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Sanofi Genzyme puts hold on arthritis medicine following surge in side effects

Sanofi, parent company of Cambridge’s Sanofi Genzyme, is based in Gentilly, near Paris.AFP/Getty Images

About 18,000 gel-filled syringes sold by the Cambridge biotech Sanofi Genzyme to treat arthritis of the knee should not be used because that batch was linked to a surge in side effects, the company says.

Sanofi Genzyme informed doctors, pharmacists, and clinics Monday that they had received packages of Synvisc-One from a batch linked to “an unexpected increase in the number of labelled adverse events,” according to a copy of the letter obtained by the Globe.

Sanofi Genzyme, a subsidiary of the French pharmaceutical giant Sanofi SA, told the recipients of the urgent “product hold” letter they should immediately stop dispensing the medicine while the company investigates.


The halt applies only to a single lot of Synvisc-One that bears the identification number 7RSL021, according to Heather Guzzi, a spokeswoman for the parent company in Bridgewater, N.J.

“We anticipate providing further guidance to our customers as soon as possible,” she said in an e-mail to the Globe.

The syringes were distributed in 36 states, including Massachusetts, between Oct. 25 and Nov. 7, Guzzi said. She declined to provide further details about why this batch was problematic and said the side effects were “consistent with documented adverse events in the product label. There have been no deaths reported.”

In the past, the company has said the most common side effects are pain, swelling, heat, redness, and fluid build-up in or around the knee.

Officials at Brigham and Women’s Hospital, Boston Medical Center, and Tufts Medical Center said they were unaware of any patients recently reporting serious side effects from the medicine.

Approved by the Food and Drug Administration in 2009, Synvisc-One is made from a substance called hyaluronan. It comes from chicken combs, the fleshy crests on top of the birds’ heads, according to the company. The substance is also found in the joints of the human body.


When injected into the knee, Synvisc-One is supposed to act as a lubricant and a shock absorber to relieve the pain of arthritis. Orthopedic surgeons and rheumatologists typically administer the injections, which are supposed to provide up to six months of pain relief, although two specialists told the Globe that they haven’t found the product to be nearly that effective.

In 2001, the FDA warned Genzyme about documentation problems and manufacturing deficiencies at its plant in Ridgefield, N.J., in connection with an earlier version of Synvisc made there. That version had to be injected three times instead of just once.

The FDA said at the time that the company could face serious consequences if their problems weren’t addressed, including failure to get approval for similar medical products.

The agency said the company had not proved it had adequately investigated product complaints; management reviews of “medical incidents” weren’t coordinated with other quality control systems; and problems in making the gel, preloaded in syringes, weren’t properly researched.

Sanofi bought Genzyme for $20.1 billion in 2011, and the subsidiary says responsibility for Synvisc-One has since been shifted to the French parent company. A generation ago, Genzyme pioneered the development of treatments for rare diseases, and it has refocused on that part of its business since being acquired by Sanofi.

Jonathan Saltzman can be reached at