The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to OPN-6602, developed by Opna Bio, for the treatment of patients with relapsed/refractory multiple myeloma (RRMM). The designation follows promising results from an ongoing Phase 1 clinical trial.
"We are pleased to have received ODD for OPN-6602 for the treatment of multiple myeloma, a further validation of the drug's therapeutic potential in patients with this disease who have limited treatment options once they have relapsed," said Gideon Bollag, PhD, chief scientific officer of Opna Bio.
Disease Background and Unmet Need
Multiple myeloma, the second most common hematological malignancy, follows a pattern of remission and relapse, with prognosis typically worsening after each treatment line. According to the Leukemia & Lymphoma Society, virtually all multiple myeloma patients eventually progress to a relapsed/refractory state, highlighting the urgent need for new therapeutic options.
Mechanism of Action and Preclinical Results
OPN-6602 is an innovative oral, small-molecule inhibitor targeting the E1A binding protein (EP300) and CREB-binding protein (CBP). Preclinical studies in multiple myeloma mouse models demonstrated impressive results:
- 71% tumor suppression as monotherapy
- 100% tumor regression when combined with standard treatments including dexamethasone, pomalidomide, or mezigdomide
- Ability to overcome resistance to standard-of-care treatments
- Down-regulation of key multiple myeloma driver genes
Ongoing Clinical Development
A Phase 1b multicenter, open-label trial is currently evaluating OPN-6602's safety and tolerability. The study includes:
- Both monotherapy and combination approaches with dexamethasone
- Adult patients with RRMM who have failed at least three prior treatment lines
- Previous exposure to immunomodulatory agents, proteasome inhibitors, and anti-CD38 antibodies required
- Primary focus on determining safety profile and maximum tolerated dose
Opna Bio expects to complete the single-agent, dose-escalation phase by 2026 and plans to explore additional combinations with standard-of-care treatments.
Clinical Implications
The orphan drug designation for OPN-6602 underscores the significant challenges in treating RRMM, where therapeutic options become increasingly limited as the disease progresses. While early data shows promise, particularly in combination therapy settings, continued investigation through the clinical trial program will be crucial in determining the drug's ultimate role in the multiple myeloma treatment landscape.
