Category: Precision Oncology

Osimertinib Plus Chemotherapy Superior to Osimertinib Alone in Advanced EGFR Mutated Non Small Cell Lung Cancer

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SUMMARY: Lung cancer is the second most common cancer in both men and women and accounts for about 13% of all new cancers and 21% of all cancer deaths. The American Cancer Society estimates that for 2023, about 238,340 new cases of lung cancer will be diagnosed and 127,070 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.

Approximately 10-15% of Caucasian patients and 35-50% of Asian patients with Adenocarcinomas, harbor activating EGFR (Epidermal Growth Factor Receptor) mutations and 90% of these mutations are either Exon 19 deletions or L858R substitution mutation in Exon 21. Approximately 25% of patients with EGFR mutated NSCLC have brain metastases at diagnosis, increasing to approximately 40% within two years of diagnosis. The presence of brain metastases often reduces median survival to less than eight months. EGFR-Tyrosine Kinase Inhibitors (TKIs) such as TARCEVA® (Erlotinib), IRESSA® (Gefitinib) and GILOTRIF® (Afatinib), have demonstrated a 60-70% response rate as monotherapy when administered as first line treatment, in patients with metastatic NSCLC, who harbor the sensitizing EGFR mutations. However, majority of these patients experience disease progression within 9-14 months. This resistance to frontline EGFR TKI therapy has been attributed to the most common, acquired T790M “gatekeeper” point mutation in EGFR, identified in 50-60% of patients.

Osimertinib (TAGRISSO®) is a highly selective third-generation, irreversible Epidermal Growth Factor Receptor TKI, presently approved by the FDA, for the first-line treatment of patients with metastatic NSCLC, whose tumors have Exon 19 deletions or Exon 21 L858R mutations, as well as treatment of patients with metastatic EGFR T790M mutation-positive NSCLC, whose disease has progressed on or after EGFR-TKI therapy. Further, Osimertinib has higher CNS penetration and is therefore able to induce responses in 70-90% of patients with brain metastases.

In the Phase III FLAURA trial, among patients with metastatic, EGFR-mutant NSCLC, first-line treatment with Osimertinib significantly improved median Overall Survival, compared with Erlotinib and Gefitinib, and Osimertinib therefore has been the preferred regimen in this patient group. The FLAURA2 trial builds on the favorable results observed in the Phase III FLAURA trial.
FLAURA2 is a randomized, open-label, multi-center, global, ongoing Phase III trial, in which 557 enrolled treatment naïve patients (N=557), with nonsquamous locally advanced (Stage IIIB-IIIC) or metastatic EGFR mutated NSCLC, were randomly assigned 1:1 to receive Osimertinib plus chemotherapy (N=279) or Osimertinib monotherapy (N=278). Patients in the combination group received Osimertinib 80 mg oral tablets once daily in combination with chemotherapy consisting of Pemetrexed 500 mg/m2 IV plus Cisplatin 75 mg/m2 IV or Carboplatin (AUC5), every three weeks for four cycles, followed by Osimertinib with Pemetrexed maintenance every three weeks. The median patient age was 62 years, approximately 62% were women and 64% were Asian. About 61% had Exon 19 deletion and 38% had L858R substitution mutation in Exon 21, 40% had CNS metastases and 53% had extrathoracic metastases. Approximately 76% of patients completed four cycles of platinum therapy. The Primary end point was investigator-assessed Progression Free Survival (PFS). Secondary endpoints included Overall Survival (OS), Objective Response Rate (ORR) and Safety. The median follow-up for progression-free survival was 19.5 months in the osimertinib–chemotherapy group and 16.5 months in the osimertinib group.

In this final analysis of the Primary endpoint of PFS, results from this study showed a significant improvement in PFS with the Osimertinib plus chemotherapy combination versus Osimertinib alone (HR=0.62; P<0.001). The median PFS was 25.5 months versus 16.7 months respectively. This represented a 38% reduction in disease progression risk, compared to Osimertinib monotherapy. The PFS benefit with Osimertinib plus chemotherapy was consistent across prespecified subgroups, including the subgroups defined according to EGFR mutation type and the presence or absence of CNS metastases at baseline. The Objective Response Rate with the combination regimen was 83%, compared to 76%, in the Osimertinib monotherapy group. The median response duration was 24 months and 15.3 months respectively. Grade 3 or higher hematologic adverse events occurred more frequently in the combination regimen group and were manageable. Data for Overall Survival were immature at the time of the analysis, and this ongoing trial will continue to assess the Secondary endpoint of Overall Survival.

The authors concluded that FLAURA2 provides compelling evidence that the addition of chemotherapy to Osimertinib in the first line treatment of nonsquamous, locally advanced or metastatic EGFR mutated NSCLC, can significantly improve outcomes, compared to Osimertinib alone, and can delay resistance to therapy and disease progression.

Osimertinib with or without Chemotherapy in EGFR-Mutated Advanced NSCLC. Planchard D, Jänne PA, Cheng Y, et al. for the FLAURA2 Investigators. N Engl J Med 2023; 389:1935-1948

Amivantamab plus Chemotherapy with and without Lazertinib after Progression on Osimertinib in Advanced Lung Cancer

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SUMMARY: Lung cancer is the second most common cancer in both men and women and accounts for about 13% of all new cancers and 21% of all cancer deaths. The American Cancer Society estimates that for 2023, about 238,340 new cases of lung cancer will be diagnosed and 127,070 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. Approximately 10-15% of Caucasian patients and 35-50% of Asian patients with Adenocarcinomas, harbor activating EGFR mutations and 90% of these mutations are either exon 19 deletions or L858R substitution mutation in exon 21.

Epidermal Growth Factor Receptor (EGFR) plays an important role in regulating cell proliferation, survival and differentiation, and is overexpressed in a variety of epithelial malignancies. EGFR targeted Tyrosine Kinase Inhibitors (TKIs) such as Gefitinib, Erlotinib, Afatinib, Dacomitinib and Osimertinib target the EGFR signaling cascade. However, patients eventually will develop drug resistance due to new EGFR mutations. Another important cause of drug resistance to TKIs is due to the activation of parallel RTK (Receptor Tyrosine Kinase) pathways such as Hepatocyte Growth Factor/Mesenchymal-Epithelial Transition factor (HGF/MET) pathway, thereby bypassing EGFR TKI inhibitors. These patients are often treated with platinum-based chemotherapy as the next line of therapy, resulting in a median Progression Free Survival of 5 months.

Amivantamab (RYBREVANT®) is a fully-human bispecific antibody directed against EGFR and MET receptors. Amivantamab binds extracellularly and simultaneously blocks ligand-induced phosphorylation of EGFR and c-MET, inhibiting tumor growth and promoting tumor cell death. Further, Amivantamab downregulates receptor expression on tumor cells thus preventing drug resistance mediated by new emerging mutations of EGFR or c-MET. By binding to the extracellular domain of the receptor protein, Amivantamab can bypass primary and secondary TKI resistance at the active site. Amivantamab also engages effector cells such as Natural Killer cells, monocytes, and macrophages via its optimized Fc domain. Amivantamab demonstrated activity against a wide range of activating and resistance mutations in EGFR-mutated NSCLC, and in patients with MET exon 14 skip mutations, and is approved for the treatment of patients with EGFR exon 20 insertion mutations, whose disease progressed on or after platinum-based chemotherapy.

Lazertinib is a highly selective, third-generation TKI that penetrates the CNS, with demonstrated efficacy in activating EGFR mutations and acquired T790M “gatekeeper” point mutation. Combining Amivantamab with Lazertinib has been shown to provide a synergistic benefit by targeting the extracellular and catalytic EGFR domains. In early phase studies, Amivantamab plus chemotherapy and Amivantamab, Lazertinib plus chemotherapy demonstrated an Objective Response Rate of 44% and 50% in advanced and refractory NSCLC, and in patients whose disease had progressed on prior TKIs, respectively.

MARIPOSA-2 is a global, randomized, Phase 3 trial, conducted to assess the efficacy and safety of Amivantamab plus chemotherapy and Amivantamab, Lazertinib plus chemotherapy versus chemotherapy alone, in patients with EGFR-mutated advanced NSCLC, whose disease had progressed on or after Osimertinib monotherapy. Amivantamab is a large molecule and was not expected to readily cross the blood-brain barrier. This was one of the main reasons for the addition of Lazertinib, a known CNS-active TKI, to Amivantamab plus chemotherapy. A total of 657 patients (N=657) with EGFR-mutated (exon 19 deletions or L858R substitution mutations) locally advanced or metastatic NSCLC, after disease progression on Osimertinib, were randomized 2:2:1 to receive either Amivantamab along with Lazertinib and chemotherapy (N=263), chemotherapy alone (N=263), or Amivantamab plus chemotherapy (N=131). Patients received Amivantamab 1400 mg IV (1750 mg for body weight 80 kg or greater) weekly for the first 4 weeks, then 1750 mg (2100 mg for body weight 80 kg or greater) every 3 weeks starting at cycle 3 (week 7). The first Amivantamab infusion was split over 2 days, with 350 mg IV on cycle 1, day 1 and the remainder on cycle 1, day 2. Lazertinib was administered at 240 mg orally daily. Chemotherapy consisted of Carboplatin AUC5 IV, starting on day 1 every 3 weeks for the first 4 cycles along with Pemetrexed 500 mg/m2 IV every 3 weeks until disease progression. The median age was 62 years, 48% of patients were Asian, about 45% of patients had a history of brain metastases, and approximately 70% of patients had Osimertinib as first line treatment and 30% had Osimertinib as second line treatment. Randomization was stratified by Osimertinib line of therapy (first or second), race (Asian or non-Asian), and history of brain metastasis (yes or no). All three treatment groups were well balanced. The dual Primary endpoints were Progression Free Survival (PFS) of Amivantamab plus chemotherapy and Amivantamab, Lazertinib plus chemotherapy, versus chemotherapy alone. Secondary endpoints included Objective Response Rate (ORR), Duration of Response, Overall Survival (OS) and Safety.

At a median follow-up of 8.7 months, the PFS was significantly longer for Amivantamab plus chemotherapy and Amivantamab, Lazertinib plus chemotherapy versus chemotherapy alone (HR for disease progression or death=0.48 and 0.44, respectively; P<0.001 for both; median of 6.3 and 8.3 versus 4.2 months, respectively). The Objective Response Rate was significantly higher for Amivantamab plus chemotherapy and Amivantamab, Lazertinib plus chemotherapy versus chemotherapy alone (64% and 63% versus 36%, respectively; P<0.001 for both). The median intracranial PFS was 12.5 and 12.8 versus 8.3 months for Amivantamab plus chemotherapy and Amivantamab, Lazertinib plus chemotherapy versus chemotherapy alone (HR for intracranial disease progression or death=0.55 and 0.58, respectively). The researchers postulated that the mechanism by which Amivantamab improves intracranial PFS could either be through direct antitumor effects or indirectly through immune-based mechanisms. The most common adverse events with the Amivantamab combinations were cytopenias, infusion-related reactions and venous thromboembolism. The researchers recommend prophylactic anticoagulation.

It was concluded that Amivantamab plus chemotherapy, as well as Amivantamab, Lazertinib plus chemotherapy, significantly improved Progression Free Survival (PFS) and intracranial PFS, compared with chemotherapy alone, in patients with EGFR-mutated advanced NSCLC with disease progression on or after Osimertinib. The authors added that MARIPOSA-2 is the first study to demonstrate improved PFS versus chemotherapy, after disease progression on Osimertinib.

Amivantamab plus chemotherapy with and without lazertinib in EGFR-mutant advanced NSCLC after disease progression on osimertinib: Primary results from the phase 3 MARIPOSA-2 study. Passaro A, Wang J, Wang Y, et al. Annals of Oncology. 2023. DOI:https://doi.org/10.1016/j.annonc.2023.10.117

FDA Approves Ivosidenib for Myelodysplastic Syndromes

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SUMMARY: The FDA on October 24, 2023, approved Ivosidenib (TIBSOVO®) for adult patients with Relapsed or Refractory MyeloDysplastic Syndromes (MDS) with a susceptible Isocitrate DeHydrogenase-1 (IDH1) mutation, as detected by an FDA-approved test. The FDA also approved the Abbott RealTime IDH1 Assay as a companion diagnostic device to select patients for Ivosidenib.

It is estimated that in the US approximately 13,000 people are diagnosed with MyeloDysplastic Syndromes (MDS) each year. The prevalence has been estimated to be from 60,000 to 170,000 in the US. MyeloDysplastic Syndromes are a heterogenous group of stem cell disorders characterized by marrow failure resulting in cytopenias, mainly symptomatic anemia, with associated cytogenetic abnormalities, and abnormal cellular maturation with morphologic changes in clonal cells. Majority of the individuals diagnosed with MDS are 65 years or older and die as a result of infection and/or bleeding, consequent to bone marrow failure. About a third of patients with MDS develop Acute Myeloid Leukemia (AML).

The International Prognostic Scoring System (IPSS) for MDS has 4 risk groups based on Total Risk Score (Low, Intermediate-1, Intermediate-2 and High). The three prognostic factors scored to predict the course of the patient’s disease include, percentage of blast cells in the bone marrow, type of chromosomal changes in the marrow cells and number of cytopenias (anemia, neutropenia or thrombocytopenia). Patients with low-risk MDS have an indolent disease course with a median survival of about 6 years with no therapeutic intervention. Patients with intermediate and higher-risk disease however have a shorter median survival even with treatment, with approximately a third of the patients progressing to AML within 3 years.

Patients with Low-risk MDS often present with symptomatic anemia and these patients are in chronic need for RBC transfusions. These patients are treated with Erythropoiesis Stimulating Agents (ESAs) as first line therapy. ESAs such as Darbepoetin alfa and Epoetin alfa are re-engineered and recombinant DNA technology products of Erythropoietin (EPO), and they stimulate erythropoiesis by binding and activating the EPO receptor. However, transfusion-dependent patients with serum EPO levels above 200U per liter are less likely to respond to ESAs. A majority of patients with higher-risk MDS are treated with hypomethylating agents such as Azacitidine and Decitabine and these agents can favorably modify the natural history of the disease, and have been shown to improve survival. However, outcomes are poor and no therapies currently exist for patients with Isocitrate Dehydrogenase 1-mutant Relapsed or Refractory MDS, following failure on a hypomethylating agent.

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% 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.

Ivosidenib is a first-in-class, oral, potent, targeted, small-molecule inhibitor of mutant IDH1. The FDA in 2018, approved Ivosidenib for adult patients with Relapsed or Refractory AML with a susceptible IDH1 mutation, and in 2019 approved Ivosidenib for newly diagnosed AML with a susceptible IDH1 (Isocitrate DeHydrogenase-1) mutation, in patients who are at least 75 years old or who have comorbidities that preclude the use of intensive induction.

The present FDA approval is supported by a pivotal Phase 1, open-label, multinational study, in which the safety, tolerability, and clinical activity of Ivosidenib was evaluated among patients with Relapsed or Refractory Myelodysplastic syndromes with an IDH1 mutation. In this study 18 eligible patients (N=18) received Ivosidenib 500 mg orally daily, continuous for 28-day cycles, until disease progression, unacceptable toxicity, or Hematopoietic Stem Cell Transplantation. The median treatment duration was 9.3 months. One patient underwent a Stem Cell Transplantation following Ivosidenib. IDH1 mutations were detected in peripheral blood or bone marrow by a local or central diagnostic test and confirmed retrospectively by the Abbott RealTime IDH1 Assay. The median age was 73 years and majority of patients had intermediate or high IPSS-R score at the time of screening for the study. The Primary efficacy end point was the Complete Response (CR) plus Partial Response (PR) rate. Secondary endpoints included duration of CR plus PR, duration of transfusion independence, and time to transfusion independence.

All observed responses were Complete Responses. The CR rate was 38.9%. The median time to Complete Response was 1.9 months and at the time of data cutoff, the median duration of Complete Responses was not estimable and ranged from 1.9 to 80.8+ months. Additionally, of the 9 patients who were transfusion dependent with Red Blood Cells or platelets at baseline, 67% became RBC and platelet transfusion independent during any 56-day post-baseline period. Of the 9 patients independent of both RBC and platelet transfusions at baseline, 78% remained transfusion independent during any 56-day post-baseline period. The most common adverse reactions included GI toxicities such as mucositis, diarrhea, constipation and nausea, fatigue, arthralgia, myalgia, cough, and rash. Differentiation syndrome was rare and manageable. It should be noted that Ivosidenib can also cause QTc prolongation.

It was concluded from this study that Ivosidenib induced durable remissions including a substantial proportion of Complete Remissions with an acceptable safety profile, in patients with Relapsed or Refractory Myelodysplastic syndromes with an IDH1 mutation. Further, a significant proportion of patients became or remained transfusion independent. This is the first targeted therapy approved for this indication.

UPDATED SUBSTUDY RESULTS FOR IVOSIDENIB IN IDH1-MUTANT RELAPSED/REFRACTORY MYELODYSPLASTIC SYNDROME. Dinardo C, Roboz G, Watts JM, et al. Hemasphere. 2023 Aug; 7(Suppl): e75740ab. DOI: 10.1097/01.HS9.0000969800.75740.ab.

Single Blood Test for Multi-Cancer Early Detection

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SUMMARY: The American Cancer Society estimates that in 2023, 1,958,310 new cancer cases and 609,820 cancer deaths are projected to occur in the United States. Although cancer mortality rates continue to decline with advances in treatment, improving early detection can reduce disease and treatment-related morbidity, improve treatment outcomes, quality of life and reduce financial burden both for the patient as well as the society as a whole. Currently the USPSTF (Unites States Preventive Services Task Force) and ACS (American Cancer Society) recommend screening for breast, cervical, colorectal, and lung cancers. Neither the ACS nor USPSTF have specific recommendations for prostate cancer screening. These cancers collectively account for only 42% of annual cancer incidence in people aged 50-79 years. It has been estimated that detection of cancer at an earlier stage could reduce cancer-related deaths by 15% or more within 5 years. Some of the available screening tests reduce cancer-specific mortality, but are associated with high false-positive rates, overdiagnosis, and overtreatment.

Galleri is a Multi-Cancer Early Detection (MCED) test developed for the early detection of multiple asymptomatic cancers that lack recommended screening tests, using a blood sample. DNA (cell free DNA) is shed into the blood stream both by tumor cells as well as healthy cells. The Galleri test uses Next Generation Sequencing (NGS) and machine-learning algorithms to isolate cell-free DNA and analyze more than 100,000 DNA regions and over a million specific DNA sites, to screen for a signal shared by cancers. The test looks for cell-free DNA and identifies whether it comes from healthy or cancer cells. DNA from cancer cells has specific methylation patterns that identify it as a cancer signal. Methylation patterns also contain information about the tissue type or organ associated with the cancer signal. So, once a cancer signal is detected, the Galleri test predicts the Cancer Signal Origin, or the tissue or organ where the cancer signal originated, to help guide diagnostic evaluation. The Galleri test is recommended for use in adults with an elevated risk for cancer, such as those aged 50 or older, and should be used in addition to routine cancer screening tests. Galleri is not recommended in individuals who are pregnant, 21 years old or younger, or undergoing active cancer treatment.

A validation study (Circulating Cell-free Genome Atlas study-CCGA) was conducted to evaluate the accuracy of the Galleri test. This study included 2,823 people with a known diagnosis of cancer and 1,254 healthy people. The overall Sensitivity for cancer signal detection was 51.5% and the Specificity was 99.5%. The sensitivity of the test increased with advanced cancer stages. Cancer signals were detected across over 50 cancer types and the overall accuracy of predicting Cancer Signal Origin in those who tested true positive was 88.7% (Ann Oncol. 2021;32:1167-1177).

PATHFINDER was a pilot, prospective cohort study conducted to investigate the feasibility of MCED testing for cancer screening. This study included 6,621 participants from oncology and primary care outpatient clinics at seven U.S. health networks who underwent MCED blood testing. Participants were 50 years or older, with no signs or symptoms of cancer, and majority were women (63.5%) and White (91.7%). Approximately 56% of participants had additional risk factors such as smoking, germline cancer predisposition, or personal history of treated cancer. The Primary outcome was time to diagnosis, and extent of diagnostic testing required to confirm the presence or absence of cancer.

MCED testing detected a cancer signal in 1.4% of the total patient sample of whom 38% had cancer confirmed (true positives), while 62% had no cancer (false positives). In patients in whom no cancer signal was detected, 95.5% were true negatives, 1.3% was false negatives, and 3.2% did not have cancer-status assessment at the end of the study. The tests accuracy in predicting the primary cancer location (Cancer Signal Origin) among the true positives was high at 97%. The median time to achieving a diagnostic resolution was 79 days, 57 days in true-positive patients and 162 days in false-positive ones. Fewer procedures were done in participants with false-positive results compared to true-positive results (30% versus 82% respectively) and few participants had surgery (one with a false-positive result and three with a true-positive result).

Among participants whose testing was true-positive and who had a confirmed new cancer diagnosis, nearly half (48%) were detected at an early stage (Stage I-II) when the potential for curative treatment is increased. Further, 74% of the MCED-detected cancers were cancer types that do not currently have USPSTF screening recommendations. These included cancers of the bile duct, pancreas, small intestine, and spindle cell neoplasm, which are all associated with high mortality rates and may be amenable to surgical resection at early stages.

In the 12 months study period, 121 cancers were diagnosed, of whom 29% had a cancer signal detected by MCED, while 31% were detected thru screening and 40% were detected clinically. The overall Positive Predictive Value of MCED was 38%, Negative Predictive Value was 98.6%, and specificity was 99.1%. The cancer yield rate was 0.53% (number needed to screen to find one MCED-detected cancer was 189).

The researchers concluded that this study demonstrates the feasibility of screening for multiple cancers using a blood test and lays the foundation for large, controlled trials necessary to establish clinical utility and cost-effectiveness. Multi Cancer Early Detection test was also able to accurately predict tumor origin, and the diagnosis of cancer was established in less than 2 months in the true-positive patients.

Blood-based tests for multicancer early detection (PATHFINDER): a prospective cohort study. Schrag D, Beer TM, McDonnell CH, et al. The Lancet 2023;402:1251-1260.

KEYTRUDA® in Combination with HER2 Blockade Improves PFS in Gastric and GE Junction Cancer

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SUMMARY: Gastroesophageal cancers consist of a group of heterogeneous tumors, including gastric cancer, gastroesophageal junction cancer, and esophageal cancer. The majority of gastric and gastroesophageal junction cancers are adenocarcinomas, while the two main histological subtypes of esophageal cancer are esophageal adenocarcinoma and esophageal squamous cell carcinoma. The American Cancer Society estimates that in the US about 26,500 new gastric cancer cases and 21,560 new esophageal cancers will be diagnosed in 2023 and about 11,130 and 16,120 people respectively, will die of the disease. It is one of the leading causes of cancer-related deaths in the world. Patients with localized disease (Stage II and Stage III) are often treated with multimodality therapy and 40% of the patients may survive for 5 years or more. However, majority of the patients with gastric and gastroesophageal junction adenocarcinoma have advanced disease at the time of initial presentation and have limited therapeutic options with little or no chance for cure.

The Human Epidermal growth factor Receptor (HER) or erbB family of receptors, consist of HER1, HER2, HER3 and HER4. Approximately 15-20% of advanced gastric and gastroesophageal (GE) junction cancers, overexpress or have amplification of the HER2 oncogene. These patients often receive first line treatment with a combination of chemotherapy plus anti-HER2 antibody, Trastuzumab, as there is Overall Survival (OS) benefit with this combination regimen. Pembrolizumab (KEYTRUDA®) is a fully humanized, Immunoglobulin G4, anti-PD-1, monoclonal antibody, that binds to the PD-1 receptor expressed on activated T cells, and blocks its interaction with ligands PD-L1 and PD-L2. It thereby reverses the PD-1 pathway-mediated inhibition of the immune response and unleashes the tumor-specific effector T cells. In two Phase II studies, Pembrolizumab in combination with Trastuzumab and chemotherapy showed promising efficacy with manageable toxicities. The FDA in 2021 granted accelerated approval to Pembrolizumab in combination with Trastuzumab, Fluoropyrimidine and Platinum-containing chemotherapy for the first-line treatment of patients with locally advanced unresectable or metastatic HER2 positive gastric or gastroesophageal junction adenocarcinoma, based on Overall Response Rates (ORR).

KEYNOTE-811 is an ongoing, global, multicenter, randomized Phase III trial which evaluated the benefit of adding Pembrolizumab to Trastuzumab and chemotherapy in patients with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma. In this study, 698 treatment naïve eligible patients (N=698) were randomly assigned 1:1 to receive Pembrolizumab 200 mg IV (N=350) or placebo (N=348) every 3 weeks plus Trastuzumab and investigator’s choice of Fluorouracil/Cisplatin or Capecitabine/Oxaliplatin. Trastuzumab was given at 6 mg/kg IV once every 3 weeks after a loading dose of 8 mg/kg IV. Chemotherapy consisted of 5-FU 800 mg/m2 IV on days 1 to 5 of each 3-week cycle and Cisplatin 80 mg/m2 IV once every 3 weeks, or Capecitabine 1,000 mg/m2 orally twice daily on days 1 to 14 of each 3-week cycle and Oxaliplatin 130 mg/m2 IV once every 3 weeks. Treatment was continued for up to 35 cycles or until disease progression or unacceptable toxicity. Approximately 81% were male and patients were stratified by PD-L1 status, and chemotherapy received. Over 80% of patients had a PD-L1 Combined Positive Score of 1 or more. The dual Primary end points of the trial were Progression Free Survival (PFS) and Overall Survival (OS). Secondary end points included Objective Response Rate (ORR), Duration of Response, and Safety. The researchers reported the results at the third interim analysis, after a median follow up of 38.5 months.

At the third interim analysis, the results continued to show superiority with the addition of Pembrolizumab to Trastuzumab and chemotherapy. The median PFS with Pembrolizumab versus placebo was 10 months versus 8.1 months, respectively (HR = 0.73; P=0.0002). This represented a 27% reduction in risk for progression with Pembrolizumab versus placebo. The median OS showed numerical improvement and was 20.0 months versus 16.8 months (HR=0.84), but did not meet prespecified criteria for significance. Follow up for Overall Survival is continuing, and results will be updated at the final analysis. Patients whose tumors had PD-L1 Combined Positive Score of 1 or more benefitted the most, and there was little to no benefit among patients whose tumors had PD-L1 Combined Positive Scores less than 1. The researchers had previously reported an ORR of 74% in the the Pembrolizumab group and 52% in the placebo group, yielding a 22% improvement for the Pembrolizumab group (P=0.00006). Disease Control Rates were 96.2% versus 89.3% respectively. Grade 3 or more treatment-related adverse events were higher among patients assigned to Pembrolizumab versus placebo group (58% versus 51%). The most common treatment-related adverse events of any grade were diarrhea, nausea and anemia.

The authors concluded that Pembrolizumab when combined with first line Trastuzumab and chemotherapy significantly improved Progression Free Survival when compared to placebo, in metastatic HER2-positive gastroesophageal cancer. This benefit was specifically noted among patients with tumors with a PD-L1 Combined Positive Score of 1 or more. Follow up for Overall Survival is ongoing and will be updated at the final analysis.

Pembrolizumab plus trastuzumab and chemotherapy for HER2-positive gastric or gastro-oesophageal junction adenocarcinoma: interim analyses from the phase 3 KEYNOTE-811 randomised placebo-controlled trial. Janjigian YY, Kawazoe A, Bai Y, et al. Published:October 20, 2023. DOI:https://doi.org/10.1016/S0140-6736(23)02033-0

Zolbetuximab plus CAPOX in Biomarker Positive Advanced Gastric or GEJ Cancer

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SUMMARY: The American Cancer Society estimates that in the US about 26,500 new gastric cancer cases will be diagnosed in 2023 and about 11,130 people will die of the disease. It is one of the leading causes of cancer-related deaths in the world. Several hereditary syndromes such as Hereditary Diffuse Gastric Cancer (HDGC), Lynch syndrome (Hereditary Nonpolyposis Colorectal Cancer) and Familial Adenomatous Polyposis (FAP) have been associated with a predisposition for Gastric cancer. Additionally, one of the strongest risk factor for Gastric adenocarcinoma is infection with Helicobacter pylori (H.pylori), which is a gram-negative, spiral-shaped microaerophilic bacterium.

Patients with localized disease (Stage II and Stage III) are often treated with multimodality therapy and 40% of the patients may survive for 5 years or more. However, majority of the patients with Gastric and GastroEsophageal junction (GEJ) adenocarcinoma have advanced disease at the time of initial presentation and have limited therapeutic options with little or no chance for cure. The five-year relative survival rate for patients at the metastatic stage is approximately 6%. These patients frequently are treated with platinum containing chemotherapy along with a Fluoropyrimidine such as modified FOLFOX6 or CAPOX. Patients with HER2-positive disease are usually treated with chemotherapy plus Trastuzumab, and for those patients with HER2-negative disease, patients receive chemotherapy along with a checkpoint inhibitor, or checkpoint inhibitor alone, if the tumors express PD-L1.

CLDN18.2 protein found in normal gastric cells, and is a major component of epithelial and endothelial tight junctions controlling the flow of molecules between cells. Pre-clinical studies have shown that CLDN18.2 expression which can also be present in gastric tumors, increases as cancer progresses, and may become more exposed on the surface of the cancer cells and accessible to targeted therapies with antibodies. CLDN18.2 is expressed in 35% of Gastric adenocarcinomas.

Zolbetuximab is a first-in-class chimeric IgG1 monoclonal antibody that targets and binds to CLDN18.2, a transmembrane protein. The binding interaction of Zolbetuximab to CLDN18.2 activates Antibody-Dependent Cellular Cytotoxicity (ADCC) and Complement Dependent Cytotoxicity (CDC) resulting in cancer cell death. About 30-40% of patients with Gastric cancer have CLDN18.2 expression.

SPOTLIGHT trial is a Phase III, global, multi-center, double-blind, randomized study, in which the efficacy and safety of Zolbetuximab plus mFOLFOX6 was compared with placebo plus mFOLFOX6, as first-line treatment of patients with CLDN18.2-positive, HER2- negative, locally advanced unresectable or metastatic Gastric or GastroEsophageal Junction cancer. This study met the Primary endpoint and the median Progression Free Survival (PFS) was 10.61 months with the Zolbetuximab plus mFOLFOX6 combination versus 8.67 months with placebo plus mFOLFOX6 (HR=0.75; P=0.0066) and this was statistically significant. The Overall Survival (OS) was also significantly improved (18.23 versus 15.54 months, HR=0.750; P=0.0053), making this one of the longest durations of median OS seen in Phase III trials for this patient population.

GLOW trial is a global, multi-center, double-blind, randomized Phase III study, conducted to assess the efficacy and safety of Zolbetuximab plus CAPOX (N=254) versus placebo plus CAPOX (N=253) as a first-line treatment for patients with CLDN18.2-positive/HER2-negative, unresectable, locally advanced or metastatic Gastric or GEJ cancer. In this trial, 507 eligible patients were randomly assigned 1:1 to receive Zolbetuximab 800 mg/m2 IV as a loading dose on cycle 1, day 1, of the first 21-day cycle, followed by 600 mg/m2 IV on day 1 of subsequent cycles, along with CAPOX regimen consisting of Capecitabine 1000 mg/m2 orally twice daily on days 1-14 of each cycle and Oxaliplatin 130 mg/m2 IV on day 1 of each cycle, or the same CAPOX regimen plus placebo. CAPOX was given for 8 cycles in both treatment groups and patients could continue beyond 8 cycles with Zolbetuximab or placebo plus Capecitabine at investigator’s decision, and treatment continued until disease progression or unacceptable toxicities. CLDN18.2 positive was defined as at least 75% of tumor cells with moderate-to-strong membranous CLDN18.2 staining and patients were stratified by region (Asia versus non-Asia), number of organs with metastases, and prior gastrectomy (yes versus no). The median patient age was 60 years, majority of patients were male from Asia, not having prior gastrectomy, having stomach as the primary tumor site, and having an ECOG performance status of 1. Basline characteristics were similar in both treatment groups. The Primary end point was Progression Free Survival (PFS) and Secondary endpoints included Overall Survival (OS), Overall Response Rate (ORR), Duration of Response (DOR), and Safety.

At a median follow up of 12.6 months, the combination of Zolbetuximab plus CAPOX significantly improved PFS, and the median PFS was 8.2 months, compared with 6.8 months for those given placebo plus CAPOX (HR=0.687; P=0.0007). The median OS was 14.4 months versus 12.2 months respectively (HR=0.771; P=0.01). The PFS and OS benefits were sustained at 24 months, and the benefits were observed across most subgroups. The most common side effects were nausea and vomiting and the authors recommended increasing the infusion duration time, or splitting the dose over a 2 day period, in addition to the administration of prophylactic antiemetics.

The researchers concluded that the addition of first-line Zolbetuximab to CAPOX significantly improved PFS and OS in patients with CLDN18.2-positive, HER2-negative, unresectable, locally advanced or metastatic Gastric or GEJ cancer. The authors added that Zolbetuximab plus CAPOX represents a potential new first-line therapy for this patient group. Taken together, both GLOW and SPOTLIGHT trials showed a similar reduction in the risk of disease progression or death and a similar reduction in the risk of death with the addition of Zolbetuximab to chemotherapy, when compared with placebo plus chemotherapy.

Zolbetuximab plus CAPOX in CLDN18.2-positive gastric or gastroesophageal junction adenocarcinoma: the randomized, phase 3 GLOW trial. Shah MA, Shitara K, Ajani JA, et al. Nature Medicine 2023; 29:2133–2141

Osimertinib Plus Chemotherapy Superior to Osimertinib Alone in Advanced EGFR Mutated Non Small Cell Lung Cancer

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SUMMARY: Lung cancer is the second most common cancer in both men and women and accounts for about 13% of all new cancers and 21% of all cancer deaths. The American Cancer Society estimates that for 2023, about 238,340 new cases of lung cancer will be diagnosed and 127,070 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.

Approximately 10-15% of Caucasian patients and 35-50% of Asian patients with Adenocarcinomas, harbor activating EGFR (Epidermal Growth Factor Receptor) mutations and 90% of these mutations are either Exon 19 deletions or L858R substitution mutation in Exon 21. Approximately 25% of patients with EGFR mutated NSCLC have brain metastases at diagnosis, increasing to approximately 40% within two years of diagnosis. The presence of brain metastases often reduces median survival to less than eight months. EGFR-Tyrosine Kinase Inhibitors (TKIs) such as TARCEVA® (Erlotinib), IRESSA® (Gefitinib) and GILOTRIF® (Afatinib), have demonstrated a 60-70% response rate as monotherapy when administered as first line treatment, in patients with metastatic NSCLC, who harbor the sensitizing EGFR mutations. However, majority of these patients experience disease progression within 9-14 months. This resistance to frontline EGFR TKI therapy has been attributed to the most common, acquired T790M “gatekeeper” point mutation in EGFR, identified in 50-60% of patients.

Osimertinib (TAGRISSO®) is a highly selective third-generation, irreversible Epidermal Growth Factor Receptor TKI, presently approved by the FDA, for the first-line treatment of patients with metastatic NSCLC, whose tumors have Exon 19 deletions or Exon 21 L858R mutations, as well as treatment of patients with metastatic EGFR T790M mutation-positive NSCLC, whose disease has progressed on or after EGFR-TKI therapy. Further, Osimertinib has higher CNS penetration and is therefore able to induce responses in 70-90% of patients with brain metastases.

In the Phase III FLAURA trial, among patients with metastatic, EGFR-mutant NSCLC, first-line treatment with Osimertinib significantly improved median Overall Survival, compared with Erlotinib and Gefitinib, and should therefore has been the preferred regimen in this patient group. The FLAURA2 trial builds on the favorable results observed in the Phase III FLAURA trial.

FLAURA2 is a randomized, open-label, multi-center, global, ongoing Phase III trial, in which 557 enrolled treatment naïve patients (N=557) with nonsquamous locally advanced (Stage IIIB-IIIC) or metastatic EGFR mutated NSCLC were randomly assigned 1:1 to receive Osimertinib plus chemotherapy (N=279) or Osimertinib monotherapy (N=278). Patients in the combination group received Osimertinib 80 mg oral tablets once daily in combination with chemotherapy consisting of Pemetrexed 500 mg/m2 IV plus Cisplatin 75 mg/m2 IV or Carboplatin (AUC5), every three weeks for four cycles, followed by Osimertinib with Pemetrexed maintenance every three weeks. The median patient age was 62 years, approximately 62% were women and 64% were Asian. Approximately 76% of patients completed four cycles of platinum therapy. The Primary end point was investigator-assessed Progression Free Survival (PFS). Secondary endpoints included Overall Survival (OS), Objective Response Rate (ORR) and Safety.

In this final analysis of the Primary endpoint of PFS, results from this study showed a significant improvement in Progression Free Survival (PFS) with the Osimertinib plus chemotherapy combination versus Osimertinib alone, with an 8.8-month improvement in median PFS with the combination regimen (HR=0.62; P<0.0001). This represented a 38% reduction in disease progression risk, compared to Osimertinib monotherapy. In addition, median PFS determined by blinded Independent Central Review showed a 9.5-month improvement with the combination regimen. The Objective Response Rate with the combination regimen was 83%, compared to 76%, in the Osimertinib monotherapy group. Grade 3 or higher hematologic adverse events occurred more frequently in the combination regimen group and were manageable. Data for Overall Survival were immature at the time of the analysis, and this ongoing trial will continue to assess the Secondary endpoint of Overall Survival.

The authors concluded that FLAURA2 provides compelling evidence that the addition of chemotherapy to Osimertinib in the first line treatment of nonsquamous, locally advanced or metastatic EGFR mutated NSCLC, can further improves outcomes, compared to Osimertinib alone, and can delay resistance to therapy and disease progression.

FLAURA2 results demonstrate osimertinib plus chemotherapy superior compared to osimertinib alone (press release). Available at: https://www.iaslc.org/iaslc-news/press-release/flaura2-results-demonstrate-osimertinib-plus-chemotherapy-superior. Published Sept.10, 2023.

Germline Testing to Identify 11 Genes Linked to Aggressive Prostate Cancer

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SUMMARY: Prostate cancer is the most common cancer in American men with the exclusion of skin cancer, and 1 in 9 men will be diagnosed with Prostate cancer during their lifetime. It is estimated that in the United States, about 288,300 new cases of Prostate cancer will be diagnosed in 2023 and 34,700 men will die of the disease. The development and progression of Prostate cancer is driven by androgens. Androgen Deprivation Therapy (ADT) or testosterone suppression has therefore been the cornerstone of treatment of advanced Prostate cancer, and is the first treatment intervention. Approximately 10-20% of patients with advanced Prostate cancer will progress to Castration Resistant Prostate Cancer (CRPC) within five years during ADT, and over 80% of these patients will have metastatic disease at the time of CRPC diagnosis. The malignant transformation of prostatic epithelial cell as well as the development of CRPC has been attributed to deleterious alterations in a variety of genes including loss-of-function alterations in Homologous Recombination Repair (HRR) genes.

DNA damage is a common occurrence in daily life by UV light, ionizing radiation, replication errors, chemical agents, etc. This can result in single and double strand breaks in the DNA structure which must be repaired for cell survival. The two vital pathways for DNA repair in a normal cell are BRCA1/BRCA2 and PARP. BRCA1 and BRCA2 are tumor suppressor genes that recognize and repair double strand DNA breaks via Homologous Recombination Repair (HRR) pathway. Homologous Recombination is a type of genetic recombination, and is a DNA repair pathway utilized by cells to accurately repair DNA double-stranded breaks during the S and G2 phases of the cell cycle, and thereby maintain genomic integrity. Homologous Recombination Deficiency (HRD) is noted following mutation of genes involved in HR repair pathway. At least 15 genes are involved in the Homologous Recombination Repair (HRR) pathway including BRCA1, BRCA2, PALB2, CHEK2 and ATM genes. Mutations in these genes predispose an individual to develop malignant tumors. Mutations in BRCA1 and BRCA2 account for about 20-25% of hereditary breast cancers and about 5-10% of all breast cancers. They also account for 15% of ovarian cancers, in addition to other cancers such as Colon and Prostate. BRCA mutations can either be inherited (Germline) and present in all individual cells or can be acquired and occur exclusively in the tumor cells (Somatic). Somatic mutations account for a significant portion of overall BRCA1 and BRCA2 aberrations. Loss of BRCA function due to frequent somatic aberrations likely deregulates HR pathway, and other pathways then come in to play, which are less precise and error prone, resulting in the accumulation of additional mutations and chromosomal instability in the cell, with subsequent malignant transformation. Homologous Recombination Deficiency therefore indicates an important loss of DNA repair function.

The current National Comprehensive Cancer Network (NCCN) guidelines for prostate cancer (version 1.2022) recommend germline testing for the subsets of patients with prostate cancer who are more likely to have germline DNA repair mutations. They include men with node positive, high-risk or very high-risk localized prostate cancer, men with metastatic prostate cancer, and men meeting family history criteria. NCCN recommends considering germline testing for men with personal history of prostate cancer and intermediate risk prostate cancer and intraductal/cribriform histology and personal history of exocrine pancreatic, colorectal, gastric, melanoma, pancreatic, upper tract urothelial, glioblastoma, biliary tract or small intestinal cancers. Germline testing panel sizes vary from dedicated BRCA1/2 testing to extended 91 plus-gene panels

The goal of this study was to investigate the association between rare deleterious variants and Variants of Unknown Significance (VUS) across the genome and in candidate genes, particularly DNA repair genes, and identify genes associated with aggressive prostate cancer.

The researchers conducted a two-stage exome-sequencing genetic association study, to identify rare genetic variants associated with aggressive prostate cancer. This analysis included 17,546 patients of European ancestry with prostate cancer from 18 epidemiological studies across the US, Europe and Australia. The study population included 9185 men with aggressive prostate cancer and 8361 men with nonaggressive prostate cancer. Aggressive prostate cancer was defined as at least one of the following: T4 disease, T3 plus a Gleason score of 8 or more, metastatic disease, or death from prostate cancer, while nonaggressive prostate cancer was defined as localized T1/T2 disease and a Gleason score of 6 or less. The researchers focused their study on 29 DNA repair pathway and cancer susceptibility genes previously linked with prostate cancer, in addition to a group of 167 genes thought to be related to DNA damage repair. They then looked for associations between deleterious genetic variants or Variants of Uncertain Significance (VUS) and aggressive versus nonaggressive prostate cancer, using a relatively modest threshold for significance.

The strongest evidence of association with aggressive or metastatic prostate cancer was noted for rare deleterious variants in known prostate cancer risk genes BRCA2 and ATM (P<0.0000019), followed by NBN (P=0.00017). This study found nominal evidence (P <0.05) of association with rare deleterious variants in MSH2, XRCC2, and MRE11A. Five other genes analyzed, TP53, RAD51D, BARD1, GEN1, and SLX4, had evidence of greater risk with an Odds Ratio (OR) of 2 or more, but carrier frequency differences between aggressive and nonaggressive prostate cancer were not statistically significant. Deleterious variants of the 11 candidate genes identified in the study were carried by 2.3% of patients with nonaggressive prostate cancer, 5.6% with aggressive prostate cancer, and 7.0% with metastatic prostate cancer.

In conclusion, the researchers from this analysis of the largest cohort of prostate cancer patients were able to identify DNA repair pathway gene variants, associated with aggressive prostate cancer. Testing should be extended to men without aggressive prostate cancer, as men carrying deleterious variants in these genes are likely to develop advanced disease.

Germline Sequencing Analysis to Inform Clinical Gene Panel Testing for Aggressive Prostate Cancer. Darst BF, Saunders E, Dadaev T, et al. JAMA Oncol. Published online September 21, 2023. doi:10.1001/jamaoncol.2023.3482

FDA Approves Pralsetinib for Non Small Cell Lung Cancer with RET gene fusions

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SUMMARY: The FDA on August 9, 2023, granted regular approval to Pralsetinib (GAVRETO®) for adult patients with metastatic Rearranged during Transfection (RET) fusion-positive Non-Small Cell Lung Cancer (NSCLC) as detected by an FDA approved test. Pralsetinib was previously granted accelerated approval for the NSCLC indication in Sept. 2020, based on initial Overall Response Rate (ORR) and Duration of Response (DOR) in 114 patients enrolled in the ARROW trial. The conversion to regular approval was based on data from an additional 123 patients and 25 months of additional follow up, to assess Durability of Response.

Lung cancer is the second most common cancer in both men and women and accounts for about 13% of all new cancers and 21% of all cancer deaths. The American Cancer Society estimates that for 2023, about 238,340 new cases of lung cancer will be diagnosed and 127,070 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 accounts for approximately 85% of all lung cancers.

In addition to the well characterized gene fusions involving ALK and ROS1 in NSCLC, genetic alterations involving other kinases including EGFR, BRAF, RET, MET, KRAS, NTRK, are all additional established targetable drivers. These genetic alterations are generally mutually exclusive, with no more than one predominant driver in any given cancer. The hallmark of all of these genetic alterations is oncogene addiction, in which cancers are driven primarily, or even exclusively, by aberrant oncogene signaling, and are highly susceptible to small molecule inhibitors.

RET kinase is a transmembrane Receptor Tyrosine Kinase and plays an important role during the development and maintenance of a variety of tissues, including neural and genitourinary tissues. RET signaling activates downstream pathways such as JAK/STAT3 and RAS/RAF/MEK/ERK and leads to cellular proliferation, survival, invasion, and metastasis. Oncogenic alterations to the RET proto-oncogene results in uncontrolled cell growth and enhanced tumor invasiveness. RET alterations include RET rearrangements, leading to RET fusions, and activating point mutations occurring across multiple tumor types. RET fusions have been identified in approximately 2% of NSCLCs, 10-20% of non-medullary thyroid cancers. Activating RET point mutations account for approximately 60% of sporadic Medullary Thyroid Cancers (MTC) and more than 90% of inherited MTCs. Other cancers with documented RET alterations include colorectal, breast, and several hematologic malignancies.

Patients without a driver mutation are often treated with a platinum-doublet cytotoxic chemotherapy with/without Immune checkpoint inhibitors, or with Immune checkpoint inhibitor monotherapy. However, outcomes with immune checkpoint inhibitors remain poor in patients with RET fusion–positive NSCLC, regardless of PD-L1 expression.

Pralsetinib (GAVRETO®) is an oral, highly potent, selective RET kinase inhibitor targeting oncogenic RET alterations, including fusions and mutations, regardless of the tissue of origin. The efficacy of Pralsetinib was investigated in a multicenter, open-label, multi-cohort, Phase I/II basket clinical trial (ARROW), in patients with tumors showing RET alterations. Identification of RET gene alterations was prospectively determined in local laboratories using either, Next Generation Sequencing (NGS), Fluorescence In Situ Hybridization (FISH), or other tests. (In a basket trial, tumors with different histologies and single biomarker are placed in different baskets and receive a single treatment). Phase I Pralsetinib dose escalation study determined 400 mg QD as the recommended Phase II trial dose. Phase II trial evaluated Pralsetinib in multiple expansion groups, defined by disease type and treatment history.

The FDA regular approval was based on the efficacy of Pralsetinib in a total of 237 patients (N=237) with locally advanced or metastatic RET fusion-positive NSCLC. Patients received Pralsetinib 400 mg once daily until disease progression or unacceptable toxicity. Among the patients studied, 107 (N=107) were treatment-naïve and 130 patients (N=130) were previously treated with platinum-based chemotherapy. The main efficacy outcome measures were Overall Response Rate (ORR) and Duration of Response, as determined by a Blinded Independent Review Committee, using RECIST criteria.

The median age of the 107 patients in the treatment-naïve group was 63 years and 28% of patients had a history of or active CNS/brain metastases. The ORR in this group was 78%, with a Complete Response (CR) rate of 7%. The median Duration of Response was 13.4 months and 45% of patients experienced a Duration of Response of 12 months or longer.

The median age of the 130 patients in the group that was previously treated with platinum-based chemotherapy, was 59 years and 41% had a history of or active CNS/brain metastases. The ORR in this group was 63% with a CR rate of 6%. The median Duration of Response of 38.8 months and 66% of patients experienced a Duration of Response of at least 12 months.

In patients with measurable intracranial metastases, the intracranial response rate was 70%.

The most common adverse reactions were fever, fatigue, cough, constipation, diarrhea, musculoskeletal pain, hypertension and edema.

It was concluded from this study that treatment with Pralsetinib produced robust efficacy including intracranial activity, in patients with advanced RET fusion–positive NSCLC who are treatment-naive or are refractory to standard-of-care chemotherapy. Results from the confirmatory Phase III AcceleRET Lung study of Pralsetinib versus standard of care in the first-line setting are eagerly awaited and may further support the use of Pralsetinib for RET fusion-positive NSCLC in the first-line setting.

https://www.fda.gov/drugs/drug-approvals-and-databases/fda-approves-pralsetinib-non-small-cell-lung-cancer-ret-gene-fusions

FDA Approves AKEEGA® for Metastatic Castration Resistant Prostate Cancer with BRCA1/2 Mutations

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SUMMARY: The FDA on August 11, 2023, approved the fixed dose combination of Niraparib and Abiraterone acetate (AKEEGA®) with prednisone, for adult patients with deleterious or suspected deleterious BRCA-mutated Castration Resistant Prostate Cancer (mCRPC), as determined by an FDA-approved test. Prostate cancer is the most common cancer in American men with the exclusion of skin cancer, and 1 in 9 men will be diagnosed with Prostate cancer during their lifetime. It is estimated that in the United States, about 288,300 new cases of Prostate cancer will be diagnosed in 2023 and 34,700 men will die of the disease.

The development and progression of Prostate cancer is driven by androgens. Androgen Deprivation Therapy (ADT) or testosterone suppression has therefore been the cornerstone of treatment of advanced Prostate cancer and is the first treatment intervention. Androgen Deprivation Therapies have included bilateral orchiectomy or Gonadotropin Releasing Hormone (GnRH) analogues, with or without first generation Androgen Receptor (AR) inhibitors such as CASODEX® (Bicalutamide), NILANDRON® (Nilutamide) and EULEXIN® (Flutamide) or with second-generation Androgen-Receptor Pathway Inhibitors (ARPI), which include ZYTIGA® (Abiraterone), XTANDI® (Enzalutamide) and ERLEADA® (Apalutamide). Approximately 10-20% of patients with advanced Prostate cancer will progress to Castration Resistant Prostate Cancer (CRPC) within five years during ADT, and over 80% of these patients will have metastatic disease at the time of CRPC diagnosis. The estimated mean survival of patients with CRPC is 9-36 months, and there is therefore an unmet need for new effective therapies.

DNA damage is a common occurrence in daily life by UV light, ionizing radiation, replication errors, chemical agents, etc. This can result in single and double strand breaks in the DNA structure which must be repaired for cell survival. The two vital pathways for DNA repair in a normal cell are BRCA1/BRCA2 and PARP. BRCA1 and BRCA2 genes recognize and repair double strand DNA breaks via Homologous Recombination Repair (HRR) pathway. Homologous Recombination is a type of genetic recombination and is a DNA repair pathway utilized by cells to accurately repair DNA double-stranded breaks during the S and G2 phases of the cell cycle, and thereby maintain genomic integrity. Homologous Recombination Deficiency (HRD) is noted following mutation of genes involved in HRR pathway. At least 15 genes are involved in the HRR pathway including BRCA1, BRCA2 and ATM genes. The BRCA1 gene is located on the long (q) arm of chromosome 17 whereas BRCA2 is located on the long arm of chromosome 13. BRCA1 and BRCA2 are tumor suppressor genes and functional BRCA proteins repair damaged DNA, and play an important role in maintaining cellular genetic integrity. They regulate cell growth and prevent abnormal cell division and development of malignancy. Recently published data has shown that deleterious Germline and/or Somatic mutations in BRCA1, BRCA2, ATM, or other Homologous Recombination DNA-repair genes, are present in about 30% of patients with advanced prostate cancer, including metastatic CRPC. Patients with metastatic CRPC harboring BRCA alterations and other HRR gene alterations have poor outcomes and earlier resistance to commonly used systemic therapies.

The PARP (Poly ADP Ribose Polymerase), family of enzymes include, PARP1and PARP2, and is a related enzymatic pathway that repairs single strand breaks in DNA. In a BRCA mutant, the cancer cell relies solely on PARP pathway for DNA repair to survive. PARP inhibitors trap PARP onto DNA at sites of single-strand breaks, preventing their repair and generating double-strand breaks that cannot be repaired accurately in tumors harboring defects in HRR genes, such as BRCA1 or BRCA2 mutations, and this leads to cumulative DNA damage and tumor cell death. PARP inhibitors have demonstrated significant activity in patients with prostate cancer and HRR gene alterations, with the greatest clinical benefit noted in BRCA1/2 mutation carriers. Niraparib (ZEJULA®) is a highly selective PARP-1 and PARP-2 inhibitor approved for several indications, including ovarian, fallopian tube, and primary peritoneal cancers. When given along with Abiraterone and Prednisone, the combination targets two oncogenic drivers in patients with metastatic CRPC (mCRPC), which include alterations in the Androgen Receptor axis and BRCA1/2 in the HRR pathway.

MAGNITUDE is a multicenter, multicohort, placebo-controlled, randomized, double-blind, Phase III study, prospectively designed as a precision medicine study to identify the specific population of patients who would most benefit from Niraparib with Abiraterone Acetate plus Prednisone, and potentially increase the likelihood of treatment success. This study involved 3 cohorts of patients: Cohort 1: Participants with mCRPC and HRR Gene Alteration. Cohort 2: Participants with mCRPC and No HRR Gene Alteration. Cohort 3 (Open-label): Participants with mCRPC

The present FDA approval was based on the safety and efficacy data from Cohort 1 group of patients with metastatic CRPC with HRR gene mutation. In this cohort, 423 patients (N=423) with HRR gene-mutated mCRPC were randomized (1:1) to receive Niraparib 200 mg orally once daily along with Abiraterone acetate 1,000 mg plus Prednisone 10mg daily, or placebo and Abiraterone acetate plus Prednisone daily. Patients with HRR positive biomarker included those with ATM, BRCA1, BRCA2, BRIP1, CDK12, CHEK2, FANCA, HDAC2, PALB2 gene alterations. Approximately 53% had BRCA gene mutations. Patients were required to have a prior orchiectomy or be receiving GnRH analogues. Patients with mCRPC were eligible if they had not received prior systemic therapy in the mCRPC setting except for a short duration of prior Abiraterone acetate plus Prednisone (up to four months) and ongoing ADT. Patients could have received prior chemotherapy with Docetaxel or Androgen-Receptor (AR) targeted therapies in earlier disease settings. Randomization was stratified by prior Docetaxel, prior AR targeted therapy, prior Abiraterone acetate plus Prednisone, and BRCA status. The Primary endpoint of this trial was radiographic Progression Free Survival (rPFS) assessed by blinded Independent Central Review. Secondary endpoints included time to initiation of cytotoxic chemotherapy, time to symptomatic progression and Overall Survival.

The combination of Niraparib and Abiraterone with Prednisone significantly improved rPFS in all HRR-positive patients (HR=0.73; P=0.022). This improvement was most pronounced in patients with BRCA1/2 gene mutations and the median rPFS was 16.6 months versus 10.9 months (HR=0.53; P=0.0014), with a 47% reduction in the risk of disease progression. With additional median follow up at 24.8 months in the BRCA subgroup, rPFS by Independent Central Review demonstrated a consistent and clinically meaningful treatment benefit favoring Niraparib plus Abiraterone, with a median rPFS of 19.5 months, compared with 10.9 months for placebo plus Abiraterone and Prednisone. Additionally, in the BRCA gene mutated patients, an exploratory OS analysis demonstrated a median of 30.4 versus 28.6 months favoring the Niraparib combination (HR=0.79). Further there was a strong improvement in time to symptomatic progression and clinically meaningful improvement in time to initiation of cytotoxic chemotherapy in the Niraparib combination group. The most common Grade 3 Adverse Events were anemia and hypertension, and the Niraparib combination also maintained overall quality of life, compared to placebo plus Abiraterone and Prednisone.

It was concluded from this study that Niraparib in combination with Abiraterone and Prednisone significantly improved radiographic Progression Free Survival and other clinically relevant end points compared to placebo plus Abiraterone and Prednisone, in patients with BRCA1/2 gene altered metastatic Castration Resistant Prostate Cancer. The authors added that MAGNITUDE study enrolled the largest cohort of BRCA1/2-positive patients for the first line treatment of metastatic Castration Resistant Prostate Cancer to date, emphasizing the importance of identifying patients with these molecular alterations.

Niraparib plus abiraterone acetate with prednisone in patients with metastatic castration-resistant prostate cancer and homologous recombination repair gene alterations: second interim analysis of the randomized phase III MAGNITUDE trial. Chi KN, Sandhu S, Smith MR, et al. Annals of Oncology 2023;34:772-782.