analyzed.

It was noted that RNF43 mutations were identified in 29% of BRAF V600E-mutated MicroSatellite-Stable (MSS) metastatic CRC tumors, and this finding was strongly associated with a clinical response to anti-BRAF/EGFR-based combination therapy. When compared to BRAF V600E-mutated, MicroSatellite-Stable metastatic CRC patients without the RNF43 mutation (RNF43 wild-type), patients with BRAF V600E-mutated, MicroSatellite-Stable metastatic CRC carrying a RNF43 mutation had a Response Rate of 72.7% versus 30.8% (P=0.03), longer median Progression Free Survival (10.1 months versus 4.1 months, HR=0.30; P=0.01) and longer median Overall Survival (13.6 months versus 7 months, HR=0.26; P=0.008). Conversely, the predictive value of RNF43 mutations seen in MicroSatellite-Stable tumors was not observed in MicroSatellite Instability (MSI)-High tumors.

The researchers concluded that these findings suggest that RNF43 may be a potential stratification biomarker that could help with decision making, in patients with MicroSatellite-Stable, BRAF V600E–mutant metastatic Colorectal cancer. They added that RNF43 gene may be a predictive biomarker of a response to treatment with anti-BRAF/EGFR combination therapy in this patient group.

RNF43 mutations predict response to anti-BRAF/EGFR combinatory therapies in BRAF V600E metastatic colorectal cancer. Elez, E, Ros J, Fernandez J, et al. Nature Medicine 2022;28:2162–2170.