0934 GMT - Sanofi and Regeneron Pharmaceuticals' potential successors to blockbuster medicine Dupixent might lag behind rival drugs Pfizer and AbbVie are developing, Citi analysts say in a research note. The new experimental drugs Sanofi and Regeneron will jointly develop under their alliance focus solely on extending the dosing interval of Dupixent without compromising efficacy or tolerability, but there is no expectation of a superior performance, Citi says. This suggests those medicines might struggle to compete with Pfizer's tilrekimig and AbbVie's zumilokibart, both of which have shown potential for better efficacy in midstage trials, according to Citi. Moreover, it might be challenging for Sanofi and Regeneron to get reimbursement for those drugs from healthcare payers after copycat versions of Dupixent become available, the analysts add. Sanofi shares fall 3.4%.