Merck's division Merck Serono has announced a collaboration with US biopharmaceutical company Ambrx, Inc. to develop and commercialise Ambrx's long-acting growth hormone products. The collaboration will focus initially on the development of ARX201, the most advanced product candidate, currently in phase I/II clinical trials.

ARX201 has improved pharmacological properties, which should allow less frequent administration than the daily dosing regimen of currently available growth hormones.

Under terms of the agreement, Merck Serono will receive worldwide commercialisation rights for ARX201. Merck Serono will make an initial payment to Ambrx, and Ambrx is eligible to receive undisclosed clinical, regulatory and commercial milestone payments based on the successful development and commercialisation of products, as well as undisclosed royalties on net sales of such products.

In addition, Ambrx retains an option to co-promote products in the US market. If the option is exercised, Ambrx and Merck Serono will share US commercialisation expenses as well as profits. In the event Ambrx declines to exercise its option, it will receive undisclosed royalties on net sales of products worldwide.

"Merck Serono has a long-term commitment to children and adults with disorders requiring growth hormone treatment," said François Feig, head of global therapeutic area endocrinology and cardio-metabolic cCare, Merck Serono. "We believe that ARX201 has the potential to establish a new standard of care in growth hormone therapy. Less frequent administration would represent a significant advance for patients in terms of improved convenience and quality of life. This may lead to improved treatment outcome for the patients."

James W. Young, Ph.D., interim CEO of Ambrx, added, "Merck Serono is a leader in the development and commercialisation of innovative approaches to growth hormone therapy. This alliance is consistent with our strategy to work with industry leaders in their respective fields and is a validation of Ambrx's ability to deliver differentiated, high-value drug candidates."