Peptech's arthritis dAb comes up trumps

Sydney biotech Peptech has reported "outstanding" results from a cut-down experimental antibody molecules a potential treatment for the crippling autoimmune disorder, rheumatoid arthritis.

Peptech said that in pre-clinical trials in an industry-standard animal model of rheumatoid arthritis, the prototype molecule -- technically a domain antibody, or dAb, completely blocked the onset of symptoms.

It took UK-based antibody engineering company Domantis, one-third owned by Peptech, just 14 months to develop the new dAb, using proprietary technology pioneered by Domantis' founder, Dr Greg Winter.

Peptech's managing director Stephen Kwik described the 14-month turnaround time for the project as "outstanding".

He said it was too early to comment about how Peptech might commercialise a new dAb therapeutic, but said it was "an exciting development, that is good for Peptech and Domantis".

The new dAb targets the same TNF-alpha receptor as conventional monoclonal-antibody therapeutics marketed by Europe's Abbott Laboratories, and US-based Johnson & Johnson subsidiary Centocor. Centocor's Remicade currently dominates the multi-billion dollar market for anti-TNF-alpha therapies for autoimmune disorders.

Abbott and Centocor would be among potential partners for Peptech in commercialising the new molecule, although Abbott has already signed up Domantis to develop its own dAb-based therapeutics.

Both companies need to find second-generation anti-TNF-alpha therapeutics to retain their markets. Centocor is currently involved in a dispute with Peptech, over its refusal to pay royalties on Peptech's generic anti-TNF-alpha patents.

In a statement, Peptech said domain antibodies were less than one tenth the size of conventional antibodies and combined the best attributes of small-molecule drugs -- ease of formulation, versatility in delivery, broad target range, and low production costs -- with the enormous diversity, great specificity and low toxicity of conventional antibodies.

Peptech said more than a quarter of all products in pharmaceutical development today are therapeutic antibodies; more than 50 per cent of these are humanised or fully human, and the new Peptech dAb, while it works in animals, is fully humanised.

Eleven therapeutic antibodies are already on the market and worldwide product sales are predicted to reach $US10 billion by 2010.