Editor’s Briefing: October 1, 2026

In Short. Overnight, Sanofi paid Regeneron $1 billion upfront to co-develop four next-generation immunology antibodies meant to extend the Dupixent franchise, Boehringer and Zealand’s dual-hormone obesity shot met late-stage goals in people with diabetes but gut side effects drove many dropouts as Zealand shares fell, Lilly’s amylin-plus-tirzepatide combo beat tirzepatide alone and will enter phase 3, and the FDA started a priority review of Roche’s oral multiple-sclerosis pill in both major disease forms.

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Sanofi and Regeneron deepen their immunology alliance

Dupixent is an antibody that blocks two immune signals, interleukin-4 and interleukin-13, that drive type 2 inflammation in eczema, asthma, and related diseases. More than 1.5 million people now take it. Sanofi and Regeneron said they will add four Regeneron-invented, longer-acting antibodies to that alliance: REGN20423, a long-acting IL-13 antibody already in a first-in-human study in healthy volunteers and eczema patients, plus three preclinical programs that include an IL-4xIL-13 bispecific. Regeneron receives $1 billion upfront and up to $7 billion more in milestones. The partners will split development and commercial costs, and any future profits, fifty-fifty. Regeneron will lead research; Sanofi will lead global sales. Existing Dupixent profit-sharing stays put, and earlier collaboration litigation is settled. (Sanofi; Fierce Biotech)

Zealand slides as survodutide posts diabetes obesity data

Survodutide is a once-weekly shot that activates two gut-hormone receptors at once, glucagon and GLP-1. Zealand discovered it; Boehringer Ingelheim develops and sells it worldwide. In SYNCHRONIZE-2, 755 adults with obesity or overweight plus type 2 diabetes were randomized to weekly survodutide or placebo. At 76 weeks, using an analysis that assumes everyone stayed on assigned treatment, mean weight loss reached 13.1% on the high dose versus 3.1% on placebo, and up to 79.3% lost at least 5% of body weight versus 32.7% on placebo. Blood sugar (A1C) fell by as much as 1.21 percentage points. Gastrointestinal side effects led 18% on survodutide to stop treatment, versus 1.2% on placebo. Results were presented at the European diabetes meeting and published in The New England Journal of Medicine. Zealand shares fell about 11% to 12% in Copenhagen trading. (Fierce Biotech; Boehringer)

Lilly’s amylin combo beats tirzepatide alone

Amylin is another fullness hormone. Eloralintide is Lilly’s selective amylin-receptor agonist; tirzepatide (sold as Zepbound for obesity) already hits GIP and GLP-1. EloraTZP pairs the two. In a 48-week phase 2b trial of 367 adults with obesity or overweight and type 2 diabetes, the highest dose combination cut body weight by 23.3% and A1C by 2.9 percentage points, versus 14.8% and 2.4 points on tirzepatide 15 mg alone and 3.0% and 0.3 points on placebo (efficacy estimand). Gut side effects were common during dose escalation; adverse-event discontinuations ranged from 10.8% to 27% on the combinations. Lilly plans phase 3 trials of a co-formulated product in the fourth quarter. (Lilly; BioSpace)

FDA accepts Roche’s oral MS pill for priority review

Multiple sclerosis damages the nerves that carry signals in the brain and spinal cord. Relapsing forms bring flare-ups; primary progressive MS worsens steadily with few clear attacks. Fenebrutinib is an oral drug that blocks Bruton’s tyrosine kinase (BTK), an enzyme used by immune cells involved in both relapse and longer-term damage. The FDA accepted Roche’s application under priority review for both settings, the first BTK inhibitor filing accepted in the pair. In two phase 3 relapsing trials, fenebrutinib cut annualized relapse rates by 51.1% and 58.5% versus teriflunomide over 96 weeks. In primary progressive disease, it met non-inferiority versus Ocrevus on a composite disability measure (hazard ratio 0.88). Roche reported a death imbalance across the pivotal program with varied causes and timing, and called the overall safety profile manageable in more than 2,700 participants. (Roche; BioPharma Dive)

What to watch

pdufa.bio still lists Merck/Daiichi ifinatamab deruxtecan for October 10 (stale after the voluntary withdrawal). Still ahead: Roche Tecentriq adjuvant stage III colon (October 9), Roche Enspryng in thyroid eye disease (October 15), Viatris/Opus phentolamine ophthalmic (October 17). Summit’s ivonescimab HARMONi filing sits on a November 14 PDUFA. Sanofi and Regeneron host a joint call this morning on the new alliance.