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More Information Released on Thelin Pulmonary Hypertension Drug
by John C. Martin
Article Date: 06-09-05
Researchers at a California medical conference last month unveiled more findings of a pivotal Phase 3 clinical trial testing the safety and efficacy of an investigational medication for pulmonary arterial hypertension.1 The trial is one of the bases for a pharmaceutical manufacturer's move to seek approval of the drug from the U.S. government.
A Hidden Cause
Pulmonary hypertension is a rare lung disorder in which the blood pressure in the pulmonary artery—which runs from the heart to the lungs—rises far above normal levels. The reason is still unknown. This abnormally high blood pressure, in turn, leads to abnormal changes in the small blood vessels in the lungs. Increased resistance to blood flowing through the vessels results, placing a strain on the heart's right ventricle, eventually leading to right-heart failure, and possible death. In the United States, about 500 to 1,000 new cases of primary pulmonary hypertension are diagnosed each year. More women than men are diagnosed, according to estimates, and it's most commonly found in those between ages 20 and 40.2
Comparing Thelin to Placebo
The trial, lasting 18 weeks, put the drug Thelin, also known by its generic name sitaxsentan, to the test in a group of 246 patients with the disease. The participants were assigned at random to groups receiving one of two doses of the medication, or a group given a placebo as a comparison. A group in the study also received the already approved PH drug, Tracleer (bosentan), to compare the results.
The study investigators reported Thelin improved the distance that patients were able to walk in a standard 6-minute test. This was seen particularly in those taking 100 mg doses. Their walking distance increased "significantly", according to the drug's maker, Encysive Pharmaceuticals, by an additional 31 meters (34.3 yards) versus those on placebo.
By contrast, those taking Tracleer increased their walking distance in 6 minutes by about 29 meters (32.3 yards), the study team reported. While that was also a positive finding, it was later found that starting at week 12 of the study, those taking 100 mg of Thelin continued to improve, whereas those taking Tracleer "trended down". Thelin also improved function (based on WHO criteria) compared to placebo, but Tracleer did not, the investigators noted.
Patients were also assigned 50-milligram doses of the drug, but the investigators said the findings in that group were not significant. Thus, Encysive says it doubts the drug will be made available to patients at this dose.
Encysive Seeks FDA Endorsement
"We are very pleased with the clinical results of our second-generation, selective endothelin antagonist, whether compared to placebo or to bosentan, the only approved oral product for pulmonary arterial hypertension," said Bruce Given, MD, Encysive's President and CEO, in a company press release. "Data from [this trial] and our other Phase 2 and 3 studies form the basis of our New Drug Application", which was scheduled to be filed in May.
Side effects reported in trials of Thelin include headache, edema (fluid build-up), nausea, upper respiratory tract infection, dizziness, insomnia, nasopharyngitis, and nasal congestion.3
1. ATS 2005. The International Conference of the American Thoracic Society. 2005 May 20-25. San Diego, CA.
2. American Heart Association. Primary or Unexplained Pulmonary Hypertension. Available at: http://www.americanheart.org/presenter.jhtml?identifier=4752. Accessed June 9, 2005.
3. Barst RJ, Langleben D, Frost A et al. Sitaxsentan therapy for pulmonary arterial hypertension. Am J Respir Crit Care Med 2004 Feb 15;169(4):441-7. Epub 2003 Nov 20.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
Fund to Aid Family of Nichole Kellogg, Who Fought Rare Disease
19 July 2005 - A rare disorder kept Omahan Nichole Kellogg out of school beyond the eighth grade, but it didn't keep her from caring for others.
Diagnosed with primary pulmonary hypertension (a disorder characterized by high blood pressure) 10 years ago, Nichole died Wednesday, less than a month shy of her 24th birthday.
Her memorial service was held Saturday.
"She was limited in what she could do," said her mother, Terri Kellogg Steinspring, who is fighting the same disease. "After eighth grade she couldn't go to school anymore. She was in and out of the hospital, and we flew to Chicago every six months to see specialists.
"It's so rare that they're still doing studies on it. Most doctors don't really know what causes it."
In the years before her death, Nichole needed a double lung transplant and had reached the top of the transplant list, her mother said, but was doing so well she was put on inactive.
Then, six months ago, Nichole was diagnosed with a blood disorder that is linked to leukemia. That, her mother said, knocked Nichole off the transplant list.
A PPH support group helped with a portion of the funeral and burial costs, but financial help is needed.
A fund has been set up through U.S. Bank. Donations can made to the Nichole Kellogg Fund at any U.S. Bank or by mail to U.S. Bank, 431 Gateway Road, Elkhorn, NE 68022.
Source: Omaha World - Herald
Serotonin Helps Lose Weight
New research sheds light on how the brain chemical serotonin, when spurred by diet drugs such as Fen-phen, works to curb appetite.
New research sheds light on how the brain chemical serotonin, when spurred by diet drugs such as Fen-phen, works to curb appetite.
That knowledge could aid in the design of safer anti-obesity drugs nearly a decade after Fen-phen was banned for causing harmful side effects.
The study led by a UT Southwestern Medical Center , which tested the effect of several drugs that alter serotonin levels in the brain, found that serotonin activates some neurons and melanocortin-4 receptors, or MC4Rs, to curb appetite and at the same time blocks other neurons that normally act to increase appetite.
The dual effect helps explain how such drugs, including Fen-phen, spur weight loss.
The finding, available in the July 20 issue of Neuron, also reinforces the role of serotonin – a regulator of emotions, mood and sleep – in affecting the brain’s melanocortin system, a key molecular pathway that controls body weight.
“The more we understand about the pathways and the way serotonergic drugs regulate body weight, the more it one day might lead to harnessing beneficial properties of anti-obesity treatments like Fen-phen and minimizing the harmful side effects,” said Dr. Joel Elmquist, professor of internal medicine at UT Southwestern and co-senior author of the study.
In the United States, about 66 percent of adults are obese or overweight, as are 16 percent of young people aged 6 to 19, according to the Centers for Disease Control and Prevention. The trend is significant because being overweight or obese increases the risk of harmful health consequences, such as heart disease, stroke, diabetes, non-alcoholic liver disease and death.
Drugs that enhance the brain’s release of serotonin have helped people lose weight. Fen-phen, which paired fenfluramine with phentermine, had such success. The drug combination, however, also led some patients to develop cardiac complications, Dr. Elmquist said. The drug was removed from the market in 1997.
But the mechanisms of how it caused weight loss were never fully determined, he said.
So a few years ago, Dr. Elmquist and his research team set out to detail how fenfluramine affected the brain’s molecular pathways to reduce appetite. In 2002, they examined the region of the brain’s hypothalamus containing the arcuate nucleus, or ARC. In the ARC, drug-induced serotonin activates brain cells called pro-opiomelanocortin neurons, or POMC, which in turn release a hormone that acts on the MC4R to reduce appetite.
Researchers studied the effect of Fen-phen and other serotonin-inciting drugs on both normal and genetically engineered lean and obese mice. They found that serotonin’s dual regulation of POMC and AgRP neurons is necessary to promote weight loss.
“The finding increases the understanding of the molecular circuitry that controls body weight in response to changing levels of serotonin,” Dr. Elmquist said. “An overarching goal of this understanding, for humans, is to design specific, safe drugs to fight obesity.”
Source: UT Southwestern Medical Center
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