Lilly brings retatrutide knee pain data to ACR 2026

Eli Lilly said on November 5, 2026 that it will present knee osteoarthritis results for retatrutide, its investigational once-weekly triple hormone receptor agonist, from two Phase 3 trials at ACR Convergence 2026, the American College of Rheumatology’s annual meeting, running Nov. 6-11 in Orlando. Lilly will also present one-year data on using its psoriasis and arthritis drug Taltz (ixekizumab) together with Zepbound (tirzepatide).

Retatrutide activates the receptors for GIP, GLP-1 and glucagon. It is not approved anywhere. Lilly’s release says it is an investigational molecule that “cannot be legally sold or marketed for human use.”

TRIUMPH-4: the plenary

TRIUMPH-4 (NCT05931367) is scheduled as a plenary talk on Sunday, Nov. 8, at 11:15 a.m. Eastern (abstract 0871). According to the published ACR abstract, the double-blind trial enrolled 445 adults with painful knee osteoarthritis and obesity or overweight. They were randomized equally to retatrutide at the abstract’s “9 mg” or “12 mg” arms or to placebo for 68 weeks. ClinicalTrials.gov lists the trial as completed with actual enrollment of 445.

The trial had two co-primary endpoints: change in the WOMAC pain score and percent change in body weight at week 68. The abstract reports mean WOMAC pain changes of -4.48 and -4.41 on the two retatrutide arms versus -2.43 on placebo. Mean body weight changes were -26.4% and -28.7% versus -2.1% on placebo. The abstract reports all of those comparisons with placebo as statistically significant. Average baseline pain was 5.95 on the 0-10 scale.

Lilly’s release rounds those results. It says retatrutide reduced knee pain by up to an average of 4.5 points, or 75.8%, from an average baseline of 6.0, and that more than 1 out of 8 retatrutide-treated patients had no knee pain at the end of the trial.

The abstract says the most common adverse events were mild to moderate gastrointestinal events, mostly during dose escalation.

TRIUMPH-1: the knee osteoarthritis poster

The first detailed knee osteoarthritis findings from TRIUMPH-1 (NCT05929066), an 80-week Phase 3 trial, will be shown as a poster on Tuesday, Nov. 10 (abstract 2573). Lilly says retatrutide reduced knee pain by up to 4.3 points, or 73.1%, from a baseline of 6.0, and that more than 1 out of 6 retatrutide-treated patients had no knee pain at the end. The release does not give per-arm numbers for this subgroup; those are expected in the poster.

The post hoc caveat

The headline percentages need a caveat that Lilly itself puts in a footnote: the percent change in the WOMAC pain score “was not pre-specified and was estimated from a post-hoc analysis.” The prespecified endpoint was the point change. Placebo patients also improved noticeably in TRIUMPH-4 (a -2.43 point change in the abstract), so the gap versus placebo is smaller than the headline reduction from baseline.

TOGETHER-PsA: Taltz plus Zepbound

The third highlighted presentation is an oral talk on Wednesday, Nov. 11, at 9:45 a.m. Eastern (abstract 2942) on the Phase 3b TOGETHER-PsA trial. It compared Taltz plus Zepbound with Taltz alone in adults with psoriatic arthritis and obesity or overweight with at least one weight-related condition.

Lilly says the share of patients reaching ACR50, a 50% improvement on the American College of Rheumatology response criteria, “further increased from Week 36.” The ACR abstract for the talk reports ACR50 of 43.7% at week 52 with the combination versus 15.7% with Taltz alone. At the week-36 primary analysis, published earlier in a peer-reviewed paper indexed on PubMed, ACR50 was 33.5% with the combination versus 20.4% with Taltz alone. Lilly also notes that week-52 analyses are prespecified but exploratory objectives “without multiplicity control,” and that comparisons between timepoints are descriptive.

What is not known

• Full results. The TRIUMPH-1 knee data and the TOGETHER-PsA one-year data are not yet public beyond the release’s summary. The presentations are scheduled for Nov. 10 and Nov. 11.
• Peer review. None of these knee osteoarthritis results has been published in a peer-reviewed journal yet. A meeting abstract is a shorter and less fully reviewed record.
• Regulatory filings. The release does not say when Lilly will seek approval of retatrutide for knee osteoarthritis pain.

Retatrutide’s sleep apnea results appeared in NEJM last month (report), and Lilly reported a head-to-head Phase 3 win over Ozempic in type 2 diabetes in October (report).

This story summarizes a company press release and a meeting abstract. It is not medical advice.