• Roche on Monday said its immunotherapy Tecentriq helped stave off tumor growth in a Phase 3 study of previously untreated people with metastatic bladder cancer, a result that could bolster the Swiss pharma’s efforts in the competitive field. 
• How meaningful Roche’s declared trial success is, however, won’t be clear until fuller results are disclosed from the Phase 3 study, known as IMvigor-130. The drugmaker noted data on Tecentriq’s survival benefit were “encouraging,” but not yet mature enough for a statistical comparison to chemotherapy alone.
• Interpreting studies without complete data is always fraught, but it’s especially the case with IMvigor-130 given its history. A mid-stage test designed to confirm Tecentriq’s accelerated approval in first-line bladder cancer failed to show an improvement on survival, and last year the Food and Drug Administration warned against use of the drug alone in bladder cancer patients with low levels of a biomarker called PD-L1.

Tecentriq (atezolizumab) first won U.S. approval in bladder cancer, and the indication still makes up a fifth of Roche’s sales of the drug, even as OKs in lung and breast cancers followed. 

Results from IMvigor-130 could help solidify Tecentriq’s place as a treatment for the tumor type at a time when studies of competing drugs are advancing. In a familiar story for the immuno-oncology field, Roche’s early advantage has come under pressure from Merck & Co.’s Keytruda (pembrolizumab), which also holds an approval for use in previously untreated patients. 

About 5% of Keytruda sales in the U.S. come from treatment of bladder cancer as of Merck’s last estimate, yet the absolute figure rivals Roche’s due to the much higher sales numbers for Keytruda. 

Phase 3 studies of immunotherapies in first-line bladder cancer

*Estimated SOURCE: Companies, clinicaltrials.gov

Last year, the FDA restricted first-line use of both Tecentriq and Keytruda to only patients whose tumors express PD-L1, a biomarker correlated with improved responses to immunotherapy drugs.

The change resulted from emerging data from Merck’s KEYNOTE-361 study and Roche’s IMvigor-130 showing PD-L1-low patients receiving the immunotherapies as monotherapy were dying sooner than those given chemo. As a result, the companies stopped enrolling PD-L1-low patients into the monotherapy arms of their respective studies. 

Both studies are also designed to compare chemo plus Keytruda or Tecentriq versus chemo alone. On that measure, Roche said Monday the Tecentriq combination reduced the risk of disease worsening or death compared to just chemo. 

Notably, given the FDA’s earlier caution, Roche said no new safety signals were identified with the Tecentriq-chemo pairing. 

Roche plans to present full results from the study at an upcoming medical meeting and to share the data with health authorities including the FDA. Knowing how PD-L1 status correlates to responses will likely be a focus, as will the magnitude of improvement on progression-free survival. 

The pharma has four ongoing Phase 3 studies of Tecentriq in early or advanced bladder cancer.