Atezolizumab Treatment Safe and Effective in Metastatic Urothelial Cancer Patients

Patients with metastatic urothelial cancer treated with atezolizumab monotherapy demonstrated tolerability for the drug and general ability to manage adverse effects, according to a study published in JAMA Oncology.

While chemotherapy often leads to poor outcomes in treating locally advanced or metastatic urothelial carcinoma, advanced technology in cancer treatment has created more effective ways in managing symptoms and prolonging life. Atezolizumab is a humanized, engineered monoclonal antibody that prevents programmed death ligand 1 (PD-L1) from binding to receptors programmed death 1 and B7.1. This creates long-term responses in anticancer immunity by activating T cells in lymph nodes. The therapy’s safety and benefit have been proven in previous clinical trials and studies.

Long-term safety and efficacy outcomes after atezolizumab treatment in patients with metastatic urothelial cancer were recorded from the 95-patient cohort in the phase 1 study. Patients had a median follow-up of 37.8 months while 3-year overall survival rate and safety outcomes were recorded.

The cohort received atezolizumab intravenously at 15 mg/kg every 3 weeks until progression continued, resulting in a loss of clinical benefit. Safety evaluations took place every 3 weeks and the final evaluation took place approximately 90 days after the final dose. Adverse events, including acute infections, infusion reaction syndromes, and rashes resulting from treatment were also recorded.

The results show that 47% of the cohort received atezolizumab as third-line therapy or greater with only 9% experiencing grade 3 to 4 treatment-related adverse events. The most common adverse events included fatigue, asthenia, decreased appetite, and pruritus. Only 1 patient experienced a grade 4 treatment-related adverse event.

Median progression-free survival was 2.7 months and median overall survival was 10.1 months. The longest ongoing response duration in a patient was approximately 41 months. The 3-year overall survival rate was 27% and no treatment-related deaths occurred.

The authors concluded that the 3-year follow-up proved the tolerability of atezolizumab in patients with metastatic urothelial cancer. It was found that adverse events were generally manageable and there were no safety concerns in long-term atezolizumab treatment. Previously published literature correlate well with the long-term results of this study, proving the clinical benefits of atezolizumab after unsuccessful chemotherapy treatment.

“Ongoing studies of single-agent atezolizumab and combination therapies in a variety of settings will be required to fully delineate and confirm the clinical correlates of response and survival in patients with urothelial cancer,” the authors recommended.

Reference

Petrylak DP, Powles T, Bellmunt J, et al. Atezolizumab (MPDL3280A) monotherapy for patients with metastatic urothelial cancer: long-term outcomes from a phase 1 study. Jama Oncl. Published online ahead of print February 08, 2018. doi:10.1001/jamaoncol.2017.5440