Wong, Risa Liang;
Duong, Mai T.;
Tangen, Catherine;
Agarwal, Neeraj;
Cheng, Heather H.;
Vogelzang, Nicholas J.;
Hussain, Maha H. A.;
Thompson, Ian Murchie;
Quinn, David I.;
Yu, Evan Y.
Survival outcomes and risk group validation from SWOG S0925, a randomized phase II study of androgen deprivation (AD) +/- cixutumumab, in new metastatic hormone-sensitive prostate cancer (mHSPC)
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Media type:
E-Article
Title:
Survival outcomes and risk group validation from SWOG S0925, a randomized phase II study of androgen deprivation (AD) +/- cixutumumab, in new metastatic hormone-sensitive prostate cancer (mHSPC)
Contributor:
Wong, Risa Liang;
Duong, Mai T.;
Tangen, Catherine;
Agarwal, Neeraj;
Cheng, Heather H.;
Vogelzang, Nicholas J.;
Hussain, Maha H. A.;
Thompson, Ian Murchie;
Quinn, David I.;
Yu, Evan Y.
imprint:
American Society of Clinical Oncology (ASCO), 2020
Description:
<jats:p> 106 </jats:p><jats:p> Background: Cixutumumab, a monoclonal antibody targeting insulin-like growth factor I receptor, did not improve rate of undetectable PSA at 28 weeks when combined with AD in the randomized phase II SWOG S0925 trial for patients with new mHSPC. We now present mature radiographic progression-free survival (rPFS) and overall survival (OS) analyses, along with pre-specified secondary and exploratory endpoints. Methods: We used Kaplan-Meier curves to analyze OS, rPFS, and castration resistance-free survival by treatment arm, disease volume (as per CHAARTED), and risk (as per LATITUDE). We explored differences in survival by treatment arm via covariate-adjusted Cox proportional hazard models adjusted for disease volume and risk. Results: The trial enrolled 210 patients, 105 per treatment arm. Median follow-up was 5.3 years. No difference was seen between treatment arms in OS (HR 1.01 [0.70-1.45]; p=0.97), rPFS (HR 1.17 [0.85-1.60]; p=0.35), or castration resistance-free survival (HR 1.02 [0.75-1.41]; p=0.88). At baseline, 105/198 (53.0%) patients had high risk and 119/210 (56.7%) had high volume disease. 17.3% of high volume patients were classified as low risk and 15.9% of low volume patients were classified as high risk; together, 16.7% of patients had discordant classification of high or low category for risk and volume. Adjusting for risk or volume yielded no differences in OS between arms. Inferior survival was observed in high risk (HR 1.89 [1.29-2.80]; p=0.001) and high volume (HR 2.75 [1.84-4.10]; p<0.0001) disease. Disease volume was a better fit to survival data than risk (AIC 878.3 vs. 889.2). Compared to patients achieving undetectable PSA at 28 weeks, inferior survival was observed in patients whose PSA was >0.2 to ≤4.0 ng/mL (HR 3.72 [1.99-6.95]; p<0.0001) or >4.0 ng/mL (HR 7.13 [4.24-11.9]; p<0.0001). Conclusions: In new mHSPC, adding cixutumumab to AD did not improve survival measures. Baseline risk and disease volume carried prognostic value for this distinct trial population, though disease volume was a better predictor of survival. PSA treatment response was a strong intermediate endpoint for survival. Clinical trial information: NCT01120236. </jats:p>