June 8 (Reuters) - Eli Lilly ( LLY ) shares jumped 4% premarket on Monday, driven by compelling new data for its next-generation obesity drug, retatrutide, with analysts and investors expecting it to extend the drugmaker's lead in the booming weight-loss market.

Lilly presented full data from two retatrutide trials, one in naive type 2 diabetes patients and another in patients with obesity, at the American Diabetes Association meeting in New Orleans.

Investors were most encouraged by the performance of the lower 4 mg dose of retatrutide, which produced roughly 19% weight loss, comparable to the highest dose of current blockbuster therapy Zepbound.

Tolerability was broadly in line, including similar rates of treatment discontinuation and relatively low levels of vomiting.

However, side effects increased at higher doses.

"The 4mg dose efficacy data for retatrutide are compelling enough that first-line positioning cannot be dismissed," Citi analysts said in a note, adding that this positions the drug as "the next step for patients who have exhausted Lilly's tirzepatide efficacy."

Drugmakers in the obesity market are increasingly competing on tolerability, aiming to balance strong results with fewer side effects and simpler dosing to push wider adoption.

Lilly shares have gained 5.2% so far this year, following a huge rally in 2025. In contrast, its closest rival Novo Nordisk has seen a roughly 15% year-to-date decline.

"LLY has the pieces in place to further raise the standard of care in the obesity space, and we see the company if anything further extending its leadership position in the $200bn+ incretin/obesity market longer term," J.P. Morgan analyst Chris Schott said.

Lilly also presented additional data on other candidates, including its approved weight-loss pill and another experimental injectable, eloralintide.

RBC Capital Markets analyst Trung Huynh said the depth of Lilly's obesity portfolio "highlighted its leadership growing rather than a narrowing gap with competitors".

(Reporting by Mrinalika Roy in Bengaluru; Editing by Shinjini Ganguli)