Roche has said it plans to press ahead with a filing for its PD-L1 inhibitor atezolizumab in advanced bladder cancer after reporting additional positive results in a phase II trial.
The Swiss pharma company said that it will submit the data of people with locally advanced or metastatic urothelial carcinoma (mUC) "imminently" to the US FDA and other regulatory authorities around the world.
mUC accounts for around 90% of all cases of bladder cancer in the US and Europe and while initial response rates with chemotherapy can be quite high median survival remains very low at around 15 months from diagnosis.
Only around 15% of patients are still alive five years later, and Roche notes that there have been no major treatment advances in nearly 30 years.
The phase II IMvigor 210 trial revealed that in mUC patients who had already been heavily treated with chemotherapy, atezolizumab (MPDL3280A) therapy was associated with longer survival than would be expected in this population, with some patients showing complete responses to therapy. Preliminary data from the study were revealed last year.
Patients with high-levels of PD-L1 expression in their tumours had a median overall survival time of 11.4 months, while for the overall study population median OS was 7.9 months. Moreover, the results also showed that 84% of subjects who responded to atezolizumab continued to show a benefit - regardless of their PD-L1 status - over almost 12 months of follow-up.
The IMvigor 210 trial also includes a second cohort of previously-untreated patients unsuitable for first-line chemotherapy, but data from this arm are not yet available.
Last year, the FDA granted a breakthrough therapy designation for atezolizumab in people whose metastatic bladder cancer expressed PD-L1.
If approved, atezolizumab will join a new generation of checkpoint inhibitor cancer immunotherapies, which work by blocking mechanisms that help tumours evade detection by the immune system.
Two drugs with a similar mechanism of action (PD-1 inhibition) - Bristol-Myers Squibb's Opdivo (nivolumab) and Merck & Co's Keytruda (pembrolizumab) - are already on the market for melanoma and non-small cell lung cancer (NSCLC) while Opdivo was also recently approved for kidney cancer.
Meanwhile, Keytruda is also in late-stage testing for bladder cancer so could pose near-term competition to Roche's drug. Roche has suggested in the past however that atezolizumab's mechanism of action could help separate it from the PD-1 inhibitors, and may lead to better cure rates in the long term.
The PD-1/PD-L1 inhibitors as a whole are expected to bring in sales of $35bn or more at peak thanks to their unprecedented efficacy across multiple tumour types.