The sleep apnea device developer has raised more than $71m since 2009 from investors including Medtronic and Johnson & Johnson Development Corporation.

Inspire Medical Systems, the US-based sleep apnea device spinout of medical device producer Medtronic, has raised $12.5m in funding, according to a regulatory filing on Tuesday.

The company has not disclosed the identity of the participants in the latest round, but the filing indicates it is targeting $37.5m for a final close.

Founded in 2007, Inspire has developed a US Food and Drug Administration-approved implanted neurostimulation device that treats obstructive sleep apnea by stimulating airway muscles based on a patient’s…