Cobenfy's $155M Miss Exposes Structural Adoption Barriers That Will Haunt Every Muscarinic Follower

BMS' Cobenfy Faces Market Challenges Despite Novel Schizophrenia Approval

Bristol Myers Squibb's (BMS) Cobenfy, approved by the FDA in 2024 as the first novel schizophrenia drug in 35 years, is facing challenges gaining market traction, with 2025 sales reaching $155 million, significantly below analyst predictions. Despite its novel muscarinic mechanism of action, tolerability issues, particularly gastrointestinal side effects, persist. BMS attributes the slow uptake to the time physicians need to become confident prescribing a new drug class. Meanwhile, MapLight Therapeutics is positioning its muscarinic receptor agonist, ML-007C-MA, as a competitor, having reported mixed Phase 2 results that showed efficacy but were viewed by analysts as less impactful than Cobenfy's Phase 3 data. The broader schizophrenia market, characterized by high unmet need, is seen as having room for multiple muscarinic drugs.

• Cobenfy's Market Performance and Tolerability Challenges: Approved in 2024, Bristol Myers Squibb's Cobenfy (xanomeline and trospium chloride) was hailed as a breakthrough for schizophrenia. However, its 2025 sales of $155 million fell short of early analyst forecasts. Despite its novel muscarinic agonist/antagonist mechanism, the drug faces tolerability issues, particularly pro-cholinergic gastrointestinal symptoms, which can impact patient compliance. BMS suggests the slow adoption is typical for new mechanisms of action, as prescribers require time to gain confidence.
• MapLight's Competitive Entry and Phase 2 Results: MapLight Therapeutics is developing ML-007C-MA, another muscarinic receptor agonist, aiming to compete with Cobenfy. Its Phase 2 ZEPHYR trial showed the twice-daily formulation met the primary endpoint, reducing schizophrenia symptoms on the PANSS by 4.5 points at five weeks. However, a once-daily version failed, and analysts noted the efficacy appeared less robust than Cobenfy's 8-10 point reduction in Phase 3. MapLight emphasizes its drug's potential differentiation in tolerability and cognitive signals.
• Evolving Schizophrenia Treatment Landscape: The schizophrenia treatment paradigm is shifting towards muscarinic receptor agonists to address the severe side effects associated with older dopamine-targeting antipsychotics. While Cobenfy is the first-to-market, the high unmet need in schizophrenia suggests there is ample room for additional muscarinic drugs. Other companies like AbbVie (with emraclidine), Neurocrine BioSciences, and Neumora Therapeutics are also developing candidates in this space, highlighting a growing focus on novel mechanisms to improve both efficacy and tolerability.

Cobenfy's Tolerability Profile and Early Market Performance in Schizophrenia

Across the pivotal EMERGENT-2 and EMERGENT-3 trials in schizophrenia, xanomeline-trospium chloride (KarXT) demonstrated a generally favorable tolerability profile, with adverse event-related discontinuation rates closely comparable to placebo (7% vs. 6% in EMERGENT-2; 6.4% vs. 5.5% in EMERGENT-3). The most commonly reported treatment-emergent adverse events were gastrointestinal in nature, reflecting the compound's muscarinic mechanism. In EMERGENT-2, nausea occurred in 19% of KarXT-treated patients versus 6% on placebo; vomiting in 14% versus 1%; dyspepsia in 19% versus 8%; and constipation in 21% versus 10%. Comparable rates were observed in EMERGENT-3. Importantly, the majority of these procholinergic and anticholinergic events were mild, transient, and concentrated in the first one to two weeks of treatment — with median durations ranging from one day for vomiting to 13 days for dry mouth.

The role of trospium in attenuating xanomeline's cholinergic burden was specifically characterized in a dedicated Phase 1 study (NCT02831231). Relative to xanomeline administered alone, the combination reduced the composite incidence of five prespecified cholinergic adverse events — nausea, vomiting, diarrhea, excessive sweating, and salivary hypersecretion — by 46%, with each individual event reduced by at least 29%. Postural dizziness occurred in 11.4% of KarXT-treated subjects compared with 27.2% in the xanomeline-alone arm, and no episodes of syncope were observed in the KarXT group versus two in the xanomeline-alone group. Electrocardiographic parameters, vital signs, and laboratory values showed no meaningful differences between KarXT and placebo arms across studies.

A clinically significant differentiator for KarXT relative to established antipsychotic agents is its tolerability across domains typically associated with dopamine D2 receptor blockade. Extrapyramidal symptoms and akathisia were each reported at 0–1% in both treatment and placebo arms of EMERGENT-2, and no clinically relevant changes in body weight, metabolic parameters, or prolactin were observed. Somnolence rates were similarly low and comparable between groups (5% vs. 4% in EMERGENT-2). This absence of the cardiometabolic and motor side effects that frequently drive non-adherence with conventional and atypical antipsychotics represents a meaningful point of differentiation in the tolerability profile of this mechanism class.

MapLight's ML-007C-MA Phase 2 Results and Differentiation in Schizophrenia

Recent clinical trials in schizophrenia have evaluated novel mechanistic approaches beyond traditional dopamine D2 antagonism, yielding compelling efficacy and tolerability data. The studies below represent key Phase 2 and Phase 3 programs with distinct pharmacological profiles and well-characterized outcome data.

• EMERGENT-2 and EMERGENT-3 (Xanomeline/Trospium Chloride): These 5-week, randomized, double-blind, placebo-controlled trials in adults with acute schizophrenia demonstrated PANSS total score improvements of 9.6 points (EMERGENT-2; 95% CI −13.9 to −5.2; P < 0.001) and 8.4 points (EMERGENT-3; 95% CI −12.4 to −4.3; P < 0.001) versus placebo. A pooled analysis confirmed a least squares mean difference of −9.9 (95% CI −12.4 to −7.3; p < 0.0001; Cohen's d = 0.65), with an NNT of 5 (95% CI 4–8) for ≥30% PANSS reduction at Week 5. Subgroup analyses consistently favored active treatment regardless of age, sex, race, BMI, or baseline PANSS score.

• EMERGENT-2 and EMERGENT-3 Safety Profile: The combination was generally well tolerated, with most treatment-emergent adverse events (TEAEs) rated mild-to-moderate and NNH estimates >10 for the majority of TEAEs. Nausea and vomiting were exceptions, though discontinuation rates due to these events remained low (NNH = 49; 95% CI 28–182). Indirect comparisons indicated xanomeline/trospium was least likely among assessed agents to be associated with weight gain or somnolence/sedation, with likelihood-to-be-helped-or-harmed (LHH) analyses favoring active treatment across all assessed outcomes.

• EMERGENT-4 Long-Term Extension (Xanomeline/Trospium Chloride): Two 52-week open-label studies confirmed durability of response, with >75% of participants achieving a >30% PANSS improvement and a mean total score decrease of 33.3 points at one year. Participants who had received placebo during the randomized phases demonstrated statistically significant improvements across all efficacy measures beginning at Week 2 upon switching to active treatment. Long-term tolerability was confirmed with no new safety signals identified.

• Ulotaront Phase 2 Trial (TAAR1 Agonist): A 4-week double-blind, placebo-controlled study of ulotaront demonstrated a statistically significant improvement in PANSS total score versus placebo (p < 0.001; effect size: 0.45), with improvements also observed across secondary endpoints. Post-hoc analyses provided additional support for an effect on negative symptoms. In the subsequent 26-week open-label extension, further symptomatic improvement was observed, with a 67% completion rate. The safety profile was favorable — the incidence of adverse events was numerically lower than placebo (45.8% vs. 50.4%), and NNH values for individual ulotaront-associated adverse events were all >40.

The Evolving Muscarinic Landscape and Competition in Schizophrenia

The muscarinic receptor modulation space in schizophrenia is attracting increasing pipeline activity, with several compounds advancing through clinical development alongside xanomeline/trospium chloride (KarXT). Two notable emerging agents target M1 and/or M4 muscarinic acetylcholine receptors, consistent with the mechanistic rationale underpinning KarXT's efficacy. However, available literature does not detail specific intervention models (e.g., parallel assignment, crossover) for these trials.

Navigating the Novelty: Muscarinic Agonists in Schizophrenia

The recent FDA approval of Cobenfy (xanomeline-trospium) marked a significant milestone, introducing the first truly novel mechanism for schizophrenia treatment in over three decades. By targeting muscarinic M1 and M4 receptors, Cobenfy offers a non-dopaminergic pathway to address both positive and negative symptoms, a critical advance given the limitations and side effects associated with traditional dopamine D2 receptor antagonists. This shift is particularly important as existing evidence indicates a substantial unmet need for therapies that improve cognitive and negative symptoms without inducing metabolic or extrapyramidal side effects.

However, the initial market performance of Cobenfy, falling short of analyst expectations, highlights the inherent challenges in launching a pioneering drug. While the literature supports its efficacy and novel mechanism, the reported tolerability issues, particularly gastrointestinal adverse events, appear to be a significant hurdle. This underscores that even with a breakthrough mechanism, a drug's real-world success hinges on its overall benefit-risk profile and physician comfort with a new class.

The competitive landscape is also rapidly evolving. Other muscarinic agonists, such as MapLight Therapeutics' ML-007C-MA and Cerevel Therapeutics' emraclidine, are progressing through clinical development. Emraclidine, for instance, has shown a potentially favorable side-effect profile in early trials, with adverse events similar to placebo. ML-007C-MA, while having mixed Phase 2 results, is positioned as a potent dual M1/M4 agonist. This emerging competition means that future muscarinic drugs will need to demonstrate clear differentiation, perhaps through superior tolerability, once-daily dosing, or enhanced efficacy across a broader symptom spectrum, to carve out their market share. The schizophrenia market, characterized by high unmet need, certainly has room for multiple effective treatments, but differentiation will be key.