When the Food and Drug Administration (FDA) approved a cancer immunotherapy for the first time in 1990, the treatment was indicated for patients with bladder cancer. This year, it is estimated that nearly 80,000 new cases of bladder cancer will be diagnosed in the United States, making it the sixth most common cancer in the country. More than 16,300 people will die from the disease this year. Bladder cancer also has a high rate of recurrence, and patients must undergo extended surveillance periods. The disease typically starts in transitional epithelial cells found in the inner lining of the bladder and expands to connective tissues and muscles. In more advanced forms of the disease, it spreads to lymph nodes and organs around the pelvis, which allows it to metastasize to other organs throughout the body.
A New Therapy for Patients with Urothelial Carcinoma
The five-year survival rate associated with bladder cancer has not changed in the past decade because no new drugs have received approval from the FDA. However, the FDA recently gave accelerated approval for Genentech’s Tecentriq (atezolizumab), which is a programmed death-ligand 1 (PD-L1) blocking antibody. The FDA has indicated the treatment for locally advanced or metastatic urothelial carcinoma, which accounts for nearly all instances of bladder cancer. Tecentriq provides a new option for patients who have experienced disease progression while on platinum-based chemotherapy and have very few, if any, avenues for treatment.
The FDA’s approval of Tecentriq is a landmark event for anti-PD-L1 cancer immunotherapy. Moreover, it is the first treatment for a specific form of bladder cancer to receive approval in three decades. The treatment is indicated only for patients who have experienced disease progression during or following platinum-containing chemotherapy. Patients may also be eligible if they have shown signs of disease progression within 12 months of platinum chemotherapy before or after surgery. To make the option as accessible as possible, Genentech has announced a patient assistance program through Genentech Access Solutions.
The Findings of Genentech’s Atezolizumab Studies
The accelerated approval from the FDA came following early clinical evidence of the clinical benefit of the drug. The judgment comes from tumor response rate and duration of response observed during a phase II IMvigor 210 study of the drug in patients with locally advanced or metastatic urothelial bladder cancer. The open-label, two-cohort study took place at multiple centers and involved a total of 310 participants, all of whom received a 1,200-milligram intravenous dose of the drug in 21-day cycles. Since the Phase II study aimed to evaluate efficacy and safety, participants continued to receive the drug until unacceptable levels of toxicity were reached or the disease showed clinical progression.
At the end of the study, researchers reported an objective response rate of 22 percent. About one in five patients with disease progression following platinum-based therapy experienced tumor shrinkage. Some patients experienced such a marked recovery that they were able to return to everyday life with minimal discomfort. While such results are heartening, the durability of such effects remains undetermined. At the same time, the drug is well tolerated in the minority of patients for whom the drug achieved an effect and could prove life-altering for this subset of individuals with the disease. The drug also marks the first time in three decades that patients with this type of bladder cancer have a new option for treatment.
Continued FDA approval of Tecentriq remains contingent on the confirmatory Phase III IMvigor 211 study, which compares the effects achieved by the drug and traditional chemotherapy in populations with locally advanced or metastatic urothelial bladder cancer that has progressed during or after a platinum-containing regimen. The trials are ongoing at multiple centers around the globe. The study, which includes more than 700 patients, aims to measure overall survival rates, as well as the duration of response, progression-free survival rates, and the incidence of adverse effects. The study could provide more information about who could potentially benefit from the drug and for how long.
Other Immuno-Oncology Approaches to Bladder Cancer Treatment
Outside of Tecentriq, several other immunotherapies are currently in clinical trials for the treatment of bladder cancer. Some of these approaches include oncolytic virus therapy, which uses a modified virus that causes tumor cells to self-destruct, and monoclonal antibodies, which are designed to target specific antigens found on the surface of tumor cells. Bladder cancer researchers are also looking into adoptive T-cell transfer, which is the removal of T-cells from a patient so that he or she can be genetically modified to better fight cancer cells. Then, these cells are reintroduced into the patient’s body. Cytokines, messenger molecules that control the growth and response rate of the immune system, could also play a role in the future of bladder cancer treatment.
In addition, several checkpoint inhibitors outside of atezolizumab are in clinical trials. These drugs include CTLA-4 antibody tremelimumab, PD-L1 antibody durvalumab, and two therapies that are already indicated for the treatment of other forms of cancer: nivolumab and pembrolizumab.