Retrospective analysis of treatment-induced peripheral neuropathy (TIPN) in multiple myeloma (MM).

Abstract

e19530 Background: Peripheral neuropathy (PN) is commonly present at MM diagnosis and exacerbated or induced by MM treatments. TIPN poses significant morbidity, and may result in therapy modifications (TM). We examined the “real-life” onset and severity of TIPN in newly diagnosed patients (pt) receiving anti-MM therapies. Methods: Medical records from a US community oncology network were reviewed. Newly diagnosed MM pt treated between 1/1/08 and 7/1/10, ≥18 years, and followed for ≥24 months were eligible. The protocol pre-defined inclusion of an equal number of TIPN and non-TIPN cases. Regimen-related TIPN was based on clinician judgment and/or correspondence of TIPN with regimen start/end dates. Uni- and multi-variate (MV) analyses examined association of demographic and regimen characteristics with TIPN, TIPN severity, and TM. Results: In all, 716 MM records were screened; 367 were deemed ineligible or incomplete. Of 349 eligible records, 229 were abstracted, 10 had unusable data, and 219 formed the analytic set; 120 records were excluded since the accrual target (N=225) had been met. Average age of pts was 67.0 years, 49.3% were female, 57.5% Caucasian, and 36.0% African-American (AA). A majority (56.6%) had 1 regimen prior to 1st disease progression, 26.0% had 2 and 17.4% had >2 regimens. Overall, 138/219 (63.0%) developed PN, 123/219 (53.7%) with documented TIPN. TIPN developed during 1st line therapy in the majority 110/123 (89.4%). Univariate analysis revealed that TIPN pt were younger, more likely to be AA, and treated more frequently with bortezomib-based regimens BTZ-BR (63.3 v 9.3%). MV analysis showed TIPN was associated with BTZ-BR (OR=14.5, 95% CI=6.5-32.2), but not age, race, gender, and diabetes. BTZ-BR compared to non BTZ-BR were associated with severe and grade 3/4 TIPN (79.3 v 20.7%; χ2=5.36, p=0.02), and TM (65.7 v 34.3%, χ2=5.57, p=0.02). Notable TM included dose reductions (66.7 v 33.3%) and delays (83.3 v 16.7%). Conclusions: In this study of newly diagnosed MM pt, TIPN developed frequently during 1st line therapy. BTZ-BR were associated with TIPN that was severe and resulted in greater TM. While this analysis represents a small pt population, the results are provocative and warrant further study.