Estimações de entrada de medicamentos genéricos no Brasil usando modelos de contagem versus modelos ordenados

Resumo

Two major changes in Brazilian legislation during the 1990s reshaped the local
 pharmaceutical industry: the ratification of the TRIPS agreement including a provision
 for pipeline inventions in 1996, and a Generic Drug Act in 1999, which introduced
 bioequivalence tests and facilitated generic drugs’ substitution for the pioneer drugs
 at dispensing. Genuine generic drug entry may be dated back to 2000, when the first
 applications were approved. Price controls were gradually resumed in the turn of the
 century. The present article estimates entry of generic versions of off-patent drugs into
 various therapeutic classes using both count data and ordered multinomial models. Results point out that a simple Poisson model fits the data poorly, calling for further modelling of overdispersion or of excess zeros by applying Negative Binomial and zero-inflated count models. Ordered models seem to provide a worse fit, even though the explaining variables display the same pattern of significance and signs. Most of the explaining variables utilized are significant, in particular a proxy for potential market (lagged revenues of the drug), market concentration, and age of the pioneer drug. Multiple brands (rather than simply own-generics) and evergreening strategies seem to be effective in deterring entry.

Ficha do documento

Tipo

Estudo

Ano

2010

Instituição

Instituto de Pesquisa Econômica Aplicada (Ipea)

Fonte

Repositório do Ipea

Idioma

Português

Acesso

Acesso aberto

Identificador

oai:repositorio.ipea.gov.br:11058/1379

Licença

Licença Comum

Abrangência

Brasil

Temas

Desenvolvimento Econômico

Palavras-chave

Medicamentos genéricosIndústria farmacêuticaLei dos genéricosPatente de medicamentos