The U.S. Food and Drug Administration (FDA) has granted accelerated approval to Imfinzi (durvalumab) to treat locally advanced or metastatic urothelial carcinoma, the most common type of bladder cancer.
The approval, announced by AstraZeneca and its research and development arm, MedImmune, is for patients whose disease has progressed despite having been previously treated with platinum-containing chemotherapy, with or without surgery.
“The usual course of treatment for patients with advanced bladder cancer begins with a standard platinum-containing chemotherapy. Patients who have disease progression during or following chemotherapy are left with few other treatment options,” Dr. Nicholas J. Vogelzang, a clinical professor at the University of Nevada School of Medicine, said in a press release. “The approval of Imfinzi to treat this population of select patients signifies hope for those who are currently suffering, or may find themselves with limited options in the future.”
The FDA’s accelerated approval was based on the results from Study 1108 (NCT01693562), a multicenter, open-label, first-in-human, Phase 1/2 study designed to assess the safety and efficacy of Imfinzi in patients with advanced solid tumors.
The trial included 182 urothelial carcinoma patients in the bladder cancer cohort who received intravenous injections of Imfinzi every two weeks until the disease resumed its progression or until an unacceptable level of toxicity was reached.
Imfinzi is a monoclonal antibody that blocks the action of PD-L1, which halts the action of immune cells that could fight the cancer. Interestingly, in this study, 4 percent of patients whose tumors had low or zero levels of PD-L1 on their surfaces also responded to Imfinzi, along with those whose tumors were PD-L1 positive.
In addition, 31 patients (17 percent of the total) responded to Imfinzi, while 25 responded partially, and five responded completely. Three of 14 patients whose tumor PD-L1 levels could not be evaluated also showed a response.
“The durable responses observed in this larger data set from Study 1108 confirm the promising efficacy we’ve already seen for durvalumab in patients with advanced bladder cancer,” said David Berman, senior vice president and head of Oncology Innovative Medicines at MedImmune. He said the company would keep testing durvalumab in combination with tremelimumab and as monotherapy in the bladder cancer first-line setting in its ongoing Phase III DANUBE trial (NCT02516241).
AstraZeneca is currently conducting clinical trials of Imfinzi to treat other solid tumors, including lung and breast cancer.