“This drug has the potential to be one of the greatest drugs in our history.” Novartis CEO Vasu Narasimhan told CNBC on Tuesday that the Swiss drugmaker is backing its experimental multiple sclerosis drug remibrutinib, aiming for peak annual sales of more than $4 billion.
Days earlier, Barclays cut its peak sales forecast for the drug after detailed results from two late-stage clinical trials showed the drug did less to reduce relapses in MS patients than analysts expected.
This highlights the challenge for Novartis as it prepares to outline its long-term growth strategy in mid-November.
The company reported increased sales this week despite losing important patent protection for its blockbuster heart drug Entresto. But Barclays analysts said the market was already eyeing the next patent cliff, with best-selling Kisqali and Kesimpta facing patent expiration around 2032.
That’s “the bigger question in the market,” Barclays analysts said Wednesday, noting that the Kiscali and Kesimpta expirations alone were worth $18 billion in peak sales.
Against this background, Novartis has announced that it aims to achieve total sales of remibrutinib of more than $8 billion, including indications other than relapsing MS.
Amit Bar-O, a multiple sclerosis specialist at the University of Pennsylvania, told CNBC that while remibrutinib appears to offer a promising safety profile, it is unlikely to control relapsing MS as effectively as high-potency antibodies like Novartis’ Kesimpta.
He added that the drug’s greatest opportunity to expand the market could arise if it proves effective in ongoing trials in progressive multiple sclerosis, where treatment options remain limited.
How remibrutinib works
Remibrutinib belongs to a class of medicines known as BTK inhibitors, which aim to reduce immune system activity that damages nerves in MS patients.
Kesimpta works differently. This is a monoclonal antibody that binds to the CD20 protein, depleting B cells involved in the autoimmune response in MS.
Unlike Kesimpta, remibrutinib aims to control cellular activity without eliminating it.
Bar-Or distinguished the biology of relapsing MS, in which patients experience flare-ups, from progressive MS, in which patients gradually worsen over time.
Bar-Or said remibrutinib’s clinical performance in relapsing MS appears to be similar to Roche’s rival BTK inhibitor fenebrutinib, but it is less effective at preventing relapses than anti-CD20 treatments such as Kesimpta.
No head-to-head trials comparing remibrutinib with fenebrutinib or anti-CD20 therapy have yet been conducted, making a direct comparison difficult.
It may still be an attractive switch for patients experiencing progressive MS while receiving anti-CD20 therapy, he added. Ongoing clinical trials investigating whether remibrutinib can effectively treat progressive MS are expected to yield results in 2031.
One potential benefit of BTK inhibitors is that they control immune cells rather than eliminate them, which could make them safer in the long term than existing MS treatments, Bar-Or said. However, there is not yet enough long-term safety data to confirm this, he added.
A Novartis spokesperson told CNBC that the company does not view remibrutinib as a replacement for kesimpta sales, but primarily as an opportunity to expand its MS portfolio.
The company is targeting newly diagnosed patients, patients currently receiving oral therapy, and patients on anti-CD20 therapy who may be eligible to switch.
Novartis sees a peak annual sales opportunity for Kesimpta of more than $6 billion, alongside more than $4 billion for remibrutinib for relapsing MS.
Sales outlook for remibrutinib
Morningstar analyst Jay Lee told CNBC that Novartis’ prediction of peak sales of more than $4 billion for remibrutinib for MS is “within the realm of possibility” but not “risk-mitigated.”
Lee added that this will depend on how remibrutinib compares with Roche’s rival fenebrutinib, drug price negotiations, whether potential tolerability benefits translate into longer treatment times for patients, and whether clinical trials support patients switching from existing MS treatments.
“In the short term, we expect the largest market for remibrutinib to be the oral switch market, where patients receiving generic oral therapy need to switch, particularly for tolerability reasons.”
Investors are currently focused on the RESHAPE trial, which enrolled patients aged 40 to 70 taking Roche’s anti-CD20 antibody Ocrevus, with results expected in 2028.
While this could allow remibrutinib to take some market share from CD20 drugs such as Ocrevus and Kesimpta, “it could still work in Novartis’ favor if it means gaining overall RMS patient share from Roche, which currently leads the market,” Lee said, adding that Novartis estimates that about 75% of CD20 switch-eligible patients are not taking Kesimpta.
Additionally, remibrutinib is already approved for the treatment of certain forms of chronic urticaria, and a late-stage clinical trial testing remibrutinib for the chronic inflammatory skin disease hidradenitis suppurativa (HS) is expected to report results by November 19.
Barclays estimates the peak annual sales opportunity in HS to be $2 billion, but gives the drug only a 50% chance of success, citing an unusual dose-response pattern in mid-term trials and a history of late-stage trial failures in HS.
