The U.S. Food and Drug Administration (FDA) has approved Imfinzi (durvalumab) with the FLOT chemotherapy regimen of fluorouracil, leucovorin, oxaliplatin and docetaxel as a presurgical and postsurgical treatment followed by single-agent Imfinzi for adults with resectable gastric or gastroesophageal junction adenocarcinoma (GC/GEJC).
The approval was announced in a notice from the agency.
The effectiveness of the treatment was determined in the MATTERHORN clinical trial, a randomized, double-blind, placebo-controlled multicenter trial which enrolled 948 patients with previously untreated and resectable stage 2 to 4A GC/GEJC, with patients evenly randomized to receive either Imfinzi and FLOT or placebo and FLOT.
The median event-free survival was not reached in the Imfinzi and FLOT arm and it was 32.8 months in the placebo and FLOT arm. The median overall survival was not reached in either arm. The pathologic complete response rate was 19.2% in the Imfinzi plus FLOT arm and it was 7.2% in the placebo plus FLOT arm.
Event-free survival (EFS): the length of time after treatment during which a person has no major problems related to their cancer.
Progression-free survival (PFS): the amount of time during and after treatment that the cancer does not grow or spread.
Overall survival (OS): the total length of time from diagnosis or the start of treatment that patients are still alive, no matter what happens with the cancer itself.
The treatment’s prescribing information includes warnings and precautions for immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic hematopoietic stem cell transplantation and embryo-fetal toxicity, according to the agency.
The recommended dosage of Imfinzi for patients with a body weight of at least 30 kilograms is 1,500 milligrams every four weeks with chemotherapy for up to four cycles of presurgical, or neoadjuvant, and postsurgical, or adjuvant, treatment, followed by 1,500 milligrams as a single agent every four weeks for up to 10 cycles. The recommended Imfinzi dose for patients with a body weight of less than 30 kilograms is 20 milligrams per kilogram with chemotherapy every four weeks for up to four cycles of neoadjuvant and adjuvant treatment and 20 milligrams per kilogram as a single agent every four weeks for up to 10 cycles, with treatment advised to continue until disease progression, recurrence or unacceptable toxicity or until a maximum of 12 cycles after surgery, the FDA reported.
Imfinzi, as defined by the National Cancer Institute, is a monoclonal antibody that is designed to active the immune system to exert a cytotoxic t-lymphocyte response against B7H1-expressing tumor cells. It has previously been approved to treat patients with bladder cancer, biliary tract cancer, endometrial cancer, hepatocellular carcinoma, non-small cell lung cancer and small cell lung cancer.