Andreas Hochhaus, MD, professor of medicine, Ruprecht-Karls-Universitat, Heidelberg, Germany, and colleagues found that 45% of 61 patients in their study experienced a clinical benefit when using nilotinib.

"Nilotinib has clinical activity in systemic mastocytosis, as demonstrated by overall response rates of 2% complete remission and stable disease in 43% of patients," Dr. Hochhaus said in his poster presentation on December 10^th.

Systemic mastocytosis is an uncommon condition involving proliferation of mast cells, often located in cartilage, bone, and blood. Mast cells mediate the skin's response to mild injuries. Patients with systemic mastocytosis produce immediate reddening of the skin when exposed to any mild injury due to the release of histamine from granules within the cell. An overproduction of mast cells can occur at any age; it is seen more often in men than in women. The exact prevalence of systemic mastocytosis is not known and there has not been any discovery linking it to a familial condition.

In their study Dr. Hochhaus and his team recruited adults who had been diagnosed with systemic mastocytosis. They were prescribed 400 mg of oral nilotinib twice daily. Most of these patients were identified as having neoplastic cells that expressed the oncogenic mutants that nilotinib is known to suppress.

"Nilotinib inhibits growth and proliferation of cells expressing these mutations, more potently comparable to imatinib," Dr. Hochhaus said.

Dr. Hochhaus said 1 patient had a complete remission; 2 had pure clinical responses, 4 had good partial response, 7 had incomplete remission, 3 had a minor response, 26 had stable response, 5 had progressive response, 6 were not evaluable, and follow-up was not available for 7 patients.

"Nilotinib was generally well tolerated in patients with systemic mastocytosis," said Dr. Hochhaus. "Nilotinib represents a promising novel agent as targeted therapy for patients with systemic mastocytosis," he concluded.

This study was supported by Novartis Pharma, East Hanover, New Jersey.


[Presentation title: A Phase II Study of Nilotinib, a Novel Inhibitor of c-Kit, PDGFR, and Bcr-Abl, Administered to Patients With Systemic Mastocytosis. Poster 2703]

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