Onyx Pharmaceuticals has licensed the Japanese marketing rights to its investigational multiple myeloma drug carfilzomib and a related compound to Ono Pharmaceutical Co.

Under the terms of the deal, Onyx is getting an upfront fee of 5 billion yen (about $59 million) and development and sales-based payments related to the compounds that could reach $280 million. The US firm also noted that it is eligible for double-digit royalties on sales in Japan, "commensurate with a late-stage asset".

Onyx recently announced top-line results from a Phase IIb study in which carfilzomib, a highly selective proteasome inhibitor, achieved an overall response rate of 24% and a duration of response of more than seven months in patients who entered the study after receiving a median five prior lines of therapy. The company has begun a  Phase III clinical trial, studying the combination of carfilzomib, lenalidomide, and low-dose dexamethasone in patients with relapsed MM and a New Drug Application for the compound is expected to be submitted by the end of the year in the USA.

An additional late-stage trial is planned to evaluate carfilzomib in patients with advanced myeloma and it is also being studied in advanced solid tumours. The other compound covered by the deal is ONX 0912, which is in Phase I and is based on the same chemistry as carfilzomib.

Onyx chief executive Anthony Coles said Ono "is an ideal partner in Japan" while his firm will  keep the rights to the drugs in the USA and Europe. His counterpart at the Japanese drugmaker, Gyo Sagara, said the agreement "facilitates Ono's strategic expansion of its development pipeline in the oncology area with these exciting new compounds from a proven class of drugs".