US-listed fertility treatment provider OvaScience has agreed to merge with Millendo Therapeutics, a US-based endocrine disease drug developer backed by pharmaceutical companies Roche and AstraZeneca.

The unified company will take Millendo’s name and OvaScience’s stock listing on the Nasdaq Capital Market. Millendo’s investors will own 80% of the combined company and Ovascience shareholders 20%.

The all-stock deal will be boosted with $30m from investors including Roche subsidiary Roche Venture Fund and Innobio, which is managed by French state-backed organisation Bpifrance.

New Enterprise Associates (NEA), Osage University Partners, Altitude Life Science Ventures, Adams Street Partners, Frazier Healthcare Partners and Longwood Fund, all of which are Millendo investors, are also backing the round.

Founded in 2012 as Atterocor, Millendo is working on therapeutics to treat diseases of the endocrine system, the hormone-based messenger system that includes the thyroid and adrenal glands.

The company’s lead drug candidate, a treatment for a rare genetic disease known as Prader-Willi syndrome, has produced positive effects in a phase 2 clinical trial, and a phase 2b/3 trial is slated for early 2019.

Frazier Healthcare Partners and 5AM Ventures co-led Millendo’s $16m series A round in 2012 and joined Roche Venture Fund, NEA, Osage, Adams Street, Altitude, Longwood, Renaissance Venture Capital Fund and the regents of University of Michigan for a $62m series B in 2016.

AstraZeneca took a stake of undislcosed size in Millendo through a licensing agreement sealed at the same time as the series B round.

OvaScience’s stock peaked at just over $50.00 in 2015 but has largely been on a downward trajectory since, dipping below $5.00 in late 2016. Its shares were priced at $0.90 each on the day of the announcement and are $0.78 at time of publication, giving it a market cap of $28.2m.