How does Exxua (gepirone) compare to buspirone and available options for MDD?

Comment by InpharmD Researcher

Due to its recent approval and limited commercial use (withdrawn and relaunched), there appears to be a lack of comparative data between gepirone and other options for major depressive disorder (MDD) at this time. Available studies are placebo-controlled or to establish dosing protocols (see Tables). However, preliminary data suggests gepirone may have a favorable tolerability profile compared to other antidepressants.

Background

Gepirone is a newly approved antidepressant with a novel mechanism as a selective 5-HT1A receptor agonist, distinguishing it from first-line SSRIs and SNRIs. While its overall antidepressant effect size is considered modest, gepirone's key advantages lie in its favorable tolerability profile, notably a reduced risk of sexual dysfunction and emotional blunting compared to common antidepressants. This positions it as a potential alternative for patients who are intolerant of, or do not respond to, first-line therapies, particularly those with anxious depression. In comparison to the related azapirone buspirone, which is primarily used for anxiety, gepirone is specifically developed and approved for Major Depressive Disorder (MDD) in an extended-release formulation, and it is expected to hold greater clinical relevance for this condition. Although its commercial journey has been interrupted (approved in 2023, withdrawn in 2024, with a planned relaunch in 2025), gepirone offers a distinct therapeutic option for MDD, especially for patients prioritizing tolerability. [1, 2]

Based on the 2019 APA guidelines for treating depression in adults, the panel recommends that clinicians offer either psychotherapy or second-generation antidepressants as initial treatment, using a shared decision-making approach with patients. For psychotherapy, comparative effectiveness studies showed similar results across different models, so the panel does not recommend one specific type over others among behavioral therapy, cognitive therapy, cognitive-behavioral therapy, interpersonal psychotherapy, psychodynamic therapy, and supportive therapy. If combined treatment is being considered, the panel specifically recommends cognitive-behavioral therapy or interpersonal psychotherapy paired with a second-generation antidepressant. For patients who are partial or non-responders to initial antidepressant treatment, the panel recommends switching from medication alone to cognitive therapy alone or switching to a different antidepressant medication. Regarding relapse prevention, the panel conditionally suggests offering psychotherapy rather than antidepressant medication or treatment as usual. The guidelines emphasize that most patients prefer psychotherapy over medication (about 75%), though an important minority (25%) prefer pharmacotherapy. While combined treatments may be more effective than either treatment alone in some populations, they also involve greater costs, side effects, and patient demands, with some research suggesting they may interfere with psychotherapy's enduring effects. For patients with chronic and treatment-resistant depression, combined treatment is typically recommended. The panel notes that psychotherapies generally demonstrate longer-term effects lasting 6-12 months after treatment ends, while antidepressants have very high relapse rates after discontinuation, making psychotherapy potentially superior for long-term outcomes. [3]

The 2022 Department of Veterans Affairs (VA)/Department of Defense (DoD) clinical guidelines on the management of major depressive disorder (MDD) provide recommendations regarding the use of pharmacologic and non-pharmacologic interventions in adult patients. The guideline emphasizes an evidence-based approach, combining both pharmacotherapy and psychotherapy based on patient preference and specific clinical scenarios. It advocates for treatment in either primary care settings using collaborative care models or within specialty mental health care with a focus on patient-centered practices and shared decision-making. In patients with uncomplicated MDD, psychotherapy or pharmacotherapy monotherapy is recommended based on patient preference, with consideration of treatment modalities based upon individual factors such as the severity, chronicity, prior treatment response, and patient characteristics. Psychotherapy options include behavioral therapy, cognitive behavioral therapy, and psychodynamic therapy, among others; no ranking of psychotherapy type is provided. For the treatment of uncomplicated MDD in patients who are initiating pharmacotherapy treatment or previously responded well to pharmacotherapy, the following are recommended: bupropion, mirtazapine, a serotonin-norepinephrine reuptake inhibitor, trazodone, vilazodone, vortioxetine, or a selective serotonin reuptake inhibitor. A combination of pharmacotherapy and psychotherapy is recommended for patients with severe, persistent (>2 years), or recurrent (≥2 episodes) MDD. The guideline also delineates strategies for managing cases with partial or no response to initial treatments, highlighting the potential role of pharmacologic augmentation with second-generation antipsychotics, switching to another antidepressant drug class, or alternatives such as repetitive transcranial magnetic stimulation (rTMS) and electroconvulsive therapy (ECT). The guidelines underscore the importance of ongoing monitoring and the use of measurement-based care to track treatment progress and outcomes. In high-risk populations, such as those with persistent depressive disorder, the guidelines suggest extending treatment duration to prevent relapses. Overall, the guideline provides a comprehensive, systematic framework for aligning depression treatment with the latest evidence and clinical practice, ensuring a patient-centric approach to managing MDD in both veteran and active military populations. [4]

References:

[1] Konstantakopoulos G, Argyropoulos D, Tsionis A. The preclinical discovery and development of gepirone hydrochloride extended-release tablets: the first oral selective 5-HT1A receptor agonist for the treatment of major depressive disorder. Expert Opin Drug Discov. 2025;20(10):1223-1237. doi:10.1080/17460441.2025.2552144
[2] Phillips B, O'Connor C, St Onge E. Gepirone: A New Extended-Release Oral Selective Serotonin Receptor Agonist for Major Depressive Disorder. J Pharm Technol. 2024;40(5):230-235. doi:10.1177/87551225241269179
[3] American Psychological Organization (APA). APA Clinical Practice Guidelines for the Treatment of Depression Across Three Age Cohorts. Published February 2019. November 24, 2025. https://www.apa.org/depression-guideline/guideline.pdf
[4] Department of Veterans Affairs/Department of Defense (VA/DoD). VA/DoD Clinical Practice Guideline for the Mangement of Major Depressive Disorder. Published February 2022. Accessed November 24, 2025. https://www.healthquality.va.gov/guidelines/MH/mdd/VADODMDDCPGFinal508.pdf

Literature Review

A search of the published medical literature revealed 2 studies investigating the researchable question:

How does Exxua (gepirone) compare to buspirone and available options for MDD?

Level of evidence

X - No data  Read more→



Please see Tables 1-2 for your response.


Sustained efficacy of gepirone-IR in major depressive disorder: a double-blind placebo substitution trial
Design

Double-blind, placebo-controlled trial

N= 134 (open-label phase)

N= 70 (double-blind phase)

Objective To evaluate the efficacy of gepirone immediate-release (gepirone-IR) for relapse prevention in outpatients with major depressive disorder (MDD) who had responded to initial gepirone-IR therapy
Study Groups

Gepirone-IR (n= 36)

Placebo (n= 34)

Inclusion Criteria Outpatients at least 18 years of age with MDD of at least 4 weeks' duration and a HAM-D25 score ≥20
Exclusion Criteria Primary psychiatric diagnosis other than MDD, history of manic episode, organic mental disorder, substance abuse within the past year, seizure disorder, hypersensitivity to gepirone or buspirone, clinically significant medical condition, recent exposure to psychotropic medications, women of childbearing potential
Methods

Patients with MDD were treated with open-label gepirone-IR 20 to 90 mg/day for 6 weeks. Responders were randomized to gepirone-IR or placebo for an additional 6 weeks. Efficacy was assessed using HAM-D17, HAM-D25, and CGI scales. Adverse events, vital signs, ECG, and laboratory tests were monitored.

Duration Open-label phase: 6 weeks Double-blind phase: 6 weeks
Outcome Measures

Primary: Time to relapse defined by HAM-D17 and CGI criteria

Secondary: Incidence of adverse events

Baseline Characteristics   Gepirone-IR (n= 36) Placebo (n= 34)
Males: Females 19:17 20:14
Race - Caucasian 33 (92%) 33 (97%)
Age (mean ± S.D. years) 42.7 ± 9.1 42.7 ± 10.1
Weight (mean ± S.D., lbs) 169 ± 38.1 174 ± 37.6
Mean HAM-D17 total score at beginning of phase (S.D.) 7.6 (5.3) 9.1 (4.6)
Results   Gepirone-IR (n= 36) Placebo (n= 34) p-Value
Relapse rate (HAM-D17 criterion) 26% 55% 0.030
Relapse rate (CGI criterion) 31% 61% 0.023
Adverse Events The most frequent adverse events with gepirone-IR were dizziness, nausea, headache, and somnolence. Discontinuations due to adverse events were 26.9% in the open-label phase and 6% in the double-blind phase
Study Author Conclusions Gepirone-IR was significantly more effective than placebo for relapse prevention in MDD and demonstrated acceptable tolerability. A longer duration study is needed to confirm these results.
Critique The study demonstrated the efficacy of gepirone-IR in preventing relapse of MDD, but the high rate of adverse events and discontinuations due to intolerability are limitations. The study's relatively short duration and the need for a longer relapse-prevention study are noted. The potential for improved tolerability with an extended-release formulation is suggested.

 

References:

Timmer CJ, Sitsen JMA. Single- and multiple-dose pharmacokinetics and tolerability of gepirone extended-release. Clin Drug Investig. 2002;22(12):819-826. doi:10.2165/00044011-200222120-00002

Single- and Multiple-Dose Pharmacokinetics and Tolerability of Gepirone Extended-Release
Design

Three randomised, placebo-controlled studies

N= 115

Objective To determine the single- and multiple-dose pharmacokinetic profile of gepirone extended-release (ER) in healthy individuals
Study Groups

Study 1: Gepirone-ER 10, 20, 25, 40, 75mg (n= 60)

Study 2: Gepirone-ER 20mg (n= 39) Study 3:

Gepirone-ER 120mg (n= 16)

Inclusion Criteria Healthy male volunteers aged 18-40 years, in good health, bodyweight 60-90kg, within 10% of ideal weight
Exclusion Criteria History of drug or alcohol abuse, gastrointestinal disease, malabsorption, renal or hepatic disease, significant psychiatric disorders, concomitant medication, previous gepirone studies, heavy smoking
Methods

Blood samples were obtained to measure plasma levels of gepirone and 1-PP metabolite. Pharmacokinetic parameters included Cmax, tmax, and AUC. Dosages ranged from 10 to 75 mg/day for 6 days (study 1), 20 mg/day for 7 days (study 2), and 120 mg/day for 7 days (study 3).

Duration

Study 1: 6 days

Study 2: 7 days

Study 3: 7 days

Outcome Measures

Primary: Pharmacokinetic profile (Cmax, tmax, AUC)

Secondary: Tolerability and incidence of adverse events

Baseline Characteristics   Study 1 (n= 60) Study 2 (n= 39) Study 3 (n= 16)
Age, years 18-40 18-40 18-40
Gender Male Male Male
Bodyweight, kg 60-90 60-90 60-90
Results   Study 1 Study 2 Study 3
Cmax (μg/L) 1.20 to 9.14 3.96 to 4.44 18.7
AUC (μg*h/L) 14.4 to 121.0 45.54 to 51.41 237.8
tmax (h) 5 3.1 to 4.1 4-6
Adverse Events Gepirone-ER was generally well tolerated at all doses except for 120 mg/day. Adverse events included headache, dizziness, and nausea, with higher incidence in gepirone-ER than placebo recipients
Study Author Conclusions

Gepirone and 1-PP exhibited linear pharmacokinetic profiles. Gepirone-ER reduced peak/trough fluctuations in plasma concentrations while maintaining total exposure. Gepirone-ER may reduce adverse events compared with gepirone immediate-release, potentially improving response.

Critique

The study's strengths include a well-defined pharmacokinetic analysis and clear demonstration of reduced plasma fluctuations with gepirone-ER. Limitations include the focus on healthy male volunteers, which may not generalize to broader patient populations, and the exclusion of female participants and those with comorbid conditions.

 

References:

Timmer CJ, Sitsen JMA. Single- and multiple-dose pharmacokinetics and tolerability of gepirone extended-release. Clin Drug Investig. 2002;22(12):819-826. doi:10.2165/00044011-200222120-00002