Estimating Health State Utilities for IDH-Mutant Diffuse Glioma.

Background: Isocitrate dehydrogenase-mutant (mIDH) gliomas are malignant central nervous system tumours. After initial resection, patients with mIDH gliomas with favourable prognosis may live without receiving oncologic treatment for years, but ultimately patients will experience recurrence and require radio- and/or chemotherapy (RT/CT). Cost-utility analyses (CUA) can explore the value of treatments that delay recurrence and initiation of RT/CT. This study aimed to estimate health state utilities for mIDH glioma over the full disease course.

Method: Vignettes were developed to describe states from post-initial resection with no immediate need for RT/CT through to RT/CT and palliative care after recurrence. These were developed on the basis of literature review, patient-reported outcomes data from a clinical trial and qualitative interviews with clinicians and patients. The health state vignettes were valued by members of the UK public using the EQ-5D-5L and time trade-off methods. Subsequently, the vignette-derived utilities were re-weighted with the utility data from a clinical trial to estimate health state utilities for CUA.

Results: Health state utilities were similar following the initial resection for targeted therapy or active observation (0.74) but lower in later stages of disease. Mean utilities for receiving first- and second-line RT/CT ranged from 0.34 to 0.55. Mean utilities ranged from 0.21 to 0.42 for recovery after tumour resection following recurrence and from -0.05 to 0.14 for palliative care.

Conclusion: This study estimates health state utilities in glioma from after the initial resection through to palliative care and suggests that new treatments capable of delaying time to disease recurrence and initiation of RT/CT could produce a net gain in quality of life for individuals with mIDH glioma.