Novartis has claimed a first-in-class regulatory approval in the US for oral BTK inhibitor remibrutinib as a second-line treatment for chronic spontaneous urticaria (CSU), also known as chronic hives.
The FDA has cleared remibrutinib under the Rhapsido trade name as the first oral alternative to current injectable treatments, namely Novartis’ anti-IgE antibody Xolair (omalizumab), which has been a mainstay of refractory treatment for CSU for many years, and Sanofi/Regeneron’s recently approved IL-4 and IL-13 inhibitor Dupixent (dupilumab).
CSU affects around 1% of the global population and, in severe cases, causes itching and swelling that can last for weeks at a time and resist even very high doses of antihistamines, which are the first-line therapy of choice but don’t work in around 60% of cases.
Novartis estimates that there are around 1.7 million people with uncontrolled CSU in the US alone, with more than half not responding adequately to antihistamines alone, but fewer than 20% of eligible patients are currently receiving the injectable drugs second-line.
There is no question that CSU is enormously debilitating, with almost two-thirds of patients experiencing mental health disorders, including depression and anxiety, so the availability of an additional therapeutic option for those most severely affected by symptoms is a major step forward, according to the Allergy & Asthma Network patient organisation.
“Many CSU patients feel misunderstood and settle for treatments that don’t fully meet their needs,” said Lynda Mitchell, the group’s chief executive. “This convenient new oral therapy offers a promising new way to manage CSU and potentially improve daily life for those living with this challenging condition.”
The FDA approval comes on the back of a pair of phase 3 trials – REMIX-1 and REMIX-2 – which showed that a twice-daily dose of Rhapsido achieved significant improvements in urticaria activity, itch severity, and hive severity scores compared to placebo.
Almost half of the patients treated with Novartis’ drug were completely free of itch and hives at the end of the 52-week follow-up period.
Novartis said that Rhapsido will cost $4,521 for a 30-day supply at list prices and will be available to patients within the next few days. Meanwhile, applications have been filed in the EU, China, and Japan.
Analysts have suggested that approval in CSU alone could make the drug a blockbuster, with sales of more than $1 billion a year, and Novartis is running phase 3 trials for chronic inducible urticaria (CINDU) and multiple sclerosis (MS), and phase 2 studies in hidradenitis suppurativa (HS) and food allergy indications.
Sanofi is also developing an oral BTK inhibitor called rilzabrutinib for CSU, which has had phase 2 results in hand since 2024 but has not yet advanced into phase 3 for this indication. It is also being tested for asthma, IgG4-related disease, and other inflammatory diseases and was recently approved by the FDA as Wayrilz for immune thrombocytopenia (ITP).
