News Roundup [abridged Versions Appear In The Paper Journal]

Cloned chickens to help fight cancer

BMJ 2000; 321 doi: (Published 16 December 2000) Cite this as: BMJ 2000;321:1491
  1. Bryan Christie
  1. Edinburgh

    The scientists who created Dolly the sheep are planning to clone a hen that can lay “golden” eggs that are rich in proteins to fight human cancer.

    They have announced a project aimed at breeding flocks of genetically altered chickens that will act as living pharmaceutical factories, producing anticancer treatments in their eggs.

    The scientists at the Roslin Institute near Edinburgh are confident of success and said that their work will result in a new generation of cancer treatments, produced much more cheaply and easily, with the potential of extending the benefit to many more patients with cancer worldwide.

    Many of the promising new treatments are based on antibodies but have to be given in much higher doses than traditional drugs. These can be produced only at considerable expense and in restricted supplies using conventional pharmaceutical manufacturing methods.

    Roslin has already bred transgenic chickens and shown that proteins useful in treating human disease can be extracted from their eggs. Only a small number of the offspring of these chickens carry the protein, however, making the process inefficient. The next step is to clone identical chickens, each genetically adapted to produce the necessary proteins.

    Dr Helen Sang, who is leading the avian project at Roslin said that the creation of Dolly had shown the future of this type of technology: “The next stage is to deliver the benefits of the Dolly technology to an expectant world. Whilst animals such as cows, sheep, goats, and rabbits are being developed to produce proteins in their milk, avian technology promises a much faster, cheaper, and virtually unlimited production process marked by the chicken's prolific egg laying capacity.”

    She said that the team at Roslin hoped that within a year it would be able to clone the first chicken carrying the protein, adding, “The existing technology is expensive, and there is a growing and urgent need to produce these new drugs in quantity. I am very confident that we will achieve our goal.”

    A US drug company, Viragen, is funding the work, and the first protein produced in a chicken is expected to be based on one of its treatments for skin cancer. Viragen will hold the rights to commercialise this technology and will make it available to other companies for mass producing their emerging new treatments.

    Professor Ian Wilmut, who created Dolly, the first animal to be cloned from an adult cell, said that Roslin was unique in having the technology both for cloning and for breeding transgenic chickens to make this leap a real possibility.

    The director of the UK Cancer Research Campaign, Professor Gordon McVie, said: “There is no question we need an easier way to mass produce proteins in a form that is both clean and reliable.

    “There is a touch of marketing hype about this and nothing has been achieved yet but if anyone is going to do this they [the Roslin team] will.”

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