On May 18, 2016, the US Food and Drug Administration (FDA) approved atezolizumab (Tecentriq; Genentech) for the treatment of patients with locally advanced or metastatic urothelial carcinoma who have disease progression during or after platinum-containing chemotherapy, or who have disease progression within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy.
“Tecentriq provides these patients with a new therapy targeting the PD-L1 pathway. Products that block PD-1/PD-L1 interactions are part of an evolving story about the relationship between the body’s immune system and its interaction with cancer cells,” said Richard Pazdur, MD, Director of the FDA’s Office of Hematology and Oncology Products.
The approval of atezolizumab was based on the results of the IMvigor 210 study, an open-label, multicenter, single-arm, phase 2 study involving 310 patients with locally advanced or metastatic urothelial carcinoma who received 1200 mg of atezolizumab intravenously. The study’s primary end point was objective response rate (ORR), and the secondary end point was the duration of response.
Atezolizumab conferred an ORR of 14.8%, with a median duration of response lasting more than 2.1 months and exceeding 13.8 months. The ORR was 9.5% in patients with programmed death ligand 1 (PD-L1) expression <5%, and the ORR was 26% in patients with PD-L1 expression ≥5%, suggesting that the level of PD-L1 expression may help identify patients who are more likely to respond to therapy with atezolizumab.
On the same day, in conjunction with this approval, the FDA approved the Ventana PD-L1 (SP142) assay, a companion diagnostic that detects the expression of PD-L1 levels on the tumor, which can help clinicians identify patients who would benefit most from atezolizumab treatment. Although all patients in the study showed some tumor shrinkage with the drug, the greater impact was seen in patients with PD-L1 expression.
The most common (≥20%) adverse reactions (all grades) associated with atezolizumab included fatigue (52%), decreased appetite (26%), nausea (25%), urinary tract infection (22%), pyrexia (21%), and constipation (21%). The most common (≥4%) grade 3/4 adverse reactions included abdominal pain (4%), fatigue (6%), urinary tract infection (9%), and dyspnea (4%).
Atezolizumab received a breakthrough therapy designation, priority review, and accelerated approval for this indication, all of which are designed to expedite the development and review of certain new drugs that may benefit patients with serious or life-threatening conditions.