Study launches of novel PSMA-targeting antibody in biochemically recurrent prostate cancer

The first patient has been enrolled in the phase 2 ProstACT TARGET study (NCT05146973), which is exploring TLX591 (177Lu-DOTA-rosopatamab) in combination with external beam radiation therapy (EBRT) in patients with biochemically recurrent, oligometastatic, PSMA-positive prostate cancer, according to Telix Pharmaceuticals and GenesisCare, the codevelopers of the investigational antibody.^1,2

The first patient was enrolled at GenesisCare's integrated cancer centre at the St John of God Hospital Murdoch campus in Western Australia. Overall, the study has a target enrollment of 50 patients across multiple clinical sites in Australia.

"I'm excited to commence this important study that builds on the momentum of ProstACT SELECT. With previous studies having confirmed the preliminary efficacy and safety profile of TLX591, GenesisCare is pleased to partner with Telix to further their therapeutic antibody-based program, which has potential to improve health outcomes for thousands of men living with prostate cancer in Australia and worldwide," TARGET principal investigator Nat Lenzo, BSc, MBBS, GenesisCare Group Medical Director (Theranostics), stated in a press release.

Some of the additional inclusion criteria for the TARGET study are ECOG performance status of 0-2, Gleason score ≥7 at primary presentation, previous radical prostatectomy with curative intent, and no prior chemotherapy. The study defines biochemical relapse per EAU-ESTRO-SIOG guidelines (serum PSA > 0.2 ng/mL, confirmed by repeat measurements) and oligometastatic disease as ≤5 metastatic lymph nodes.

The primary outcome measure is PSA progression-free survival, defined as the time period from enrollment to PSA level increasing by >25%. The estimated primary completion date is June 30, 2023.

"Enrolling a first patient in the ProstACT TARGET study is a significant milestone in Telix's overall clinical mission to support men with prostate cancer at every step in their journey with a PSMA antibody approach to targeted radiation therapy. Alongside ProstACT SELECT, this program will add value and clinical insight to Telix's antibody therapy candidate TLX591, as we progress global regulatory submissions for the ProstACT GLOBAL phase 3 study. We wish to express our gratitude to Professor Nat Lenzo and his clinical team, as well as the patients who will contribute to the study," Dr. Colin Hayward, chief medical officer, Telix, stated in the press release.

References

1. First Patient Enrolled in ProstACT TARGET Study. Published online September 26, 2022. Accessed September 27, 2022. https://prn.to/3LKq9iZ

2. External Beam Therapy With Theranostic Radioligand Therapy for Oligometastatic Prostate Cancer (ProstACT TARGET). NIH ClinicalTrials.gov. NCT05146973. First posted December 7, 2021. Last updated July 20, 2022. https://clinicaltrials.gov/ct2/show/NCT05146973