fulfils gbp 3.1 million domantis commitment

23 February 2005
ASX / MEDIA ANNOUNCEMENT

Peptech fulfils GBP 3.1 million Domantis commitment
Australian biotechnology company, Peptech Limited, today confirmed it had paid GBP 3.1
million (AUD 7.5 million) to Domantis Limited, the UK-based drug development company in
which Peptech holds the major interest of 36.1 per cent.

The payment is part of a commitment made by Peptech one year ago, to help fund Domantis’
promising domain antibody (dAb) product research pipeline.

“With ourselves and other shareholders contributing a total of more than GBP 8 million,
Domantis is assured the cash reserves necessary to develop its exciting drug program,” said Mel
Bridges, Executive Chairman, Peptech.

“Domantis continues to deliver on its milestones, and we expect to see new human dAb-based
therapeutics move into clinical trials in 2006,” he added.
Other investors in Domantis include the UK venture capitalists MVM and 3i, as well as an
undisclosed US institutional investor.

An update on progress at Domantis will be included in the next edition of the Peptech Update
shareholder newsletter, which will be distributed to the market through the ASX at the end of
March.

About Domantis:

Domantis is a drug discovery company developing the next generation of antibody molecules:
human domain antibodies (dAbs). ‘dAbs’ are therapeutic molecules that combine the benefits of
small molecules with those of conventional antibodies. Like small molecules, they are small and
highly stable, resulting in a choice of therapeutic formats, delivery formulations and
manufacturing options. And, like human antibodies, dAbs can also be designed to have
specificity and high affinity for the biological target of interest.

Domantis is working on more than a dozen proprietary dAb therapeutic programs, primarily in
the fields of inflammation and oncology. Due to its exclusive intellectual property and
technology position in dAbs, Domantis is the only company capable of fully exploiting dAbs
from human or other species.

B/3423111/1

In January this year, Domantis was invited to join the European Commission’s ‘Bloodomics’
heart disease project and, in December 2004, the company announced that its new ‘albudAb’
technology extends the serum half-lives of many drugs. More information: www.domantis.com
Background:

Peptech Limited focuses on the research and development of peptides and proteins in the areas of
human pharmaceuticals and animal health. The company is positioned to become a globally
recognised leader in biopharmaceutical development.

More information: www. peptech.com
Further information:
Mr Mel Bridges Dr Paul Schober
Executive Chairman Investor Relations
Peptech Limited Peptech Limited