Groundbreaking Glioblastoma Drug Shows Promising Survival Rates

Groundbreaking Drug More Than Doubles Survival for Glioblastoma Patients

Glioblastoma, the most common and aggressive primary brain tumor in adults, has long been a challenge for both patients and doctors. Standard treatments—surgery, radiation, and chemotherapy—offer limited survival benefits, with median survival after failure of initial treatments typically only around 8 months. However, a recent clinical trial has provided hope for patients battling this devastating condition, demonstrating that a novel drug formulation developed by The University of Texas Health Science Center at San Antonio (UT Health San Antonio) significantly improves survival outcomes.


The drug, Rhenium Obisbemeda (186RNL), a unique investigational formulation, has shown to more than double the median survival and progression-free survival in patients with recurrent glioblastoma, compared to standard treatments. The trial results, published in Nature Communications on March 7, 2025, revealed that the drug not only extended survival but did so without dose-limiting toxic effects, which is a significant breakthrough for glioblastoma treatment.

A Promising New Approach to Glioblastoma Treatment

Dr. Andrew J. Brenner, a professor and chair of neuro-oncology research at Mays Cancer Center at UT Health San Antonio, and lead author of the study, highlighted the need for durable treatments in glioblastoma due to the tumor’s tendency to recur, its resistance to many chemotherapy drugs, and its overall difficulty to treat. “This trial provides hope, with a second phase under way and planned for completion by the end of this year,” said Brenner.

The Rhenium Obisbemeda (186RNL) formulation utilizes rhenium-186 (186Re), a beta-emitting radioisotope, which is encapsulated in tiny liposomes. These liposomes are artificial vesicles that help deliver the radioactive substance directly to the tumor, enabling precise targeting of the cancer while sparing surrounding healthy tissue. The liposomes are designed with a custom molecule known as BMEDA, which facilitates the transportation of the rhenium isotope into the interior of the liposome, where it is irreversibly trapped.

This innovative approach is a significant departure from traditional methods, as it allows for a highly concentrated dose of radiation to be delivered directly to the tumor site. This method, combined with convection-enhanced delivery (CED), uses neuronavigation and specialized catheters to administer the drug precisely into the tumor. This combination of technologies helps deliver a high absorbed dose of radiation to the tumor while minimizing toxicity to healthy brain tissue, which has traditionally been a major concern with radiation therapy.

Trial Details and Results

The Phase 1 ReSPECT-GBM trial, which enrolled 21 patients between March 2015 and April 2021, was designed to evaluate the safety, maximum tolerated dose, and efficacy of Rhenium Obisbemeda. All enrolled patients had failed one to three previous therapies, including surgery, radiation, and chemotherapy. The patients received the drug administered directly to their tumors through the specialized convection catheters.

The trial demonstrated remarkable results, especially for patients who received higher absorbed doses of the drug. In these patients, the median overall survival increased to 17 months, compared with the typical 8 months seen with standard treatments. Additionally, progression-free survival was extended to 6 months for patients who received doses greater than 100 gray (Gy), a unit of radiation measurement. This result is noteworthy, as it far surpasses the typical outcomes for glioblastoma patients receiving conventional therapies.

Importantly, the trial did not report any dose-limiting toxic effects, which is a common issue with many cancer treatments. Most of the adverse effects were mild and deemed unrelated to the investigational drug. This is a critical point, as it suggests that Rhenium Obisbemeda (186RNL) can offer glioblastoma patients a viable treatment option with minimal side effects, a major improvement over traditional therapies.

The Future of Glioblastoma Treatment

The results of this trial represent a significant step forward in the treatment of glioblastoma. Dr. Brenner and his colleagues are optimistic that this drug could provide long-term survival benefits for patients who have few other options. The ongoing Phase 2 trial, which is currently enrolling participants, will further assess the effectiveness of the drug and its potential as a standard treatment for glioblastoma.

In addition to UT Health San Antonio, researchers from several prestigious institutions contributed to the trial, including UT Southwestern Medical Center, Case Western Reserve University, University of Texas MD Anderson Cancer Center, and Plus Therapeutics, Inc., the pharmaceutical company sponsoring the trial. Their collaborative efforts in the development of this treatment highlight the importance of interdisciplinary work in the fight against cancer.

The success of Rhenium Obisbemeda is particularly significant because it offers a potential treatment that directly targets the tumor with a high dose of radiation while minimizing harm to healthy tissues. This makes it a promising option for patients whose tumors have recurred after multiple rounds of traditional treatments.

Conclusion: A New Hope for Glioblastoma Patients

The results from the Phase 1 ReSPECT-GBM trial offer a glimmer of hope for glioblastoma patients, who have historically faced a poor prognosis due to the aggressive nature of the disease and the limited treatment options available. Rhenium Obisbemeda could be a game-changer, providing a more effective and safer treatment for patients suffering from this devastating condition. As Phase 2 of the trial continues, the scientific community eagerly anticipates further results, hoping that this innovative therapy could eventually become a cornerstone of glioblastoma treatment.

Study Reference: https://www.nature.com/articles/s41467-025-57263-1