ADA: Obesity partners Zealand and Roche aim for weight loss ‘sweet spot’ with amylin agonist

Roche and Zealand Advance Petrelintide to Phase 3 with Focus on Tolerability

Roche and Zealand Pharma presented Phase 2 data for their amylin analog, petrelintide, at the 2026 American Diabetes Association conference. The ZUPREME-1 study showed 9% weight reduction at 42 weeks, which, while below analyst expectations and a rival Eli Lilly candidate, met Roche's internal goals. The companies emphasize petrelintide's tolerability, with a placebo-like discontinuation rate, positioning it as a first-line option for patients seeking approximately 10% weight loss without significant side effects. They aim to address unmet needs in the complex obesity landscape by offering a differentiated treatment modality.

• Roche and Zealand Pharma are strategically positioning petrelintide, an amylin analog, not for maximum weight loss but for optimal tolerability and adherence. Despite achieving 9% weight reduction at 42 weeks in the Phase 2 ZUPREME-1 study, which was less than some analyst predictions and a competitor, the companies believe this level of efficacy with placebo-like side effects represents a 'sweet spot' for a first-choice medicine, catering to patients prioritizing comfort over aggressive weight loss.
• Beyond petrelintide, Roche is also advancing enicepatide, a dual GLP-1/GIP receptor agonist, which demonstrated substantial efficacy in its Phase 2 CT388-103 trial. This candidate achieved a 22.5% placebo-adjusted weight loss after 48 weeks, with a significant proportion of participants (26% losing >30% and nearly 40% shedding >25%) achieving profound weight reduction and many no longer meeting the definition of obesity, highlighting its potential for significant health benefits.
• Both petrelintide and enicepatide are progressing rapidly in their development pipelines. Petrelintide is slated to enter Phase 3 studies in the second half of the year, with a focus on quick market access. Enicepatide is already in two standalone Phase 3 studies, and a mid-stage trial combining enicepatide with petrelintide is also planned for the latter half of this year, indicating a comprehensive strategy to address various patient needs in the obesity treatment landscape.

Petrelintide's ZUPREME-1: A Tolerability-Focused Approach to Weight Loss

Tirzepatide Clinical Evidence (2025)

A comprehensive analysis of nine randomized controlled trials encompassing 7,111 participants demonstrated tirzepatide's substantial efficacy in obesity management. This dual GIP/GLP-1 receptor agonist, administered as a weekly injection ranging from 5 mg to 15 mg, achieved a mean percentage body weight reduction of 16.03% (95% CI -18.91 to -13.14) at medium-term follow-up of 12-18 months. The proportion of participants achieving clinically meaningful 5% weight reduction increased significantly with a risk ratio of 3.60 (95% CI 2.44 to 5.30). Long-term efficacy at 3.5 years remained robust, with sustained weight reduction of 15.66% and continued high rates of clinically significant weight loss.

From a safety perspective, tirzepatide demonstrated an acceptable tolerability profile with some notable considerations. Medium-term treatment was associated with an increase in non-serious adverse events (RR 1.33, 95% CI 1.03 to 1.71), while showing little difference in major adverse cardiovascular events (MACE) or mortality compared to placebo. The intervention showed little difference in adverse events leading to treatment withdrawal, though there was very uncertain evidence regarding serious adverse events. Long-term safety data revealed similar patterns, with maintained tolerability and no significant differences in MACE or mortality outcomes.

Network Meta-Analyses of Anti-Obesity Medications (2025)

A systematic evaluation of 22 reviews, with 14 prioritized for analysis, established the comparative effectiveness landscape of current obesity pharmacotherapies. At six months, subcutaneous tirzepatide emerged as the most effective intervention, achieving weight reductions ranging from 9 kg at the 5 mg dose to 12 kg at the 15 mg dose. Subcutaneous semaglutide 2.4 mg demonstrated comparable efficacy with weight loss between 11.5 and 12.5 kg across multiple network meta-analyses. Updated analyses incorporating 11 additional trials confirmed tirzepatide's superiority at the 15 mg dose when indirectly compared to semaglutide 2.4 mg, though lower tirzepatide doses (5 mg and 10 mg) did not demonstrate this advantage.

The safety profile analysis revealed a consistent pattern where agents achieving the greatest weight loss, specifically tirzepatide and semaglutide 2.4 mg, were generally associated with increased risk of safety issues compared to placebo. However, both interventions maintained favorable benefit-risk profiles sufficient to support their clinical use. The network meta-analyses provided robust evidence for positioning these agents as first-line pharmacological interventions for obesity management, with dose-dependent efficacy considerations informing optimal prescribing strategies.

Male Fertility Impact Study (2025)

A comprehensive analysis of 32 studies specifically examined the effects of obesity interventions on male reproductive health outcomes. Bariatric surgery studies (18 investigations) revealed no clinically significant changes in semen parameters or DNA damage following surgical intervention, suggesting reproductive safety of this approach. Pharmacotherapy studies evaluating metformin and liraglutide (5 studies) provided insufficient data to draw definitive conclusions regarding fertility impact, highlighting an important evidence gap requiring further investigation.

Lifestyle intervention studies (10 investigations) demonstrated modest but statistically significant improvements in sperm quality parameters. Specifically, lifestyle modifications achieved improvements in sperm normal morphology with a mean difference of 0.59% (95% CI 0.23, 0.94) and enhanced progressive motility by 10.56% (95% CI 8.97, 12.15). These findings suggest that comprehensive lifestyle approaches may offer dual benefits for weight management and reproductive health in men with obesity, though the clinical significance of these improvements requires further longitudinal assessment to determine impact on fertility outcomes.

Enicepatide's CT388-103: Unlocking Significant Weight Loss and Health Benefits

The current landscape of obesity clinical trials demonstrates remarkable diversity in therapeutic approaches, ranging from novel pharmacological interventions to advanced endoscopic procedures and comprehensive lifestyle modifications. These studies collectively represent the most comprehensive effort to address obesity through evidence-based interventions, with trial designs evolving to capture both efficacy and real-world applicability across diverse patient populations.

Roche's Strategic Portfolio: Combining Therapies for Diverse Obesity Needs

Recent clinical trials are investigating several promising combination therapy approaches for obesity, with pharmaceutical companies exploring both multi-target single molecules and combinations of existing agents. These strategies aim to achieve greater weight loss efficacy than monotherapy approaches while addressing the complex pathophysiology of obesity through multiple mechanisms of action.

The most extensively studied combination approach involves bimagrumab plus semaglutide, currently in Phase 2 trials with 507 adults with obesity. This combination targets both metabolic regulation through GLP-1 receptor agonism and muscle preservation through activin receptor inhibition. The high-dose combination (bimagrumab 30 mg/kg plus semaglutide 2.4 mg) achieved superior weight loss of -17.8 kg at 48 weeks compared to -14.2 kg with semaglutide alone and -9.3 kg with bimagrumab alone, demonstrating clear synergistic effects. Additionally, tirzepatide is being evaluated in specialized populations, including a Phase II trial combining it with standard fertility-sparing treatment for obese patients with endometrial cancer, reflecting the expanding therapeutic applications of combination approaches.

Multi-receptor agonist molecules represent another significant advancement, with retatrutide emerging as the leading triple agonist targeting GLP-1, GIP, and glucagon receptors. In Phase 2 studies, retatrutide achieved remarkable weight loss of up to 24.2% in individuals with obesity and 16.9% in those with type 2 diabetes, while improving multiple cardiometabolic parameters including an 82% reduction in hepatic steatosis. Survodutide, a dual GLP-1/glucagon receptor agonist, is advancing through Phase 3 trials (SYNCHRONIZE-1) in 725 participants across 14 countries, targeting both obesity and associated comorbidities. These unimolecular multi-agonist approaches offer the advantage of coordinated receptor activation while potentially reducing pill burden and improving adherence compared to combination regimens of separate agents.