Impact of list price changes on out-of-pocket costs and adherence in four high-rebate specialty drugs

Abstract

Background: Insurers manage the cost of specialty medicines via rebates, however it is unclear if the savings are passed on to patients, and whether reducing rebates may lead to changes in patient out-of-pocket (OOP) costs and medication adherence. This study examined two drug classes to understand the impact of reducing list prices to net prices, via lower-priced national drug codes (NDCs) or authorized generics, on patient OOP costs and adherence.

Methods: This retrospective analysis assessed IQVIA PharMetrics ® Plus adjudicated medical and pharmacy claims for commercially insured patients. Patient OOP costs per prescription and payer drug costs were assessed for evolocumab or alirocumab (proprotein convertase subtilisin/kexin type 9 inhibitors [PCSK9is]) or velpatasvir/sofosbuvir or ledipasvir/sofosbuvir (hepatitis C virus [HCV] medications). For PCSK9is and HCV medications, the original and lower-priced versions were compared. Adherence was estimated based on proportion of days covered (PDC) (PCSK9is) and receipt of full treatment regimen (HCV medications).

Results: In total, 10,640 patients were included (evolocumab, 5,042; alirocumab, 1,438; velpatasvir/sofosbuvir, 2,952; ledipasvir/sofosbuvir,1,208). After list price reductions, mean payer drug costs decreased by over 60%, while patient OOP cost reductions ranged from 14% to 55% (evolocumab: 55%, p < 0.01; alirocumab: 51%, p < 0.01; velpatasvir/sofosbuvir: 30%, p < 0.01; ledipasvir/sofosbuvir: 14%, p = 0.03). Patients with coinsurance as the largest contributor to their OOP costs had the largest reductions in OOP costs, ranging from adjusted, mean values of US$135 to US$379 (>60% reductions). Six-month PDC for PCSK9is and proportion receiving full HCV treatment regimen were high with the original versions and did not substantially differ with the new, lower-priced versions.

Conclusions: Reducing list prices to approximate net prices (as a proxy for reducing rebates) resulted in lower patient OOP costs, particularly for those with coinsurance. Our findings suggest that future reduction of rebates may assist in patient affordability, although additional transparency is needed.

Fig 1. Study concept.

^aProportion distributed through different channels is unknown. ^bOther costs may include items such as administrative fees. ^cMay include copayments, coinsurance, and deductibles. NDC, national drug code; OOP, out of pocket.

Fig 2

A) Adjusted mean allowed amounts per-prescription. B) Adjusted mean patient OOP per-prescription amounts. C) Adjusted mean OOP: subgroup with copayment as largest contributor to OOP cost. D)^a Adjusted mean OOP: subgroup with coinsurance as largest contributor to OOP cost. Model adjusted for age, sex, region, payer type, plan type, polypharmacy (3+ medications), Charlson Comorbidity Index and index month. Allowed amounts are the contracted or accepted reimbursable amount for medications that the health plan agrees to pay service providers such as pharmacies. ^aInsufficient sample to obtain robust estimates for Ledipasvir/sofosbuvir given data outliers. HCV, hepatitis C virus; OOP, out of pocket; PCSK9i, proprotein convertase subtilisin/kexin type 9 inhibitor.

Fig 3

Adjusted mean OOP costs with deductibles included for A) total OOP costs; B) subgroup with copayment as largest contributor to OOP cost; C)^a subgroup with coinsurance as largest contributor to OOP cost; and D) subgroup with deductible as the largest contributor to OOP cost. Model adjusted for age, sex, region, payer type, plan type, polypharmacy (3+ medications), Charlson Comorbidity Index, and index month. ^aInsufficient sample for estimates for Ledipasvir/sofosbuvir. HCV, hepatitis C virus; OOP, out of pocket; PCSK9i, proprotein convertase subtilisin/kexin type 9 inhibitor.