Neurocrine's Triple Agonist Enters Phase 1 Behind Identical Competitor With No Evident Differentiation

Neurocrine Initiates Phase I Trial for Triple Agonist Obesity Drug

Neurocrine Biosciences has initiated a Phase I clinical study for NBIP-‘1968, an investigational triple agonist targeting glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon receptors, as a potential treatment for obesity. The trial aims to assess the tolerability and safety of single ascending doses of NBIP-‘1968 in adult participants who are overweight or obese. This long-acting drug is intended for once-weekly subcutaneous injection, reflecting Neurocrine's commitment to exploring multiple scientific approaches to obesity.

• NBIP-‘1968 is designed as a triple agonist for GLP-1, GIP, and glucagon receptors, aiming to influence appetite control, energy regulation, and glycaemic balance. The therapy incorporates balanced glucagon receptor activity to support tolerability while seeking to optimize metabolic effects, addressing the complex biological pathways involved in obesity.
• This investigational therapy emerged from Neurocrine’s internal research efforts and is part of a broader obesity development program. The program also includes NBIP-‘2118, a corticotropin-releasing factor type 2 receptor agonist, which is also in Phase I trials, with future plans to develop NBIP-‘1968 in a fixed-dose combination with NBIP-‘2118.
• Obesity is recognized as a complex chronic disease driven by multiple biological pathways, underscoring the need for additional treatment options. It is associated with a range of serious health conditions such as type 2 diabetes, cardiovascular disease, sleep apnoea, certain cancers, osteoarthritis, and metabolic dysfunction-associated fatty liver disease.

Addressing Obesity's Complex Pathways with Triple Agonism

Current obesity treatment approaches — spanning lifestyle intervention, pharmacotherapy, and bariatric surgery — are constrained by a convergence of physiological, pharmacological, and clinical challenges that limit long-term efficacy. Obesity's chronic, relapsing nature means that no single intervention has demonstrated durable outcomes in isolation, and the field continues to grapple with the gap between short-term weight reduction and sustained metabolic benefit.

• Weight regain upon treatment discontinuation remains the most clinically significant limitation of pharmacotherapy. Discontinuation of GLP-1 receptor agonists results in a mean body weight gain of 5.63 kg and an HbA1c increase of 0.25%. Semaglutide carries the highest rebound risk (MD = −5.15 kg), followed by exenatide (MD = −3.06 kg), orlistat (MD = −1.66 kg), and liraglutide (MD = −1.50 kg), with rebound magnitude increasing with longer follow-up periods (>26 weeks: 7.31 kg vs. 2.51 kg).

• Compensatory metabolic adaptation undermines sustained weight loss by amplifying appetite signaling. Greater divergence between measured and predicted resting metabolic rate correlates with increased hunger, desire to eat, and composite appetite scores. Lifestyle-induced weight loss is further complicated by elevated ghrelin levels, which promote caloric intake and counteract weight loss programming.

• Gastrointestinal tolerability is a primary limitation of GLP-1 receptor agonists, with nausea, vomiting, diarrhea, and constipation representing the most frequently reported adverse effects for both semaglutide and tirzepatide. Post-bariatric surgery patients face additional GI morbidity, including flatulence, vomiting, and dumping syndrome — the latter reported in 65.5% of surgical patients.

• Serious but less frequent adverse events further complicate the pharmacological risk-benefit profile. Liraglutide carries a higher reporting frequency of pancreatitis, gallbladder disorders, and thyroid tumors, while semaglutide is more strongly associated with vomiting and abdominal pain. GLP-1 receptor agonists also pose aspiration risk under anesthesia due to delayed gastric emptying and may interfere with bowel preparation for colonoscopy.

• Nutritional deficiencies following bariatric surgery represent an inherent and often lifelong complication. Vitamin B12 deficiency is among the most prevalent micronutrient deficits in this population, and alopecia — reported in 79.3% of post-surgical patients alongside nail texture changes — serves as a clinical marker of underlying nutritional insufficiency. Despite this, dietary supplementation adherence in the postoperative period remains inconsistent and sporadic.

• Absence of long-term maintenance strategies reflects a systemic gap in clinical guidelines. Drug-dependent weight regain following anti-obesity pharmacotherapy discontinuation underscores the necessity of managing obesity as a chronic disease, with treatment frameworks that explicitly address not only initiation and titration but also long-term maintenance and safe discontinuation protocols.

Triple Agonists: The Next Frontier in Obesity Treatment?

The initiation of a Phase I study for NBIP-‘1968 by Neurocrine Biosciences signals a significant step in the ongoing evolution of obesity pharmacotherapy. With the global prevalence of obesity continuing to rise, there is an urgent and growing unmet need for therapies that can offer substantial and sustained weight loss, alongside improvements in metabolic health. Current anti-obesity medications, while effective, often fall short of the efficacy seen with bariatric surgery, highlighting the demand for more potent pharmacological interventions.

NBIP-‘1968, as a triple agonist targeting GLP-1, GIP, and glucagon receptors, represents the cutting edge of incretin-based therapies. Existing evidence suggests that multi-receptor agonists, particularly those incorporating glucagon receptor activity, can enhance energy expenditure in addition to reducing calorie intake, leading to augmented body weight loss. Studies indicate that dual and triple agonists demonstrate more pronounced reductions in blood pressure and overall mortality compared to single GLP-1 receptor agonists, without increasing risks of hypoglycemia or pancreatitis. This potential for enhanced efficacy and broader metabolic benefits positions NBIP-‘1968 to potentially differentiate itself in a market increasingly populated by GLP-1 and dual GLP-1/GIP agonists.

However, the development path for such complex molecules is not without its challenges. A key consideration for triple agonists is the careful balancing of activity across all three receptors to achieve optimal therapeutic effect while managing potential side effects. Gastrointestinal adverse events, such as nausea and vomiting, are common with incretin-based therapies and can impact patient tolerability and adherence, especially at higher doses. While the once-weekly subcutaneous dosing aims to improve convenience, the initial Phase I study will be crucial in establishing a favorable safety and tolerability profile, which is foundational for subsequent clinical development. The journey from early-phase trials to a widely adopted therapy is long, and the ability to demonstrate superior efficacy and a manageable safety profile will be paramount for NBIP-‘1968 to carve out a meaningful space in the future of obesity treatment.