Immunotherapy Usage Drops Amid FDA Safety Concerns

The FDA’s accelerated approval program has been criticized recently for pushing drugs into the market before they undergo randomized phase 3 clinical trials.

Use of 2 immunotherapies, the PD-1 inhibitor pembrolizumab and the PD-L1 inhibitor atezolizumab, dropped by approximately 50% 6 months after the FDA moved to restrict the label of the drugs, according to a new study from the Abramson Cancer Center at the University of Pennsylvania. These findings offer reassurance that oncologists can be nimble enough to incorporate the latest guidelines into practice when new safety data comes to light, according to the study published in JAMA.

The FDA’s accelerated approval (AA) program has been criticized recently for pushing drugs into the market before they undergo randomized phase 3 clinical trials, which are considered the gold standard in medical and drug development research, the study authors wrote.

The study examined the usage rates of 2 immunotherapies approved for first-line use in patients with advanced bladder cancer who are not eligible for standard cisplatin-based chemotherapy: the PD-1 inhibitor pembrolizumab and the PD-L1 inhibitor atezolizumab. The FDA approved both therapies in 2017 based on phase 2 studies.

However, data from ongoing phase 3 studies showed patients had decreased survival when taking these drugs compared with first-line platinum-based chemotherapy. This led the FDA to restrict the label indications compared with the original approval. The restrictions went into effect in June 2018.

The researchers initiated a study to examine the treatment for 1965 patients with advanced bladder cancer using a de-identified data set from the Flatiron Health database, derived from the health records from more than 280 oncology clinics across the United States.

Between May 2018 and January 2019, the rate of immunotherapy usage among these patients decreased from 51.9% to 30.3% per 100 patients. The rate of chemotherapy usage increased from 37% to 60.6% per 100 patients. Rates of PD-L1 testing also increased from 9.3% to 21.2% per 100 patients.

Although this study provides reassurances about the agility of oncologists, the researchers caution there are other factors that could be contributing to the trends they observed, adding that further study is needed to continue assessing the effect of label changes on clinical practice.

Reference

Oncologists Respond Swiftly to FDA Safety Alerts, Penn Study Finds [press release]. Philadelphia, PA. Penn Medicine News Website. Published September 24, 2019. https://www.pennmedicine.org/news/news-releases/2019/september/oncologists-respond-swiftly-to-fda-safety-alerts-penn-study-finds. Accessed September 26, 2019.