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FDA approves drug to treat rare disorders that attack blood cell production

The U.S. Food and Drug Administration’s approval of an injectable drug called Dacogen for the treatment of myelodysplastic syndromes, or MDS, concludes a long journey of research that started at USC.

How the drug works was first discovered in the early 1980s at Childrens Hospital Los Angeles in the lab of Peter Jones, now director of the USC/Norris Comprehensive Cancer Center.

The drug was found “quite by accident,” Jones said, as he and his colleagues started to analyze 5-azacytidine, an agent that originated from a famous chemistry institute in what was then Czechoslovakia.

“It was a stealth drug in that it fooled cells into thinking that it was a normal chemical that belonged in DNA,” Jones said. “[Cells] could not recognize it as fake and incorporated it into both RNA and DNA.”

Upon further exploration, the scientists learned that 5-azacytidine and its sister drug—what is now known as Dacogen—worked by inhibiting DNA methylation.

In that process, methyl groups are added to DNA. As a result, certain genes that play a role in how cells acquire a “type,” or differentiate themselves, and how they proliferate are rendered inactive.

“Our experiments were the first to prove that DNA methylation and differentiation were linked,” Jones said.

The drugs in question were eventually used in thousands of scientific studies to switch on silenced genes, he said.

“Thus, the rationale and basic science behind these drugs was mostly done at USC,” Jones said.

In May, the FDA approved Dacogen for the treatment of MDS—a rare collection of disorders characterized by bone marrow’s inability to produce enough mature blood cells.

Symptoms of MDS include weakness, fatigue, easy bruising, frequent infections, bleeding, fever, weight loss, and a sense of feeling full.

The disease, which mostly occurs in people over age 60, can develop due to exposure to certain chemicals or radiation or have no known cause. Some forms of the MDS can progress to acute myeloid leukemia—a type of cancer in which the body produces too many white blood cells.

Dacogen works by promoting the normal development of blood cells, according to the FDA. It is recommended for treatments of patients with various forms of MDS, including previously treated and untreated forms with no known origin, and secondary MDS of all French-American-British subtypes.

Steven Galson, director of the FDA Center for Drug Evaluation and Research, said that the recent approval of Dacogen “offers patients with this rare disease an additional treatment option that may help these patients avoid blood transfusions.”

Dacogen was evaluated in 268 patients in three trials. About 22 percent of those patients experienced complete or partial responses to the drug.

Common side effects in the clinical trials included: neutropenia (low white blood cell count); thrombocytopenia (a reduction in the number of platelets); anemia; fatigue; fever; nausea; cough; bleeding in the skin; constipation; diarrhea; and hyperglycemia (high blood sugar).

Dacogen is manufactured by Pharmachemie B.V. Haarlem, The Netherlands, for MGI PHARMA INC., Bloomington, MN.

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FDA approves drug to treat rare disorders that attack blood cell production

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