OBJECTIVES: Patient characteristics and healthcare costs were compared between initiators of intravenous infusion (IV) and subcutaneous injection (SC) drug regimens of belimumab for systemic lupus erythematosus (SLE) and tocilizumab for rheumatoid arthritis (RA).

METHODS: Demographics of IV vs SC initiators were described one year following FDA approval of SC belimumab (2017) and tocilizumab (2013) from the US Medicare database. Healthcare costs 1 year from drug initiation were compared between IV and SC initiators.

RESULTS:

Mean age was about 70 years for SC (n=754) and IV belimumab initiators (n=1744), and 72 years for SC (n=979) and IV tocilizumab initiators (n=8215). Among belimumab initiators, 92% SC vs 89% IV patients were female. Among tocilizumab initiators, 87% SC vs 76% IV patients were female. Patients who initiated SC belimumab were 18% Black and 6% Hispanic relative to 11% Black and 3% Hispanic among IV belimumab initiators. Patients who initiated SC tocilizumab were 14% Black and 15% Hispanic relative to 5% Black and 2% Hispanic among IV tocilizumab initiators. One third of patients initiating SC tocilizumab were from the Pacific relative to 5% from the Northeastern whereas 15% patients initiating IV tocilizumab were from Pacific relative to 17% from the Northeastern. While mean inpatient healthcare costs were 49% higher during the year following initiation of SC ($33,150) compared to IV ($22,265) belimumab, mean outpatient healthcare costs were 35% lower for SC ($6,511) vs IV ($10,010) belimumab initiators (p<0.05). Mean inpatient healthcare costs were 26% lower for SC ($20,324) vs IV ($25,538) tocilizumab initiators (p<0.05) and mean outpatient healthcare costs 87% lower for SC ($2,560) vs IV ($19,720) tocilizumab initiators (p< 0.05).

CONCLUSIONS: Women and minorities more frequently access SC versus IV belimumab and tocilizumab. Patients from Pacific more frequently access SC instead of IV regimens compared to Northeast. Lower outpatient healthcare costs were associated with SC regimens.