(UroToday.com) The 2023 ASCO annual meeting included a prostate cancer session, featuring a presentation by Dr. Ken Herrmann discussing preliminary results of building a predictive model for outcomes with 177Lu-PSMA-617 in patients with metastatic castration-resistant prostate cancer (mCRPC) using VISION data. Because of the VISION trial showing improved OS and rPFS compared to standard of care, 177Lu-PSMA-617 is approved in adults with PSMA positive mCRPC in both the US and Europe.1 However, predictors of outcomes after treatment with 177Lu-PSMA-617 are needed to aid the clinical interpretation of targeted radioligand therapy. This analysis of VISION data presented by Dr. Herrmann and colleagues at ASCO 2023 aimed to build predictive models for clinical outcomes after 177Lu-PSMA-617.
In VISION, adults with PSMA positive mCRPC received 177Lu-PSMA-617 (7.4 GBq every 6 weeks, ≤6 cycles) + protocol-permitted standard of care or standard of care alone. In this post hoc analysis, 29 baseline parameters were assessed for prognostic and predictive value on overall survival (OS), radiographic progression-free survival (rPFS) and PSA response (≥50% reduction; PSA50). A list of the 29 parameters is as follows:
Parameters associated with outcome regardless of treatment were prognostic, and those associated with outcome after treatment with 177Lu-PSMA-617 + standard of care vs standard of care were predictive. Cox proportional hazards (for OS and rPFS) or logistic regression (for PSA50) models were used in univariate analyses for parameter selection and to build statistical models.
Data from 831 adults were analyzed, and in the initial univariate analyses, 76% of parameters assessed were prognostic for OS, 69% for rPFS, and 38% for PSA50. The OS model included 10 parameters and had a c-index of 0.73 (95% CI 0.70-0.76):
The multivariate model for rPFS included seven parameters and had a C-index of 0.68 (95% CI 0.65-0.72):
The multivariate model for PSA50 included three parameters and the area under the ROC curve was 0.72 (95% CI 0.68-0.77):
Dr. Herrmann concluded his presentation discussing preliminary results of building a predictive model for outcomes with 177Lu-PSMA-617 in patients with mCRPC using VISION data with the following take-home points:
- Bayesian modeling identified parameters that could be combined into a multivariate model to predict outcomes in patients treated with 177Lu-PSMA-617 + standard of care in VISION with good performance. More parameters were identified as having predictive value in these multivariate analyses than in previous models of outcomes after 177Lu-PSMA-617 treatment
- A broader range of parameters were prognostic for OS and rPFS than for PSA50. General health status of patients with mCRPC treated with 177Lu-PSMA-617 + standard of care appears to be more important in predicting mid-to-long-term outcomes such as OS and rPFS, than shorter-term outcomes such as PSA50, which may be driven by PSMA expression
Presented by: Ken Herrmann, Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, Chicago, IL, Fri, June 2 – Tues, June 6, 2023.