Enolen was safe and feasible for the treatment of patients with early-stage prostate cancer.
Enolen, an implant for the localized, sustained delivery of enzalutamide (Xtandi), was safe and feasible for patients with early-stage prostate cancer, according to data from a phase 1 trial (NCT06257693) presented during the
Findings from the trial revealed that all patients treated with Enolen (n = 18) were able to undergo planned postimplant multiparametric MRI and radical prostatectomy. Additionally, no adverse effects (AEs) higher than grade 3 related to the procedure or the implants were reported.
“Our trial was feasible, and we completed accrual in February of 2026,” Braden Millan, MD, MSc, FRCSC, a urologic oncology fellow at the National Cancer Institute in Bethesda, Maryland, stated during a presentation of the data. “All patients completed planned study interventions with no grade 3 or higher AEs related to the implant procedure or drug. We observed effective local delivery of the drug without systemic exposure.”
The trial enrolled patients with at least 1 measurable lesion greater than 5 cm per MRI.1 Patients were also required to have prostate-specific antigen (PSA) levels greater than 3 ng/mL, grade group 2 disease or higher, and be planning to undergo radical prostatectomy. Other key eligibility criteria included being at least 21 years old, having an ECOG performance status of 0 or 1, having adequate organ function, and having aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase levels less than 2.5 times the upper limit of normal.4
After screening, patients underwent MRI-US fusion-guided placement of Enolen implants in situ, followed by standard prostatectomy either 6 to 12 weeks or 4 to 12 months post implant procedure. Afterward, they proceeded to tissue bioanalysis. 1 The Enolen implants contained a 20% polymer matrix and an 80% drug payload.
The dual primary end points were the incidence of AEs associated with Enolen implants and assessing pharmacokinetic measures.4 Secondary end points included MRI changes, changes in PSA levels, and changes in testosterone.
Additional efficacy findings from the phase 1 study revealed that all but 2 patients treated with Enolen experienced tumor volume shrinkage from baseline to the preradical prostatectomy MRI.1 Notably, 1 patient experienced 100% tumor volume shrinkage over this time frame; this patient had Enolen implanted for 60 days. Other patients experienced shrinkage rates of 55%, 46%, 42%, and 39%.
In terms of safety, AEs deemed to be related to the implant procedure that occurred on the day of the implant consisted of pain, stomach pain, dysgeusia, dysuria, urinary frequency, hematuria, urinary retention, and perineal pain; all these events were grade 1, except for one instance of grade 2 urinary retention in a single patient. One patient experienced grade 1 hematospermia, constipation, and hematuria on days 2 through 4 post implant, and another experienced grade 1 myalgia, arthralgia, fatigue, and perineal pain on the second day following the implant procedure.
Medication was used in 7 instances to treat AEs. These AEs included grade 2 abdominal pain, urinary tract infection, abdominal distention and pain, and sore throat; a grade 3 thromboembolic event; and grade 1 laryngeal inflammation, extremity pain, and constipation.
“We observed tumor volume reduction on imaging,” Millan explained in his conclusion. “We are currently enrolling 2 additional cohorts to investigate dose levels as well as duration.”
Disclosures: Millan had no relevant financial disclosures.
