NU676 Unit 7 Journal Club, EMERGENT-2 Appraisal Example

A New Mechanism for One Clinic's Decision: A Journal Club Appraisal of EMERGENT-2, the Xanomeline-Trospium Trial, for a Patient Who Gained Twenty Kilograms on Olanzapine

[Student Name]

Purdue University Global

NU676: PMHNP Diagnosis and Management Across the Lifespan Clinical II

Unit 7 Journal Club Appraisal

[Instructor Name]

[Date]

The clinic and patient are composite; details are bracketed. The trial is real and cited.

The Clinic's Question

Mr. [E.] is a [34]-year-old man with schizophrenia who has been stable on olanzapine [15] mg for [three] years after two hospitalizations. He has gained [20] kg, his A1c is [6.2] percent and he has stopped playing basketball because of his weight. He asks whether there is "a drug that won't do this." Xanomeline-trospium, a combination that acts on muscarinic receptors rather than blocking dopamine D2 receptors, has recently become available. The clinic's question: for a stable outpatient with metabolic problems on olanzapine, is there enough evidence to switch him to xanomeline-trospium?

The Trial

EMERGENT-2 was a five-week, randomized, double-blind, placebo-controlled, flexible-dose phase 3 trial at sites in the United States. It enrolled adults with schizophrenia experiencing an acute exacerbation of psychosis requiring hospitalization; [252] participants were randomized to xanomeline-trospium or placebo. The primary outcome was the change in total score on the Positive and Negative Syndrome Scale at week five (Kaul et al., 2024).

Results. The PANSS total score fell by [21.2] points with xanomeline-trospium and [11.6] points with placebo, a difference of [9.6] points, with a Cohen's d of [0.61]. All secondary outcomes also favored the drug. The most common adverse events were constipation, dyspepsia, nausea, vomiting and headache; hypertension was reported in [10] percent of the treatment group and [1] percent of the placebo group. Rates of extrapyramidal symptoms, akathisia, weight gain and somnolence were similar to placebo, as was discontinuation for adverse events (Kaul et al., 2024).

Appraisal: Is the Trial Valid?

Strengths. Randomization and double-blinding protect against the most common biases. A prespecified primary outcome, a validated scale and a modified intention-to-treat analysis are appropriate. The effect is sizable. The adverse event profile was reported in detail.

Limits. First, the comparator was placebo, not an existing antipsychotic, so the trial cannot say whether the drug is as effective as olanzapine. Second, the trial lasted five weeks, far shorter than the years for which Mr. [E.] would take it; longer open-label studies were under way at publication. Third, the trial was funded by the manufacturer, which does not invalidate it but is a reason to look for independent replication. Fourth, the cholinergic side effects, nausea, vomiting and constipation, were common enough to matter for adherence.

How big is the effect? A network meta-analysis of oral antipsychotics for acute treatment of multi-episode schizophrenia found that almost all established drugs outperformed placebo, with most effect sizes in the small to moderate range and clozapine among the most effective (Huhn et al., 2019). An effect size of about [0.6] in a single five-week trial places xanomeline-trospium within the range of established agents, though comparison across trials is uncertain.

Appraisal: Does It Apply to Mr. [E.]?

The trial answers whether the drug reduces acute psychosis more than placebo in hospitalized adults over five weeks; the clinic is asking whether a stable outpatient will stay well and lose weight after switching from olanzapine, which is a different question.

Three gaps matter most for this decision.

1. Population. Trial participants were acutely ill and hospitalized; he is stable. The risk that concerns the clinic is relapse during a switch, which the trial did not study.

2. Comparison. There was no olanzapine arm. The absence of weight gain versus placebo over five weeks is encouraging, but it does not show weight loss after switching from a drug that caused gain.

3. Duration. Five weeks cannot show long-term metabolic benefit or long-term tolerability.

Recommendation for the Clinic

The trial supports xanomeline-trospium as an effective treatment for acute psychosis with a side effect profile that avoids weight gain and movement effects in the short term. It does not yet show that switching a stable patient from olanzapine is safe or that it will reverse his weight gain. For Mr. [E.], the journal club recommended:

1. Discuss the switch as an option, explaining what is and is not known, and let him weigh it.

2. If he chooses to switch, cross-taper slowly over [four to six] weeks, with close monitoring for relapse and for nausea, constipation and blood pressure.

3. In parallel, address weight directly with lifestyle support and consider metformin, which reduced antipsychotic-related weight gain in a randomized trial in adults with schizophrenia, especially combined with lifestyle intervention (Wu et al., 2008), whether or not he switches.

4. Revisit the decision when longer-term and comparative data are published.

How the Recommendation Was Shared With Him

At his next visit, the journal club's conclusion was explained to Mr. [E.] in plain terms. A new kind of antipsychotic has shown in a short trial that it can reduce psychosis without the weight gain or stiffness of older drugs, but it has not yet been tested against olanzapine or over years, and nobody knows how people do when they switch from a medicine that is working. The likely side effects in the first weeks are nausea, indigestion and constipation, and his blood pressure would need checking. He asked whether he would lose the weight he had gained. He was told that the trial did not answer that, that switching might stop further gain, and that losing weight would still depend on the lifestyle plan and possibly metformin. He decided to start the weight plan and metformin now and to revisit the switch in three months, after talking with his mother, who had seen his last relapse.

What the Journal Club Learned

The discussion showed very clearly how easily a new mechanism and a clear headline can be read as an answer to a question the trial never asked. Matching each element of the trial, population, comparator, outcome and duration, to the clinic's actual decision was what made the gaps visible. The group agreed to use the same four-part match for the next new drug the clinic considers, and to write down, before reading the results section of any trial, the exact question the clinic needs it to answer. Doing so separates what a trial shows from what the clinic hopes it shows, and it makes the gaps easier to explain to patients who have read about a new medicine and want to know whether it is right for them in particular.

References

Huhn, M., Nikolakopoulou, A., Schneider-Thoma, J., Krause, M., Samara, M., Peter, N., Arndt, T., Bäckers, L., Rothe, P., Cipriani, A., Davis, J., Salanti, G., & Leucht, S. (2019). Comparative efficacy and tolerability of 32 oral antipsychotics for the acute treatment of adults with multi-episode schizophrenia: A systematic review and network meta-analysis. The Lancet, 394(10202), 939-951. https://doi.org/10.1016/S0140-6736(19)31135-3

Kaul, I., Sawchak, S., Correll, C. U., Kakar, R., Breier, A., Zhu, H., Miller, A. C., Paul, S. M., & Brannan, S. K. (2024). Efficacy and safety of the muscarinic receptor agonist KarXT (xanomeline-trospium) in schizophrenia (EMERGENT-2) in the USA: Results from a randomised, double-blind, placebo-controlled, flexible-dose phase 3 trial. The Lancet, 403(10422), 160-170. https://doi.org/10.1016/S0140-6736(23)02190-6

Wu, R.-R., Zhao, J.-P., Jin, H., Shao, P., Fang, M.-S., Guo, X.-F., He, Y.-Q., Liu, Y.-J., Chen, J.-D., & Li, L.-H. (2008). Lifestyle intervention and metformin for treatment of antipsychotic-induced weight gain: A randomized controlled trial. JAMA, 299(2), 185-193. https://doi.org/10.1001/jama.2007.56-b