Sunesis' $28.5M Stock Sale to Fund Voreloxin Phase III Trial
July 02, 2010 - Bioworld Today
By Catherine Hollingsworth
Staff Writer
Sunesis Pharmaceuticals Inc. has closed a $28.5 million stock sale, the final part a 2009 private placement of stock priced at 0.275 cents per share, money that will be used to initiate a pivotal Phase III trial of voreloxin in patients with acute myeloid leukemia.
It was the third part of a $43.5 million financing announced last year, starting with an initial $10 million in Series A preferred stock, followed by a $5 million close in October. With the third tranche of $28.5 million in common stock, the company's shares have returned to a single class of stock, the South San Francisco-based firm said.
The added cash from this latest tranche, plus the company's current cash, gives Sunesis close to $50 million, which could last into 2012, CEO Daniel Swisher told BioWorld Today. That's enough to take voreloxin substantially into Phase III testing, he said.
And the further along the product goes with good results, the greater value it presumably could command in any partnership negotiations. Asked if the company was engaged in any talks with potential partners, Swisher would not comment directly, but did say that Sunesis' strategy has been to keep an open dialogue.
Voreloxin is a first-in-class anticancer quinolone derivative, a class of compounds that has not been used previously for the treatment of cancer.
Quinolones are a family of antibiotics that kill bacteria cells, but in the case of voreloxin, no anti-infective properties are present in the drug and only the cell-killing (cytotoxic) properties remain.
Sunesis in-licensed voreloxin from Japan's Dainippon Pharmaceutical Co. (now part of Dainippon Sumitomo Pharma Co. Ltd.), which had chemically manipulated the molecule to target rapidly dividing cancer cells.
One potential advantage of a cytotoxic quinolone is that it could avoid some of the drug resistance seen with chemotherapy use, Swisher said. That may explain why voreloxin is showing activity in refractory patients, he said.
Another potential benefit, he said, is the drug's pharmaceutical properties that make it combine well with other therapy without showing any drug-to-drug reaction.
In a Phase II study of voreloxin plus the chemo drug cytaribine, the median survival was 7. 1 months among first relapse and primary refractory patients, according to data presented last month at the American Society of Clinical Oncology annual meeting. The Phase III voreloxin trial that is slated to start later this year also is designed as a survival trial.
Other recent data for cytarabine combination regimens show that the treatment typically demonstrates a median survival of four months.
Voreloxin also has been shown to be active as a single agent in a study of elderly patients with AML. But Swisher said that if all goes well in Phase III, the company is likely to seek voreloxin approval initially as a combination therapy.
A Phase II single agent clinical trial in platinum-resistant ovarian cancer has also completed enrollment.
Participants in the private placement included funds managed by Bay City Capital, New Enterprise Associates, Alta Partners, Caxton Advantage Life Sciences Fund, Merlin Nexus, Nextech Venture, OpusPoint Partners, Venrock Associates and Vision Capital Advisors and members of Sunesis' management.
Rachel Leheny, managing director of Caxton Advantage Venture Partners, told BioWorld Today, "The reason we invested is that the product has tremendous efficacy" as demonstrated in studies of patients with AML and refractory ovarian cancer. And she said that the side effects seen with voreloxin were less than what has been observed with competing agents.
Currently, cytarabine is the standard-of-care treatment for AML and there has been no new therapy for the disease in 30 years.
AML is the largest of the acute leukemias, with about 13,000 new cases each year in the U.S. and a prevalence of about 25,000, with similar numbers in Europe. The treatment-eligible size of the patient population is around 22,000, according to Sunesis.
The company estimates that net proceeds from the closing will be about $26.7 million, with associated fees to the placement agents in the 2009 private placement due in the third quarter.
Shares in Sunesis (NASDAQ:SNSS) were down 2 cents, closing at 45 cents.
