FDA Grants Priority Review to Antibody Drug Conjugate for Diffuse Large B-Cell Lymphoma

The Food and Drug Administration (FDA) granted a priority review to polatuzumab vedotin in combination with bendamustine plus Rituxan (rituximab; BR) for the treatment of patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), according to Genentech, the anti-CD79b antibody drug conjugate’s manufacturer.

The biologic license application was based on results from the global, randomized phase 1b/2 GO29365 study, designed to evaluate the safety, tolerability and activity of polatuzumab vedotin in combination with BR or Gazyva (obinutuzumab) in relapsed or refractory follicular lymphoma or DLBCL. The primary endpoint was complete response at the end of treatment, while secondary endpoints included objective response by investigator assessment and best objective response at the end of treatment by investigator and independent review committee assessment. Exploratory endpoints included duration of response, progression-free survival, event-free survival and overall survival.

The trial showed that polatuzumab vedotin plus BR improved median overall survival compared to BR alone (12.4 vs. 4.7 months) in patients who are not eligible for a hematopoietic stem cell transplant. In addition, 40 percent of patients treated with the polatuzumab vedotin combination achieved a complete response, compared with just 18 percent of those treated with BR alone.

In addition, the investigational arm demonstrated an increase in progression-free survival, which led to a 66 percent reduction in the risk for disease worsening or death compared to BR alone (median progression-free survival, 7.6 vs. 2 months). In addition, the polatuzumab vedotin arm demonstrated a longer time between first response to treatment and disease worsening compared with those treated with BR alone (10.3 vs. 4.1 months).

Updated safety results are similar to those previously described, with infections and cytopenias remaining the most common grade 3 to 4 side effects.

“Polatuzumab vedotin, a potential first-in-class antibody drug conjugate, in combination with bendamustine and Rituxan, improved clinical outcomes including survival in some people with relapsed or refractory diffuse large B-cell lymphoma compared to bendamustine and Rituxan alone,” Sandra Horning, M.D., chief medical officer and head of global product development, said in a press release. “We are working with the FDA to bring this important new option to patients with this aggressive disease as quickly as possible."

The FDA is expected to make its decision by Aug. 19, 2019.