Viltepso: Japan’s first antisense drug, sold directly in the US (2020)

If the customers can be counted, stand on your own

The company that had handed the entire world outside Japan to a partner for selexipag put its own staff into the United States and sold Viltepso itself. That it could choose opposite ways of delivering within the same rare-disease field seems to come down to the different shape of the destination. Patients carrying an exon 53 mutation converge on counterparts that can be counted — specialist hospitals, patient organizations, insurers. A mid-sized firm with no broad sales network can still stand on its own feet if the other side is countable, and the fact that US sales reached 3.7 times domestic sales in fiscal 2024 shows the reading was not wrong.

The ground beneath that self-built footing is unsteady, however. RACER53, the trial that was a condition of approval, failed to meet its primary endpoint, and with the protocol for a successor trial submitted, the drug’s standing in the United States is still in the hands of discussions with the regulator. Insurance-renewal reviews have tightened, and some patients have come off treatment. Exactly to the degree that it delivered early by riding a system that approves first and verifies later, the proof owed afterwards weighs heavily. The outcome of research that was once nearly abandoned in the late 1990s is still not settled.