Assessing tolerability with the Functional Assessment of Cancer Therapy item GP5: psychometric evidence from LIBRETTO-531, a phase 3 trial of selpercatinib in medullary thyroid cancer.

Authors

• Antoine Regnault
• Laurine Bunod
• Angely Loubert
• Marcia S Brose
• Lisa M Hess
• Patricia Maeda
• Yan Lin
• Rebecca M Speck
• Adrienne M Gilligan
• Nalin Payakachat

Publication/Presentation Date

12-19-2024

Abstract

BACKGROUND: This psychometric analysis generated evidence to support the use of the Functional Assessment of Cancer Therapy item GP5 (GP5) as a measure of tolerability and confirms the appropriateness of categorizing "high side-effect burden" using a rating of 3 or 4 (score ranges 0-4) in patients with advanced/metastatic RET-mutant medullary thyroid cancer (MTC).

METHODOLOGY: Blinded, pooled interim data from the safety population (n=290) enrolled in the phase 3 LIBRETTO-531 trial (NCT04211337) were used. Intraclass correlation coefficients (ICC) were calculated for test-retest reliability using data from cycles 1-2 post-baseline. Construct validity was evaluated by examining the correlations of GP5 ratings with (a) symptomatic adverse events (AEs; measured by the PRO-CTCAE), and (b) functioning scores of EORTC QLQ-C30. The ability to detect change over time was examined by Cochrane-Mantel-Haenszel tests for GP5 ratings and PRO-CTCAE. The relationship of "high side-effect burden" categories with QLQ-C30 functioning scores was examined.

RESULTS: ICCs for the GP5 ratings after cycle 1 ranged between 0.80 and 0.85, indicating good reliability. Correlations between GP5 and PRO-CTCAE items ranged from 0.18 to 0.62 and ranged from -0.37 to -0.50 for QLQ-C30 functioning scores, consistent with study assumptions. Post-baseline GP5 ratings showed significant associations with PRO-CTCAE scores (p< 0.001). Participants with GP5 ratings of 3 or 4 had worse physical function than those with GP5 ratings of 0 to 2 (p< 0.0001).

CONCLUSIONS: This analysis generated evidence supportive of the psychometric properties of the GP5 as a fit-for-purpose measure to assess treatment tolerability in patients with advanced/metastatic MTC. The definition of "high side-effect burden" was associated with the clinical feature of tolerability.

Volume

8

Issue

1

First Page

149

Last Page

149

ISSN

2509-8020

Published In/Presented At

Regnault, A., Bunod, L., Loubert, A., Brose, M. S., Hess, L. M., Maeda, P., Lin, Y., Speck, R. M., Gilligan, A. M., & Payakachat, N. (2024). Assessing tolerability with the Functional Assessment of Cancer Therapy item GP5: psychometric evidence from LIBRETTO-531, a phase 3 trial of selpercatinib in medullary thyroid cancer. Journal of patient-reported outcomes, 8(1), 149. https://doi.org/10.1186/s41687-024-00823-8

Disciplines

Medicine and Health Sciences

PubMedID

39694978

Department(s)

Hematology-Medical Oncology Division

Document Type

Article