FDA Grants Fast Track Designation to Novel Enzalutamide Delivery Implant for Localized Prostate Cancer

The FDA has granted fast track designation to Enolen, a first-of-its-kind implant for the localized, sustained delivery of enzalutamide (Xtandi), for the treatment of patients with low- to intermediate-risk localized prostate cancer.¹

The Enolen platform consists of novel antiandrogen–eluting implants containing enzalutamide and leverages Alessa Therapeutics’ proprietary local drug delivery technology to administer antiandrogens directly to diseased prostate tissue. This localized approach is intended to mitigate the toxicities associated with systemic antiandrogen and testosterone-lowering therapies, including sexual dysfunction, loss of muscle mass, cognitive impairment, metabolic syndrome, and cardiovascular complications.

“Receiving fast track designation for Enolen is further evidence of the urgent need for new treatment options for early-stage prostate cancer. Patients living with prostate cancer deserve an alternative to active surveillance or being faced with the considerable negative [adverse] effects [AEs] common with the more aggressive treatment options available today,” said Cam Gallagher, president and chief executive officer of Alessa Therapeutics, in a news release. “We will continue to collaborate closely with the FDA to advance a new treatment option for men suffering not only from the disease itself, but who often face a heavy burden in deciding between not treating their cancer or pursuing therapies with significant health and lifestyle consequences.”

To date, preclinical and clinical studies have both demonstrated that Alessa’s implant technology enables durable, continuous release of anticancer agents. This results in high intraprostatic drug concentrations and simultaneously minimizes systemic exposure.

Is Enolen currently under clinical investigation in prostate cancer?

The safety and patient tolerance of Enolen for the localized delivery of enzalutamide into the prostate is being evaluated in a single-center, open-label, phase 1 feasibility trial (NCT06257693) in the United States.²

This study plans to enroll up to 20 patients at least 21 years of age with histologically confirmed adenocarcinoma of the prostate who are qualified for and planning to undergo radical prostatectomy. Patients must have at least 1 prostate lesion measurable by MRI that is at least 0.5 cm; have a prostate-specific antigen (PSA) level greater or equal to 3 ng/mL within 3 months of screening; have a Gleason score of 3+4 or higher; and ECOG performance status of 0 or 1; have adequate organ function; and be willing to undergo post-treatment imaging by MRI.

Patients will not be permitted to enroll if they have received or undergone prior radiotherapy or surgery for prostate cancer; ongoing hormonal therapy for prostate cancer or hormone therapy less than 3 months before treatment initiation; or prior prostate procedures, such as transurethral resection of the prostate, transurethral microwave thermotherapy of the prostate, high-intensity focused ultrasound, or minimally invasive Benign Prostate Hyperplasia.

At baseline, patients will undergo multiparametric prostate MRI, followed by placement of drug-eluting Enolen implants. Six to 12 weeks later, patients will undergo repeat MRI and then proceed to standard-of-care radical prostatectomy. Postoperatively, patients will be followed for an additional 6 to 12 weeks, during which clinical laboratory assessments, correlative sample collection, and patient-reported quality-of-life questionnaires will be conducted at scheduled follow-up visits.

The study’s primary end points are the incidence of AEs and pharmacokinetic parameters. Secondary and exploratory assessments include MRI-based changes, alterations in testosterone levels at 6 to 12 weeks following implantation, and changes in PSA levels at 6 to 12 weeks following radical prostatectomy.

Alessa expects to report initial findings from the study in 2026.¹

References

1. Alessa Therapeutics announces FDA fast track designation for Enolen, a first-of-its-kind treatment for localized prostate cancer. News release. Alessa Therapeutics. January 8, 2026. Accessed January 9, 2026. https://alessatherapeutics.com/news/alessa-therapeutics-announces-fda-fast-track-designation-for-enolen-a-first-of-its-kind-treatment-for-localized-prostate-cancer/
2. Enzalutamide implants (Enolen) in patients with prostate cancer. ClinicalTrials.gov. Updated June 28, 2024. Accessed January 9, 2026. https://clinicaltrials.gov/study/NCT06257693