Platelet E-News – May 17, 2007

This e-newsletter is a monthly publication of The Platelet Disorder Support Association. The information in this newsletter is for educational purposes only. For advice on your unique medical condition, please consult a health care professional.

Contents:

  •  Enrolling: AMG 531 Versus Standard Care for ITP
  •  Enrolling: AKR-501 Phase 2 Clinical Trial
  •  Phase 1 Study of Anti-RhD Sym001 in Healthy Volunteers
  •  TPO-Mimetics Showing Promise
  •  Rituximab in ITP: Larger Studies Needed
  •  Reports of Thrombocytopenia from Acetaminophen
  •  New CMS Codes for IVIG Products
  •  Immunoglobulin Reinstated on WHO’s “Essential Medicines”
  •  FDA Warns Consumers About Internet Counterfeit Drugs
  •  CDC Renames Division of Hereditary Blood Disorders
  •  Does Flossing Prevent Plaque in the Arteries?
  •  Arsenic in Chicken
  •  Don’t Flush Old Drugs


ENROLLING: AMG 531 VERSUS STANDARD CARE FOR ITP

AMG 531 (Amgen) binds to and activates the receptor for thrombopoietin, a growth factor that induces bone marrow to make more platelets. The drug is being tested for its ability to increase platelet production. A phase 3b, open-label trial in which patients are randomized to either AMG 531 or standard of care for ITP is enrolling patients who are 18 or older with ITP who have not had their spleen removed and have received at least 1 prior therapy for ITP. Treatment period is 52 weeks. The study began enrolling in November 2006, in 21 states, Canada, and Europe.  www.clinicaltrials.gov

ENROLLING: AKR-501 PHASE 2 CLINICAL TRIAL

AKR-501 - This Phase 2, multi-center, double-blind, randomized, placebo-controlled, dose-ranging, parallel-group study will assess the efficacy, safety and tolerability, of AKR-501 tablets, as compared to placebo, in the treatment of patients with ITP.  Approximately 65 eligible patients will be randomized for 28 days. Each AKR-501 dosing group will consist of 15 patients while the placebo group will consist of 5 patients. All study patients will be evaluated weekly with a final assessment for safety and effectiveness to be done 2 weeks after the last study dose. You can find out more information about the study at www.PlateletStudies.com/pdsa.

PHASE 1 STUDY OF ANTI-RHD Sym001 IN HEALTHY VOLUNTEERS

A recombinant, antibody product that is comprised of 25 different anti-Rhesus D antibodies is moving into a phase 1 trial in healthy volunteers. It is being developed for treatment of ITP and for prevention of hemolytic disease of the newborn. Up to 39 RhD positive and 19 RhD negative healthy volunteers will be enrolled in the double-blind, randomized, placebo-controlled trial to assess safety and tolerability following a single intravenous infusion. The trial is being conducted at a clinic in the U.S.

According to the company news release, “Sym001 is the first ever recombinant polyclonal antibody to enter human clinical trials.” The drug is being developed by Symphogen, a pharmaceutical company in Denmark, and Biovitrum, a biopharma company in Sweden and the U.K.

TPO-MIMETICS SHOWING PROMISE

TPO-mimetics are drugs that bind to the thrombopoietin (TPO) receptor, but bear no structural resemblance to TPO. The hypothesis is that these TPO-mimetics might treat ITP without causing production of anti-TPO antibodies. Examples of TPO-mimetics are AMG 531, Eltrombopag, and AKR-501. Researchers from New York Presbyterian Hospital reported on a phase 1/2 trial of AMG 531 in ITP. After testing various doses in phase 1, phase 2 included 16 patients with long-term ITP in a double-blind, placebo controlled trial. The compound produced a dose-dependent increase in platelet counts in ITP patients. A reviewer writes, “Although the data on TPO-mimetics are currently tantalizing, the long-term effects of these compounds remain to be established.”

Abrams C. Are TPO-Mimetics Better Than the Real Thing? The Hematologist, March/April 2007, Vol 4(2), pg. 7.

RITUXIMAB IN ITP – LARGER STUDIES NEEDED

Rituximab, a monoclonal antibody against CD20-positive B cells, is increasingly used to treat ITP, but data to support its use are limited. A review of the literature between 1997 and 2004 found just 19 reports that described five or more patients; nine of those were abstracts only. None of the studies were randomized trials. The drug can induce remissions in ITP, but it is difficult to estimate its true efficacy since the literature is biased by small case reports touting high response rates. The reviewer concludes that it would be “worthwhile and beneficial for both patients and physicians to study rituximab in a larger cohort.”

Abrams, C. Rituximab in ITP – When and Why Does it Work? The Hematologist. May/June 2007, Vol 4(3), pg. 8

REPORTS OF THROMBOCYTOPENIA FROM ACETAMINOPHEN

Researchers at the Blood Center of Wisconsin reported that a 4-year-old girl experienced several episodes of acute thrombocytopenia (low platelet count) after taking acetaminophen (Tylenol). Years earlier they had found a similar reaction to acetaminophen and naproxen (Aleve), and determined that the triggers for platelet destruction were acetaminophen sulfate and naproxen glucuronide. For the more recent patient, the metabolite trigger was different: acetaminophen glucuronide.

Bougie DW, Benito AI, Sanchez-Abarca LI, Torres R, Birenbaum J, Aster RH. Acute thrombocytopenia caused by sensitivity to the glucuronide conjugate of acetaminophen. Blood, 15 April 2007, pg. 3608-9.

NEW CMS CODES FOR IVIG PRODUCTS

The Centers for Medicare and Medicaid has established new, brand-specific codes for 4 intravenous immune globulin (IVIG) products and one Rho(D) immune globulin product. This enables brand-specific reimbursement for Medicare beneficiaries. The IVIG products with their own codes are Octagam, Gammagard, Flebogamma, and Gamunex. The Rho(D) receiving its own code is Rhophylac.

IMMUNOGLOBULIN REINSTATED ON WHO’S “ESSENTIAL MEDICINES”

Immunoglobulin is included in the 15th edition of the World Health Organization (WHO) list of Essential Medicines.  From the WHO website: “The WHO List of Essential Medicines provides a model for countries to select medicines addressing public health priorities according to quality, safety and efficacy standards.”

http://mednet3.who.int/EMLib/

FDA WARNS CONSUMERS ABOUT INTERNET COUNTERFEIT DRUGS

The Food and Drug Administration (FDA) warned U.S. consumers that Web sites may be distributing counterfeit prescription drugs, after reports of 24 Web sites distributing fake Xenical, a drug prescribed for weight loss. FDA advice: Be wary if 1) there is no way to contact the Web site pharmacy by phone, 2) if prices are dramatically lower than the competition, or 3) if no prescription from your doctor is required. FDA’s Web site contains tips for consumers as well as the list of 24 questionable Web sites.

www.fda.gov/buyonline/

CDC RENAMES DIVISION OF HEREDITARY BLOOD DISORDERS

The Centers for Disease Control and Prevention’s (CDC) Division of Hereditary Blood Disorders has been officially renamed the Division of Blood Disorders. The Division works with multiple partners to implement specialized prevention programs for persons with blood disorders and their families.

www.cdc.gov/ncbddd/hbd

DOES FLOSSING PREVENT PLAQUE IN THE ARTERIES?

A study in The New England Journal of Medicine tested whether aggressive treatment of gum disease can decrease chronic inflammation and thereby reduce risk for atherosclerosis. The authors demonstrated that a single intensive treatment of severe periodontal disease was associated with a sustained improvement in dental health, endothelial function, and markers of chronic inflammation. Endpoints, however, were surrogate markers for inflammation and blood vessel health.  Larger studies are needed.

Silverstein R. Flossing May Prevent Plaque (of a Different Sort)! The Hematologist. May/June 2007, Vol 4(3), pg. 6.

ARSENIC IN CHICKEN

The New York Times and other media outlets reported that arsenic, a recognized cancer-causing agents that may also contribute to heart disease and diabetes, is deliberately given to chicken in the U.S. Arsenic is a government-approved additive in poultry feed because it kills parasites and promotes growth in chickens.

Organic chicken and those labeled “antibiotic-free” do not contain arsenic. Tyson Foods, the nation’s largest chicken producer, has stopped using arsenic in chicken feed; but “there are many more arsenic-fed than arsenic-free chickens for sale in the U.S.”

Burros M. Chicken with Arsenic? Is that O.K.? The New York Times, April 5, 2006.
 
(Note: Arsenic can reduce platelet counts)

DON’T FLUSH OLD DRUGS

The federal government is warning consumers to stop flushing old drugs down the toilet. Pharmacy groups used to recommend flushing unused drugs to prevent pets and curious children from retrieving them from wastebaskets. But now prescription drugs are found flowing down the nation’s rivers and have been linked with reproductive problems in fish and drug-resistant germs spread by waterfowl. The new campaign, called SMARxT, recommends unused drugs be disposed through municipal hazardous-waste-collection programs. The next best choice is putting them in the trash. But first, individuals are asked to crush pills or dissolve them in water; add them to sawdust, kitty little or some other inedible material; and seal them in a plastic bag.

Science News, April 7, 2007, vol 171, pg. 222.

CORRECTION: ITP REGISTRY IN THE UK

In our April e-news we reported that the United Kingdom’s adult ITP registry has been sitting dormant since 2004 for lack of funding.  This was incorrect.  The ITP registry was put on hold because of a change in staffing.  Dr. Provan has returned to the project which is now very active and accumulating data.  The aim of the registry is to learn more about ITP, its prevalence, clinical behavior, and responses to treatment. Progress reports for the study will be published in a bi-monthly newsletter, at www.ukitpregistry.com. The study coordinator is Ameet Sarpatwari (avs31@medschl.cam.ac.uk)

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