FDA Approval

FDA Approval

FDA approval is how the US Food and Drug Administration reviews new drugs and authorizes them for sale. A drug company must submit a New Drug Application (NDA) or Biologics License Application (BLA) with full data from laboratory studies and clinical trials showing that the drug is safe and effective for its intended use. The FDA reviews the drug’s chemistry, manufacturing, pharmacology, efficacy data and safety profile in detail. The review usually takes 10 to 12 months from submission to decision, though priority review can shorten it to about six months.

A new drug usually reaches approval through a set sequence of clinical phases. Phase 1 trials establish safety and dosing in small groups. Phase 2 trials look at efficacy and side effects in larger groups. Phase 3 trials provide the definitive evidence of efficacy and safety that the FDA requires, in large randomized, double-blind, placebo-controlled studies. For obesity drugs, the FDA generally expects clinically meaningful weight loss (statistically significant and greater than placebo) along with acceptable safety and tolerability. Effects on cardiovascular risk factors have also become increasingly important in the review of metabolic drugs.

Retatrutide is not approved anywhere, and no application has been filed. Its pivotal Phase 3 trials in obesity and type 2 diabetes have reported. Lilly says it plans to file for approval no later than the first quarter of 2027. On October 2, 2026 the FDA ruled that the application must be a New Drug Application (NDA); Lilly disputes that in court and has not said which pathway it will use (see the FDA ruling and the approval timeline). If approved, retatrutide could become the first triple agonist therapy available to patients, a new class of treatment for obesity and related metabolic conditions.