Royalty Pharma has agreed to pay Sunesis up to $25 million in return for a slice of royalties from future global sales of the latter’s Phase III-stage acute myeloid leukemia (AML) candidate vosaroxin (formerly voreloxin). The anticancer quinolone derivative (AQD) is being evaluated in a pivotal Phase III study, termed Valor, which is currently enrolling 450 patients with first relapsed or refractory AML. The trial employs an adaptive design that will allow the Data and Safety Monitoring Board to agree a one-time, 225-patient increase in sample size at the interim analysis, to ensure the study retains adequate power across a broader range of survival outcomes. The interim analysis is expected to be carried out during the latter half of 2012.
Based on this timeline, under terms of the agreement between Sunesis and Royalty Pharma, the latter will invest $25 million after the Valor trial interim analysis in return for a percentage of royalties that will depend on certain conditions. If the study is stopped early on positive efficacy grounds, Royalty will get a 3.6% royalty payment on future net sales of Vosaroxin. If the one-time sample size increase is effected, Royalty will earn 6.5% in sales royalties, plus two warrants. Each warrant will allow Royalty to buy 1 million shares in Sunesis common stock at a price of $3.48, and $4.64 per share, respectively. Should, however, the trial continue with its originally planned 450 patient enrolment, Royalty has an option to make a $25 million investment on unblinding of the trial, in exchange for 3.6% royalties.
“This innovative transaction will provide us with access to added capital that extends our runway beyond the unblinding of Valor and enables our team to actively prepare for vosaroxin’s regulatory filings and U.S. commercial launch,” comments Eric Bjerkholt, Sunesis’ executive vp for corporate development and finance. “It will also allow us to selectively expand our development program and enhance our strategic flexibility on the timing and terms of vosaroxin partnering arrangements outside the U.S.”
Sunesis is focused on the development of drugs targeting solid and hematologic cancers. Lead candidate vosaroxin is in development primarily for the treatment of AML, but has also successfully completed a Phase II trial in patients with platinum-resistant ovarian cancer. Sunesis says objective tumor responses have separately been achieved in a variety of solid tumors, including non-small cell and small cell lung cancer. The drug exerts its anticancer activity through a mechanism involving DNA intercalation and inhibition of topoisomerase II activity, resulting in replication-dependent, site-selective double-strand breaks in DNA. Sunesis says the DNA damage induced by Vosaroxin is similar to that caused by quinolone antibiotics in bacterial cells.