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weekly, bi-weekly, or monthly injections of dupilumab at a high (300 mg), medium (200 mg), or low (100 mg) dose, or a placebo, and tracked their results for 16 weeks. The study’s main goal was to significantly reduce patients’ symptoms, as measured by a mean change on what’s called the Eczema Area and Severity Index (EASI)—a clinically-validated, composite score used to measure the prevalence and severity of patients’ eczema lesions—compared to placebo. Investigators also looked at whether dupilumab could help wipe out the lesions altogether, and if it helped alleviate itching.
Regeneron and Sanofi are saying today that dupilumab hit all of its marks, with the higher doses scoring better than the lower ones. Patients on weekly 300 mg doses of dupilumab, for instance, saw their EASI scores drop by 74 percent over the course of treatment; those on the lowest 100 mg, monthly dose saw their scores drop by 45 percent. By comparison, scores for patients getting the placebo treatment dropped by an average of 18 percent.
The two companies are also saying that between 12 and 33 percent of the patients treated with dupilumab had their lesions either completely or almost completely cleared, as measured by an investigator’s global assessment (IGA) scale, compared to 2 percent of the patients in the placebo group (they didn’t specify any further). On average, those patients started the trial with a 3.5 on the scale, which essentially means they had moderate or severe eczema lesions, according to Pirozzi.
“That’s a pretty impressive result given that even cyclosporine in the short term barely reaches these levels,” he says.
Regeneron and Sanofi also reported that patients taking dupilumab had anywhere from a 16.5 percent to 47 percent reduction in their itching, compared to 5 percent on average in placebo.
There is, of course, still a long way to the finish line for Regeneron and Sanofi. The two have to recreate these results in bigger, longer late-stage studies (likely at least a year long with more than 1,000 patients combined), and see them hold up, and also make sure no big safety issues crop up along the way—like serious infusion site reactions, always a potential problem with injectable biologic drugs. While infusion reactions, along with colds, were some of the most common side effects seen so far, Pirozzi says the majority of the reactions have been mild to moderate and tend to go away after a few hours. None were severe.
“That’s something that we’ll certainly monitor very closely,” he says.
Pirozzi notes that the main goal of a Phase 3 study in Europe will be a mean change in EASI score while in the U.S., the primary endpoint will be a change in IGA. The secondary goal for both will be to reduce patients’ itching. Pirozzi is confident dupilumab will make it through intact.
“Honestly I think the only thing that could be a problem would be an unexpected safety issue coming up in the Phase 3 that we haven’t seen so far,” he says.
Dupilumab is one of several drugs that are part of Regeneron’s big partnership deal with Sanofi, which also includes two late-stage antibodies—cholesterol-lowering drug alirocumab, and rheumatoid arthritis prospect sarilumab—and a few other candidates in earlier testing. Regeneron gets $160 million in R&D funding per year through the collaboration and splits the profits from the drugs that come out of the deal with Sanofi 50/50 in the U.S., and on a sliding scale internationally.
Sanofi, meanwhile, has also been accumulating more and more shares in Regeneron over the years. Sanofi held about 16 percent of Regeneron in January; it now owns 22.5 percent of the stock, and is allowed to hold up to 30 percent. Sanofi has publicly shot down the prospect of a takeover several times, however.