Lilly Advances Next-Wave Obesity Pipeline With Japanese Phase 1 Combo Study

Eli Lilly And Company (LLY) announced an update on their ongoing clinical study.

Study Overview: Eli Lilly and Company is running a Phase 1 trial in Japan titled “A Multiple-Ascending Dose Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of LY3841136 Monotherapy, and LY3841136 in Combination With Tirzepatide, in Japanese Participants With Obesity or Overweight.” The study aims to see how safe the new drug LY3841136 is on its own and when used together with Lilly’s obesity drug tirzepatide, and how the body handles and responds to it. This work is an early step in testing a possible next-generation obesity treatment in an important regional market.

Intervention/Treatment: The study tests LY3841136, an injectable drug given under the skin, both alone and in various combinations with tirzepatide. Placebo injections are also used for comparison. LY3841136 is designed to help with weight management, and pairing it with tirzepatide could aim for stronger or more durable weight-loss effects than tirzepatide alone.

Study Design: This is an interventional, randomized trial, meaning participants are randomly assigned to different treatment groups. It uses a parallel-group model, so each group receives a different drug or combination at the same time. The trial is double-blind, so neither participants nor investigators know who is getting the active drugs or placebo. The main purpose is treatment-focused, looking at safety and early effectiveness signals rather than proving final clinical benefit.

Study Timeline: The study has been listed as completed, with follow-up and analysis already underway. Key setup work, including initial submissions, began around March 1, 2024, marking the formal start of the regulatory process. Primary results would be expected soon after final participant visits, with the estimated full completion set before the latest update. The trial record was most recently updated on January 15, 2026, signaling that Lilly has refreshed key information and that data review or reporting is progressing.

Market Implications: For investors, this update reinforces Lilly’s push to build a deeper pipeline around obesity, beyond its current star drug tirzepatide. A safe and effective LY3841136, especially in combination with tirzepatide, could extend Lilly’s lead in the fast-growing weight-loss market and support long-term revenue growth. The completed Phase 1 status lowers early development risk but does not yet answer questions on real-world weight loss or long-term safety. Competitors like Novo Nordisk and emerging players in obesity drugs will watch closely, as strong data could tighten the race and support Lilly’s premium valuation. Near term, sentiment for LLY may benefit from the perception of a broad and layered obesity franchise, but share price impact will likely depend on the strength and timing of forthcoming data readouts.

This study has been completed and recently updated, and further details are available on the ClinicalTrials portal.

To learn more about LLY’s potential, visit the Eli Lilly And Company drug pipeline page.