Genzyme Corp has issued a warning saying that supplies of its Gaucher and Fabry disease therapies will continue to be disrupted over the next few months.

In a filing to the US Secrites & Exchange Commission, the troubled firm says it expects to supply “approximately the same amount” of Cerezyme (imiglucerase) for Gaucher disease “in July as we have in each of the past two months”. This equates to around 50% of demand and Genzyme added that supplies should increase in the following months.

However the company noted that there will be “regional variations in when Cerezyme will be available, and in some countries patients' infusion schedules may need to shift due to short-term shipping delays”. Genzyme’s problems began when its Allston Landing facility in Boston was temporarily shut down last year after a bioreactor was contaminated with a virus, particularly affecting production of Cerezyme and Fabrazyme (agalsidase beta) for Fabry disease. Then, in November, the FDA warned of the potential for foreign particle contamination in all lots of the two aforementioned therapies plus Myozyme (alglucosidase alpha) for Pompe disease, Aldurazyme (laronidase) for mucopolysaccharidosis type I and Thyrogen (thyrotropin alpha) for thyroid cancer.

Genzyme, which noted that “we continue to work with extremely limited inventory, says supply of Cerezyme in the coming months “could particularly be affected by two factors”, the impact of the production disruptions relating to water system problems and secondly preparations for implementation of the consent decree agreed with the US Food and Drug Administration in May which will also see the company return $175 million from profits “obtained by improper or illegal acts”.

As for Fabrazyme, supplies will remain at the current level, some 30% of demand, but Genzyme says it expects supply to be “tight in the July-August timeframe”.

Genzyme’s continuing problems are a boon for Shire, which received a favourable opinion last week from the European Medicines Agency’s Committee for Medicinal Products for Human Use for its Gaucher disease drug Vpriv (velaglucerase alfa). The latter was approved in the USA at the end of February.