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Analysis: New Drugs Attack Blood Diseases

Posted on: Tuesday, 12 December 2006, 18:00 CST

By ED SUSMAN

Scientists said Tuesday that new experimental medications are being rolled out from pharmaceutical companies to defeat some of the uncommon but deadly and mysterious diseases -- cancers and other illnesses that arise from cells that go awry in blood.

I went into hematology 25 years ago because one of my mentors explained that we had a better molecular understanding of blood diseases than we did of other medical disorders, Kenneth Kaushansky, professor and chair of the Department of Medicine at the University of California-San Diego.

That knowledge translates into new drugs that specifically target molecular errors that create diseases such as lymphoma and leukemia, and triggers excitement when that insight is turned into a drug such as Gleevec (imatinib) that revolutionized treatment and outcomes of chronic myeloid leukemia, Kaushansky, the president-elect of the American Society of Hematology, said at the organization's 48th annual meeting in Orlando, Fla.

We see that excitement among the 21,000 doctors and scientists at this meeting, he told UPI, who are developing dozens of new drugs that may alleviate many of these devastating diseases.

Among the new pharmaceuticals discussed at the five-day meeting:

-- Nilotinib, a drug similar to Gleevec but apparently more able to overcome resistance to Gleevec that occurs in a minority of patients. While doctors are using nilotinib in patients who relapse on Gleevec, researchers are also using it in other areas.

One such area is in treatment of systemic mastocytosis, a disease of mast cells -- cells that are located in cartilage, bone and blood.

Andreas Hochhaus, professor of medicine at Ruprecht-Karls-Universit&164;t in Heidelberg, Germany, and colleagues found that 45 percent of 61 patients in their study experienced a clinical benefit when using nilotinib, including one person who had a complete response to the disease while taking the drug.

Patients were treated with nilotinib twice a day. Nilotinib represents a promising novel agent as targeted therapy for patients with systemic mastocytosis, said Hochhaus, whose study was supported by Novartis Pharma in East Hanover, N.J.

Kaushansky said it is not unusual that one of these agents that is directed at one of the hematological diseases works in another -- often without any good explanation of the drug's mechanism of action.

-- Another experimental drug, banoxantrone (also known as AQ4N) showed signs of durable activity in treating patients with lymphomas. One patient with follicular lymphoma -- a particularly difficult cancer to treat -- had a partial remission with a duration of six months, said Richard Furman, assistant professor of medicine at Weill Medical School of Cornell University in Ithaca, N.Y.

The phase 1 clinical trial mainly tested the drug's safety among 11 patients in late stages of various diseases. Those studies did not reveal any signals of toxicity. In fact, patients were able to tolerate all doses of the drug tried in the early studies, sponsored by Novacea, based in South San Francisco, Calif.

Further trials of intravenous banoxantrone as monotherapy and in combination with other anti-cancer drugs and radiation are being planned based on the evidence of response, no dose-limiting toxicity and good tolerability, Furman said.

-- Researchers said they were encouraged by the Phase 1/2 studies of lumiliximab, a monoclonal antibody that may be effective as an additional compound for treating patients with chronic lymphocytic leukemia.

In a study in which 31 patients were enrolled, the addition of the new agent being developed by Biogen Idec in San Diego appeared to help half the patients achieve a complete response, meaning clinical evidence of their disease disappeared.

Lumiliximab was added to a standard treatment regimen of anti-cancer drugs fludarabine, cyclophosphamide and rituximab in the early clinical trial.

These data suggest that lumiliximab plus these drugs may produce a higher complete response rate than just the combination -- without additional toxicity, said John Byrd, director of the hematological malignancies program at the Arthur James Comprehensive Cancer Center at Ohio State University in Columbus. Based upon this data, a multicenter, global, randomized study of the combination with lumiliximab compared with the drug without lumiliximab is being initiated.

-- Researchers looked at the use of 5-axacitidine (Vidaza) in combination with a experimental drug, MS-275, a histone deacetylase inhibitor -- a drug that disrupts a cancer cell's DNA replication -- in treatment of patients with disorders such as myelodysplastic disorders and leukemia.

The combination is clinically tolerable and leads to substantial remissions, said Steven Gore, an associate professor of oncology at the Johns Hopkins University School of Medicine in Baltimore who enrolled 31 patients in his study. He said that MS-275 is being further studied by an international research group.

Whether these or other drugs will reach approval will depend on the results of the clinical trials and scrutiny of adverse events that might be associated with them, Kaushansky told UPI.

Ten years ago we might have had one or two of these targeted agents in testing, he said. Today, we have many, many of these drugs, plus older ones that are finding new treatment niches. That is what all the excitement is about in this field.

Source: United Press International

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