Kiniksa touts 3rd approval for aging Arcalyst — a good haul for just $5M in cash it paid Regeneron for the drug
Kiniksa bet $5 million cash back in 2017 that Regeneron’s Arcalyst could help patients with recurrent pericarditis, a painful autoinflammatory heart disease. Now, more than three years later, that bet continues to pay off.
Regulators approved Arcalyst (rilonacept) to treat recurrent pericarditis and reduce the risk of recurrence in patients 12 years and older, Kiniksa said on Thursday. The Bermuda-based biotech is planning a commercial launch — its very first — this April, and will split the profits 50/50 with Regeneron.
“We’re clearly very excited to have the approval of our first commercial product,” general manager Ross Moat said in a call with investors on Thursday. “Not only does Arcalyst become the first and only approved drug in recurrent pericarditis, but it has the potential to become the standard of care.”
The FDA’s decision was based on results from the Phase III RHAPSODY trial, in which patients given Arcalyst achieved a 96% reduction in the risk of a recurrent pericarditis event, with a p-value of 0.0001, according to Kiniksa. Median time to treatment response was 5 days, with a 97% treatment response rate. For patients in the Arcalyst arm, 92% of trial days were “pain free or at most experiencing minimal pain,” compared to 40% of days for those on the placebo.

“Median time to first occurrence in the Arcalyst arm could not be calculated as there were not enough recurrent events during the observation period to allow for the number to be calculated,” CMO John Paolini said during the investor call.
The most common adverse events were injection site reactions and upper respiratory tract infections.
On Friday morning, $KNSA shares hovered around $20.83 apiece.
Recurrent pericarditis typically presents with chest pain and is often linked to changes in electrical conduction and sometimes pericardial effusion, or the buildup of fluid around the heart, according to Kiniksa. The recurrent disease affects about 40,000 patients in the US each year, 14,000 of whom experience a second recurrence.
“Our focus is on the 14,000 patients on their second recurrence, who have the highest unmet need,” Moat said. “These patients have failed on current systemic non-targeted treatments and require a solution that directly addresses interleukin-1 alpha and beta, the underlying drivers of pericardial inflammation.”
Arcalyst, which targets IL-1α and IL-1β, was first approved in 2008 for cryopyrin-associated periodic syndromes (CAPS), including familial cold autoinflammatory syndrome and Muckle-Wells syndrome. It got another OK in December 2020 for the maintenance of remission of deficiency of IL-1 receptor antagonist (DIRA). Kiniksa controls full sales and distribution of the drug for all three indications in the US.
“Whilst our promotional efforts will be focused on recurrent pericarditis, we remain fully committed to serving patients who are and will be treated with Arcalyst across all of the indications,” Moat said.
Moat says the company has hired a cardiology specialist sales team of 27 people, who will be “ready to roll over the coming days.” Arcalyst costs $20,000 per month, a price Moat said is “consistent with other specialty biologics.”
“We aim to secure broad access with minimal payer restrictions for our target population,” he added.