Attainment of early, deep prostate-specific antigen response in metastatic castration-sensitive prostate cancer: A comparison of patients initiated on apalutamide or enzalutamide
Bibliographic record
Abstract
• Prostate-specific antigen reduction ≥90% (PSA90) is important in metastatic castration sensitive prostate cancer (mCSPC) prognosis • This real-world study compared PSA90 among patients with mCSPC initiating apalutamide or enzalutamide • Patients treated with apalutamide were more likely to attain PSA90 than those treated with enzalutamide • Treatment with apalutamide was also associated with a faster time to PSA90 than enzalutamide • Findings may be clinically important given the association between PSA90 and survival outcomes in patients with mCSPC Deep prostate-specific antigen (PSA) response, defined as a ≥90% decline in PSA (PSA90), is an important early response indicator for achieving radiographic progression-free and overall survival in patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with a next-generation androgen signaling inhibitor (ASI), such as apalutamide or enzalutamide. The objective of this study was to compare deep PSA response among patients with mCSPC newly initiated on apalutamide or enzalutamide. Clinical data from 69 community urology practices in the United States were evaluated. Patients with mCSPC were classified into cohorts based on their first dispensation (index date) for apalutamide or enzalutamide and were followed until the earliest of treatment discontinuation, initiation of a new next-generation androgen receptor signaling inhibitor, end of clinical activity (including death), or end of data availability (03/05/2021). Inverse probability of treatment weights (IPTW) were used to reduce baseline confounding. PSA90 was defined as the earliest ≥90% PSA decline relative to baseline PSA. The proportion of patients achieving PSA90 and time to PSA90 were reported using weighted Kaplan-Meier analysis and weighted Cox proportional hazards models, respectively. The apalutamide and enzalutamide cohorts comprised 186 and 165 patients, respectively. Patient characteristics were generally well balanced after IPTW. By 6 months, patients initiated on apalutamide had a 56% greater likelihood of attaining PSA90 than those initiated on enzalutamide ( P = 0.014). This result remained significant through the end of the observation period. The median time to achieving PSA90 was 3.1 months with apalutamide and 5.2 months with enzalutamide. This real-world study demonstrated that apalutamide initiation is associated with a significantly higher likelihood of achieving ≥90% reduction in PSA as compared to initiation of enzalutamide. Moreover, this deep PSA response was observed to occur earlier with apalutamide treatment than with enzalutamide.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".