Indian drugs giant Cipla's subsidiary in the United States has formalised a two-stage agreement to acquire Avenue Therapeutics Inc for about $215 million. Avenue Therapeutics is focussed on the development and commercialisation of an intravenous version of Tramadol, a painkiller. Executed through Cipla's US subsidiary InvaGen Pharmaceuticals Inc, the deal involves two closing stages for the proposed acquisition. The first stage involves InvaGen or its affiliates acquiring up to 33.3 per cent stake in Avenue by buying new shares for $35 million. The second stage closing involves InvaGen or its affiliates acquiring the remaining shares of Avenue's common stock for up to $180 million, or approximately $13.92 per share, the company said. The deal is expected to be financed through a dollar-based loan in the US.