Milestone Launches CARDAMYST, Shifting Focus from Regulatory to Commercial Risks

What happened

Milestone Pharmaceuticals has initiated the U.S. commercial launch of CARDAMYST (etripamil) nasal spray, its first FDA-approved product for self-administered treatment of PSVT. This follows the resolution of a March 2025 FDA Complete Response Letter that had cited manufacturing and third-party inspection issues, delaying the original timeline. The drug is now available through retail pharmacies, with a national sales force set to begin promotional activities in mid-February 2026 and a $25 copay cap for eligible commercially insured patients. A patient assistance program aims to support access, but the company remains pre-revenue with a shareholders' deficit and significant convertible debt. This launch transitions Milestone from a development-stage entity facing binary regulatory risk to one now confronting commercial execution and adoption challenges in a competitive healthcare landscape.

Implication

FDA approval and launch de-risk the regulatory overhang highlighted in prior analyses, shifting the catalyst path to commercial milestones. However, Milestone must now prove it can drive physician adoption against entrenched emergency room standards and increasing use of catheter ablation, with payer reimbursement and patient copay structures remaining untested. The $25 copay cap and assistance program are positive steps, but real-world uptake may be slow due to competitive pressures and the need for behavioral change in PSVT management. Financial sustainability is a concern, as the company has a leveraged balance sheet with $55.2 million in convertible notes and a history of dilution, potentially requiring additional financing if revenue generation lags. Investors should prioritize monitoring quarterly sales data, cash burn rates, and any updates on market penetration to assess whether the launch can achieve profitability without further shareholder dilution.

Thesis delta

The investment thesis shifts from a speculative hold centered on FDA approval risks to a focus on commercial execution and financial sustainability. Regulatory hurdles have been cleared with the launch, but the hold rating persists due to adoption challenges, competitive headwinds, and balance sheet constraints. Success now depends on Milestone's ability to generate sustainable revenue and navigate payer dynamics without resorting to dilutive financings.