New Alpha Radioligand Undergoes Assessment in 2 Metastatic CRPC Cohorts

AB001, a ²¹²Pb alpha radioligand therapy (ART), is now under assessment as a treatment in 2 cohorts of patients with metastatic castration-resistant prostate cancer (CRPC) in the phase 1 ARTISAN trial (NCT07214961), according to a news release from the developers, ARTBIO.¹

Currently, the ARTISAN trial is being conducted across multiple sites in the US, but the developers plan to expand enrollment on the trial to other countries beginning in the second half of 2026. Furthermore, an investigational new drug application for AB001 was cleared by the FDA in September 2025.

"The ARTBIO team is excited to continue to advance AB001 as our lead clinical asset for patients with and without prior Lu177-PSMA–targeted therapy," said Margaret Yu, MD, chief medical officer of ARTBIO, in the press release.¹ "We are proud to collaborate with team members at BAMF Health and United Theranostics and are especially grateful to the patients who have enrolled in this study."

The open-label phase 1 study will include a dose-escalation and dose-expansion portion. In the dose-escalation portion of the trial, the safety and tolerability of AB001 will be assessed, and the recommended phase 2 dose (RP2D) will be determined among patients with and without prior ¹⁷⁷Lu-PSMA.² The dose-expansion portion will further characterize the antitumor activity and safety profile of the RP2D in these 2 groups to further develop AB001 in specific patient groups.

In the ¹⁷⁷Lu-PSMA naive cohort, patients will receive a starting dose of 100 MBq of AB001 given via slow injection on day 1 of each 42-day cycle. Patients will undergo a planned 4 cycles of treatment, continuing to a maximum of 6 study cycles if they meet treatment continuation criteria. Further cohorts will be opened for the purpose of dose finding and schedule optimization of AB001.

For those treated in the ¹⁷⁷Lu-PSMA pretreated group, a similar scheduled will be followed at the same starting dose. Similarly, patients will be scheduled for 4 treatment cycles up to a maximum of 6, and subsequent cohorts will be initiated for the purpose of dose finding and schedule optimization.

The primary end point of the phase 1 trial is safety and tolerability, which include the incidence of treatment-emergent adverse effects (AEs), and assessing the recommended schedule and dose of AB001. Other end points include the preliminary antitumor activity of AB001 based on measures such as prostate-specific antigen (PSA) levels and objective response rate. Pharmacokinetics is also a secondary end point of the trial.

“AB001 PSMA-targeted radioligand therapy has the potential to reshape the treatment landscape for patients with metastatic [CRPC] who urgently need additional pathways forward," Brandon Mancini, MD, MBA, FACRO, medical director at BAMF Health, clinical associate professor at the Michigan State University College of Human Medicine, and editor-at-large for The Rad Onc Review, concluded in the news release.¹

Patients 18 years and older with an ECOG performance status of 0 to 2, progressive metastatic CRPC, prior treatment with a minimum of 1 androgen receptor pathway inhibitor, and prior receipt of orchiectomy and/or ongoing androgen deprivation therapy are eligible for enrollment on the phase 1 trial. Additional inclusion criteria include at least 1 PSMA-avid distant metastatic lesion; prior treatment with at least 1 taxane-based regimen, as well as refusal to undergo or being considered appropriate for delay of a taxane-based regimen; and adequate bone marrow, renal, and hepatic function.

References

1. ARTBIO announces dosing of two cohorts with AB001 in ARTISAN, a phase 1 alpha radioligand therapy clinical trial for metastatic castration resistant prostate cancer. News release. ARTBIO Inc. January 12, 2026. Accessed January 12, 2026. https://tinyurl.com/527phjfm
2. Study of alpha radioligand therapy AB001 in patients with metastatic castration resistant prostate cancer (mCRPC) (ARTISAN). ClinicalTrials.gov. Updated December 22, 2025. Accessed January 12, 2026. https://tinyurl.com/yhrwtv3a