Long-Term Oncologic Outcomes of Neoadjuvant Tumor-Directed Immunotherapy (PROSTVAC) Before Radical Prostatectomy for Localized Prostate Cancer: A Secondary Analysis of a Neoadjuvant Trial.
Braden Millan, Alexander P Kenigsberg, Charles Hesswani et al.
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In 30 seconds
This secondary analysis of a phase II neoadjuvant trial assessed long-term oncologic outcomes in 26 patients with localized prostate cancer who received PROSTVAC before radical prostatectomy. At a median follow-up of 8.9 years (range 7.0-10.1), six patients (23.1%) had biochemical recurrence and none developed metastatic disease. Patients with PSA-specific immune responses had 100% 8-year biochemical recurrence-free survival, compared with 70.0% among nonresponders; this difference was not statistically significant (p = 0.247).
Key findings
- At median follow-up of 8.9 years (range 7.0-10.1), biochemical recurrence occurred in six patients (23.1%); none developed metastatic disease.
- PSA-specific immune responders had 100% 8-year BCR-free survival versus 70.0% in nonresponders (p = 0.247).
- Any tumor-associated antigen response was associated with 85.7% versus 66.7% 8-year BCR-free survival (p = 0.149).
- Patients with tumor-site or invasive-margin CD4+ or CD8+ T-cell responses had 86.2% versus 58.9% 8-year BCR-free survival (p = 0.257).
Why it matters
The extended follow-up provides an early view of whether immune responses after neoadjuvant vaccination may correspond to durable cancer control in localized prostate cancer. The observed recurrence-free survival patterns support further study of immune response as a potential correlate of outcome, while the small cohort and nonsignificant comparisons mean the findings are not evidence of established benefit.
What to keep in mind
This secondary analysis included only 26 patients, and the immune-response comparisons were not statistically significant. The abstract does not report a control group.