Cost-effectiveness of pramipexole augmentation for acute phase and maintenance therapy of treatment-resistant depression compared to placebo augmentation: economic evaluation of the PAX-D randomised controlled trial.
Łaszewska A., Helter T., Baldwin A., Cleare AJ., Cowen PJ., Evans J., Huys QJM., Kurkar M., Lewis AC., Nixon N., Rastogi A., Watson S., Geddes JR., Browning M., Simon J.
BACKGROUND: Pramipexole augmentation of antidepressant treatment for treatment-resistant depression (TRD) has been shown to improve symptom burden over 12 weeks but with some adverse effects compared to placebo augmentation. We aimed to evaluate the cost-effectiveness of pramipexole augmentation for TRD. METHODS: We conducted an economic evaluation as part of the PAX-D trial over 12 and 48 weeks. Two costing perspectives, National Health Service and Personal Social Services (NHS + PSS) and societal, were adopted. The primary outcome was quality-adjusted life year (QALY) based on the EQ-5D-5L. Secondary outcomes included year of full capability (YFC) based on the ICECAP-A, and capability-weighted life year (CWLY) based on the OxCAP-MH. Incremental cost-effectiveness ratios (ICERs), cost-effectiveness planes and cost-effectiveness acceptability curves were reported alongside sensitivity analyses. The trial was registered with ISCTRN (ISRCTN84666271) and EudraCT (2019-001023-13) and is complete. FINDINGS: From the NHS + PSS perspective, mean incremental cost of pramipexole was £60 (95% CI: -£55, £176) over 12 weeks and £811 (95% CI: £110, £1513) over 48 weeks. The difference in QALY gained was 0.012 (95% CI: 0.003, 0.021) over 12 weeks and 0.090 (95% CI: 0.036, 0.144) over 48 weeks, equivalent to 4 (95% CI: 1, 8) and 33 (95% CI: 13, 52) days in perfect health. The ICER was £5069/QALY (95% CI: -£3642, £35,608) over 12 weeks and £9007/QALY (95% CI: £2,219, £27,258) over 48 weeks, representing over 90% probability of cost-effectiveness at £20,000/QALY threshold. From the societal perspective, pramipexole was on average cost saving and more effective over 48 weeks. Alternative analyses provided consistent conclusions. INTERPRETATION: Pramipexole augmentation for TRD has demonstrated both clinical and cost-effectiveness. Further trials, directly comparing pramipexole to other augmentation strategies, will be useful in determining the position of this repurposed medication in the treatment pathway of depression. FUNDING: National Institute for Health and Care Research, Efficacy and Mechanism Evaluation Programme.