Protherics Plc announces Prolarix(TM) dose selected for phase 2 liver cancer study
Cheshire, UK--(Marketwire - July 12, 2007) -
Prolarix(TM) dose selected for phase 2 liver cancer study
London, UK; Brentwood, TN, US; 12 July 2007 - Protherics PLC ("Protherics" or
the "Company"), the international biopharmaceutical company focused on critical
care and cancer, today announces the maximum tolerated dose ("MTD") of
Prolarix™ has been determined in a phase 1 study being conducted under the
auspices of Cancer Research UK. Prolarix™ is a novel targeted prodrug therapy
being developed for the treatment of primary liver cancer (hepatocellular
carcinoma) and other selected tumours.
Treatment with Prolarix™ involves the co-administration of two small
molecules: a prodrug, tretazicar, which is activated by an endogenous enzyme
called NQO2 in the presence of a cosubstrate, caricotamide. The dose of
caricotamide was fixed early in the study, while the dose of tretazicar was
escalated until the MTD was determined. Twenty three patients have been treated
in the study to date, and activation of the prodrug has been indicated in all
patients where pharmacokinetic analyses have been performed.
Six additional patients with a range of tumour types will now be treated with up
to six cycles of Prolarix™ at the MTD to further investigate drug effects in
the tumour, safety and to make a preliminary assessment of potential efficacy.
Patients will have tumour biopsy samples taken once they have been enrolled in
the study to determine tumour NQO2 levels and the pharmacodynamic effects of
Cancer Research UK is expected to report the study in the first half of 2008.
Meanwhile, Protherics is planning to start a phase 2 proof of concept study in
the first half of 2008 to investigate the efficacy of Prolarix in primary liver
cancer, where NQO2 levels have been found to be elevated.
Andrew Heath, Chief Executive of Protherics commented:
"Prolarix™ is a novel prodrug based cancer therapy with great potential in
the treatment of primary liver cancer. We look forward to investigating its
effects in this difficult to treat cancer in a phase 2 study next year."
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For further information please contact:
Andrew Heath, CEO +44 (0) 20 7246 9950
Nick Staples, Director of Corporate Affairs +44 (0) 7919 480510
Saul Komisar, President Protherics Inc +1 615 327 1027
Financial Dynamics - press enquiries
London: Ben Atwell, Anna Keeble +44 (0) 20 7831 3113
New York: John Capodanno, Jonathan Birt +1 212 850 5600
Or visit www.protherics.com
Notes for Editors:
Prolarix is a targeted chemotherapy being developed for the treatment of primary
liver cancer (hepatocellular carcinomas, HCC) and other select tumours.
Prolarix is a combination therapy of two low molecular weight compounds, a
prodrug* (called tretazicar; previously CB1954) and an enzyme co-substrate*
(called caricotamide; previously EP-0152R).
The prodrug tretazicar can be activated, by an endogenous enzyme called NQO2, to
a highly reactive, short-lived cytotoxic agent which causes a high degree of DNA
cross-linking. The NQO2 enzyme is latent and therefore inactive in body tissue,
but Protherics' scientists have discovered that the enzyme is active in the
presence of a co-substrate called caricotamide.
The NQO2 enzyme is absent or in low levels in many normal body tissues,
including bone marrow, but its activity is increased in certain tumour types
(particularly hepatocellular carcinomas). The coadministration of the prodrug
tretazicar, and the cosubstrate, caricotamide, is therefore expected to result
in the enhanced activation of the prodrug in the target tumour cells, resulting
in their death while minimising harm to healthy, non-cancerous cells.
Prodrug* - A compound that is converted within the body into its active form and
that has no therapeutic effects of its own. A prodrug is useful when the active
drug may be too toxic to administer systemically, the active drug is absorbed
poorly by the digestive tract, or the body breaks down the active drug before it
reaches its target.
Co-substrate* - A molecule that interacts with an enzyme and is required for its
Cytotoxic* - A chemical which has a direct toxic effect to cells, causing their
Tretazicar* is 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB 1954), an antitumour
Caricotamide* is 1-carbamoylmethyl-3-carbamoyl-1,4-dihydropyridine (EP-0152R),
the most stable of a series of co-substrates discovered by Protherics
Protherics (LSE: PTI, NASDAQ: PTIL) is a leading biopharmaceutical company
focused on the development, manufacture and marketing of specialised products
for critical care and cancer.
Protherics has developed and manufactures two biologics for critical care which
are FDA approved and currently sold in the US: CroFab™, a pit viper antivenom
and DigiFab™, a digoxin antidote. The Company's strategy is to use the
revenues generated from its marketed and out-licensed products to help fund the
advancement of its broad, late stage pipeline.
Protherics has two major development opportunities in its critical care
portfolio. CytoFab™ is being developed by AstraZeneca, for the treatment of
severe sepsis, after a major GBP195 million ($340 million) licensing deal with
AstraZeneca in December 2005. An additional, expanded phase 2 programme is
planned to start in the second half of 2007. In addition, Protherics is
currently undertaking a phase 2b study with Digoxin Immune Fab for the treatment
of pre-eclampsia. This study is expected to report in the first half of 2008.
Protherics has a pipeline of four novel cancer products in clinical development,
and intends to undertake the sales and marketing of these products in the US and
EU. Protherics is preparing to resubmit a BLA for Voraxaze™, an adjunct to
high dose methotrexate therapy, under a rolling submission in the US starting in
Protherics has a strong cash position, having completed a GBP38 million equity
fundraising in January 2007 and received a GBP10 million milestone payment from
AstraZeneca in April 2007.
With headquarters in London, the Company has approximately 270 employees across
its operations in the UK, US and Australia.
For further information visit: www.protherics.com
This document contains forward-looking statements that involve risks and
uncertainties including with respect to future growth, product development and
clinical studies, receipt of milestone payments, product sales and regulatory
approval of Protherics' products for marketing and distribution. Although we
believe that the expectations reflected in such forward-looking statements are
reasonable at this time, we can give no assurance that such expectations will
prove to be correct. Given these uncertainties, readers are cautioned not to
place undue reliance on such forward-looking statements. Actual results could
differ materially from those anticipated in these forward-looking statements due
to many important factors, including the market for the Company's products, the
timing and receipt of regulatory approvals, the progression and results of
clinical studies, the successful integration of acquired businesses and
intellectual property, and other factors discussed in Protherics' Annual Report
on Form 20-F and other reports filed from time to time with the U.S. Securities
and Exchange Commission. We do not undertake to update any oral or written
forward-looking statements that may be made by or on behalf of Protherics.
This information is provided by RNS
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