Emerging Drug Developer: Acceleron

Acceleron close to partnering on promising bone-building therapy

Acceleron Pharmaceuticals is closing in on a licensing deal for its lead therapeutic development program. “We are in discussions with partners on ACE-011 where we would keep significant value,” says CEO John Knopf, PhD, in an interview with FierceBiotech. “And we expect in the next several months to announce a partnership.”

If Knopf wraps a deal in the first quarter of ’08, as he expects, Acceleron would be well ahead of the average timeline for most biotech pacts. While many biotech companies would prefer to wait for proof-of-concept data from a mid-stage trial, Knopf says Acceleron is well positioned to do a deal now because of clear indications that its bone-building therapy--which is headed to a mid-stage trial--can be effective for treating cancer patients. An early-stage trial of ACE-011 “demonstrated an increased level of a biomarker of osteoblast (bone forming cells) activity,” he adds. Another deal for a separate, earlier-stage therapeutic program for building muscles is in discussion, says Knopf, but any pact there probably wouldn’t be completed until well after Acceleron is partnered on ACE-011.

Initially, researchers are focusing on the impact the therapy has on multiple myeloma patients. Acceleron wants to demonstrate that ACE-011 can restore the bones of cancer victims, healing lesions that lead to non-impact fractures--a common symptom of multiple myeloma.

Scientists at the company have been concentrating on the activin receptor type IIA, a receptor for activin--a member of the GDF protein family which naturally inhibits the body’s bone-building activity. Researchers have combined the portion of ActRIIA that binds tightly to activin along with a component of an antibody molecule, giving them an inhibitor that can trigger fresh bone formation.

ACE-011 would have an advantage over other therapies in the same field, says Knopf, because it has a longer half life that would allow for once-a-month dosing. Researchers also point out that the therapy offers the potential for fresh bone development that could significantly improve the health of cancer patients.

Acceleron and others working in this field found clues to new bone- and muscle-building therapies in nature.

Researchers found that breeds of heavily muscled cattle lacked the myostatin gene. Then there were bully whippets, which lacked both myostatin genes. And in the lab, researchers found out that by knocking out the myostatin gene in mice they could triple their skeletal muscle mass. That kind of science has attracted some heavyweights in the drug development field, including Wyeth and Amgen.

Little Acceleron, though, has provided enough progress in its development programs to keep its investors happy. Just days ago Acceleron announced a third venture infusion of $31 million. That followed a $30 million round last year and a $25 million Series A in 2004. Bessemer Venture Partners, MPM BioEquities and QVT Financial led the round, with Advanced Technology Ventures, Flagship Ventures, OrbiMed Advisors, Polaris Ventures, Sutter Hill Ventures and Venrock all participating.

Some of that new money is being budgeted to start a Phase I trial for ACE-031 in muscle building. Earlier this year Acceleron announced preclinical data on the program that indicated the therapy has the potential to be a revolutionary new treatment for muscle-wasting diseases such as muscular dystrophy and ALS. And researchers are also anxious to bring the company’s third drug candidate--ACE-041, which inhibits VEGF and FGF-induced angiogenesis--into the clinic next year.

That’s a lot of work for a company with 80 employees, agrees Knopf. Over the next 18 months, he expects the company to grow considerably, but stay short of 150. By sticking to a familiar scientific approach and keeping much of the work in-house, Knopf is enthusiastic that a small player like Acceleron can be a model of efficiency.

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Emerging Drug Developer: Acceleron