ASCO 2022: Alkaline Phosphatase Decline and Overall Survival in Patients With Metastatic Castration-Resistant Prostate Cancer Treated With Radium-223 in the REASSURE Study

( At the 2022 American Society of Clinical Oncology Annual Meeting held in Chicago and virtually, the poster session focused on Prostate, Testicular, and Penile cancers on Monday afternoon included a presentation from Dr. Nicholas D. James discussing the prognostic value of alkaline phosphatase (ALP) decline among patients with metastatic castration-resistant prostate cancer (mCRPC) treated with radium-223 (Ra-223) in the REASSURE study.

The ALSYMPCA trial demonstrated both quality of life and overall survival benefits to radium-223 in men with mCRPC. However, it has been relatively poorly adopted. Predictive of response to therapy would be beneficial to select patients more likely to benefit from Ra-223 therapy. In the context of the ALSYMPCA study, there was a correlation between ALP decline and longer OS. In this abstract, the authors sought to further assess that association in the context of the global real-world REASSURE study.

Using these real-world data, the authors categorized patients receiving Ra-223 on the basis of their baseline ALP (≤147 U/L vs >147 U/L) and response at week 12 of therapy (any ALP decline vs no decline) at. The 147 U/L cut-off was selected based on the highest upper limit of normal for ALP from literature. Any patient who showed a trend of decreasing ALP at closest value to week 12 between weeks 8 and 16 was included in the any decline group. The association between ALP decline and OS was assessed in the ≤147 U/L and >147 U/L groups separately. Median OS is provided with an unadjusted hazard ratio (HR) (95% confidence interval [CI]). Multivariate Cox models provided adjusted HRs (95% CI) for the association of ALP decline with OS.

Among 1465 patients in the REASSURE study, 785 had baseline ALP measurements and 779 of those men had subsequent week 12 measurements. Based on baseline levels, 443 had normal ALP (≤147 U/L) and 336 had elevated ALP (>147 U/L).

When stratified by baseline ALP status, an ALP decline was prognostic in both groups. Among those me with ALP ≤147 U/L at baseline, median OS was 23.0 months (95% CI 20.9–25.7) in patients with ALP decline (n=329) and 16.4 months (95% CI 14.1–20.4) in those with no decline (n=114) (adjusted HR 0.67, 95% CI 0.51-0.90). Among those with an initially elevated ALP (>147 U/L), the median OS was 12.9 months (95% CI 11.7–14.3) in patients with ALP decline (n=295) and 8.1 months (95% CI 5.6–10.3) in those with no decline (n=41) (adjusted HR 0.22 (95% CI 0.13-0.38).

ASCO 2022_Nicholas D. James_REASSURE_0 

Thus, the authors conclude that patients with an ALP decline in first 12 weeks of Ra-223 treatment had longer OS, regardless of baseline ALP level.

Presented by: Professor Nicholas James BSc, MB, BS, FRCP, FRCR, Ph.D., Institute of Cancer and Genomic Sciences NIHR Senior Investigator, Consultant in Clinical Oncology at the Queen Elizabeth Hospital Birmingham and Professor of Clinical Oncology at the University of Birmingham

Written by: Christopher J.D. Wallis, University of Toronto, Twitter: @WallisCJD during the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting, Chicago, IL, Fri, June 3 – Mon, June 7, 2022.



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