Decline in Buprenorphine/Naloxone Prescriptions in a State Medicaid Population Following Formulary Conversion from Suboxone to Bunavail.

INTRODUCTION

A large, statewide, fee-for-service Medicaid plan recently (October 2015) executed a complete switch from sublingual buprenorphine-naloxone [(SLBN), Suboxone] to buccal buprenorphine-naloxone [(BBN), Bunavail] on its preferred drug formulary. This complete formulary switch provided an opportunity to assess dynamic changes in prescribing patterns, patient/physician acceptance, and indices of potential misuse/diversion.

METHODS

For the period January 1, 2015 through December 31, 2016, two datasets were analyzed: prescriptions and associated costs for buprenorphine-naloxone (BN) products and urine toxicology test results for patients in the Medicaid plan. The dataset comprised 1370 unique providers ordering 643,225 prescriptions for opioid addiction therapy. Patient and order volumes, and the rate of monthly positive laboratory values for opioid molecules and cocaine were reviewed. A targeted survey of physicians treating opioid-dependent patients with state Medicaid plan coverage was also conducted.

RESULTS

Upon plan conversion to BBN, there was a rapid increase in monthly BBN prescriptions mirrored by a rapid decrease in SLBN prescriptions. Peak in BBN prescriptions (2633 in November 2015) was approximately 60% lower than peak in SLBN prescriptions (6531 in July 2015). An unexpected finding was a 68% reduction of the overall BN market, indicating that many BN prescriptions were abandoned. The reduction was associated with quarterly cost savings to the Medicaid plan of approximately $3.5 million. Toxicology results indicated a reduction in drug positivity (defined as positivity for cocaine and/or any opioids except buprenorphine and methadone) from 13-16% in 2015 to less than 10% in 2016. Heroin positivity decreased from approximately 9% in December 2015 to an average of less than 1% during the last quarter of 2016, while positivity for norbuprenorphine, the major metabolite of buprenorphine, showed a marked increase in 2016 vs 2015. Among physicians who responded to the targeted survey most rated BBN as more difficult to abuse or misuse than SLBN.

CONCLUSION

The rapid reduction in the overall BN market following a complete formulary switch from SLBN to BBN was associated with quarterly savings of $3.5 million for the state Medicaid plan. Toxicology data suggest that this cost saving was realized in the context of improved physician and patient adherence to treatment protocols. The changing market dynamics can potentially be explained by a number of contributory factors, including a reduction of diversion and illicit distribution of BN following formulary conversion. These results are considered hypothesis-generating and future research should systematically compare the propensity for diversion and abuse of BN products using various epidemiological tracking tools.

FUNDING

BioDelivery Sciences International, Inc.