This study analyzed factors contributing to an increase in the actual volume of sales compared to the quantities of drugs provided under the Price Volume Agreement (VPA) in South Korea. The volume of new drug sales listed on the national formula is tracked as part of the VPA policy. If the actual volume of sales exceeds the agreed volume by 30% or more, the drug is subject to a price decrease. Logistic regression assessed the factors related to whether the drugs were VPA price-reduction drugs. A generalized linear model, with gamma distribution and a log link, assessed the factors that influence the increase in actual volume relative to the expected volume of VPA price reduction drugs. Of 186 VPA-controlled drugs, 34.9% were price-reducing drugs. Drugs marketed in therapeutic markets by previously employed pharmaceutical companies were more VPA price-cutting drugs than drugs distributed by companies without prior employment. Drugs from multinational pharmaceutical companies were more VPA price-cutting drugs than domestic companies. More alternative drugs have been significantly associated with an increased chance of being VPA price-reducing drugs. Among VPA-reduced drugs, the actual volume rate was significantly higher than the expected volume for drugs with clinical benefit. By focusing negotiation efforts on these targeted drugs, VPA policy can be managed more effectively with improved predictability of pharmaceutical quantities.
Keywords: Forecast volume; THE VPA; Pharmaceutical spending Price-volume agreement. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.