After a virus invades, Genzyme scrubs down

Dozens of decontamination specialists are busy stripping insulation from pipes at the company’s biotech drug plant overlooking the Charles River in Allston. Their prep work involves dismantling equipment, peeling gaskets from the lids of 2,000-liter vats called bioreactors, and scrubbing down every surface in sight with spore-killing bleach.

When everything is ready, they will wheel in the “vaporizers.’’ The squat machines, which look like industrial versions of the Star Wars robot R2-D2, will disperse clouds of vaporized hydrogen peroxide throughout the 185,000-square-foot production area. But first, the workers will be evacuated.

“It kills all known living things,’’ said Mark R. Bamforth, senior vice president for corporate operations at Cambridge-based Genzyme.

The intensive cleanup follows the discovery of a virus in one of six bioreactors at the red-brick plant, which makes two expen sive drugs to treat rare genetic disorders. Although the virus is not harmful to humans, it could affect the growth of cells used to make the treatments, Cerezyme and Fabrazyme, so production was halted almost two weeks ago.

Company officials won’t disclose how much they are spending on the cleanup, which is being performed by workers from a Pennsylvania decontamination contractor, but supervised by Genzyme engineers. Genzyme said it is looking toward a “rolling restart’’ of the Allston Landing plant in July, with all operations resuming by the end the month.

“At the end of this process, this whole facility will be disinfected,’’ Bamforth promised as he watched the cleanup operation in progress from a glassed-in viewing gallery. “We want to be sure we’ve eradicated the virus so future production won’t be affected.’’

Genzyme executives aren’t the only ones paying attention. This is the third time in the past nine months that the virus strain, called Vesivirus 2117, has been detected at a Genzyme manufacturing site. The first time was in September at a plant in Geel, Belgium, and the second incident occurred in November in Allston. The problem is being watched by the Food and Drug Administration.

“The FDA is currently monitoring this situation and providing advice on Genzyme’s ongoing analysis of the problems encountered at its manufacturing facility,’’ said Karen Riley, spokeswoman for the agency, which launched its own investigation last week. “The FDA is also discussing these issues with its regulatory counterparts. So far, a root cause [of the contamination] has not yet been determined.’’

Last week, Genzyme reported that a new lab analysis tool it developed found the virus in the “5A reactor,’’ one of the half-dozen bioreactors that make Cerezyme and Fabrazyme.

The drugs are produced by growing genetically modified Chinese hamster ovary cells in the bioreactors, which are filled with nutrients. Cerezyme treats Gaucher disease, while Fabrazyme treats Fabry disease. Both conditions cause waste to build up in the body, swelling organs. The drugs, taken intravenously about every other week, cost about $200,000 a year per patient. As a result of the production shutdown, doses of the drugs will have to be temporarily rationed.

In the previous two incidents, production runs for a third Genzyme drug, Myozyme, another enzyme replacement therapy that treats a rare disorder called Pompe disease, ended abruptly when cells began to die. Typically, that’s caused by foreign agents, such as bacteria or a virus. While the company sterilized production areas, it wasn’t until last month that it identified Vesivirus 2117 as the culprit. Officials at Genzyme have yet to pinpoint how the virus was able to infiltrate cell-culture production, though they suspect it got into the plant through raw materials in nutrients supplied by an outside vendor.

Genzyme and some outside biotech manufacturing specialists said viral contamination takes place occasionally, forcing companies to undertake the kind of decontamination process Genzyme has begun, but such problems are seldom publicly disclosed. The company did not make the two earlier cases public when they happened because it had stockpiled enough Myozyme to continue shipments. The company was compelled to publicize the most recent case because it interrupted the supply of Cerezyme and Fabrazyme to about 8,000 patients.

“It’s a very common problem to have in biomanufacturing plants,’’ said Maik Klasen, senior director of the healthcare and life sciences consulting group at Frost & Sullivan, a market research firm in San Francisco. “But most companies have a contingency plan and enough inventory that they don’t have to shut down an entire plant.’’

Genzyme is calling the interruption a suspension of production, not a plant shutdown, because more than 300 of the 500 employees at Allston Landing continue to work in administrative offices and in a “fill finish’’ area, where they fill vials with biotech products made elsewhere, freeze-dry them, and prepare them for shipment to customers.

Unlike last fall, Bamforth said, this time Genzyme was caught with lower drug stockpiles than it ideally would have because it was shifting the 13-year-old Allston plant to Cerezyme and Fabrazyme production - moving bulk production of Myozyme to Belgium - and had yet to build up sufficient inventory. Genzyme is building a $300 million plant in Framingham to further boost its production capacity for Cerezyme and Fabrazyme. Construction is scheduled to be completed this fall, but FDA approval will be required before the company can start manufacturing drugs at the site.

As cumbersome as the current decontamination work may be, Genzyme executives say they view it as vital to assuring the integrity of a complex manufacturing process. Bamforth, looking down from the viewing gallery at open bioreactor ports and stainless steel pipes stripped of insulation and marked with yellow signs reading “Sterile Process,’’ said the tedious operation is intended to reach a simple goal:

“What we want is to do this once, and do it well.’’

Todd Wallack of the Globe staff contributed to this story. Robert Weisman can be reached at weisman@globe.com.