Darolutamide Improves Survival in Nonmetastatic Castration Resistant Prostate Cancer Patients

Prostate cancer is the second leading cause of cancer-related death among men in the United States. While effective treatments are available, tumors reappear with a concurrent increase in prostate-specific antigen (PSA), frequently leading to cancer relapse. Under these circumstances, doctors use androgen deprivation therapy that lowers down testosterone levels, a hormone that makes prostate tumors grow faster, with chemically “castrating” drugs. But sometimes, this treatment fails to work leading to the formation of nonmetastatic castration-resistant prostate cancer (nmCRPC). The cancer is called nonmetastatic because cancer spread at the time of screening is undetectable with imaging technology and castration-resistant. After all, it can no longer respond to testosterone reducing treatments.

By Ruchi Jhonsa, Ph.D.

“Patients with nmCRPC are at risk for progression to metastatic disease, which is often accompanied by the onset of cancer-related symptoms in this previously asymptomatic population,” described authors of the publication.

Doctors had limited options for treating nmCRPC, until recently, when three drugs got FDA approval for the condition. Apalutamide was approved in Feb 2018, enzalutamide in July 2018, and the latest-darolutamide in August 2019. All three drugs work on the same principle. They stop testosterone from binding to its receptors in cells.

Darolutamide, a structurally distinct androgen-receptor inhibitor, got FDA approval based on phase 3 ARAMIS trial that showed the drug surpassed ongoing testosterone deprivation therapy at improving median metastasis-free survival-time taken by the metastasized tumor to appear on imaging scans. Addition of darolutamide prolonged median MFS by 22 months. The drug got FDA approval based on this figure alone. But it remained to determine how long does a patient survive when put on the treatment. Prolonging overall survival is a key therapeutic goal in patients with nmCRPC.

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Darolutamide Improves Overall Survival

In the recently published data in the New England Journal of Medicine, authors report the overall survival data for the patients treated with the drug. The percentage of patients alive at 3 years was 83% in the drug group and 77% in the placebo group. According to the authors, the drug’s treatment effect was most prominent in the subgroup, which included nmCRPC patients with PSA doubling time of 10 months or less. The risk of death in this subgroup reduced by 31% following the drug treatment.

In addition to overall survival benefits, the drug significantly improved all secondary endpoints. The treatment with darolutamide increased the time of need for cytotoxic chemotherapy for a patient. It also increased the time of appearance of the first cancer-related symptom of skeletal muscles and pain progression time.

Relatively safe for brain

While giving all these benefits, the drug maintained a favorable safety profile. The percentage of patients who reported adverse events and discontinued the treatment was unchanged from the time of primary analysis. This indicates that patients with nmCRPC can continue receiving androgen-receptor inhibitor for a prolonged time. The common adverse events observed were falls, seizures, mental impairment disorders, and hypertension. A significant benefit of darolutamide treatment is the reduced occurrence of neurological adverse events. Other androgen-receptor inhibitors had a higher incidence of CNS-related adverse events than placebo, whereas the patient population in darolutamide trial had a lower incidence of these events. However, the authors believe that this difference could be due to the difference in treatment duration and follow-up time.

The ARAMIS trial was a significantly large-sized trial, which enabled a robust statistical analysis for overall survival data. However, a lack of diversity in the trial prevents researchers from making conclusions about the effect of treatment on particular races or ethnic groups.

Related Article: Genomics in Prostate Cancer and Beyond: Interview with Dr. Colin Collins, Senior Scientist at the Vancouver Prostate Centre

Reference:

1.https://www.nejm.org/doi/full/10.1056/NEJMoa2001342?query=featured_home

Author

Ruchi Jhonsa