PCa immunotherapy: Response better when given before ADT
Administering sipuleucel-T (Provenge) before androgen deprivation therapy in men with hormone-sensitive biochemically recurrent prostate cancer appears to result in a more robust immunologic response than when the immunotherapy is given after androgen deprivation therapy, according to a new phase II randomized trial.
“Patients who failed radical prostatectomy and/or radiation therapy were selected for this trial, whereby they had PSA relapse and were considered at high risk for progression. This patient population still represents an unmet need regrading an approved therapy, as these patients invariably receive a form of androgen deprivation therapy, with its attendant well-described adverse events,” said study co-author Neal D. Shore, MD, of Carolina Urologic Research Center, Myrtle Beach, SC. “Sequencing sipuleucel-T either before or after androgen deprivation therapy was well tolerated, and there was a suggestion that the immunologic parameters evaluated were more robust when sip-T was given before ADT. Nonetheless, additional and larger patient cohorts are needed to confirm these findings.”
The ideal would be to have an immune-oncologic therapy that could preclude or delay androgen deprivation therapy use in prostate cancer, Dr. Shore told Urology Times.
“[This] would be a welcome addition to the prostate cancer armamentarium and for patient-physician shared decision-making,” he said.
The era of immunobiologic therapy was introduced for advanced genitourinary oncology with the approval of sipuleucel-T in 2010, when the IMPACT phase III trial demonstrated a statistically significant survival benefit in patients with metastatic castration-resistant prostate cancer, according to Dr. Shore.
“Since that approval, the science and clinical applications for immune-oncologic therapy have bourgeoned dramatically throughout all of advanced cancer care and research. Hence, it makes great sense to evaluate the application of sip-T, a very well-tolerated therapy, administered over a 4- to 6-week period. [Evaluating the immunotherapy in such a way] does not preclude other approved prostate cancer therapies in order to evaluate its ability to augment the immune system and prevent disease progression for high-risk PSA relapse patients who have failed interventional therapy,” Dr. Shore said.
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While researchers historically use advanced prostate cancer endpoints of overall survival and radiographic progression-free survival, these scientists looked for “PA2024-specific T cell response (Enzyme-Linked ImmunoSPOT [ELISPOT]) over time,” according to the study’s abstract. The study was published online in Clinical Cancer Research (Nov. 10, 2016).