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Regulatory Filings • Nov 10, 2009

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Corporate | 10 November 2009 18:00

Cytos Biotechnology updates on the development of the hypertension vaccine CYT006-AngQb

Cytos Biotechnology AG / Research Update

10.11.2009

Dissemination of a Corporate News, transmitted by
DGAP - a company of EquityStory AG.
The issuer / publisher is solely responsible for the content of this announcement.

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Schlieren (Zurich), Switzerland, November 10, 2009 - Cytos Biotechnology
Ltd (SIX:CYTN) today gave an update on the development of its hypertension
vaccine CYT006-AngQb. In a first phase IIa study (study 01) the vaccine was
safe, well tolerated and efficacious in lowering the mean ambulatory blood
pressure by -9/-4 mmHg (systolic/diastolic) vs. placebo (Lancet 371:821
(2008)). In this study the vaccine was administered in a conventional
treatment regimen with injections at weeks 0, 4, and 12.

In a second study (study 02), the vaccine was administered more frequently
and in shorter intervals than in study 01 with injections at weeks 0, 2, 4,
6 and 10. The intention of the altered regimen was to achieve higher
antibody titers and a stronger reduction of the blood pressure. While, as
expected, titers were higher in study 02 than in study 01, the decrease in
blood pressure was less than reported for study 01, and the antibodies
induced by vaccination had a significantly lower affinity towards
angiotensin II, i.e. they bound angiotensin II less tightly, which could
explain the lower blood pressure reduction.

Study 03 had an identical design as study 02 and was initiated shortly
after the start of study 02. The goal of study 03 was to investigate
safety, tolerability and efficacy of a higher dose of the vaccine (2.7 mg
total for study 03 vs. 1.5 mg total for study 02). Study 03 used the same
dosing schedule as study 02. Following the observation of significantly
lower affinities induced by the altered treatment regimen in study 02,
study 03 should clarify whether lower antibody affinities induced by the
altered regimen are a reproducible finding which could explain the lower
treatment effect.

Study 03, which included 83 patients suffering from mild to moderate
hypertension, essentially reproduced the findings of study 02. While
antibody titers were again higher than in study 01, the affinities, which
were determined by two independent methods, were in both assays
significantly lower than in study 01 and comparable to study 02.
Accordingly, blood pressure reduction was also lower than in study 01 and
did not achieve significance level vs. placebo.

A plausible explanation for the lower affinities in the accelerated
treatment regimens in study 02 and 03 may lie in a natural process called
affinity maturation which may be disturbed by too frequent injections of
the vaccine. The immune system generates over time antibody responses of
increased affinities by selectively expanding those B-cells which get best
access to the antigen through binding via surface-bound high affinity
antibodies. Those B-cell clones that bind the antigens best are selectively
expanded at the expense of those clones that bind them weakly. If too much
antigen is delivered too quickly, predominantly weakly binding antibodies
may be expanded at the expense of those binding well. This could have
happened in studies 02 and 03.

The conclusions drawn from the results of the three studies are that the
altered treatment regimen of studies 02 and 03 reproducibly leads to
qualitatively different antibody responses with a significantly lower
affinity than the conventional treatment regimen of study 01. Therefore
studies 02 and 03 do not invalidate the positive outcome of study 01, where
the vaccine was efficacious. Furthermore, antibody affinity, which is of
critical importance in cases where small target molecules like angiotensin
II (8 aminoacids) are to be neutralized, can potentially be controlled by
adjusting treatment parameters like the timing of booster injections. Cytos
Biotechnology has therefore decided to continue its R&D program in
hypertension.

About the hypertension vaccine CYT006-AngQb

CYT006-AngQb is a therapeutic vaccine in development for the treatment of
hypertension (1, 2). It is designed to instruct the patient's immune system
to produce an antibody response against angiotensin II. Angiotensin II is a
small peptide in the body and part of the renin-angiotensin system (RAS),
which is an important regulator of blood pressure. Angiotensin II causes
blood vessels to narrow, resulting in increased blood pressure. In a phase
IIa study with hypertensive patients, vaccination with CYT006-AngQb has
been shown to significantly reduce the mean ambulatory day-time blood
pressure by induction of antibodies that bind angiotensin II (The Lancet
2008, 371:821). A particularly strong blood pressure reduction has been
observed in the early morning hours - a crucial time of day when adverse
cardiovascular events are more likely to occur than during other times of
the day.

CYT006-AngQb is a first-in-class product candidate in this important
indication and represents a completely novel approach to hypertension
treatment. Treatment with CYT006-AngQb should allow for convenient dosing
schedules and a smooth control of blood pressure due to a sustained
antibody response induced by vaccination.

About hypertension

Hypertension, also termed high blood pressure, is a medical condition where
the blood pressure is chronically elevated. Although symptomless in nature
and in itself rarely an acute problem, persistent hypertension is one of
the most important preventable causes of premature death worldwide and
contributes to around half of all cardiovascular diseases(3). It is one of
the major risk factors for stroke, myocardial infarction, heart failure,
and vascular disease, and is a leading cause of chronic renal failure.
Genetic predisposition and lifestyle habits such as inadequate physical
activity, high fat diet, and high salt intake promote high blood pressure.
Up to 30% of adults in most countries suffer from hypertension. Despite
effective and relatively inexpensive treatment available, less than one out
of four hypertensive individuals have their blood pressure controlled
successfully (4, 5). This poor overall treatment success is mainly
attributed to the symptomless nature of hypertension and the necessity for
long-term treatment with currently available medications that require at
least once daily self-administration.

Glossary

Affinity: A measure which describes how strong an antibody binds to its
target molecule.

Ambulatory blood pressure: Blood pressure measured by numerous readings
over a 24-hour period or longer. Provides accurate and reliable information
about a person's blood pressure.

Angiotensin II: A small peptide that is part of the renin-angiotensin
system (RAS). Induces narrowing of blood vessels and other effects to raise
blood pressure.

Antibody: Class of blood proteins generated by the immune system to
neutralize foreign materials such as bacteria or viruses. Can also be
directed against the body's own disease-associated molecules.

Diastolic blood pressure: Lowest pressure within the arterial blood stream
occurring with each heart beat.

Phase IIa: clinical trial that examines a new drug candidate's safety,
tolerability and preliminary efficacy in a small number of patients.

Renin-angiotensin system (RAS): Important system in the body that regulates
blood pressure.

Systolic blood pressure: The highest pressure within the arterial blood
stream occurring with each heart beat.

Titer: A relative measure for the amount of antibodies that bind to a
target molecule.

References

1. Journal of Hypertension; A vaccine for hypertension based on virus-like
   particles: preclinical efficacy and phase I safety and immunogenicity;
   2007, 25:63

2. The Lancet; Effect of immunization against angiotensin II with
   CYT006-AngQb on ambulatory blood pressure: a double-blind, randomized,
   placebo-controlled phase IIa study; 2008, 371:821

3. Centres for Disease Control and Prevention (CDC); The Atlas of Heart
   Disease and Stroke, 2004

4. Journal of the American Medical Association (JAMA); The Seventh Report
   of the Joint National Committee on Prevention, Detection, Evaluation, and
   Treatment of High Blood Pressure; 2003, 289:2560

5. National Institute for Health and Clinical Excellence (NICE), Centre for
   Health Services Research, UK; Essential Hypertension: managing adult
   patients in primary care; August 2004

About Cytos Biotechnology

Cytos Biotechnology Ltd is a public Swiss biotechnology company that
specializes in the discovery, development and commercialization of a new
class of biopharmaceutical products - the Immunodrugs(TM). Immunodrugs(TM)
are intended for use in the treatment and prevention of common chronic
diseases, which afflict millions of people worldwide. Immunodrugs(TM) are
designed to instruct the patient's immune system to produce desired
therapeutic antibody or T cell responses that modulate chronic disease
processes. Taking advantage of the high flexibility of its Immunodrug(TM)
platform, Cytos Biotechnology has built a diversified pipeline of
Immunodrug(TM) candidates in various disease areas, of which six are
currently in clinical development. The Immunodrug(TM) candidates are
developed both in-house and together with Novartis, Pfizer and Pfizer
Animal Health. Founded in 1995 as a spinoff from the Swiss Federal
Institute of Technology (ETH) in Zurich, the Company is located in
Schlieren (Zurich). Currently, the Company has 86 full-time employees.
Cytos Biotechnology Ltd is listed on the SIX Swiss Exchange (SIX:CYTN).

This foregoing press release may contain forward-looking statements that
include words or phrases such as 'may', 'will', 'should', 'designed',
'can', 'could', 'intend' or other similar expressions. These
forward-looking statements are subject to a variety of significant
uncertainties, including scientific, business, economic and financial
factors, and therefore actual results may differ significantly from those
presented. There can be no assurance that any further therapeutic entities
will enter clinical trials, that clinical trial results will be predictive
for future results, that therapeutic entities will be the subject of
filings for regulatory approval, that any drug candidates will receive
marketing approval from the U.S. Food and Drug Administration or equivalent
regulatory authorities, or that drugs will be marketed successfully.
Against the background of these uncertainties readers should not rely on
forward-looking statements. The company assumes no responsibility to update
forward-looking statements or adapt them to future events or developments.
This document does not constitute an offer or invitation to subscribe or
purchase any securities of Cytos Biotechnology Ltd.

Wolfgang A. Renner, PhD
Chief Executive Officer
Cytos Biotechnology Ltd
Phone: +41 44 733 47 03
Fax: +41 44 733 47 04
e-Mail: wolfgang.renner@cytos.com
Website: www.cytos.com

10.11.2009 Financial News distributed by DGAP. Media archive at www.dgap-medientreff.de and www.dgap.de

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Language: English
Company: Cytos Biotechnology AG
Wagistr. 25
8952 Schlieren
Schweiz
Phone: +41 44 733 4747
Fax: +41 44 733 4740
E-mail: info@cytos.com
Internet: www.cytos.com
ISIN: CH0011025217, CH0029060735
WKN: -
Listed: Freiverkehr in Berlin, München, Stuttgart; Open Market in
Frankfurt; Foreign Exchange(s) SWX

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