DASL-HiCaP Interim Results in Very High-Risk Localized Prostate Cancer

Tamim Niazi, MDCM, opens by reviewing the 2022 STAMPEDE meta-analysis, in which adding abiraterone acetate (Zytiga) and prednisolone to 3 years of hormone therapy improved metastasis-free survival, with an overall survival benefit subsequently confirmed. The findings changed practice, he says, including in Canada for patients meeting STAMPEDE (NCT00268476) criteria.

He explains that when DASL-HiCaP (NCT04136353) was designed, the standard for both primary and salvage patients was locoregional radiation therapy with or without long-term ADT, and STAMPEDE had not yet read out. Which patients benefit from intensification remains unclear, he notes, so DASL-HiCaP defined a new very high-risk group across both settings.

At the interim analysis, the prespecified boundary was crossed and the independent data monitoring committee recommended release. Four-year metastasis-free survival by conventional imaging improved from 88% with placebo to 95% with darolutamide (HR, 0.42), a 58% risk reduction. With a tight confidence interval well below 1, he expects the result to hold at next year's final analysis and, per the ICECaP meta-analysis, potentially translate to an overall survival benefit.1,2

More than 70% of enrolled patients had grade group 5 disease and nearly 30% had nodal disease, a population Niazi says is common in practice. He places the DASL-HiCaP definition between STAMPEDE and the broader ENZARAD (NCT02446444) and ATLAS (NCT02531516) eligibility criteria, closer to STAMPEDE. He adds that metastasis-free survival by conventional imaging was chosen as the primary end point as a validated surrogate and notes an early signal of fewer prostate cancer deaths with darolutamide. On safety, profiles were similar between arms, with no new toxicity and most of the grade 3 or higher difference explained by fatigue.

In the next episode, Niazi compares the salvage findings with EMBARK (NCT02319837), discusses treatment duration, and names the referral change he wants urologists to make.