Prostate-Specific Antigen Reduction After Androgen Receptor Pathway Inhibitor Initiation: Real-World Comparison of Disease Progression Among Patients With Metastatic Castration-Sensitive Prostate Cancer
Bibliographic record
Abstract
Background Prostate-specific antigen (PSA) has been used as both a screening tool and a marker for treatment response for advanced prostate cancer. With the introduction of androgen receptor pathway inhibitor (ARPI)-based treatment for metastatic castration-sensitive prostate cancer (mCSPC), there is a need to understand the impact that early treatment response, as measured by PSA, has on long-term clinical outcomes. Objectives To assess whether long-term indicators of treatment success differ among ARPI-naïve patients with mCSPC who did or did not attain ≥90% reduction in PSA levels within 6 months of treatment initiation. Methods Patients with mCSPC initiating a first ARPI (ie, apalutamide, enzalutamide, abiraterone acetate, darolutamide) were identified using electronic medical record data linked to insurance claims in the United States (1/1/2016–9/30/2022). Eligible patients were classified based on whether they achieved ≥90% reduction in PSA measured between pre-treatment and a window of 30 to 180 days after ARPI initiation. Cohorts were balanced using inverse probability of treatment weighting. Weighted Kaplan-Meier analysis was used to compare overall survival and castration-resistance–free survival by 36 months post-index between those with and without ≥90% PSA reduction. Results Weighted cohorts included 1192 patients with early PSA reduction ≥90% and 699 without. By 36 months, significantly better overall survival was observed in those with early PSA reduction ≥90% than in those without (71.5% vs 54.7%; hazard ratio [HR]: 0.40, 95% confidence interval [CI]: 0.31, 0.50; P <.001). Similarly, significantly better castration-resistance–free survival was observed in those with early PSA reduction ≥90% than in those without (53.3% vs 36.8%; HR: 0.51, 95% CI: 0.43, 0.60; P < .001). Discussion Early reduction of PSA levels by ≥90% within 6 months of ARPI initiation among patients with mCSPC in the real world is a robust indicator of treatment success, with improved long-term clinical outcomes, including survival and reduction in disease progression. Conclusions These findings corroborate those of clinical trials and highlight the long-term benefits of an early and deep PSA response to ARPIs among real-world patients with mCSPC in the United States.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".