(Salem, OR) -- The Oregon Attorney General has filed a 900-million-dollar lawsuit over high prices for insulin. The lawsuit alleges drug makers Novo Nordisk, Sanofi and Eli Lilly conspired with pharmacy benefit managers Express Scripts, CVS Caremark and Optum to dominate the insulin market and keep prices high. The pharmacy benefit managers are also accused of excluding lower-cost insulin options. The lawsuit was filed in Multnomah County Circuit Court.