Curium Advances Prostate Cancer Therapy with Key Safety Data

BOSTON, MA – February 26, 2026

Nuclear medicine leader Curium today unveiled pivotal safety data for its investigational prostate cancer therapy, signaling a potential enhancement to treatment protocols for patients with advanced disease. The announcement, made at the prestigious American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU), details favorable dosimetry and pharmacokinetics for Lutetium-177 Zadavotide Guraxetan, a targeted radioligand therapy designed for metastatic castration-resistant prostate cancer (mCRPC).

The data, derived from a substudy of the ongoing Phase 3 ECLIPSE trial, suggests the therapy has a favorable safety profile, particularly concerning radiation exposure to healthy organs. This finding is significant enough that it has already supported a key change in the clinical trial, potentially paving the way for a more robust treatment regimen for a patient population with pressing unmet needs.

The Science of Safety and Efficacy

At the heart of Curium's announcement is the science of dosimetry—the measurement of the absorbed dose of radiation in tissue. For radioligand therapies, which use radioactive particles to destroy cancer cells, dosimetry is paramount. It helps ensure that the therapy is potent enough to attack tumors while minimizing collateral damage to healthy organs.

The data presented from the 26-patient substudy demonstrated that Lu-177 zadavotide guraxetan resulted in favorable radiation doses to critical organs. Most notably, the mean cumulative radiation dose to the kidneys—often the dose-limiting organ for this class of drugs—remained low. This encouraging safety signal has given Curium the confidence to amend its ECLIPSE trial protocol, increasing the maximum number of treatment cycles from four to a total of six.

"These data represent the first published dosimetry data for our investigational formulation of Lu-177 zadavotide guraxetan, with projected mean cumulative renal doses remaining low for a six-cycle treatment regimen," said Sakir Mutevelic, MD, Curium’s Chief Medical Officer, in a statement. He emphasized that this supports the protocol amendment and reinforces the company's long-term vision.

The ability to safely administer more cycles is a critical step forward. For patients, it could translate into a greater cumulative dose of radiation delivered directly to tumors, potentially leading to deeper and more durable responses against the cancer.

Frankis Almaguel, MD, PhD, of Loma Linda University Health Cancer Center and the presenting author of the poster, highlighted the broader implications of the findings. "These data reinforce the clinical utility of using dosimetry data to inform clinical trial protocol design, as well as identify organs at highest risk of radiation exposure," he noted. This underscores a move towards more personalized and optimized approaches in the rapidly evolving field of nuclear medicine.

A New Hope for Advanced Prostate Cancer

The context for Curium's development is the challenging landscape of metastatic castration-resistant prostate cancer. This advanced stage of the disease occurs when the cancer has spread beyond the prostate and no longer responds to hormone therapies designed to lower testosterone. While treatment options exist, including next-generation androgen receptor pathway inhibitors (ARPIs) and chemotherapy, patients often develop resistance, leaving them with a poor prognosis and a significant need for new, effective therapies.

The introduction of PSMA-targeted radioligand therapies has been a watershed moment for the field. These drugs act like guided missiles, using a targeting agent that binds to Prostate-Specific Membrane Antigen (PSMA)—a protein overexpressed on the surface of most prostate cancer cells—to deliver a payload of cell-killing radiation.

By potentially enabling a longer treatment course, Curium's Lu-177 zadavotide guraxetan could offer renewed hope. An extended regimen may provide a better chance to control the disease, improve quality of life, and extend survival for patients who have exhausted other options. The ECLIPSE trial is specifically studying patients who have progressed on prior ARPIs but have not yet received chemotherapy, positioning this therapy as a potential option in an earlier line of treatment.

Navigating a Competitive Radiopharmaceutical Market

Curium's progress does not exist in a vacuum. The company is entering a dynamic and increasingly competitive radiopharmaceutical market, particularly in the prostate cancer space. The clear frontrunner is Novartis's Pluvicto (Lutetium-177 vipivotide tetraxetan), which gained FDA approval in 2022 and has since established itself as a standard of care for pre-treated, PSMA-positive mCRPC patients.

To succeed, any new entrant must demonstrate a clear clinical advantage, whether through superior efficacy, an improved safety profile, or applicability to a different patient population. Curium's strategy appears to focus on these differentiators. The favorable dosimetry data suggests a strong safety profile that could be a key advantage, especially if it reduces concerns around long-term kidney toxicity, a known issue with this class of drugs.

Furthermore, by conducting the ECLIPSE trial in a taxane-naïve population, Curium is positioning its therapy for use earlier in the mCRPC treatment paradigm. Success in this setting could capture a significant patient population before they are eligible for Pluvicto under its initial approval indication. With the primary endpoint of the trial—a significant extension in radiographic progression-free survival—already met, Curium has cleared a major hurdle in demonstrating its drug's clinical benefit.

The Road to Approval

The positive data from ASCO GU represents another important step on a long regulatory journey. While the ECLIPSE trial has already met its primary goal, the study is not scheduled for final completion until 2029, as researchers continue to collect long-term data on critical secondary endpoints like overall survival.

This long-term follow-up is essential for providing regulators like the FDA with a complete picture of the drug's benefits and risks. After the final data is collected and analyzed, Curium will face the rigorous process of submitting a New Drug Application (NDA) for review.

While a market launch may still be several years away, the steady accumulation of positive data builds a compelling case for Lu-177 zadavotide guraxetan. The latest safety findings not only de-risk the clinical development program but also provide a glimpse into how this next-generation therapy could one day refine the standard of care for thousands of men battling advanced prostate cancer.