Review mist etrapamil

Milestone Pharmaceuticals (MIST) is a biopharmaceutical company focused on developing and commercializing innovative cardiovascular medicines, with a primary product candidate being CARDAMYST (etripamil), a fast-acting nasal spray for the treatment of paroxysmal supraventricular tachycardia (PSVT) and atrial fibrillation with rapid ventricular rate (AFib-RVR). Etripamil is a novel calcium channel blocker that works by inhibiting the entry of calcium ions into the slow L-type calcium channels, thereby reducing the frequency and duration of PSVT episodes.

**Clinical Development and Results**

1. **Phase 3 Trials**: Etripamil has shown promising results in Phase 3 trials for PSVT. The RAPID Phase 3 study met its primary endpoint, with a statistically significant greater proportion of patients who self-administered etripamil converting from PSVT to sinus rhythm within 30 minutes compared to placebo (40.5% vs. 15.9%, respectively; hazard ratio [HR] = 3.00; p<0.001). Topline results from the Phase 3 study conducted by Ji Xing Pharmaceuticals Ltd in China also reported positive outcomes, with a greater proportion of patients converting to sinus rhythm with etripamil compared to placebo.
2. **FDA Review and Potential Approval**: The FDA has set a Prescription Drug User Fee Act (PDUFA) review goal date for the treatment of PSVT for March 27, 2025, assuming approval, Milestone plans to launch CARDAMYST by mid-2025.
3. **Commercial Potential**: Analysts estimate a peak US sales of $441 million for etripamil by 2033, indicating a strong commercial potential for the treatment.

**Conclusion**: Etripamil, branded as CARDAMYST, represents a significant advancement in the management of PSVT and AFib-RVR, offering a rapid, self-administered therapy with the potential to significantly improve patient outcomes. The upcoming FDA review and the planned launch in 2025 highlight the imminent opportunity for this innovative treatment to enter the market, addressing unmet needs in the cardiovascular space.