'New' Peptech monoclonal a possible rival for Remicade

Sydney peptide therapeutics developer Peptech (ASX:PTD) has reported "outstanding" results from a trial of an anti-TNF monoclonal antibody (mAb) resurrected from its tumour necrosis factor (TNF) research program of the late 1980s.

The company dusted off a mouse mAb and ran it through a well-recognised preclinical model of rheumatoid arthritis, and found it completely prevented the development of the disease in susceptible mice.

Announcing the result, Peptech's executive chairman, Mel Bridges, said the company was now in the enviable position of having two potential potent drugs against a wide range of inflammatory diseases in a worldwide market currently valued at more than US$6.4 billion.

Last month Peptech announced it had taken delivery from its UK ally Domantis of a custom-designed domain antibody (dAb) against TNF.

The anti-TNF dAb is a potentially more versatile and efficacious successor -- and commercial rival -- to lucrative anti-TNF mAbs like Centocor's market-leading Remicade and Abbott Laboratories' Humira, currently used to treat autoimmune disorders like rheumatoid arthritis and inflammatory bowel disease (Crohn's disease).

Peptech's investor relations manager, Dr Paul Schober, said the new/old anti-TNF monoclonal dated back to the company's research into TNF, which led to its broad patent covering therapeutic use of antibodies that target TNF.

The TNF signalling system has a key role in triggering the inflammatory process -- and in pathological inflammatory disorders like rheumatoid arthritis and Crohn's disease.

Peptech's own anti-TNF mAb currently exists in its original mouse form. The company would need to 'humanise' the molecule to avoid adverse immune reactions in human patients.

Schober said the early history of the Peptech mAb, relative to the later developed IP around the current commercial antibody products, gave it freedom to operate in the anti-TNF antibody commercial space, in competition with its IP licensees Abbott and Centocor, but it would seek a commercial partner to undertake later development and marketing the drug itself.

Peptech decided to revisit its anti-TNF mAb at the time when it was in dispute with Abbott and Centocor over their refusal to pay royalties for access to its anti-TNF patents; both companies have since agreed to pay royalties on all sales of Humira and Remicade, providing a lucrative income stream for Peptech.

Schober said the Peptech mAb could be used as a back-up therapy in cases where patients did not respond to Humira or Remicade, or became resistant to the effect of existing antibody drugs. Despite its identical action, the molecule differs sufficiently in structure to avoid neutralising antibodies directed at these therapeutics.

Schober said the mAb's similarities to Humira and Remicade meant it should to have a relatively straightforward path to the clinic, given that these molecules had already blazed the trail for mAb anti-inflammatory therapies.

Peptech's R&D Director, Dr Phil Jennings, said the encouraging results of the mouse trial bode well for the development of a new anti-TNF mAb that would expand current treatment options for patients with inflammatory disease.

"Patient need is high and the market is correspondingly large. An additional agent that can be used to treat new patients, or some patients who have become resistant to earlier therapies, is likely to be of considerable value," Jennings said.

It remains to be seen whether Peptech will now follow through with developing a commercial version of its 'me-too' mAb, and license it to a third party as a potential competitor for Remicade and Humira -- and as a potential further source of royalties from the growing $6.4 billion anti-TNF therapeutics market.

Neither Abbott nor Centocor would welcome a new player on their lucrative commercial patch, and either may be tempted to take on the development of the Peptech antibody rather than letting it get into the hands of a rival.