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Clopidogrel makers to study genetics

Sanofi-Aventis and Bristol-Myers Squibb have agreed to work with the FDA to conduct studies of clopidogrel bisulfate (Plavix) that will allow a better understanding of genetic factors, as well as the effects of other drugs-especially proton pump inhibitors (PPIs)-on the effectiveness of clopidogrel.


The FDA is aware of published reports that clopidogrel is less effective in some patients than in others, and that effectiveness may be related to genetic differences in how the body metabolizes clopidogrel or interaction with certain other drugs, which can affect how clopidogrel is metabolized.


A few studies have suggested that some PPIs may make clopidogrel less effective. Until further information is available, healthcare providers should continue to prescribe clopidogrel and patients should continue to take it as directed. Healthcare providers should evaluate the need for starting or continuing treatment with a PPI in patients taking clopidogrel, the FDA advises.


Seroquel XR available for bipolar depression

Once-daily quetiapine fumarate (Seroquel XR) extended-release tablets are now available for the acute treatment of the depressive episodes associated with bipolar disorder and the manic and mixed episodes associated with bipolar I disorder. Seroquel XR is also used in the maintenance treatment of bipolar I disorder or as adjunctive therapy to lithium or divalproex. A product of AstraZeneca, once-daily Seroquel XR is now available in two new tablet strengths, 50 mg and 150 mg.


Seroquel XR is also approved for the acute and maintenance treatment of schizophrenia.


Consult product labeling for prescribing precautions and instructions.


Anticoagulant from genetically engineered animals

The FDA approved ATryn, an anticoagulant used for the prevention of blood clots in patients with hereditary antithrombin (AT) deficiency, which puts them at high risk for thromboemboli. ATryn is a therapeutic protein derived from goat's milk that has been genetically engineered by introducing a segment of DNA into the goat's genes with instructions to produce human antithrombin in the milk.


ATryn was approved as an orphan drug and is a product of GTC Biotherapeutics. The FDA based the approval of ATryn on studies of 31 patients with hereditary AT deficiency who received ATryn to prevent thromboemboli before, during, or after surgery or childbirth. Only one of the 31 patients treated with ATryn developed a thromboembolism.


The most common adverse events were hemorrhage and reactions at the infusion site, which occurred in approximately 5% of patients. The health of the goats was unaffected and followed over seven generations. The genetically engineered goats were also determined not to cause any significant impact on the environment. All are healthy and no adverse reactions from the recombinant DNA construct or its expression have been seen thus far.

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FDA warns of rare infection caused by psoriasis drug

The FDA issued a public health advisory to notify healthcare practitioners of three confirmed and one possible report of progressive multifocal leukoencephalopathy (PML) in patients using efalizumab (Raptiva). Three of the patients have died. According to the FDA, all four patients were treated with the drug for more than 3 years. None received other treatments that suppress the immune system.


The FDA is reviewing the situation and is taking steps to ensure that the risks of efalizumab do not outweigh its benefits and that patients prescribed the drug are clearly informed of the signs and symptoms of PML. Healthcare professionals should carefully monitor patients for the possible development of PML.

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In October 2008, the efalizumab's product labeling was revised to include a boxed warning highlighting the risks of life-threatening infections including PML.