Sanofi and Regeneron’s investigational IL-33 antibody has hit its primary endpoints against placebo in a phase 2 asthma study, but failed to outperfom the partners’ existing treatment Dupixent.
This has cast doubt on it prospects, and those of a rival IL-33 pipeline candidate.
REGN3500 is a IL-33 inhibitor which targets one of the key proteins thought to play a role in type 1 and type 2 inflammation.
The companies are looking to build on the success of Dupixent, which is already a $1bn+ blockbuster, and is picking up multiple licences across inflammatory conditions.
Dupixent inhibits the IL-4 and IL-13 proteins, and is already approved in severe asthma in the EU, and gained its atopic dermatitis approval in the US in March.
However the new results for REGN3500 are underwhelming. The phase 2 trial involved 296 adult patients with moderate-to-severe asthma, who were not well controlled by inhaled corticosteroid and long-acting beta-agonist therapy. REGN3500 met its primary endpoint, improvement in loss of asthma control, when compared to the placebo group, and also met the secondary endpoint of showing significant improvement in lung function in comparison to the placebo group.
However one arm of the trial also compared REGN3500 with Dupixent, and these results showed the established drug performed numerically better than the candidate across all endpoints.
The trial also showed that when combined, REGN3500 and Dupixent did not show increased benefit when compared to Dupixent monotherapy in this trial, although the companies point out that the trial was not powered to demonstrate this endpoint.
REGN3500 is also being studied in phase 2 trials for chronic obstructive pulmonary disease and atopic dermatitis.
Sanofi/Regeneron have promised more detailed results are upcoming, but the results are disappointing and leave the partners in a quandry about how to proceed with further trials.
The underwhelming results also hit shares of biotech AnaptysBio’s, which has its own IL-33 antibody therapy in development in atopic dermatitis.