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Dr Scott Furbish, Associate Director of Technical & Educational Programs at Genzyme Corporation was formerly with the team which originally developed enzyme replacement therapy at the US National Institute of Health. At the Second Conference in November 1994, he described the manufacturing process of Ceredase and Cerezyme, the new recombinant enzyme replacement therapy which it is hoped will eventually replace the placental version.
Dr Furbish explained that the enzyme for Ceredase was extracted from millions of placentae which are collected and then processed in France. He described the rigorous processing designed to remove any trace of viruses, such as Hepatitis B and HIV which might be present. The final filtration step is carried out by another company in the US which specialises in this process.
Cerezyme, the recombinant synthetically produced enzyme which will replace Ceredase, is made in a completely different way. It is made from genetically altered material based on Chinese hamster ovary cells. At present there is a pilot plant producing the recombinant enzyme on a limited scale in operation.
Dr Furbish reported two trials carried out comparing Ceredase and Cerezyme. Dr Grabowski in America showed that Cerezyme was as good if not better than Ceredase, see Cerezyme and Ceredase Compared. Dr Ari Zimran in Israel compared the same dose of Cerezyme given to some patients once every two weeks and to other patients given fractionated (divided up) three times a week - see report.
Dr Furbish said that the results indicate that Cerezyme is as effective as Ceredase, and frequency does not improve response for Cerezyme (although Dr Zimran still believes it improves response for Ceredase). Dr Furbish added: 'There is a hint that it is possibly superior as it has been beat up less'.
At the moment Cerezyme is being produced in three 160 litre fermentors in batches which is enough for about 120 patients. The eventual aim is to have a continuous process in four 2,000 litre fermentors.
'If the process doesn't work, we are also developing 320 litre fermentors at another site as a back up'. Dr Furbish said that 300 staff were working on a three shift basis to get the production process operational.
In answer to a question about inadequate supplies of Ceredase due to shortage of placenta, Dr Furbish said this could occur although he said there was no supply limitation at the present time.
Commenting on whether Cerezyme would be cheaper than Ceredase, he said the company did not know what the eventual cost would be, but using the present 160 litre fermentors the cost is 10% more than Ceredase.
He said that Genzyme does not pay a dividend to shareholders. 'What profit we declare is re-invested in manufacturing Cerezyme and carrying out research and development for other products such as a treatment for cystic fibrosis.'
Dr Richard Moscicki, Vice President of Genzyme, reported at the NGF Conference in Philadelpia on 7 November 1994 that due to a limited supply of suitable placentae, Ceredase was only available to around 1,000 patients. Recombinant Cerezyme would ultimately allow unlimited amounts of the enzyme. However, several major technical hurdles need to be overcome prior to large scale production. Current methods allow the production of 4.5 million units a year which he said would be enough for only 80-100 patients. Larger scale production is not expected until 1995 and full production in 1996. .
Source: Gauchers News February 1995
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