Chinese health officials announced today, Monday 21st April, that the contaminant found in batches of the blood thinner heparin whose main ingredients were made in China, was not to blame for the deaths and adverse allergy reactions that have been reported in the US.
Deputy director-general of the China National Institute for the Control of Pharmaceutical and Biological Products, Jin Shaohong said only some of the batches used by the patients involved contained the contaminant, an oversulfated form of chondroitin sulfate.
According to Reuters, Shaohong told the press that their own investigation concluded that the oversulfated chondroitin could not be the root cause of the heparin adverse events.
A month ago, following interviews with scientists in China and the US, the New York Times identified the contaminant as a chemical similar to chondroitin sulfate. It was a counterfeit product, made to act like heparin, said the report.
Chondroitin sulfate is made from animal cartilage and can be altered to an oversulfated form that acts like the anticoagulant, heparin. In unaltered form, it is widely used as a dietary supplement to ease joint pain, such as that which occurs with osteoarthritis.
An earlier investigation by the US Food and Drug Administration (FDA) found some of the suspect batches contained oversulfated chondroitin sulfate.
However, none of the authorities involved has made a direct link between the contaminant and the dozens of deaths and hundreds of adverse allergic reactions that have been reported after patients have used heparin.
The active ingredient is made from pig intestines and is mainly sourced from China.
After the adverse events reports started coming in, Baxter International, the manufacturer of the suspected batches and one of the two main suppliers in the US, recalled most of its heparin products in February.
The suspect batches contained an active ingredient sourced from one plant in China, which the FDA was supposed to have checked but the name of the plant was mixed up with another one on the FDA database.
Since then the FDA has announced a plan to establish offices in China, staffed by US and locally recruited staff. A memorandum of agreement on the matter was signed by the US agency and two FDA counterpart Chinese agencies in December, and all parties are now awaiting the go ahead from the Chinese government.
In the meantime, Chinese health officials will be visiting Baxter’s plant in New Jersey, Shaohong is reported by Reuters to have told the press.
He added that other factors could account for the reported problems with the heparin products, including how it is injected, or issues to do with the health of the patients using the drug.
Baxter denies that any of the deaths of patients who used their heparin products were caused by the contaminated heparin. Their last communication was on 15th March where they said neither their own, nor the FDA investigations had confirmed that Baxter heparin caused any of the deaths as a result of an allergic reaction.
Although the company itself has also received reports of a number of deaths, including four patients who “received Baxter heparin and suffered an allergic-type reaction to heparin that may have contributed to the adverse outcome”, the company pointed out that in each of these cases, “the patient had multiple underlying complex medical conditions and patients in three of these four cases had either undergone, or were in the process of undergoing, invasive cardiac surgery”.
Sources: Reuters, FDA, Baxter International, MNT archives.
Written by: Catharine Paddock, PhD