ASCO: Bavencio boosts survival post-chemo in bladder cancer

Merck KGaA and Pfizer have reported overall survival (OS) data for their PD-1 inhibitor Bavencio in bladder cancer at ASCO, backing up use of the drug as a maintenance therapy after chemotherapy.

The two companies first teased the OS data from the JAVELIN Bladder 100 trial in January, and at ASCO reported the data for the first time in the study, which involved patients with local-advanced or metastatic urothelial carcinoma (UC) that wasn’t treatable with surgery and had been treated with at least four cycles of chemo.

Treatment with Bavencio (avelumab) resulted in a 31% reduction in the risk of death compared to supportive care with no drug treatment – and extended median survival by more than seven months – in patients initially treated for bladder cancer with first-line chemo.

Patients in the Bavencio treatment group had a median OS of 21.4 months, compared to 13.3 months for the control group. After 12-months, 71% of patients on Bavencio maintenance were alive compared to 58% of patients receiving supportive care.

The PD-1 inhibitor is already approved as a second-line treatment for bladder cancer after platinum-based chemotherapy, getting a green light for this indication from the FDA in 2017.

It has to compete with other checkpoint inhibitors as a second-line therapy after chemotherapy failure, including Merck & Co/MSD’s market-leading Keytruda (pembrolizumab), Bristol-Myers Squibb’s Opdivo (nivolumab), AstraZeneca’s Imfinzi (durvalumab) and Roche’s Tecentriq (atezolizumab) which have transformed the prospects for bladder cancer patients.

Keytruda is also approved for first-line use in patients who aren’t eligible for chemo, but as yet no other drugs have approval for the first-line maintenance indication. That provides an opportunity for Bavencio to get ahead of its blockbuster rivals and kickstart sales, which were just $114m last year from UC, kidney cancer and Merkel cell carcinoma.

The FDA awarded breakthrough designation to the drug for first-line maintenance use in April, and the investigators reckon the drug could be a ‘game changer’ in this setting.

UC is a large market, accounting for around 90% of all bladder cancer diagnoses. When it reaches the metastatic stage, the five-year survival rate is just 5%.

Rare gynaecological cancer

There was more good news for Merck and Pfizer at this year’s ASCO from a small phase 2 study of Bavencio in gestational trophoblastic tumours (GTTs), a rare form of gynaecological cancer that develops in placental tissue during or after pregnancy.

TROPHIMMUN is the first trial of an immunotherapy for GTTs, and showed that Bavencio prevented relapses in eight of 15 patients resistant to single-agent chemotherapy, with lead investigator Benoit You of Lyon University Hospital in France suggesting that treatment may have been curative for some of them.

At the moment no other PD-1/PD-L1 inhibitors are approved in GTTs, so it could become another niche for Bavencio that is free of competition if this initial data is backed up in further studies.