Silence Therapeutics’ Partner Quark Pharmaceuticals Announces Results From Phase 2 PF-04523655 Study in Diabetic Macular Edema
(AIM: SLN) (“Silence” or the “Company”) a leading global RNA interference
(RNAi) therapeutics company, announces today that its partner, Quark
Pharmaceuticals, has received results from a prospective randomized Phase 2
trial, the DEGAS study. The study evaluated the safety and efficacy of
PF-04523655 (RTP801I- 14) in patients with diabetic macular edema (DME).
PF-04523655 incorporates Silence’s AtuRNAi technology and was sub-licensed to
Pfizer Inc. by Quark Pharmaceuticals.
The key highlights of the announcement are:
– Interim results at 12 months showed there were no drug related Serious
– Best results achieved at 3mg dose level, mean improvement from baseline
on a visual acuity test was 5.8 letters for all patients enrolled in the 3mg
dose group versus 2.4 letters on average in patients treated with laser
photocoagulation control (the current standard of care)
– Separate secondary analysis of the 111 patients who completed the 12
month follow up visit showed mean improvement from baseline on a visual
acuity test in the 3mg group of 9.1 letters versus 3.2 letters on average
(p<0.01) in patients treated with laser photocoagulation control
– Quark Pharmaceuticals will conduct a Phase 2b study
The announcement issued by Quark Pharmaceuticals is shown below:
In a Phase 2 Study PF-04523655 (RTP801I-14) Showed Improved Vision Over
Standard of Care in Patients with Diabetic Macular Edema at 12 Months
Quark Pharmaceuticals to Initiate Phase 2b Study
pharmaceutical company engaged in the discovery and development of RNAi-based
therapeutics, today announced that it has received results from a prospective
randomized Phase 2 trial, the DEGAS study. This study evaluated the safety
and efficacy of PF-04523655 (RTP801I- 14) in patients with diabetic macular
edema (DME). 184 patients were randomly assigned to four treatment groups;
three dose levels of PF-04523655 (RTP801I-14) (0.4mg, 1mg, and 3mg) or laser.
The study was designed with a primary endpoint of mean visual acuity
improvements over baseline at 24 months.
Interim results at 12 months showed there were no drug related Serious
Adverse Events (SAEs). Following 12 months of treatment with PF-04523655
(RTP801I-14), a dose dependent improvement in visual acuity was observed with
the best results achieved at the 3mg dose level. At this dose, the mean
improvement from baseline on a visual acuity test was 5.8 letters for all
patients enrolled in this dose group while in patients treated with laser
photocoagulation control (the current standard of care) visual acuity
improved by only 2.4 letters on average (p=0.08). Furthermore, in a separate
secondary analysis of the 111 patients who completed the 12 month follow up
visit, the mean improvement from baseline on a visual acuity test in the 3mg
group was 9.1 letters while in patients treated with laser photocoagulation
control visual acuity improved by only 3.2 letters on average (p<0.01).
The study was terminated at 12 months based upon this interim analysis
suggesting that higher doses would be necessary to produce a therapeutic
effect sufficiently superior to the current standard of care to benefit
patients over the long term given emerging new therapeutic modalities. Based
upon these results, and in view of a dose related effect on vision, Quark and
Pfizer have mutually agreed that a Phase 2b study will be conducted by Quark
at its own expense under a protocol mutually agreed upon by Quark and Pfizer.
Quark will test higher doses of PF-04523655 (RTP801I-14) and determine the
optimal dose for pivotal Phase 3 studies. It is designed as a randomized,
dose ranging comparator study that will evaluate the safety and efficacy of
PF-04523655 (RTP801I-14) versus Lucentis(R).
Quark and Pfizer also agreed to amend their existing agreement in order
to enable Quark to conduct the Phase 2b study. Under the amended agreement,
Pfizer has materially increased the development and product approval
milestone payments associated with the first ophthalmic use of PF-04523655
(RTP801I-14), as well as the royalty rates for the product. Under the amended
license agreement, if Pfizer chooses to continue development of PF-04523655
(RTP801I-14) following review of the Phase 2b data, Quark may receive total
developmental and sales milestones payments for all indications, including
those related to successful completion of the Phase 2b study, of up to
“We are very encouraged by the results, both by the biological activity and
the significant dose response. We look forward to initiating this Phase 2b
study with the aim to determine the optimal dose for pivotal trials.”
About the Phase 2b Study
The Phase 2b prospective, randomized, multi-center, dose-ranging,
comparator study will evaluate the efficacy and safety of PF-04523655
(RTP801I-14) versus Lucentis(R) in patients with diabetic macular edema.
Approximately 225 patients will be given the drug PF-04523655 (RTP801I-14) at
varying doses including higher doses than in the DEGAS study or will be given
About Quark Pharmaceuticals, Inc.
Quark Pharmaceuticals, Inc., is a clinical-stage pharmaceutical company
engaged in discovering and developing novel RNAi interference or RNAi-based
therapeutics. The Company has a fully integrated drug development platform
that spans therapeutic target identification based on its proprietary gene
discovery science and technology, to clinical drug development. The Company
has initially been focusing on RNAi-based therapeutics for the treatment of
diseases associated with oxidative stress and ischemic injury. Quark has
three product candidates in clinical development in five different
indications of which four are in Phase 2.
Quark is committed to leveraging a broad research pipeline of siRNA drug
candidates and novel siRNA structures to develop additional RNAi drug
Quark is headquartered in
development facilities in
Additional information is available at www.quarkpharma.com.
Notes for editors
About Silence Therapeutics plc ( http://www.silence-therapeutics.com)
Silence Therapeutics plc (AIM: SLN) is a leading global biotechnology
company dedicated to the discovery, development and delivery of targeted,
systemic RNA interference (RNAi) therapeutics for the treatment of serious
diseases. The company possesses multiple proprietary short interfering RNA
(siRNA) delivery technology platforms including AtuPLEX(TM), a system that
enables the functional delivery of siRNA molecules to targeted diseased
tissues and cells, while increasing their bioavailability and intracellular
uptake. A second, complementary delivery technology known as PolyTran(TM)
uses a library of novel peptide-based biodegradable polycationic polymers for
systemic siRNA administration. Additionally, the company has a platform of
novel siRNA molecules, AtuRNAi, which provide a number of advantages over
conventional siRNA molecules, including reduced cytokine induction and
decreased manufacturing costs. Silence’s unique RNAi assets also include
structural features for a next generation of RNAi molecules and additional
proprietary siRNA sequences against more than 50 highly valued oncology and
other disease targets.
The Company’s lead internal drug candidate is Atu027, a liposomal AtuRNAi
formulation in clinical development for systemic cancer indications and one
of the most clinically advanced RNAi therapeutics in the area of oncology.
Silence is currently conducting an open-label, single-centre, dose-escalation
Phase I study with Atu027 in patients with advanced solid tumors involving
single, as well as, repeated intravenous administration. The study is
expected to be completed in the second half of 2011.
The Company’s RNAi therapeutic platform has received key validation
through multiple partnerships with pharmaceutical companies including
AstraZeneca, Dainippon Sumitomo, Pfizer, and Quark. Silence is actively
pursuing the establishment of additional partnerships.
Forward-Looking Statements This press release includes forward-looking
statements that are subject to risks, uncertainties and other factors. These
risks and uncertainties could cause actual results to differ materially from
those referred to in the forward-looking statements. All forward-looking
statements are based on information currently available to Silence
Therapeutics and Silence Therapeutics assumes no obligation to update any
such forward-looking statements.
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