Drug Update · Endocrinology

FDA Approves orforglipron for Obesity: 11.2% Weight Loss ATTAIN-1

July 12, 2026

FDA approval date

2026-04-01 [12]

Primary efficacy (ATTAIN-1)

Mean percent change in body weight at week 72: −11.2% versus −2.1% with placebo [1]

Pivotal trial enrollment

Trial 1 randomized 3,127 patients; Trial 2 randomized 1,613 patients [1][12]

Recommended maximum dose

17.2 mg once daily (FOUNDAYO) [4]

Clinical Perspective

Endocrinologists, obesity medicine specialists, and primary care clinicians treating adults with obesity or adults with overweight plus at least one weight-related comorbid condition now have an FDA‑approved oral GLP‑1 receptor agonist, FOUNDAYO, as an option for long‑term weight management ^[2]. The approval is supported by randomized, double‑blind trial evidence reporting a mean percent body‑weight reduction at 72 weeks compared with placebo, and the label provides a specific dose‑escalation regimen and safety warnings clinicians must follow ^[1]^[2]^[3]. How clinicians will integrate FOUNDAYO with existing injectable GLP‑1 receptor agonists, and which patients will best tolerate escalation to the maximum labeled dose, remain practical questions for prescribing clinicians?

Dr. Amit Desai · Endocrinology

The FDA approved orforglipron (FOUNDAYO) on April 1, 2026 for use in combination with a reduced-calorie diet and increased physical activity to reduce excess body weight and maintain weight reduction long term in adults with obesity or adults with overweight with at least one weight-related comorbid condition ^[2]. Approval was supported by randomized, double-blind trials reporting a mean percent change in body weight at week 72 of -11.2% versus -2.1% with placebo in the pivotal ATTAIN-1 trial ^[1]^[3].

Clinical Context

Orforglipron is a small-molecule, nonpeptide, oral glucagon-like peptide-1 (GLP-1) receptor agonist developed and marketed by Eli Lilly and Company as FOUNDAYO ^[1]^[2]. The drug is indicated for chronic weight management in adults with obesity or adults with overweight plus at least one weight-related comorbid condition, to be used in combination with reduced-calorie diet and increased physical activity ^[2]. The FDA prescribing information notes that FOUNDAYO is taken orally once daily and may be administered with or without food ^[2]. Clinicians should consult current prescribing information for full dosing guidance. The label includes a boxed warning regarding thyroid C‑cell tumors and contraindicates use in patients with personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) ^[2].

Key Findings

The ATTAIN-1 trial showed a mean percent change in body weight from baseline to week 72 of -11.2% versus -2.1% with placebo, as reported in the randomized, double-blind phase 3 trial of orforglipron in adults with obesity without diabetes (ATTAIN-1) ^[1].
In ATTAIN-1, multiple orforglipron treatment groups had greater reductions in waist circumference, systolic blood pressure, triglyceride levels, and non–HDL cholesterol levels compared with placebo ^[1].
Treatment discontinuation due to adverse events occurred more frequently in orforglipron groups (5.3% to 10.3%) than in the placebo group (2.7%) in ATTAIN-1 ^[1].

Safety & Tolerability

BOXED WARNING: Risk of thyroid C‑cell tumors observed with GLP‑1 receptor agonists in rodents; orforglipron did not produce tumors in rodents but is pharmacologically active at the human GLP‑1 receptor. FOUNDAYO is contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or MEN 2 ^[2].
Acute pancreatitis has been reported with GLP‑1 receptor agonists, including FOUNDAYO; discontinue if pancreatitis is suspected ^[2].
Severe gastrointestinal adverse reactions have been associated with FOUNDAYO; patients with severe gastroparesis are not recommended to use FOUNDAYO ^[2].
Acute kidney injury due to volume depletion has been reported; monitor renal function in patients reporting adverse reactions that could lead to volume depletion ^[2].
Hypoglycemia risk may increase when FOUNDAYO is used concomitantly with insulin or insulin secretagogues; dosage reduction of those agents may be necessary ^[2].
Serious hypersensitivity reactions, including anaphylaxis and angioedema, have been reported; discontinue FOUNDAYO if suspected ^[2].
Additional labeled warnings include diabetic retinopathy complications in patients with type 2 diabetes, acute gallbladder disease, and pulmonary aspiration during general anesthesia or deep sedation ^[2].
The most common adverse reactions reported in ≥5% of patients treated with FOUNDAYO include nausea, constipation, diarrhea, vomiting, dyspepsia, abdominal pain, headache, abdominal distension, fatigue, eructation, gastroesophageal reflux disease, flatulence, and hair loss ^[2].

Study Design

FOUNDAYO approval was supported by randomized, double‑blind, placebo‑controlled trials (Trials 1 and 2) of once‑daily orforglipron given with lifestyle intervention; Trial 1 enrolled 3,127 adult patients without diabetes and Trial 2 enrolled 1,613 adult patients with type 2 diabetes, each with a 72‑week primary efficacy assessment ^[1]^[3]. In the trials, the primary efficacy parameter was mean percent change in body weight from baseline to Week 72 ^[3]. The FDA labeling and DailyMed describe dose escalation and the recommended administration (oral, once daily, with or without food) ^[2]^[3]. Clinicians should consult current prescribing information for full dosing guidance.

FAQ

Q1 What is orforglipron (FOUNDAYO) approved for?

FOUNDAYO is approved in adults as an adjunct to a reduced‑calorie diet and increased physical activity to reduce excess body weight and maintain weight reduction long term in adults with obesity or adults with overweight in the presence of at least one weight‑related comorbid condition. The approval is described in the FDA labeling and DailyMed materials issued 04/01/2026.

Q2 How does orforglipron work?

Orforglipron is an oral GLP‑1 receptor agonist that binds to and activates the human GLP‑1 receptor; GLP‑1 is a physiologic regulator of appetite and caloric intake, and GLP‑1 receptors are present in brain regions that regulate appetite. The clinical pharmacology section of the label states that orforglipron distributed to and activated neurons in brain regions that regulate appetite and food intake in nonclinical studies.

Q3 What is the recommended dose of FOUNDAYO?

FOUNDAYO is administered orally once daily and may be taken with or without food. The recommended initiation and escalation are: start 0.8 mg once daily, after at least 30 days increase to 2.5 mg once daily, after at least 30 days on 2.5 mg increase to 5.5 mg once daily, and the dosage may be increased to subsequent levels (9 mg, 14.5 mg, or 17.2 mg once daily) after at least 30 days on the current dosage based on response and tolerability; the maximum dosage is 17.2 mg once daily. Clinicians should consult current prescribing information for complete dosing guidance.

Q4 What are the side effects of FOUNDAYO?

The FDA label lists a boxed warning regarding rodent GLP‑1 receptor‑dependent thyroid C‑cell tumors and contraindicates FOUNDAYO in patients with personal or family history of medullary thyroid carcinoma or MEN 2. Labeled serious risks include acute pancreatitis, severe gastrointestinal reactions, acute kidney injury due to volume depletion, hypoglycemia when used with insulin or insulin secretagogues, serious hypersensitivity reactions, diabetic retinopathy complications in patients with type 2 diabetes, acute gallbladder disease, and pulmonary aspiration during anesthesia. The most commonly reported adverse reactions (≥5%) include nausea, constipation, diarrhea, vomiting, dyspepsia, abdominal pain, headache, abdominal distension, fatigue, belching (eructation), gastroesophageal reflux disease, flatulence, and hair loss. If patients experience symptoms suggestive of a serious adverse reaction, clinicians should follow the labeled guidance for evaluation and discontinuation.

Clinicians should consult current prescribing information for complete dosing guidance.

FDA Approves orforglipron for Obesity: 11.2% Weight Loss ATTAIN-1

FDA Approves orforglipron for Obesity: 11.2% Weight Loss ATTAIN-1

Clinical Perspective

Clinical Context

Key Findings

Safety & Tolerability

Study Design

FAQ

References

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