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A debate on the technology of drug production in animal milk

Some types of proteins can only be produced in mammalian cells

Doubts have been evident recently regarding the potential inherent in the use of genetically modified animals for the purpose of turning them into drug factories. There have been doubts about the viability of transgenic animals for some time.
This was revealed after a company's announcement of a two-year delay in the trials of new drugs that were supposed to be the first drugs obtained by the method known as a play on words in English - PHARMING a paraphrase of FARMING (agricultural crop) and -PHARM a well-known abbreviation for the term drug.
The analysts say that today serious questions arise about the future of the industry.
The decision of PPL Therapeutics, a Scottish biotechnology company that owns the technology behind Dolly the cloned sheep, to delay the commercial marketing of alpha-1-antitrypsin (AAT) created a crisis of confidence among investors.
The reason for the delay in the drug, which is supposed to help treat lung diseases, but actually causes shortness of breath in patients in clinical trials.
For over a decade it has been possible to produce drugs that use human proteins in genetically modified bacteria. Insulin, for example, is produced in much better quality this way. However, some types of human proteins are too large or complex for bacterial cells to synthesize. PPL has patented a technology that will advance the production of human proteins in the milk of sheep or other farm animals. Together with the cloning technology, PPL will enable the industrial growth of human proteins in an economical and worthwhile way.

PPL currently has a number of genetically modified sheep that produce the protein alpha-1-antitrypsin, a protein that suppresses some of the known lung diseases - including emphysema and cystic fibrosis.
A drug made from this substance is currently in clinical trials, a procedure that must be completed according to safety regulations to prove that the drug is safe and effective.
However, PPL says that it has decided to conduct further investigations before it can bring the drug to the final stage of trials. This means that AAT will not be able to reach the market before 2007, two years later than expected.

This postponement is the latest in a series of problems caused to PPL. Julie Simmonds, an analyst at Bison Gregory says: “PPL are going backwards and not moving forward. My concern is whether this is a fundamental problem of the technology.”

PPL CEO Jeff Cook says in response: "This is definitely a disappointment, but the most important thing is to be sure that when we reach the next stage of the experiments we will have a seat belt. The legislator's requirements are strict, because this may be the first transgenic drug to reach the market."
Last year, the FDA, the US federal arm responsible for drug licensing, told PPL that it was concerned that three patients had failed the second phase of the AAT trial. According to Cook, he understands that they failed because they suffered from swelling Excess of the lungs, as a result of figs common in emphysema. PPL says that the phenomenon may have something to do with an overdose of the drug or its level of purity, or perhaps with an inhaler supplied by another company. However, initial tests failed to find the source of the problem, and now another investigation is underway.
Besides PPL there are two other companies that are advancing in the field &#;8211 the Dutch company PHARMING and the American company Genzyme. Both of these companies have stopped or slowed down their developments in the last year.
Analyst Julie Simond said that: "My main concern stems from the fact that so far, no transgenic product has been able to reach the market, although several companies have begun development for quite some time. This may be caused by the slow natural reproduction of these animals. In any case, it could be expected that it would be very easy to develop such proteins, although delivery to the patient would be more problematic."
Sally Bennett of ING Barings says: This is fundamentally bad news. They have delay after delay. Doubts have been growing about the ability of transgenic animals for some time."

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