ATTAIN-2: the orforglipron pill for weight loss in type 2 diabetes

Why this study matters

As of October 2026, orforglipron is not authorized in Canada, and this study is research for Canadian readers. Health Canada has been reviewing it since January 2026. In the United States, the FDA approved it on 1 April 2026 under the brand name Foundayo for weight management. Orforglipron is a GLP-1 receptor agonist taken as a once-daily pill. It is a small molecule, not a peptide (a protein-like molecule). ATTAIN-1 tested it in people without diabetes. ATTAIN-2 is the matching phase 3 trial in adults who also have type 2 diabetes.

Who was in the study

The trial randomized 1613 adults at 136 sites in ten countries. Everyone had type 2 diabetes and a BMI of 27 or higher. BMI, or body mass index, is weight in kilograms divided by height in metres squared. Their HbA1c was between 7% and 10%. HbA1c is a blood test that reflects average blood sugar over the past few months.

Of the 1613 people, 757 (46.9%) were female. At the start, the average body weight was 101.4 kg, the average BMI was 35.6 and the average HbA1c was 8.05%. People were screened between 5 June 2023 and 15 February 2024. In all, 1444 people (89.5%) completed the study. The published summary we reviewed does not report the age range or name the countries.

What the researchers did

This was a 72-week, phase 3, randomized, double-blind, placebo-controlled trial. Randomized means people were assigned to a group by chance. Double-blind means neither participants nor staff knew who was taking orforglipron and who was taking placebo, an inactive pill that looks the same.

After a dose-escalation phase, in which the dose was raised step by step, people took orforglipron 6 mg, 12 mg or 36 mg, or placebo, once a day. They were assigned in a 1:1:1:2 ratio: 329 people to 6 mg, 332 to 12 mg, 322 to 36 mg and 630 to placebo. All groups took the pill alongside lifestyle changes. The main result was the average percentage change in body weight from the start to week 72.

The main analysis used a treatment-regimen estimand. An estimand is the exact question the statistics answer. This one uses data from everyone who was randomized, whether or not they kept taking the pill. A second analysis, the efficacy estimand, looked at what happened in people who kept taking it, and was treated as supporting information. The published summary we reviewed does not give the efficacy estimand numbers.

What they found

At week 72, orforglipron lowered body weight more than placebo at every dose (R33-C07). A confidence interval, or CI, is the range of values the data are reasonably consistent with.

Each dose differed from placebo with P below 0.0001. The authors report that all their planned weight and heart-and-metabolism measures, including HbA1c, improved with orforglipron. The published summary we reviewed does not give those numbers.

Side effects and people who stopped

Stopping treatment because of side effects happened in 6.1% to 9.9% of people across the orforglipron groups, compared with 4.1% with placebo (R33-C08). These were mainly stomach and bowel side effects. The published summary we reviewed does not give the rate for each dose. The most common side effects with orforglipron were mild to moderate stomach and bowel symptoms, mostly while the dose was being raised.

Ten people died during the study: six who were taking orforglipron and four who were taking placebo. The abstract says investigators judged all deaths unrelated to the study treatment, except one in the placebo group and one in the 12 mg group. It then adds that no treatment-related association was reported for the orforglipron case. The full paper would be needed to understand this.

What this study does not tell you

• Our summary is based on the abstract only. It does not give HbA1c results, low blood sugar rates or the stopping rate for each dose.
• The trial ran for 72 weeks. It does not show what happens over longer periods or after stopping.
• Results here are for people with type 2 diabetes. Do not compare them with ATTAIN-1, which studied people without diabetes, or with trials of other medicines.
• Company news releases may report the efficacy estimand, which can give larger numbers than the treatment-regimen results shown here.
• The trial was funded by Eli Lilly and Company, which makes orforglipron, and several authors work for the company.

What it means in Canada

As of October 2026, orforglipron is not authorized in Canada. Health Canada has been reviewing it since January 2026. ATTAIN-2 is one of the trials a regulator would look at, but a review does not guarantee approval. You can follow emerging medicines on our medicines page. For medicines available in Canada, see semaglutide in Canada, tirzepatide in Canada and public drug coverage by province.

Related reading

Other studies in this library that bear on the same question.

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