The 33rd European Congress on Obesity closes in Istanbul on Friday May 15 after four days that reframed the obesity-pharmacology conversation around two themes. First, maintenance: the SURMOUNT-MAINTAIN Lancet publication, ATTAIN-MAINTAIN Nature Medicine publication, and Wegovy STEP UP early-responder analyses gave prescribers Phase 3 evidence for dose tapering and switching strategies — moving past the 'how much weight will I lose' question to 'how do I stay there'. Second, guideline alignment: the EASO 2026 Nature Medicine framework formally privileged semaglutide and tirzepatide as first-line therapy across most obesity complications, with complication-specific differentiation (tirzepatide for OSA/MASH; semaglutide for OA/CVD/MASH-fibrosis). Caliway CBL-514 + GLP-1R combination preclinical data and Ascletis next-generation amylin and dual-incretin candidates rounded out the four-day program.
Sector stock reaction across May 12-13: Novo Nordisk ADRs popped roughly 6% premarket May 12 on the early-responder + women's-data combination and the OASIS 4 mobility analyses; Eli Lilly traded flat as the SURMOUNT-MAINTAIN and ATTAIN-MAINTAIN dual publication confirmed expected maintenance positioning rather than producing fresh upside surprises. Analysts noted the broader 'long-term treatment' thesis — that GLP-1 obesity drugs are chronic-disease medications, not short courses — got concrete trial backing this week between SURMOUNT-MAINTAIN, ATTAIN-MAINTAIN, and STEP UP early-responder analyses. The week's narrative shift sets up the May 14-15 ECO Day 3+4 cycle and the May 29-June 2 ASCO 2026 meeting in Chicago — where peptide-drug conjugates (Bicycle BT8009, Avacta AVA6000, Pfizer FAP-Dox) take the next round of clinical-data spotlights.
Two of the year's biggest peptide-related meetings open within 24 hours of each other next week. The European Congress on Obesity 2026 runs May 12–15 in Istanbul, with Novo Nordisk presenting 52 abstracts spanning Wegovy 7.2 mg full STEP UP data, CagriSema higher-dose Phase 3 plans, Wegovy pill efficacy and tolerability, and women's-obesity / perimenopause / migraine subgroups; the 21-expert global panel will also formally propose the 10-year prospective GLP-1 cancer-prevention trial. TIDES USA 2026 runs May 11–14 in Boston with six concurrent scientific tracks across oligonucleotides, peptides, and mRNA — featuring Bachem, PolyPeptide, CordenPharma, Gilead, and Novo Nordisk on the CMC strategy and GMP capacity panels. Hims & Hers prints Q1 May 11 the same evening.