Bayer/Orion showcase results from prostate cancer challenger

Bayer and development partner Orion have released detailed results from the trial that will form the backbone of its filing for their latest prostate cancer drug, as they aim to take on two established blockbusters from Johnson & Johnson and Pfizer/Astellas.

J&J and Astellas market androgen receptor antagonists Zytiga (abiraterone) and Xtandi (enzalutamide) respectively – but Bayer hopes to take them on with a drug that may have a safety advantage if approved.

Xtandi has been shown to cross the blood-brain barrier and has been linked with neurological side-effects, while evidence gathered so far shows that darolutamide does not penetrate the barrier.

The companies are targeting patients with non-metastatic castration-resistant prostate cancer, using the darolutamide to hold back the spread of the disease while it is in its early stages.

Results of the ARAMIS trial showed a statistically significant 59% reduction in risk of metastasis or death in patients treated with darolutamide plus standard androgen receptor therapy, compared with those treated with androgen deprivation therapy (ADT) and placebo.

Median metastasis-free survival was 40.4 months in the darolutamide arm, compared with 18.4 months for the placebo arm.

However there was only a “positive trend” in overall survival, and other secondary endpoints showed a benefit in favour of darolutamide.

The company said that safety data was comparable between treatment and placebo arms.

Only fatigue occurred in more than 10% of patients (darolutamide plus ADT resulted in 12.1 per cent versus 8.7 per cent in patients with placebo plus ADT). Quality of life outcomes were similar between the treatment groups.

J&J has also developed a next-generation prostate cancer drug, Erleada (apalutamide) to recoup sales as Zytiga is threatened by generics in the US.

In a separate development, Bristol-Myers Squibb said its combination of Opdivo (nivolumab ) and Yervoy (ipilimumab) had become the first immunotherapy combination to produce a response in patients with metastatic disease.

Results from an interim analysis of the phase 2 CheckMate -650 trial showed that among 32 asymptomatic or minimally symptomatic patients whose disease had progressed after second-generation hormone therapy and who had not received chemotherapy (cohort 1), with a median follow-up of 11.9 months, the objective response rate (ORR) was 25%.

However Merck & Co seem to be ahead of the game in this indication with its checkpoint inhibitor Keytruda (pembrolizumab).

Results announced at last year’s American Society of Clinical Oncology (ASCO) conference show Keytruda produced a response in a larger 131-patient study without addition of another immunotherapy drug in patients at this stage of the disease.