Posted: Thursday, March 9, 2023
The efficacy and safety of the androgen receptor inhibitor darolutamide have now been demonstrated in the metastatic castration-resistant prostate cancer setting, according to researchers Silke Gillessen, MD, of the Istituto Oncologico della Svizzera Italiana, Bellinzona, Switzerland, and colleagues. In the Journal of Clinical Oncology, they reported that the 92-patient, randomized phase II SAKK 08/16 trial met its primary endpoint of improvement in radiographic progression–free survival at 12 weeks. All patients had received prior androgen receptor–pathway inhibitors and subsequently had at least stable disease on a taxane.
Radiographic progression–free survival at 12 weeks was 64.7% with darolutamide versus 52.2% with placebo (P = .127; significance level set at .15). Median overall survival with darolutamide maintenance—a secondary endpoint—was 24.0 months versus 21.3 months with placebo (P = .181). Treatment-related adverse events were similar in both arms, and other secondary endpoints were met, too: median radiographic progression–free survival (5.5 vs. 4.5 months; P = .017), prostate-specific antigen 50% response rate (22% vs. 4%; P = .014), and median event-free survival (5.4 vs. 2.9 months; P = .001).
Switch maintenance with darolutamide after prior taxane chemotherapy and at least one androgen receptor–pathway inhibitor resulted in “a statistically significant but clinically modest radiographic progression-free survival prolongation with good tolerability,” concluded Dr. Gillessen and co-investigators. If the findings are confirmed in larger trials, “maintenance treatment may represent a novel strategy in managing patients with metastatic castration-resistant prostate cancer. Subgroup analyses revealed that darolutamide maintenance appears especially beneficial in patients who had a radiologic response to their latest androgen receptor–pathway inhibitor.”
Although the molecular status of the SAKK 08/16 participants was unknown, the team noted that in addition to clinical features, molecular characterization may be useful in identifying patients most likely to benefit from maintenance darolutamide therapy. One potential predictive molecular biomarker is the androgen-receptor splice variant 7, probably associated with resistance to enzalutamide and abiraterone, they wrote.
Disclosure: The study authors’ disclosure information can be found at ascopubs.org.