IMFINZI® in Combination with Chemotherapy Improves Overall Survival in Advanced Biliary Tract Cancer

SUMMARY: Bile Tract cancer (Cholangiocarcinoma) is a rare, heterogenous cancer, and comprises about 30% of all primary liver tumors and includes both intrahepatic and extrahepatic bile duct cancers. Klatskin tumor is a type of Cholangiocarcinoma that begins in the hilum, at the junction of the left and right bile ducts. It is the most common type of Cholangiocarcinoma, accounting for more than half of all cases. About 8,000 people in the US are diagnosed with Cholangiocarcinoma each year and approximately 20% of the cases are suitable for surgical resection. The 5-year survival among those with advanced stage disease is less than 10%, with limited progress made over the past two decades. There is therefore an unmet need for new effective therapies.

Patients with advanced bile tract cancers often receive chemotherapy in the first and second line settings, with limited benefit. Gemcitabine and Cisplatin combination is currently the first line standard-of-care treatment. With the recognition of immunogenic features displayed by bile tract cancers, the role of immune checkpoint inhibitors for improving disease control and prolonging survival, has been increasingly explored.

IMFINZI® (Durvalumab) is a human monoclonal antibody that binds to the PD-L1 protein and blocks the interaction of PD-L1 with the PD-1 and CD80 proteins, countering the tumor’s immune-evading tactics and unleashes the T cells. IMFINZI® in combination with Gemcitabine and Cisplatin showed encouraging antitumor activity in a Phase II study, among patients with advanced bile tract cancers.

TOPAZ-1 is a double-blind, multicenter, global, Phase III trial conducted to evaluate the efficacy of first line immunotherapy given along with Gemcitabine and Cisplatin in patients with advanced metastatic biliary tract cancer. In this study, a total of 685 previously untreated patients with unresectable, locally advanced, recurrent or metastatic biliary tract cancer were randomized 1:1 to receive IMFINZI® (Durvalumab) 1500 mg IV every 3 weeks (N=341) or placebo (N=344), along with Gemcitabine 1000 mg/m2 IV and Cisplatin 25 mg/m2 IV given on Days 1 and 8, every 3 weeks for up to 8 cycles, followed by IMFINZI® 1500 mg IV every 4 weeks or placebo, until disease progression or unacceptable toxicity. Patients with recurrent disease more than 6 months following curative surgery or adjuvant therapy were also included. The median patient age was 64 years and approximately 50% of patients had an ECOG Performance Status of 0. Randomization was stratified by disease status (initially unresectable, recurrent) and primary tumor location (intrahepatic cholangiocarcinoma versus extrahepatic cholangiocarcinoma versus gallbladder cancer). Approximately 56% had intrahepatic cholangiocarcinoma, followed by gallbladder cancer (25%) and extrahepatic cholangiocarcinoma (19%). The Primary endpoint was Overall Survival (OS) and Secondary endpoints included Progression Free Survival (PFS), Objective Response Rate (ORR), and Safety.

The Primary endpoint was met at the first interim analysis and treatment with IMFINZI® plus Gemcitabine and Cisplatin significantly improved Overall Survival compared with placebo plus chemotherapy, with a 20% reduction in the risk of death (HR=0.80; P=0.021). Progression Free Survival was also greatly improved with chemoimmunotherapy vs chemotherapy alone (HR=0.75; P=0.001). The Objective Response Rate was was 26.7% in the IMFINZI® plus chemotherapy group and 18.7% in the placebo plus chemotherapy group. Grade 3 or 4 treatment-related adverse events were almost similar in both treatment groups (62.7% versus 64.9%), and treatment discontinuation due to adverse events was 8.9% in the IMFINZI® plus chemotherapy group and 11.4% in the placebo plus chemotherapy group.

It was concluded that in patients with advanced biliary tract cancers, IMFINZI® in combination with Gemcitabine and Cisplatin significantly improved Overall Survival and Progression Free Survival with manageable safety, when compared to chemotherapy alone, and should therefore be considered first line standard-of- care for this patient group.

A phase 3 randomized, double-blind, placebo-controlled study of durvalumab in combination with gemcitabine plus cisplatin (gemcis) in patients (pts) with advanced biliary tract cancer (BTC): TOPAZ-1. Oh D-Y, He AR, Qin S, et al. J Clin Oncol. 2022;40(suppl 4):378. DOI:10.1200/JCO.2022.40.4_suppl.378.