Background: The GRID trial demonstrated significant improvement in PFS for REG vs P in pts with metastatic GIST after progression on at least imatinib and sunitinib. Exploratory analyses were conducted to assess the effect of treatment on HRQoL.
Methods: The HRQoL analyses were selected a priori based on clinical relevance; the global health status/QoL (QL) and the physical functioning (PF) scales of the EORTC QLQ-C30 questionnaire were used. A linear mixed-effects model was used to examine the treatment effect on HRQoL and trends over time, assuming that missing data were missing at random. Pattern-mixture models were applied to assess the treatment effect while accounting for potentially informative missing data. Time-to-deterioration (TTD) of HRQoL and responder analyses were conducted to determine the treatment effect based on timing and proportion of patients reaching a minimal important difference (MID) change in QL/PF (?10 points).
Results: The QL and PF changes over time were numerically similar between REG and P based on the linear mixed-effects model. The pattern- mixture models grouped patients based on timing of last HRQoL assessment ( P (QL: 6.5 vs 4.0; PF 8.0 vs 4.0 weeks, respectively). Median TTD was comparable between treatments after removing disease progression from the definition. The responder analyses showed that a similar proportion of patients achieved an improvement in MID in REG vs P (QL: 26.2% vs 25.4%; PF: 18.0% vs 15.3%, respectively).
Conclusion: The findings of this exploratory analysis demonstrate that HRQoL is similar for REG and P groups, indicating that REG prolongs PFS vs P while maintaining at least comparable HRQoL.
