French pharmaceutical producer Sanofi and its subsidiary Genzyme have agreed to acquire the Caprelsa (vandetanib) rare disease therapy of British-Swedish drugmaker AstraZeneca.

Sanofi said the acquisition builds on Genzyme's long-standing commitment and scientific leadership in the field of endocrinology globally.

Under the terms of the agreement, Genzyme will pay AstraZeneca up to $300 million, including an upfront payment of $165 million to acquire the global rights to sell and further develop Caprelsa, along with further development and sales milestone payments of up to $135 million.

The transaction does not include the transfer of any AstraZeneca employees or facilities.

Currently available in 28 countries, Caprelsa is an oral kinase inhibitor treatment indicated for the treatment of symptomatic or progressive medullary thyroid carcinoma in patients with unresectable locally advanced or metastatic disease.

The drug is Phase III development for differentiated thyroid carcinoma, with trials expected to finish in the second half of 2015.

“Caprelsa is a strong strategic fit for our rare endocrinology portfolio and underscores Genzyme's commitment to addressing unmet needs in the thyroid community," said David Meeker, CEO of Genzyme.

The transaction expected to be completed in the second half of 2015, subject to closing conditions that include antitrust clearance from the US Federal Trade Commission.