Treatment Patterns Among Newly Diagnosed Multiple Myeloma Patients in the United States Veteran Population (2010-2015)

Background: Despite a relatively higher incidence in the veteran population, there are few real-world claims-based analyses to describe Multiple Myeloma (MM) treatment patterns among this patient population (Landgren O, Blood, 2006). This study aimed to assess treatment patterns among newly diagnosed MM (ndMM) patients using the US Veteran Health Administration (VHA) data.

Methods: This retrospective study identified adult patients with ≥2 claims for MM (ICD-9-CM code: 203.0x) 30 days apart and ≥1 treatment during identification period (1OCT2011-31MAR2015) from the VHA dataset. The initial course of therapy (COT1) date was the index date and included all treatments prescribed within 60 days of this date. Patients were required to have continuous enrollment for 12 months pre- and ≥6 months post-index date unless patients died within 6 months (follow up period), ≥1 full cycle of therapy with a valid COT1 regimen, no evidence of prior MM diagnosis or treatment (including autologous stem cell transplant (ASCT)), and no evidence of ASCT in the follow up period. A subsequent COT (COT2) was defined as the earliest occurrence of: the addition of a new drug or switch in regimen after the first 60 days, restart of a previous regimen after >180-day gap, or a dose increase from maintenance to relapse therapy. Dexamethasone/prednisone[d] which were assumed to be included regardless of whether or not they were observed during the study period did not impact the ongoing COT. Treatment patterns during the follow-up period were initially examined among patients treated with novel (lenalidomide [R] and/or bortezomib [V] with or without chemotherapy agents) and non-novel therapies (≥1 chemotherapy agent, steroid monotherapy) and then compared among those initiating Rd and Vd. Time to next treatment (TTNT) was defined as the duration from initiation of COT1 plus any gaps before COT2. Kaplan Meier and Cox regression analyses were performed to evaluate TTNT and assess the impact of various predictors on TTNT among patients initiating Rd and Vd.

Results: Of 1,183 patients that met the inclusion criteria, 55.4% (n=655) were treated with novel therapies and 44.6% (n=528) with non-novel therapies. Among patients treated with novel therapy, the majority initiated Rd (47.8%; n=313) as COT1 followed by Vd (31.2%; n=204), Vd with cyclophosphamide (11.5%; n=75), RVd (6.6%; n=43), Vd with a chemotherapy agent (2.4%; n=16) and Rd with a chemotherapy agent (0.6%; n=4).Rd initiators were significantly older (75.1 vs 70.6 years, p=0.0002) and a higher percentage was white (69.7% vs 47.0%; p<0.0001) than Vd treated patients. While the Charlson Comorbidities Index score did not differ between the two groups (3.6 vs 4.0, p=0.0583), a significantly higher percentage of patients treated with Vd had some comorbidities including hepatitis and renal disease. Among patients with laboratory tests, patients treated initially with Vd had lower hemoglobin (10.8 vs 11.4 g/dl, p=0.0012) and higher serum creatinine (2.3 vs 1.4 mg/dl, p<0.0001) during the pre-index period. The overall average treatment duration in COT1 was significantly longer among patients treated with Rd vs Vd (10.9 vs 7.0 months, p<0.0001). Among patients who were still on active COT1, the mean duration in COT1 was longer among patients treated with Rd than Vd (18.7 vs 13.3 months, p=0.0061). A significantly higher percentage of patients treated with Vd progressed to COT2 (52.5%, vs 26.2% p<0.0001) as compared to Rd. Among patients who progressed to COT2, those treated with Vd had a shorter TTNT compared to Rd (Mean: 9.3 vs 12.8 months, p=0.0049). After adjusting for baseline demographic and clinical factors using Cox regression, TTNT remained significantly shorter for Vd vs those treated with Rd (HR: 2.67, 95% CI: 1.9-3.7, p <0.0001).

Conclusion: Slightly over half of MM patients in the US Veteran population were treated with a regimen containing novel therapies; Rd and Vd were the most commonly observed among these. Patients treated initially with Vd had a significantly shorter TTNT compared to those treated with Rd. The difference remained significant after controlling for baseline characteristics including markers for higher disease severity among patients on Vd.