Testing the validity and responsiveness of a new cancer-specific health utility measure (FACT-8D) in relapsed/refractory mantle cell lymphoma, and comparison to EQ-5D-5L

Abstract

Background: The FACT-8D is a new cancer-specific, preference-based measure (PBM) of health, derived from the Functional Assessment of Cancer Therapy-General (FACT-G) questionnaire. The FACT-8D's measurement properties have not been tested to date. We assessed it's validity and responsiveness in relapsed/refractory mantle cell lymphoma (RR MCL) and compared the results to the EQ-5D-5L. Methods: Blinded analysis of pooled data from a phase 3 clinical trial. FACT-8D baseline and follow-up data (weeks 4, 7, 16, 31) were scored using Australian preference weights, the first available value-set. Convergent validity was assessed by estimating baseline correlations with the FACT-Lym total score, Trial Outcome Index (TOI), FACT-Lym lymphoma-specific sub-scale (LymS), EQ-5D Visual Analog Scale (VAS), and haemoglobin (HgB). Relevant clinical variables were used to categorise patients to test known groups' validity and responsiveness was investigated using data from baseline (n = 250) and week 31 (n = 130). Results were compared with EQ-5D-5L, scored using the UK 3L crosswalk and the 5L England value-sets. Results: The FACT-8D showed good convergent validity and responsiveness; baseline Pearson correlation coefficients between FACT-8D Index scores and other PRO measures were moderate to very strong (range: 0.49 for the EQ-VAS to 0.79 for FACT TOI) and the size of the change in FACT-8D Index scores at week 31 differed significantly (p < 0.005) between patients categorised as improved, worsened or stable using the FACT-Lym total score, LymS, and HgB. However, when assessing known groups' validity, FACT-8D failed to discriminate between patients categorised by health status on four of the seven variables analysed. Overall, FACT-8D and EQ-5D-5L performed similarly, although EQ-5D-5L showed better known groups' validity.

Brexucabtagene Autoleucel (Tecartus)

“…61 Data from a clinical trial of 132 patients with relapsed MCL was used to assess the validity and responsiveness of the EQ-5D-5L. 63 Convergent validity was assessed by testing a priori hypotheses about the strength of correlation with other instruments that measured similar constructs. The EQ-5D-5L showed good convergent validity, reporting moderate correlation with the EQ VAS (r = 0.50) and strong correlation with Functional Assessment of Cancer Therapy (FACT) lymphoma specific subscale (r = 0.60) and FACT lymphoma total score, Trial Outcome Index (TOI) (r = 0.70).…”

“…The index score showed good responsiveness, reporting an effect size of 0.67 for improvement and 0.80 for worsening based on the FACT lymphoma subscale. 63 Richardson et al 64 examined various instruments, including the EQ-5D-5L, in respondents who were healthy and who had a chronic disease (i.e., arthritis, asthma, cancer, depression, diabetes, hearing loss, and heart disease) through an online survey in Australia, Canada, Germany, Norway, the UK, and the US (total N = 7,933; cancer N = 772). For discriminant validity, the mean EQ-5D-5L differed between healthy respondents and respondents with a chronic disease (0.88 in healthy, 0.18 in patients with cancer [standard deviation not reported]).…”

The FACT-8D, a new cancer-specific utility algorithm based on the Functional Assessment of Cancer Therapies-General (FACT-G): a Canadian valuation study

“…Better solutions may be found in future research, particularly if similar problems arise in other valuation DCEs with positively and negatively framed items. The measurement properties of the FACT-8D (using the Australian value set) has been tested against the EQ-5D-5L (scored using the UK 3L crosswalk and the 5L England value set) [34]. The FACT-8D demonstrated good convergent validity and responsiveness but the EQ-5D-5L showed better known groups' validity.…”

Encorafenib in Combination With Binimetinib (Braftovi and Mektovi)

“…46 Data from a clinical trial of 132 patients with relapsed MCL was used to assess the validity and responsiveness of the EQ-5D-5L. 48 Convergent validity was assessed by testing a priori hypotheses about the strength of correlation with other instruments that measured similar constructs. The EQ-5D-5L showed good convergent validity, reporting moderate correlation with the EQ VAS (r = 0.50) and strong correlation with Functional Assessment of Cancer Therapy (FACT) lymphoma specific subscale (r = 0.60) and FACT lymphoma total score, Trial Outcome Index (TOI) (r = 0.70).…”

“…The index score showed good responsiveness, reporting an effect size of 0.67 for improvement and 0.80 for worsening based on the FACT lymphoma subscale. 48 Richardson et al 49 examined various instruments, including the EQ-5D-5L, in respondents who were healthy and who had a chronic disease (i.e., arthritis, asthma, cancer, depression, diabetes, hearing loss, and heart disease) through an online survey in Australia, Canada, Germany, Norway, the UK, and the US. For discriminant validity, the mean EQ-5D-5L differed between healthy respondents and respondents with a chronic disease (0.88 in healthy, 0.18 in patients with cancer).…”