Merck KGaA drops BTK inhibitor evobrutinib, marking end of road for blockbuster dreams

It’s been a quick fall from grace for evobrutinib. Only months ago, Merck KGaA was outlining hopes for a major commercialization push for the BTK inhibitor—and now the German pharma has dropped the drug completely.

Merck told Fierce Biotech that the decision was made in response to the failure of evobrutinib to beat Sanofi’s Aubagio in two phase 3 multiple sclerosis (MS) clinical trials in December 2023. With Merck having pinned blockbuster hopes on the drug, the pair of failures sent shockwaves through the BTK inhibitor space at the time.

The company revealed the decision to give up on evobrutinib in a fourth-quarter earnings results presentation, where it described how scrapping the drug came with a one-time cost of 95 million euros ($103.5 million), which Merck booked for the fourth quarter of 2024. This financial impact was counterbalanced by sales momentum and income from the PD-L1 antibody Bavencio, for which Merck re-secured the rights from Pfizer a year ago.

Merck is far from the only Big Pharma to have seen potential in BTK inhibitors to tackle smoldering MS, chronic inflammation linked to the progression of symptoms in patients who appear to have stable disease. Sanofi made a splash in the space by paying $3.7 billion to buy Principia Biopharma in 2020, while Biogen, Novartis and Roche have all taken candidates into phase 2 or 3 clinical trials.

But Merck’s December data removed the German company from the race. Specifically, the annualized relapse rates (ARR) in patients with relapsing MS were almost identical in recipients of evobrutinib and the control drug, Sanofi’s Aubagio.

Responding to the results at the time, Merck noted that the ARRs in recipients of Aubagio were lower than those seen in other recent phase 3 studies of the treatment. The ARR in recipients of evobrutinib slipped from the phase 2 trial, when the rate in patients who received 75 mg twice a day was 0.08 at week 24 and 0.11 in a recent long-term analysis. The ARR on the Aubagio label is 0.37; in another phase 3 trial the ARR was 0.29.

Up to the phase 3 readouts, the company had maintained sky-high hopes for the drug. As recently as November, Merck had outlined plans to support evobrutinib with a major commercialization push, telling investors that launch preparations would drive up costs starting in the fourth quarter and mulling whether to use a voucher to accelerate the FDA review.

On a call with analysts to discuss the earnings results, Merck CEO Belén Garijo admitted the  BTK inhibitor’s failure “was no doubt a disappointment.”

“Despite the setback with evobrutinib, we will remain focused on stringent execution of our strategies to both drive our existing product portfolio and to continue to increase optionality for our pipeline,” the CEO added.