Plant-produced monoclonal antibody enters clinical trials

Trial will test a topically applied HIV microbicide

Clinical trials for a monoclonal antibody produced in genetically modified tobacco plants have begun in the UK.

The UK Medicines and Healthcare products Regulatory Agency (MHRA) has approved the first trial in Europe, which means a plant-based production system can comply with Good Manufacturing Practice (GMP).

The trial, which is taking place at the University of Surrey Clinical Research Centre, will test a topically applied anti-HIV microbicide.

Professor Julian Ma, scientific coordinator for Pharma-Planta and Professor of Molecular Immunology at St George’s, University of London, said: ‘The approval from the MHRA for us to proceed with human trials is an acknowledgement that monoclonal antibodies can be made in plants to the same quality as those made using existing conventional production systems. That is something many people did not believe could be achieved.’

The active ingredient in the microbicide is a monoclonal antibody called P2G12. If successful, P2G12 could be used in combination with other HIV-neutralising antibodies, also produced in plants, to create a broadly protective vaginal microbicide product. If the product is proven safe in the 11 participants, the researchers will then go on to test the effectiveness of the product.

The genetically modified tobacco plants producing P2G12 were grown in containment greenhouses at the Fraunhofer Institute for Molecular Biology and Applied Ecology, IME in Aachen, Germany, and the antibody was isolated and purified in a custom-designed processing plant on the same site, the first of its kind to be granted a licence to manufacture recombinant pharmaceutical products from plants in Europe.

‘We now have a facility in Europe for producing modern medicines in transgenic plants that is unique in the world, although this has taken many years and much investment to establish. This approval is a springboard for European plant biotechnology and will enable many important medical products to be realised,’ said Rainer Fischer, Pharma-Planta coordinator and director of Fraunhofer IME.

Although most biopharmaceuticals are currently made in fermentation vats containing bacteria or mammalian cells, the mass production of medicines in genetically modified plants could reduce costs and improve access to drugs in developing countries where diseases such as HIV are a huge problem. In addition, the simple manufacturing process could be transferred to developing countries allowing local production.

The clinical trial marks the culmination of the EU Framework 6 Pharma-Planta project, which was launched by a consortium of 30 academic and industrial partners in 2004 with €12m of EU funding. The primary goal was to develop an approved manufacturing process for recombinant pharmaceutical proteins made in plants and take one such product through all the development stages including the pivotal clinical trial.

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