Bayer, Orion focus on tolerability of darolutamide as they look to challenge Erleada, Xtandi in prostate cancer

Bayer and Orion highlighted the safety profile of darolutamide in patients with non-metastatic castration-resistant prostate cancer as Phase III study data for the oral androgen receptor antagonist were presented at the Genitourinary Cancers Symposium (ASCO GU). Robert LaCaze, Bayer's head of oncology, noted that given that patients are still relatively unburdened by the disease in this setting, a drug's tolerability is a key concern for those taking it.

Data from the ARAMIS trial showed that the incidence of treatment-emergent adverse events (AEs) with at least 5 percent frequency or of grade 3 to 5 was comparable between the darolutamide and placebo arms. Bayer and Orion said that only fatigue occurred in more than 10 percent of patients, with rates of 12.1 percent for darolutamide plus androgen deprivation therapy (ADT), compared to 8.7 percent for those given placebo plus ADT.

"Patients may be on this drug for two to three, maybe four years...it really does fit this patient population, we feel, much better than maybe some of the alternatives available today," LaCaze suggested. Analysts at UBS and Jefferies said that while the side-effect profile of darolutamide was favourable, questions remained over whether this would be enough to differentiate the drug from established rivals, including Astellas and Pfizer's Xtandi (enzalutamide) and Johnson & Johnson's Erleada (apalutamide).

Bayer and Orion announced in October last year that the ARAMIS study met its primary endpoint, with darolutamide significantly extending metastasis-free survival (MFS) compared to placebo. The trial randomised 1509 patients with non-metastatic castration-resistant prostate cancer who are currently being treated with ADT and are at risk for developing metastatic disease to receive darolutamide twice a day or placebo.

Efficacy data presented at ASCO GU showed that darolutamide led to a 59 percent reduction in the risk of metastasis or death versus placebo, while median MFS was 40.4 months and 18.4 months, respectively, representing an overall improvement in median MFS of 22 months for Bayer and Orion's drug. The companies added that "a positive trend in overall survival" was observed, with an interim analysis demonstrating a 29 percent reduction in the risk of death for darolutamide.

For related analysis, see ViewPoints: Prostate cancer - darolutamide struggles to stand out from the crowd.

Bayer said that it plans to discuss the data from the ARAMIS trial with health authorities regarding the submission of new drug applications, with expectations that, if approved, darolutamide will generate peak annual sales of at least 1 billion euros ($1.1 billion). The drug, previously known as ODM-201, is being jointly developed by Bayer and Orion.

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