Updated from 9:54 a.m. EST
reported Tuesday that patients with a rare but aggressive form of blood cancer responded to treatment with the company's experimental drug pralatrexate for more than nine months.
The result signifies that pralatrexate is having a durable and meaningful benefit for patients, Allos said, and supports the company's effort to get the drug approved in the U.S. later this year.
Allos shares were up 12.8% to $9.02 in morning trading but were settling a tad in the afternoon to $8.15.
Allos is likely to seek a partnership to help market pralatrexate, or perhaps, sell the company outright to a larger drug firm.
Tuesday's data come from a phase II study that enrolled 115 patients previously treated for peripheral T-cell lymphoma (PTCL), a fast-growing cancer that affects white blood cells known as T-cells. There are no approved drugs to treat the disease.
Of the 109 patients available for evaluation in the study, 29 patients, or 27%,
, including 11 patients whose cancer went into complete remission, Allos first reported in December.
Tuesday, the company said that the median duration of response from treatment with pralatrexate was 9.4 months.
"Based on these promising data, pralatrexate has the potential to play a clinically meaningful role in the treatment of patients with relapsed or refractory PTCL," said Dr. Owen O'Connor, a blood cancer expert at New York-Presbyterian Hospital/Columbia University Medical Center and the principal investigator of the pralatrexate study.
Allos plans to submit pralatrexate for approval to the U.S. Food and Drug Administration during the first half of 2009.
Allos will be able to submit pralatrexate for FDA approval based on this small phase II study because PTCL is diagnosed in only about 5,000 U.S. patients each year. The FDA didn't require Allos to compare the response rate of pralatrexate to another drug in the study because all the enrolled patients were previously treated, most multiple times, without success.
Pralatrexate, or PDX, is a chemotherapy drug known as an "antifolate" that works by interfering with the ability of cancer cells to divide, resulting in cell death. Allos designed pralatrexate to be more potent than other antifolates, including the widely used drug methotrexate.
cancer drug Alimta is another antifolate, approved for the treatment of lung cancer.
Allos is also testing pralatrexate in other forms of non-Hodgkin's lymphoma and lung cancer. One of the lung cancer studies under way pits pralatrexate against Tarceva, a lung cancer drug marketed by
If recent history is a guide, Allos may not remain independent for long. Companies with similar blood cancer drugs that have been acquired in recent years include Corixa, Ilex Oncology, Pharmion, Salmedix, MGI Pharma, Millennium, Xanthus, Anormed and Bioenvision.
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