Biopharmaceutical group Circassia Pharmaceuticals has announced it will make a £139m cash bid for Swedish group Aerocrine.The London-listed company said the offer for Aerocrine, a developer of medical diagnostic products for use in the diagnosis and management of patients with asthma, was part of its strategy to become focused on allergy and asthma.Meanwhile, Circassia has also made a formal bid for a cash offer of up to £100m for Prosonix, a pharmaceutical company focused on the development of product candidates for the treatment of asthma and chronic obstructive pulmonary disease."The combined organisation will give us both the capability and resources to commercialise our enlarged late-stage pipeline of potential new allergy and asthma products, once approved, and thereby generate significant shareholder value," said group chief executive Steve Harris.The group said it aimed to raise £275m through a placing and open offer to finance the acquisitions.Circassia shares were down 9.16% to 290.70p at 11:09 on Friday.