Additional payments of up to $250m will fall due when future sales milestones are reached, which would take the total return to a maximum of 4.5 times the investment made.

Asthmatx develops and manufactures catheter-based medical devices for patients with severe asthma. Asthmatx’s bronchial thermoplasty, delivered by the Alair System, is a novel device-based minimally invasive treatment option for patients with severe asthma.

The Alair System has been approved for use in the US by the FDA and has received a CE mark for use in the European Union.

HBM BioVentures is a major investor in Asthmatx and has played a significant role in the company’s growth since its initial investment in 2005. In 2007, Asthmatx received $50m from Olympus for the continued financing of its product development activities.