Drug Update · Endocrinology

Orforglipron (FOUNDAYO) FDA Approved for Obesity; 11.2% vs 2.1% Mean Weight Change in ATTAIN-1

August 19, 2026

FDA approval date

2026-04-01

Indication (exact)

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 in the presence of at least one weight-related comorbid condition.

Starting dose (approved)

0.8 mg once daily

Maximum dose (approved)

17.2 mg once daily

Key efficacy (ATTAIN-1)

Mean percent change in body weight -11.2% with orforglipron versus -2.1% with placebo at 72 weeks

Key efficacy (ATTAIN-2)

Mean percent change in body weight -9.6% with orforglipron versus -2.5% with placebo at 72 weeks

Clinical Perspective

FOUNDAYO is indicated for adults with obesity (BMI ≥30 kg/m2) or adults with overweight (BMI ≥27 kg/m2) with at least one weight-related comorbidity; the pivotal trials included adults both with and without type 2 diabetes (ATTAIN-2 enrolled patients with baseline HbA1c 7% to 10%). Refer to prescribing information for patient selection and monitoring. What will postmarketing studies reveal about the risk of medullary thyroid carcinoma, long-term pediatric safety, and pregnancy exposures associated with orforglipron?

Dr. Amit Desai, MBBS, MD (General Medicine), DM (Endocrinology) · Endocrinology

The U.S. Food and Drug Administration approved FOUNDAYO (orforglipron) 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 in the presence of at least one weight-related comorbid condition ^[2]^[4]^[1]. In the randomized, double-blind, placebo-controlled 72-week ATTAIN-1 trial in adults with obesity without diabetes, orforglipron achieved a mean percent change in body weight of -11.2% versus -2.1% with placebo at 72 weeks ^[6].

Clinical Context

Orforglipron (FOUNDAYO) is an oral, small-molecule, nonpeptide glucagon-like peptide-1 (GLP-1) receptor agonist marketed by Eli Lilly and Company and approved as an adjunct to lifestyle intervention for chronic weight management in adults with obesity or adults with overweight plus at least one weight-related comorbid condition ^[1]^[2]^[4]. FOUNDAYO is administered once daily as a film-coated tablet and may be taken with or without food ^[1]^[3]^[4]. Refer to current prescribing information for full dosing guidance. The FDA noted the approval was completed under an expedited National Priority Voucher process and was supported by two randomized 72-week trials in adults with and without type 2 diabetes ^[4]^[2].

Key Findings

The ATTAIN-1 trial showed orforglipron achieved a mean percent change in body weight of -11.2% versus -2.1% with placebo at 72 weeks ^[6].
The evidence supporting approval came from two randomized, double-blind, placebo-controlled 72-week trials (Trials 1 and 2). Trial 1 (ATTAIN-1) enrolled 3,127 adults with obesity (BMI ≥30 kg/m2) or adults with overweight (BMI 27 to <30 kg/m2) without diabetes; Trial 2 (ATTAIN-2) enrolled adults with overweight or obesity and type 2 diabetes with baseline HbA1c 7% to 10% ^[7]^[6]^[5].
The FDA approval and prescribing information describe the indication as use in combination with a reduced-calorie diet and increased physical activity to reduce excess body weight and to maintain weight reduction long term in adults with obesity or adults with overweight in the presence of at least one weight-related comorbid condition ^[1]^[2]^[4].

Safety & Tolerability

Boxed warning: Risk of thyroid C‑cell tumors; FOUNDAYO is contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) ^[1]^[3].

Study Design

The FDA approved FOUNDAYO based on evidence from randomized, double-blind, placebo-controlled 72-week trials (referred to in labeling as Trials 1 and 2) evaluating mean percent change in body weight at Week 72 as the primary efficacy parameter ^[7]^[1]. Trial 1 (ATTAIN-1; N=3,127) enrolled adults with obesity without diabetes; Trial 2 (ATTAIN-2; N=1,613) enrolled adults with BMI ≥27 kg/m2 and type 2 diabetes with baseline HbA1c 7% to 10% ^[7]^[6]^[5]. The NDA review and approval were completed by the FDA, effective April 1, 2026 ^[2]^[4]^[7].

FAQ

Q1 What is FOUNDAYO (orforglipron) approved for?

FOUNDAYO (orforglipron) is approved 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 in the presence of at least one weight-related comorbid condition. Concomitant use with another GLP-1 receptor agonist is not recommended. Refer to current prescribing information for complete dosing guidance.

Q2 How does orforglipron work?

Orforglipron is an oral, small-molecule, nonpeptide GLP-1 receptor agonist that binds to and activates the human GLP-1 receptor; GLP-1 is a physiological regulator of appetite and caloric intake and GLP-1 receptors are present in brain regions that regulate appetite. The mechanism of action and central nervous system distribution are described in the prescribing information.

Q3 What is the recommended dosing and administration?

Take FOUNDAYO orally once daily, with or without food; swallow tablets whole and do not break, crush, or chew. The starting dosage is 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. The dosage may be increased after at least 30 days on the current dosage to the next level up to a maximum of 17.2 mg once daily. Do not take more than one tablet per day. Refer to current prescribing information for complete dosing guidance (consult current prescribing information for full dosing guidance).

Q4 What are the most common side effects and key safety considerations?

Most common adverse reactions reported in ≥5% of patients treated with FOUNDAYO included nausea, constipation, diarrhea, vomiting, dyspepsia, abdominal pain, headache, abdominal distension, fatigue, eructation, gastroesophageal reflux disease, flatulence, and hair loss. Boxed warning: risk of thyroid C‑cell tumors; FOUNDAYO is contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or in patients with MEN 2. Other safety signals reported include acute pancreatitis, severe gastrointestinal reactions, acute kidney injury due to volume depletion, hypoglycemia with concomitant insulin or secretagogues, hypersensitivity reactions, diabetic retinopathy complications, acute gallbladder disease, and pulmonary aspiration during anesthesia or deep sedation. Refer to current prescribing information for complete dosing guidance.

Orforglipron (FOUNDAYO) FDA Approved for Obesity; 11.2% vs 2.1% Mean Weight Change in ATTAIN-1

Direct Clinical Takeaway & Evidence Summary

Orforglipron (FOUNDAYO) FDA Approved for Obesity; 11.2% vs 2.1% Mean Weight Change in ATTAIN-1

Clinical Perspective

Clinical Context

Key Findings

Safety & Tolerability

Study Design

FAQ

References

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