- An experimental inflammatory disease medicine being developed by Pfizer bested Sanofi and Regeneron's top-selling therapy Dupixent in a late-stage study comparing the two drugs as treatment for moderate or severe eczema, Pfizer said Monday.
- According to Pfizer, the head-to-head trial showed its drug, called abrocitinib, cleared skin and reduced itching in more patients than did Dupixent. Specific results, however, weren't disclosed, nor was a detailed breakdown of side effects for the two treatments.
- Dupixent has fast become a blockbuster product for both Sanofi and Regeneron since its first approval in 2017. Several rival companies, among them Pfizer, AbbVie and Eli Lilly, are developing competitors they hope are more effective against an array of conditions like eczema and several types of arthritis.
Abrocitinib is one of Pfizer's top experimental therapies, pegged by the drugmaker for several billion dollars in peak annual sales in the future.
But its fate, along with the fate of two other drugs from AbbVie and Lilly that are designed to work similarly, are tied to a months-long safety review by the Food and Drug Administration. Over the course of this year, the agency has pushed back several approval decisions on additional indications for AbbVie's and Lilly's drugs, respectively called Rinvoq and Olumiant, and on an initial OK for abrocitinib in atopic dermatitis, or eczema.
The regulator's concerns are linked to results from a study of an older Pfizer drug called Xeljanz that targets the same immune-regulating enzymes as abrocitinib, Rinvoq and Olumiant. Findings made public in January showed treatment with Xeljanz was associated with higher rates of major heart complications and cancer than those who received one of another class of drugs widely used for inflammatory diseases.
The question now facing the FDA is whether those risks are somehow tied to the way the drugs block those enzymes, known as Janus kinases, or JAKs.
"The actions by the FDA over the last several months make it clear that the reviews of at least this generation of JAK inhibitors are inextricably linked, which is a negative outcome for any pharma counting on a differentiated label for a competitive edge," wrote Geoffrey Porges, an analyst at SVB Leerink, in a June 28 note to clients.
Pfizer initially had expected to win approval of abrocitinib in atopic dermatitis earlier this year, but the FDA delayed its decision to the early third quarter, a deadline that's since been passed. In June and again in July, AbbVie said the agency did not meet its target decision date for applications to expand use of Rinvoq — currently cleared for rheumatoid arthritis — to include atopic dermatitis, psoriatic arthritis and ankylosing spondylitis.
Analysts on Wall Street expect the FDA's review will result in a class-wide safety warning for JAK-blocking drug. But until the regulator reaches a decision, abrocitinib and its would-be rivals remain in a holding pattern.
Should abrocitinib reach market as Pfizer expects, the positive results against Dupixent should help it competitively. According to the company's Aug. 30 statement, treatment with abrocitinib helped a greater proportion of patients with moderate to severe eczema achieve a greater than 90% improvement in skin clearance after four weeks. The study will also compare the drugs at four months and at six months.
Pfizer noted a "larger percentage" of patients on abrocitinib experienced side effects compared to Dupixent, but said rates of serious adverse events, severe adverse events and adverse events leading to study discontinuation were similar between the two drugs.
Two deaths were reported among patients given abrocitinib — one due to COVID-19 and another due to brain bleeding and cardiorespiratory arrest — but neither were judged by investigators to be related to Pfizer's drug.
Pfizer plans to report full results at an upcoming medical meeting and said it will share the data with regulators.
Also on Monday, Sanofi and Regeneron reported strongly positive results in a study of Dupixent among children as young as six months with moderate or severe eczema.