Swedish authorities have recalled Sanofi Aventis' low molecular weight injectable blood thinner Lovenox (enoxaparin), known locally as Klexane, after four batches of the blockbuster drug were found to contain oversulfated chondroitin sulphate.
OSCS has been previously identified as a contaminant in batches of Baxter's unfractioned heparin product that has been linked to around 81 deaths in the US.
Lennart Forslund, medical information officer at the Swedish Medicinal Products Regulatory Agency told in-PharmaTechnologist.com that no adverse reactions had been observed in Sweden and that recall is a precautionary measure. He added that: "Sanofi found the contaminated batches and the lab at MPA did a second check on all batches of Klexane (enoxaparin) in Sweden."
Forslund also said that the contamination had not been identified in either of the two competitor low molecular weight products sold in the country, Fragmin (dalterapin sodium), sold by Pfizer, or Leo Pharma's Innohep (tinzaparin sodium), or indeed in the fractionated heparin that is also marketed by the latter firm.
Salah Mahyaoui vice president of product communication at Sanofi told in-PharmaTechnologist.com that the firm had identified the impurity using the nuclear magnetic resonance based testing procedure that it instituted on 1 April this year. He added that none of the identified batches had contained more that 7 per cent OSCS, much lower than the levels identified in unfractionated formulations of heparin in the US.
Mahyaoui also said that traceability of raw materials was a high priority for the firm but added that because investigations were at an early stage "a clear picture would take time to emerge."
While OSCS was first identified in unfractionated heparin products made by US firm Baxter International, the contaminant has since been identified in batches of the drug in Australia, Canada, China, Denmark and Japan, according to a statement issued by the US Food and Drug Administration (FDA) on 21 April.
In addition, France's Rotexmedia began withdrawing its unfractionated heparin product after it was linked to over 80 adverse reactions in patients in Germany, while Italy's Opocrin also initiated a recall of its version of the blood thinner.
US investigation ongoing
Meanwhile, US investigations into the OSCS found in Baxter's products are ongoing. On April 29, Baxter's CEO, Robert Parkinson, appeared before the House of Representatives subcommittee on oversight and investigations to defend the firm's actions.
Parkinson told the committee that the company is: "alarmed that one of our products was used in what appears to have been a deliberate scheme to adulterate a life-saving medication and that people have suffered as a result."
Also in attendance was David Strunce, president of Baxter's active pharmaceutical ingredient supplier Scientific Protein Laboratories. He commented that the problem cannot be linked to heparin processing at its Changzhou facility in China.
Nevertheless, Strunce agreed that the contamination appears to be a result of a deliberate and widespread switching of raw materials in China. He suggested that an outbreak of blue-ear disease that decimated the Chinese swine population in 2006 may have provided "some additional incentive" for a supplier to add a contaminant.
The meeting, which was entitled "The Heparin disaster: Chinese counterfeits and American failures," also heard testimony from the FDA's head of drug evaluation and research, Janet Woodcock. She said that "FDA's working hypothesis is that this was intentional contamination, but this is not yet proven," echoing earlier comments by FDA commissioner Andrew von Eschenbach.
Subcommittee Chairman Bart Stupak said that a "series of FDA blunders" in 2004 had played a part in the heparin contamination, but added that "both Baxter and SPL have failed the American public."