June 29 2011: Pharma-Planta launches a pivotal phase I clinical trial of a plant-derived microbicidal protein
Pharma-Planta is an EU Sixth Framework Integrated Project that was launched in 2004, involving 30 academic and industrial partners. The primary goal of the project was to develop from first principles an approved production pipeline for pharmaceutical proteins using plants as the production system. The benchmark for success was to take a candidate product all the way through development culminating in a phase I human clinical trial. This milestone has been achieved with the launch, this month, of Pharma-Planta’s pivotal phase I clinical study of an antibody that neutralizes HIV, produced in and isolated from tobacco plants. This antibody could one day become an inexpensive component of a microbicide used to prevent the spread of HIV/AIDS.
Plants have many advantages as a production system because they are cheap to grow on a large scale, they do not support human pathogens, and the whole production platform is portable because it can be transported as certified seed. But most biopharmaceuticals are currently made at great expense using fermentation vats containing bacteria or mammalian cells because the regulations for drug manufacturing have evolved with these systems in mind. So the Pharma-Planta consortium faced a double challenge – not only to develop a working manufacturing pipeline but also to interact with the regulators to develop a new regulatory framework that is suitable for plants.
In the early stages of the project, the consortium of researchers looked at a range of different candidate products and also a range of different production methods. Eventually they settled on the HIV-neutralizing antibody 2G12 and tobacco plants as the production system because these performed well and could be grown rapidly in specialized containment greenhouses built at the Fraunhofer IME in Aachen. The most difficult phase of the project was overcoming the regulatory burden of developing a brand new production platform. This involved long negotiations with the regulators, careful adjustment of the growing environment for the plants, and the construction and testing of a specialized processing plant on the Fraunhofer IME site for the purification of pharmaceuticals from plants according to good manufacturing practice (GMP), the strict quality criteria under which all drugs must be produced before they can be administered to humans.
While the production process was being developed and optimized by the process development team in Germany, the clinical trials team in the UK was working with the UK’s medical regulators, the MHRA, to determine the best way to carry out the clinical trial. After many months of preparation, the process development team set to work producing the ‘clinical batch’ of 2G12 which underwent thorough testing to make sure it met the conditions set by the regulators. In June 2011, the MHRA finally gave the go-ahead for the clinical trial to begin, and it was duly launched at the University of Surrey Clinical Trials Centre on 29th June.
The launch of the clinical trial marks the successful conclusion of the Pharma-Planta project, which over seven years has changed the landscape of drug manufacturing in plants by preparing a regulatory path that other organizations can follow. It has been a long and difficult journey with many hurdles along the way, but the project has succeeded in delivering not only a clinical product that has already secured funding for phase II trials, but also a production platform and facility that can be used to produce a diverse range of protein-based pharmaceuticals. The project has also spun off many additional technologies that are being adopted by researchers all over the world, and has resulted in more than 100 publications in peer-reviewed scientific journals.