Postsurgical treatment with androgen deprivation therapy and Erleada (apalutamide) resulted in a 100% 24-month biochemical recurrence (BCR)-free rate among patients with high-risk localized prostate cancer (HR LPC), research has found.
Biochemical recurrence, also known as biochemical relapse or PSA failure, is a rise in the level of prostate-specific antigen (PSA; a protein associated with the presence of prostate cancer in the body) and may indicate that cancer has returned, according to the National Cancer Institute.
The phase 2 Apa-RP study, findings from which were presented at the 2024 American Urological Association Annual Meeting and were published in the Journal of Urology, enrolled 108 patients, with a median age of 66, who had undergone radical prostatectomy (RP; removal of the prostate gland and some of the surrounding tissue).
Subsequently, two patients experienced biochemical recurrences at 24 and 30 months, bringing the biochemical recurrence-free survival rate to 98.4%, according to study co-author Dr. Neal Shore, steering committee chair and medical director, Carolina Urologic Research Center.
Additionally, the 12-month serum testosterone recovery (when a patient’s testosterone returns to baseline levels) was 76.4%, researchers reported. “[This] is important,” Shore said, “because if your testosterone levels remained suppressed, that can suppress PSA, but three quarters of our patients were essentially back to normal testosterone levels.”
Nearly all patients — 99.1%, or 107 patients — experienced treatment-emergent side effects, with 22.2% being grades 3 or 4 (severe or life-threatening) and 14.8% being serious side effects, researchers reported, noting that 13% of patients required dose reduction or interruption and 10.2% required discontinuation due to side effects.
“The Apa-RP study results suggest that treatment intensification with 12 months of [Erleada and] ADT could become an option for patients with HR LPC undergoing RP, based on a 100% BCR-free survival,” researchers wrote, noting that the safety profile of Erleada and ADT “was consistent with previous reports.”
Erleada was approved by the Food and Drug Administration (FDA) in 2018 for the treatment of patients with nonmetastatic castration-resistant prostate cancer, and in 2019 for patients with metastatic castration-sensitive prostate cancer.
Shore said the Erleada-ADT combination is also currently being studied in a pair of phase 3 trials for both patients with high-risk localized prostate cancer who are receiving radiation and for six months both before and after radical prostatectomy.
Shore explained how the combination works in the treatment of prostate cancer.
Transcript:
All cells have lots of receptors that stick off the outer area of the cell, the cell membrane. And the key prostate cancer receptor is called the androgen receptor, it’s sort of flopping in the breeze out there in the bloodstream. And it can get turned on by different fuel sources and the chief fuel source is testosterone, there are metabolites of testosterone, but the key ones we call testosterone and dihydrotestosterone. But that acts as a fuel that when that metabolite — that hormone, testosterone — comes into contact with the receptor, it turns it on, goes back into the cell and the cells start to proliferate and you make more.
The analogy that I use is the testosterone is the fuel. So, if you want to stop the car from moving, you take your foot off the gas pedal. But if you further want to stop the car from moving not only do you take your foot off the gas pedal, you put your foot also on the brake — foot on the brake, foot off the gas. The [Erleada], the androgen receptor pathway inhibitor, is putting your foot on the brake of the androgen receptor. So it’s sort of a one-two punch to shut down the cancer cell. And we’ve essentially learned that throughout the continuum now of prostate cancer, whether it’s high-risk localized or biochemical recurrence or metastatic sensitive or metastatic resistant, the use of just monotherapy androgen deprivation therapy is no longer the standard of care. We add other mechanisms of action. In this case, we’re talking about an antigen receptor pathway inhibitor [Erleada].
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