Plus Therapeutics has secured a major win: The U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to Rhenium (186Re) Obisbemeda, a promising new therapy for leptomeningeal metastases (LM) in lung cancer patients—a devastating condition with extremely limited treatment options.

Why This Matters

LM occurs when cancer spreads to the cerebrospinal fluid (CSF) and surrounding brain and spinal tissues, often proving fatal within weeks if untreated. With survival rates at just 7% after one year, there are currently no FDA-approved treatments for LM, making this breakthrough a potential game-changer for patients.

What the FDA Designation Means

The Orphan Drug Designation is given to experimental treatments for rare and serious diseases, providing critical benefits such as:

• Seven years of market exclusivity upon FDA approval
• Tax credits for clinical trials
• Exemptions from major FDA fees, including a $4.3 million waiver on regulatory charges

This milestone follows the therapy’s Fast Track Designation, reinforcing the urgency and potential of this innovative approach.

How Rhenium (186Re) Obisbemeda Works

This injectable radiotherapy is designed to deliver high-dose radiation directly to CNS tumors, offering key advantages over traditional treatments:

• Targets cancer precisely, minimizing damage to healthy tissue
• Works fast, thanks to its short half-life
• Can be tracked in real-time, improving treatment monitoring

Next Steps in Clinical Trials

Plus Therapeutics has successfully completed its ReSPECT-LM Phase 1 trial, establishing a safe dosage. The company is now moving forward with:

• A Phase 2 expansion trial
• A Phase 1 multiple-dose study
• Ongoing collaboration with the FDA to accelerate the next phase

Backed by Major Research Institutions

• ReSPECT-GBM (glioblastoma trials): Supported by the National Cancer Institute (NCI), part of the U.S. National Institutes of Health (NIH).
• ReSPECT-LM trials: Funded by a $17.6 million grant from the Cancer Prevention & Research Institute of Texas (CPRIT).

A New Hope for Patients with CNS Cancer

“This recognition from the FDA is a huge step forward for our work in targeted radiotherapy,” said Mike Rosol, Ph.D., Chief Development Officer at Plus Therapeutics. “Patients with leptomeningeal metastases have almost no treatment options—we are determined to change that.”

With strong regulatory backing and financial support, Plus Therapeutics is on track to revolutionize how we treat aggressive brain and spinal cancers.

For more updates, visit www.plustherapeutics.com.