FDA approves olanzapine injection for schizophrenia

All 3 monthly doses improved schizophrenia symptoms versus placebo in the phase 3 SOLARIS trial.

By
Mouj Hijazi
October 9, 2026
3 min

MDSpire News

Overview

The FDA approved once-monthly subcutaneous extended-release olanzapine (Weltruza) for adults with schizophrenia. Approval was supported by the phase 3 SOLARIS trial, in which all three studied doses improved PANSS total scores versus placebo at week 8. Weight gain and other adverse events were reported; no PDSS cases were observed in the reported trial data, although the prescribing information states that whether PDSS can occur with this formulation remains unknown.

Background

Long-acting injectable antipsychotics provide an extended-release formulation for treatment of schizophrenia. Weltruza is a once-monthly subcutaneous olanzapine formulation, with three strengths corresponding to daily oral olanzapine doses of 10 mg, 15 mg, and 20 mg. The approval was supported by SOLARIS, a randomized, double-blind, placebo-controlled phase 3 trial in adults aged 18 to 64 years with schizophrenia. Olanzapine has clinically important metabolic and other safety risks, and its prescribing information includes a boxed warning concerning increased mortality in older adults with dementia-related psychosis.

Data Highlights

Measure	Finding
SOLARIS initial treatment period	8 weeks; 675 adults randomized to monthly olanzapine 318 mg, 425 mg, or 531 mg, or placebo
Primary end point	Change from baseline in PANSS total score; all three olanzapine doses met the primary end point
Week 8 mean difference in PANSS change versus placebo	318 mg: −9.69 points; 425 mg: −11.25 points; 531 mg: −9.71 points
Weight gain during placebo-controlled period	35% with olanzapine versus 8% with placebo
PDSS observations	No cases reported during the initial 8 weeks; no suspected or confirmed cases across 3,470 injections through week 56
Adverse event–related discontinuations	1% to 3% in both treatment groups

Key Findings

The FDA approved Weltruza, a once-monthly subcutaneous extended-release olanzapine suspension, for adults with schizophrenia.
The formulation does not require loading doses, oral supplementation, or routine post-injection monitoring, according to the company announcement.
In SOLARIS, 675 adults aged 18 to 64 years were randomized during the initial 8-week placebo-controlled period; all three monthly doses met the primary PANSS end point.
At week 8, PANSS change differences versus placebo were −9.69, −11.25, and −9.71 points for 318 mg, 425 mg, and 531 mg, respectively. Improvements in illness severity and personal and social functioning were also reported.
Weight gain occurred in 35% of olanzapine-treated patients versus 8% of placebo recipients. Other commonly reported adverse events included somnolence, headache, constipation, and injection-site reactions.
No PDSS cases were reported in the trial data described, but the prescribing information states that whether PDSS can occur with olanzapine remains unknown. The label also identifies risks including hyperglycemia, dyslipidemia, weight gain, neuroleptic malignant syndrome, tardive dyskinesia, orthostatic hypotension, and drug reaction with eosinophilia and systemic symptoms.

Clinical Implications

Teva advises assessing metabolic risk before treatment and monitoring blood glucose and other metabolic parameters during therapy. The prescribing information states that PDSS occurrence with this subcutaneous formulation remains unknown; the absence of reported cases in SOLARIS does not establish that it cannot occur.

Conclusion

Weltruza is a newly approved once-monthly subcutaneous olanzapine option for adults with schizophrenia, supported by placebo-controlled phase 3 efficacy data. Its reported safety findings include weight gain and other known olanzapine risks, while the possibility of PDSS with this formulation remains uncertain.