In This Article:
At the American Academy of Neurology (AAN) 2025 Annual Meeting Clinical Trials Plenary Session, Sanofi presented data on tolebrutinib in patients with non-relapsing secondary progressive multiple sclerosis (nrSPMS) from the HERCULES trial and in patients with relapsing multiple sclerosis (RMS) from GEMINI 1 and GEMINI 2. The presentation highlighted tolebrutinib’s potential as the first Bruton's tyrosine kinase (BTK) inhibitor to receive regulatory approval for the treatment of progressive MS.
During the Clinical Trials Plenary Session, Sanofi announced that tolebrutinib delayed the time to onset of six-month confirmed disability progression (CDP) by 31% compared to placebo in patients with nrSPMS, meeting the primary endpoint of the HERCULES trial. In addition, tolebrutinib met some of its secondary endpoints where it delayed the time to three-month CDP by 24% compared to placebo, and significantly lowered the annualised rate of new or enlarging T2 lesions versus placebo by 38%. While a lower proportion of participants in the tolebrutinib group showed progression in the Timed 25-Foot Walk, tolebrutinib did not differentiate from placebo in the 9-hole peg test.
During the Plenary Session, Sanofi also reported that tolebrutinib failed to meet the primary endpoint of reducing annualised relapse rate over teriflunomide in patients with RMS in the GEMINI studies. A pooled analysis of GEMINI 1 and GEMINI 2 for a key secondary endpoint, not controlled for multiplicity, showed that tolebrutinib delayed the time to onset of six-month confirmed disability worsening by 29% versus teriflunomide. But the number of new Gd-enhancing T1 lesions was higher in the tolebrutinib arm and the number of new or enlarging T2 lesions was similar between both treatment arms. The results of the GEMINI trials follow Sanofi’s decision, in January 2025, to remove its tolebrutinib RMS programme from its pipeline, focusing on progressive forms of MS only. In addition to development in nrSPMS per the HERCULES trial, there is an ongoing Phase III study to investigate the efficacy of tolebrutinib compared to placebo in delaying disease progression in patients with primary progressive MS (PERSEUS). Tolebrutinib was generally well-tolerated in the HERCULES, GEMINI 1, and GEMINI 2 trials. Liver enzyme elevations, defined by greater than three times the upper limit of normal, were observed in 4.0% of tolebrutinib patients in the HERCULES trial and 5.6% of tolebrutinib patients in the GEMINI studies. However, safety concerns have been previously raised. In June 2022, the US Food and Drug Administration (FDA) placed a partial clinical hold on tolebrutinib due to reported cases of drug-liver induced injury in patients who received the drug during clinical trials. Key opinion leaders (KOLs) previously interviewed by leading data and analytics company GlobalData stated that should tolebrutinib receive approval, it is likely to be accompanied by a boxed warning and risk evaluation and mitigation strategies.