Troubled Genzyme Corp has restated its latest financial results after revealing that it has discarded a number of drugs over quality-control issues and says that fixing its manufacturing and other problems may take longer than expected.

In a filing to the US Securities Exchange Commission, Genzyme said taking an extra second-quarter write-off of $6.5 million, because since the results were announced on July 21, it has discarded “inventories that did not meet our quality specifications”. This means that the firm has posted a loss of $3.8 million, compared with net income of $23,000.

Genzyme spokesman Bo Piela told Reuters that the drugs involved are Cerezyme (imiglucerase) for Gaucher disease, Fabrazyme (agalsidase beta) for Fabry disease, Thyrogen (thyrotropin alpha) for thyroid cancer and the cholesterol treatment Cholestagel (colesevelam). However he insisted that the disposals relate to one-time quality control issues, and are not related to the manufacturing problems that have plagued the company since its Allston Landing facility in Boston was temporarily shut down last year after a bioreactor was contaminated with a virus.

In May, Genzyme entered into a consent decree with the US Food and Drug Administration and agreed to adhere to “a strict timetable” to bring the aforementioned plant in line with the regulatory requirements of the agency. The company now expects that to take three or four years rather than the original estimate of two to three years.

Ron Branning, Genzyme’s senior vice president of global product quality, told Bloomberg that “we are on track to do the things we’ve said we’re going to do”. He added that the change in the timing “doesn’t reflect anything other than a more thoughtful consideration of how we’re going to complete the remediation plan”.

Genzyme has until the end of the year to submit its plan to the FDA, and if changes take longer than the limits agreed with the agency, the company may be required to pay $15,000 a day for each drug involved in any violations.

Some observers believe that all of these factors make it difficult for Genzyme to push for a high sales price if the rumours are correct and that Sanofi-Aventis has made a bid for the US biotech.