Idorsia's rival to Merck's insomnia drug clears phase 3 test

Jean-Paul Clozel
Idorsia CEO Jean-Paul Clozel (Idorsia)

A phase 3 trial of Idorsia’s daridorexant in insomnia patients has met its primary endpoint. The Swiss biotech, which was created through Johnson & Johnson’s takeover of Actelion, also linked the dual orexin receptor antagonist to improvements in daytime performance, sending its share price up 12%.

The clinical development success of Merck’s Belsomra, which shares a mechanism of action with daridorexant, meant expectations that Idorsia’s first phase 3 trial of the insomnia drug would hit its primary endpoint were high. Even so, the details shared today were enough to send the share price of a biotech with a market cap of close to $4 billion on a double-digit surge.

Idorsia is yet to share data from the 930-subject trial but did discuss how the drug performed against several endpoints. Both doses of daridorexant improved sleep onset and sleep maintenance at month one and month three, resulting in the trial hitting its primary endpoint.

In February, analysts at Jefferies told investors they thought a positive outcome on those measures was already assumed. The uncertainty rested on whether daridorexant also improves performance of patients during the daytime, which the analysts saw as “key to assessing the commercial potential.”

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Idorsia will share the data that will inform those assessments at a later date, but its comments so far are positive. The daytime performance of participants who received daridorexant improved from baseline at month one and month three. For now, the extent of the improvement and how results in the daridorexant and placebo arms compared remains unknown.

For what it is worth, Jean-Paul Clozel, who led Actelion to its takeover by J&J, was bullish about the data in a statement to disclose the top-line findings from the clinical trial. 

“While we designed daridorexant to have the optimal profile for a sleep medicine, I am none-the-less stunned by the results. Once approved, by providing daridorexant to the millions of patients with insomnia, Idorsia will have a major impact on this medical, social and economic problem,” Clozel said.

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The primary endpoint success in the phase 3 trial comes at the start of a series of readouts that will shape Idorsia’s prospects. Data from a second trial of daridorexant in insomnia are due in the coming months. Results from a Japanese phase 3 of clazosentan in aneurysmal subarachnoid hemorrhage patients are also set for the second half of 2020, with data from a trial of lucerastat in Fabry disease to follow in 2021. 

Along with aprocitentan, the drugs form the vanguard of the broad pipeline of assets Idorsia spun out of Actelion. There are reasons to think some of the programs may fail—clazosentan, for example, has failed in phase 3 before—but the presence of multiple assets that could become big drugs gives Idorsia a shot at quickly becoming a major European biopharma company.