Lilly's weight loss pill took off 8.7% in Japan trial

On the middle dose of Eli Lilly’s weight loss pill, Japanese adults lost an average 8.7% of their weight in 72 weeks. A dummy pill took off 0.6%. The phase 3 trial was published online Oct. 30 in The Lancet Diabetes & Endocrinology.

The drug is orforglipron. The FDA approved it in the US on April 1 as Foundayo.

The surprise is the dose curve. The middle dose, 12 mg, did best. The top dose, 36 mg, averaged 7.9%.

Why it matters: Lilly’s global trial of the same pill, ATTAIN-1, found 11.2% weight loss on the top dose in 3,127 adults. The Japan trial is far smaller. It still gives doctors a separate read on one country’s patients, and the answer came in lower.

The numbers

Average weight change at 72 weeks, in the trial, named ATTAIN-J:

• 6 mg: down 5.9%
• 12 mg: down 8.7%
• 36 mg: down 7.9%
• Placebo: down 0.6%

All three doses beat placebo. The share of patients who lost at least 5% of their weight:

• 6 mg: 45.6% (28 of 61)
• 12 mg: 60.8% (35 of 57)
• 36 mg: 58.8% (35 of 60)
• Placebo: 15.2% (9 of 60)

Who was in it

The trial enrolled 238 adults at 16 hospitals and research centers in Japan. They averaged 54 years old, and 61% were men. Of the 238, 214 finished.

To qualify, patients with a BMI of 27 to under 35 needed two or more obesity related conditions. A BMI of 35 or higher needed one.

One of those conditions had to be high blood pressure, abnormal blood fats or type 2 diabetes. That matches the rules Japan uses for tirzepatide and semaglutide, the drugs in Zepbound and Wegovy, the authors wrote.

Side effects

Most side effects were mild to moderate stomach problems. Nausea made 5 of 60 patients on the top dose stop the drug, against 1 on each lower dose and none on placebo. Vomiting made 3 patients on the pill stop.

The fine print

Lilly paid for the trial, and 4 of the 8 authors work for Eli Lilly Japan. The trial tested 6, 12 and 36 mg doses. The Foundayo tablets sold in the US come in strengths from 0.8 mg to 17.2 mg, per the FDA label.

The pill is already a business. Foundayo brought in $184 million in the third quarter, Lilly reported in an Oct. 29 filing. That makes $281 million in the first nine months of 2026. Our story on the quarter has the rest.

The short version: in Japan, Lilly’s pill worked, and more pill did not mean more weight loss.