The immunotherapeutic agent, atezolizumab, which is still in investigative stages, provides high rates of anti-cancer responses among patients with advanced bladder cancer. These results were recently presented at the 2016 Genitourinary Cancers Symposium of the American Society of Clinical Oncology (ASCO GU).

Urothelial carcinoma (formerly known as transitional cell carcinoma) is a cancer involving parts of the kidney, bladder, and ureter (the tube that connects the kidney to the bladder). Urothelial carcinomas begin in the cells that line the particular organ in which the cancer develops.

Urothelial carcinoma is the most common type of bladder cancer. If bladder cancer is detected and treated early, cure rates are high. However, once bladder cancer has spread outside of the bladder to distant sites in the body, effective treatment options remain limited, particularly if a patient experiences a cancer recurrence following prior therapies.

Atezolizumab is an agent that helps to restore the body’s immune system in fighting cancer. It creates its anti-cancer effects by blocking a specific protein used by cancer cells called PD-L1, to escape an attack by the immune system. Once PD-L1 is blocked, cells of the immune system are able to identify cancer cells as a threat, and initiate an attack to destroy the cancer.

Researchers recently conducted a clinical trial to further evaluate atezolizumab in the treatment of patients with bladder cancer. The trial, referred to as the IMvigor 210 study, included patients with advanced bladder cancer that had recurred following prior therapy. Among this group of patients in the study, 41% had received at least 2 prior therapies.

• Median overall survival was 11.4 months in patients with high levels of PD-L1, and 7.9 months overall among all patients.
• At nearly one-year, 84% of patients who achieved an anti-cancer response with atezolizumab, continued to respond to the treatment, regardless of PD-L1 levels.
• The median duration of anti-cancer responses has not yet been achieved.
• At 6 months, survival without progression of cancer was achieved in 30% of patients with moderate to high levels of PD-L1, and in 23% of patients with lower levels of PD-L1.
• Atezolizumab was generally very well tolerated.

The researchers concluded that treatment with atezolizumab appears to provide long-lasting anti-cancer responses among patients with advanced bladder cancer that has recurred following prior therapy. Continued research further evaluating atezolizumab is ongoing, including its effectiveness as initial therapy, and in combination with other agents, for the treatment of bladder cancer.

Reference: Hoffman-Censits J., et al. IMvigor 210, a phase 2 trial of atezolizumab (MPDL3280A) in platinum-treated locally-advanced or metastatic urothelial carcinoma (mUC). Proceedings from the 2016 Genitourinary Cancers Symposium of the American Society of Clinical Oncology (ASCO GU). Presented Friday, 8 January 2016, [0755–0930], San Francisco, CA, USA. Abstract #355.

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