Sanofi's (NASDAQ:SNY) most advanced multiple sclerosis (MS) drug candidate, tolebrutinib, failed to meet the primary objectives in two late-stage trials targeting relapsing forms of the disease, according to an announcement made by the French pharmaceutical giant on Monday.
However, in a positive development, the drug succeeded in a separate study on a less common and more challenging progressive form of MS, leading to a surge in Sanofi's stock.
Despite the mixed outcomes, investor sentiment remained optimistic, with Sanofi's share price climbing as much as 4.5% and reaching a ten-month high by 0731 GMT.
Analysts noted that the trial failure for tolebrutinib in the common relapsing form of MS, where patients experience temporary flare-ups, was anticipated, given similar setbacks with related compounds.
Jefferies analysts highlighted that, despite the mixed results, tolebrutinib could still represent a significant market opportunity, potentially worth $1-2 billion, and is now viewed as a "largely de-risked" asset.
Sanofi confirmed that the two Phase III trials demonstrated that tolebrutinib, an experimental daily pill, was not superior to its existing MS medication, Aubagio, in reducing relapse rates in patients with relapsing MS.
However, the company mitigated the impact of this setback by revealing that a third late-stage trial showed tolebrutinib successfully met the primary goal of treating the progressive form of MS, a condition for which no effective treatment currently exists.
In the successful trial, tolebrutinib was shown to slow the progression of disability compared to a placebo, marking a significant breakthrough for patients with this steadily worsening form of MS.
"Tolebrutinib represents an unprecedented breakthrough as a potential first-in-disease treatment option with clinically meaningful benefit in disability accumulation," stated Houman Ashrafian, Sanofi's head of research & development.
Sanofi plans to discuss these findings with regulatory authorities, with the aim of filing for approval by the end of 2024.