Lilly Combo Trial Boosts Weight Loss vs Zepbound

A mid-stage, multi-arm trial of Eli Lilly’s (LLY) EloraTZP regimen found that combining tirzepatide (marketed as Zepbound) with the investigational amylin receptor agonist eloralintide produced greater weight loss than either treatment alone at 48 weeks. In the highest-dose combination arm, participants who remained on treatment achieved a 23.3% mean reduction in body weight.

In comparison, participants receiving Zepbound alone recorded an average 14.8% loss in body weight over the same 48-week period. Those treated with the highest dose of eloralintide alone saw an average 11.1% reduction, underscoring a stepwise difference between monotherapy and the combination approach in this trial.

These results come from an EloraTZP mid-stage study that evaluated multiple dosing arms to assess how adding eloralintide to tirzepatide affects body-weight outcomes. The data suggest that, within the study population that stayed on therapy, higher-dose combination treatment was associated with substantially greater mean weight reduction.

The EloraTZP trial was structured to compare the highest-dose combination of tirzepatide and eloralintide against each agent given alone. By including Zepbound-only and eloralintide-only arms, investigators were able to measure incremental effects on weight loss attributable to the combination in this mid-stage setting.

The 14.8% mean weight loss observed with Zepbound alone and 11.1% with eloralintide alone provide reference points for interpreting the 23.3% reduction seen in the highest-dose combination arm. All figures are reported for participants who remained on their assigned treatment through 48 weeks.

Across the trial, the most common adverse events were mild-to-moderate gastrointestinal issues. These side effects occurred mainly during the dose-escalation phase of treatment, when participants were being titrated to higher doses of tirzepatide, eloralintide, or the combination.

Gastrointestinal events were more frequent in the combination arms than with either drug alone. While detailed discontinuation rates and specific event frequencies were not provided in the verified data, the pattern indicates a higher burden of GI symptoms in participants receiving both agents together compared with monotherapy arms.

The efficacy and tolerability findings from this EloraTZP mid-stage trial were presented at the European Association for the Study of Diabetes annual meeting in Milan on Sept. 30, 2026. The presentation highlighted both the enhanced weight-loss outcomes with the combination and the increased rate of gastrointestinal adverse events in those arms.

These results position the tirzepatide–eloralintide combination as a potential next step in obesity and diabetes-related weight-management research, subject to further evaluation in larger and longer-duration studies. The current data set provides an early look at how pairing Zepbound with an amylin receptor agonist may expand therapeutic options, while also emphasizing the need to manage tolerability during dose escalation.