Patient-Reported Outcomes (PRO) in the Setting of Relapsed Myeloma: The Influence of Treatment Strategies and Genetic Variants Predict Quality of Life and Pain Experience

Introduction. The impact of therapy in the management of disease relapse in patients with myeloma (MM) needs to be balanced with the impact on quality of life (QoL). The benefit of a salvage autologous stem cell transplant (ASCT2) has been demonstrated in terms of durability of response over non-transplant consolidation (NTC) (G Cook, et al., Lancet Oncology, 2013 Vol. 15, No. 8, p874-885). However, the impact of ASCT2 on patient reported outcomes (PRO) has not been reported to date. Therefore, patients' experience of pain and global measures of QoL, as part of a systematic assessment of PRO were measured at key points before, during and after randomisation in this multi-centre national phase III trial.

Methods. 174 patients were randomised and data are presented on 171 who completed self-rated QoL assessments using EORTC QLQ-C30 and the EORTC myeloma module (MY-20). Pain assessments using BPI-SF were also incorporated. Genomic DNA was prepared from PBMNC using standardised GLP methods.

Results. Completion rates for EORTC QoL and BPI-SF assessments were 83.3% and 77.1% at registration, and 59.6% and 53.8% at randomisation, respectively. Over half of patients reaching 1 year post-randomisation completed both assessments. EORTC QoL and BPI-SF forms had average 6% and 10% missing data, respectively. These completion rates are commensurate with previous longitudinal studies.

EORTC QLQ-C30 Global health status/QoL subscale scores were significantly higher (better) in the NTC arm at 100 days and 6 month post-randomisation (P=0.0496), but not at later time points. BPI-SF pain scores showed significantly higher pain severity in the NTC (4.3/10) than the ASCT2 (2.9/10) patients only at 2 years post-randomisation. However, for pain interference with aspects of daily living, NTC patients reported significantly lower scores at 6 months (P=0.0155), 1 year post-randomisation (P=0.0466) and 2 years post-randomisation (P=0.0348).

The MY-20 assessment showed that at 100 days and 6 months post-randomisation, the subscale scores for Side-effects of treatment were significantly higher in the ASCT2 arm than in the NTC arm, but not at later time points up to 2 years.

Kaplan-Meier estimate of time-to-progression (TTP) by randomised allocation suggested that patients with an EORTC global QoL score greater than median (ie better QoL) at randomisation and who received ASCT2 had a significant TTP advantage over those receiving NTC (HR 0.3 (95% CI 0.15-0.61), p=0.006). However, with multivariate Cox regression analysis accounting for stratification factors this difference was not significant. Patients who reported a lower (ie better) than median level of concern on the Side-effects of treatment subscale and who received ASCT2 had a significant TTP advantage over those receiving NTC (Kaplan-Meier HR 0.24 (95% CI (0.10-0.55), p=0.003). This survival difference was still observed after multivariate Cox regression analysis (HR 5.02 (95% CI 1.00-25.20), p= 0.0499).

We tested for genomic associations of SNPs from key genes reported to be involved in pain perception and analgesic responsiveness, and subjective outcomes. There were no significant associations for the opioid mu-receptor (OPRM1) and pain or QoL. However, the rs2236861 SNP in the opioid delta-receptor (OPRD1) showed nominally significant associations with worst pain (p=0.022), average pain (p=0.03) and pain interference (p=0.02) at baseline. The rs1045642 SNP in the ABCB1 drug transporter gene was nominally associated with worst pain (p=0.047) and average pain (p=0.019) after bortezomib-based induction therapy. A SNP rs13361160 in the chaperonin CCT5 gene was associated with worst pain (p=0.033), least pain (p=0.006) and pain interference (p=0.03). It was also associated with self-reported global QoL (P=0.014).

Conclusions. We report the first PROs using self-reported QoL and pain assessments in myeloma patients having salvage ASCT or NTC. Global QoL was worse and side-effects of treatment higher after ASCT2 for up to 6 months post-randomisation but then equalised. Pain caused less interference with daily living after NTC but became more severe at 2 years, possibly associated with relapse. Patients who reported lower concerns about side-effects of treatment after ASCT2 had a significant TTP advantage. The genomic analyses suggest a potential inherited predisposition that influences both pain and quality of life and warrants further exploration.