OBJECTIVES: To compare changes in adherence and out-of-pocket costs among patients with chronic myeloid leukemia (CML) before and after state-level oral oncolytic parity laws, which require that oral oncolytics under the pharmacy benefit are covered similarly to parenteral oncolytics under the medical benefit.

METHODS: Adults with CML, ≥1 pharmacy claim for a tyrosine kinase inhibitor (TKI) and residence in any of 41 states that implemented oral oncolytic parity legislation between 1-1-2007 and 12-31-2017 were identified from the IBM^® MarketScan^® Commercial Claims Database. Continuous enrollment 3 months before and 6 months after the first TKI claim date (index date) was required. The proportion of days covered (PDC) was calculated and 30-day out-of-pocket costs (copayments, coinsurance, and deductibles as 2017 United States dollars) were assessed in the 6 months post-index; patients with a PDC ≥0.85 were categorized as adherent. Differences in outcomes before and after parity were evaluated, controlling for membership in health plans subject to parity (fully-insured health plans [FIHPs]) or not (self-funded health plans [SFHPs]).

RESULTS: Of 1,887 CML patients initiating a TKI, 678 (35.9%) were members of FIHPs and 1,209 (64.1%) of SFHPs. After parity, mean PDC improved in FIHPs and SFHPs (0.85 to 0.87 and 0.87 to 0.90, respectively). TKI adherence improved from 69.2% to 73.2% of patients in FIHPs (P=0.2817) and similarly from 73.6% to 78.3% in SFHPs (P=0.0585). In FIHPs, median (Q1–Q3) out-of-pocket costs per-patient increased from $33.48 ($18.12–$63.41) to $37.78 ($5.35–$112.03), while in SFHPs they increased from $38.26 ($23.69–$85.27) to $52.84 ($19.05–$112.03).

CONCLUSIONS: Oral oncolytic parity legislation has produced minimal impact on TKI adherence and out-of-pocket costs among CML patients. To improve clinical outcomes and protect patients from rising out-of-pocket costs, policymakers may consider amending current legislation.