Top selling expensive blood thinners are only as effective as injections of the blood thinner heparin to treat blood clots, according to researchers on Tuesday.
Deep vein thrombosis that appears most often as blood clots in the legs, is treated with injections of low-molecular weight heparin like Sanofi-Aventis' blockbuster Lovenox and Pfizer's Fragmin. These are often seen as more convenient and effective than original heparin.
Unfractionated heparin is the original blood thinner, derived from pig tissues, is mostly given intravenously in the hospital with close monitoring of patients.
The latest, more expensive version of heparin is extracted from the original heparin and has smaller molecules which would mean that it is less likely to bind to a protein in the body making it presumably more predictable and convenient to use. The injection is to be administered only once a day, and this can be done by the patient.
However a study by McMaster University researchers revealed that a weight-adjusted dosage of the original, much-cheaper heparin in a six-day course would cost $37 compared to the $712 for low-molecular-weight heparin. In addition it can be injected twice daily without an expensive hospital stay or in-hospital testing.
Study author Clive Kearon said "That was the underlying reason why we did the study: it is not necessary to do blood testing."
The study found that blood clots reappeared in less than 4 percent of 700 patients whether they were injected with the original heparin or low-molecular weight heparin. In addition the rate of major bleeding was also comparable in the two groups.
Kearon said, "This study will open the possibility of an expanded role for inexpensive, ordinary heparin," .He also noted that most of such studies are usually sponsored by drug companies that are often less motivated to recommend a treatment that costs less.
This study was published in the Journal of the American Medical Association, and was funded by The Heart and Stroke Foundation of Ontario.
Kearon said, "If you never do a study funded by a peer-reviewed agency, you're never going to reduce the cost of therapy."
However the difference in the cost of the two blood thinners is not as great in Canada or in Europe, where low-molecular weight heparin is more commonly used.
The American Heart Association has estimated that deep vein thrombosis occurs in about 2 million Americans a year, an estimated 600,000 of those who develop a pulmonary embolism in the lungs which can be deadly.