(RxWiki News) A possible new front runner is emerging in the drug war against chronic myeloid leukemia (CML). While still considered experimental, this drug is showing itself to be a powerful agent against advanced forms of the disease.
In an ongoing phase II trial, the experimental drug ponatinib, which is manufactured by Ariad Pharmaceuticals, provided relief to patients living with CML who no longer responded to existing second-line drug therapies - Sprycel (dasatinib) or Tasigna (nilotinib).
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The trial involved 449 patients with advanced CML who were resistant to Sprycel and Tasigna, drugs prescribed when patients no longer respond to Gleevec (imatinib), the first line of defense against the disease. Some of the participants also had what's known as a T31151 mutation, which is completely resistant to all available drugs.
The trial found that 47 percent of patients had a major response to ponatinib, and 39 percent of these patients achieved complete remission of their leukemia.
Roughly 65 percent of patients with T31151 mutation responded favorably to ponatinib. These patients also had a major cytogenic response.
In the company's press release announcing the results, Jorge Cortes, M.D., professor and deputy chair of the Department of Leukemia at The University of Texas M.D. Anderson Cancer Center, said, “The preliminary findings from the global PACE trial confirm strong clinical evidence of the anti-leukemic activity of ponatinib in patients who are resistant or intolerant to dasatinib or nilotinib, or who have the T315I mutation for which there are no currently available treatments.”
Thanks to these encouraging results, Ariad plans to submit the drug for FDA approval sometime next year.
Despite these findings, there are concerns with this drug. In November, 2011, the company reported that 17 percent of patients in the trial had serious side effects and four patients died.
Roughly six percent of trial participants developed pancreatitis (inflammation of the pancreas), but none dropped out as a result. Investigators described the deaths as "possibly or probably" related to ponatinib.
These patients, each of whom had advanced CML, died of pneumonia, fungal pneumonia, gastric hemorrhage and cardiac arrest, according to the report.
Ariad's chief medical officer, Frank Haluska, said in a company statement that the deaths “were likely linked to the advanced nature of their disease, including the myelosuppressive effects of ponatinib on already badly damaged bone marrows.”
These preliminary results were presented at the 53rd Annual Meeting of the American Society of Hematology. Research findings are considered preliminary until they are published in a peer-reviewed journal.