Starpharma Holdings Limited : Starpharma's dendrimers improve efficacy of docetaxel in animals
01/31/2012 | 08:30pm
Starpharma's dendrimers improve
efficacy of docetaxel in animals
• Starpharma's dendrimer-docetaxel formulation
significantly more effective than leading cancer drug
docetaxel (Taxotere®) in breast cancer model
• More than half (60%) of animals treated with
Starpharma's dendrimer-docetaxel formulation had no evidence
of tumour at 94 days whereas with docetaxel significant
tumour regrowth was observed in all animals
• Starpharma's dendrimer-docetaxel formulation improved
water solubility by 5000-fold
Melbourne, Australia; 1 February 2012: Starpharma Holdings
(ASX: SPL, OTCQX: SPHRY) today released animal data which
demonstrated that its dendrimer-docetaxel formulation
applying Starpharma's dendrimer technology to the leading
chemotherapy drug docetaxel was significantly more
efficacious than docetaxel (Taxotere®) in a
breast cancer model.
Docetaxel is a leading chemotherapy drug used to treat a wide
range of solid tumours including breast, lung and prostate.
It is marketed by Sanofi Aventis as Taxotere®
and generated sales in excess of US$3 billion in 2010.
Starpharma conducted the latest study, a breast cancer
xenograft in mice, as part of its drug delivery program for
docetaxel - having already demonstrated a marked improvement
in the water solubility of docetaxel with its dendrimer
formulation. This study was designed to assess the efficacy
of Starpharma's dendrimer-docetaxel formulations in treating
cancer.
The results of this study show Starpharma's
dendrimer-docetaxel formulation demonstrated a significant
enhancement of anticancer effect when compared to
docetaxel/Taxotere®
alone.
Furthermore, 60% of animals treated with Starpharma's
preferred dendrimer-
docetaxel formulation had no evidence of tumours at 94 days -
whereas 100% of the docetaxel treated mice showed significant
tumour re-growth or recurrence at the same time point.
Starpharma Chief Executive Officer, Dr Jackie Fairley said:
"These initial results of our dendrimer-docetaxel program are
extremely encouraging. To have a high proportion of animals
with no evidence of tumours and a significant improvement in
efficacy versus docetaxel is a great result. These findings
together with the ability of Starpharma's dendrimers to
markedly improve water solubility represent a compelling
product proposition."
In the xenograft study mice were implanted with breast cancer
cells which were allowed to grow to a predetermined tumour
size (100 mm3) and then 10 mice per group were
dosed with either dendrimer-docetaxel, docetaxel alone, or
saline on days 1, 8 and 15. Tumour
volume was then assessed by manual measurement and the mean
volume is plotted against time (days) in Figure 1.
Mean Tumour Volume (MDA-MB-231)
1600
1400
1200
1000
800
600
400
200
0
Saline
Docetaxel
Dendrimer- docetaxel
0 20
40 60
Time (Days)
80 100 120
Animals Dosed on days 1, 8 and 15
Figure 1:
Mouse Xenograft - Breast Carcinoma (MDA-MB-231)
Mean tumour volume (mm3 ) v's time (days); n=10 per group at
commencement of study
For both actives the tumour volume decreased following
dosing. However, by day 60 all tumours in the docetaxel group
began to regrow. In contrast, in the dendrimer-docetaxel
group there was no evidence of tumour regrowth up to day 94
(which is well beyond the typical duration of xenograft
studies). Based on this and other data for dendrimer
constructs it is believed that the improved efficacy of the
dendrimer-docetaxel formulation is most likely due to a
longer circulating half-life, the extended release of
docetaxel from the dendrimer
and the targeting of the dendrimer construct to tumour
tissue.
The improvements in efficacy seen in this experiment are in
addition to the benefit of improved water solubility (see
below) with docetaxel announced in June 2011 which would also
potentially allow the removal of formulation components in
existing drugs thought to cause severe allergic reactions and
fluid retention in some patients.
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Starpharma's docetaxel program will continue to run in
parallel with its partnered drug- delivery programs which
include a growing list of major pharmaceutical companies
including GSK and Lilly. Further pre-clinical studies are now
planned for the dendrimer-docetaxel formulation prior to
clinical studies.
Detailed results of this study are expected to be presented
at future scientific conferences.
Starpharma Holdings Limited (ASX:SPL, OTCQX:SPHRY) is a world
leader in the development of
dendrimers for pharmaceutical, drug delivery and other
applications. Products based
on SPL's
proprietary dendrimer technology are already on the market in
the form of diagnostic elements and laboratory reagents
through licence arrangements with partners including Siemens
and Merck KGaA.
The Company's lead pharmaceutical development product is
VivaGel® (SPL7013 Gel), a microbicide
designed to prevent the transmission of
STIs, including genital
herpes, HIV
and treat
bacterial
vaginosis. Starpharma also has a licence agreement with
Ansell Limited to develop a VivaGel®- coated condom, and a
licence agreement with Okamoto Industries Inc in relation to
the VivaGel®- coated condom for the Japanese market. Okamoto
is the market leader for condoms sold in Japan, the world's
second largest condom market.
Starpharma also has commercial agreements in place with
Lilly, Elanco,
GSK, and
Siemens
Healthcare as well as many research collaborations with some
of the world's leading organisations in the fields of
pharmaceuticals, drug delivery, cosmetics and agrochemicals.
A dendrimer is a type of precisely-defined, highly branched
nanoscale polymer.
American Depositary Receipts (ADRs): Starpharma's ADRs
trade under the code SPHRY (CUSIP number
855563102). Each Starpharma ADR is equivalent to 10 ordinary
shares of Starpharma as traded on the Australian Securities
Exchange (ASX). Starpharma's ADRs are listed on International
OTCQX, a premium market tier in the U.S. for international
exchange-listed companies.
Media:
Buchan Consulting
Rebecca Wilson
Mob: +61 417 382 391
rwilson@buchanwe.com.au
Haley Price
Mob: +61 423 139 163
hprice@buchanwe.com.au
Starpharma:
Dr Jackie Fairley, Chief Executive Officer
+61 3 8532 2704
Ben Rogers, Company Secretary
ben.rogers@starpharma.com
www.starpharma.com
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