Bayer and Paratek Pharmaceuticals Present New Data on First Antibiotic in New Class, Aminomethylcyclines (AMCs), at 14th Annual

Bayer and Paratek Pharmaceuticals Present New Data on First
Antibiotic in New Class, Aminomethylcyclines (AMCs), at 14th Annual ECCMID
Pre-Clinical Data Reveals Potent Activity Against Wide Range of Clinically
Prevalent Bacteria 


LEVERKUSEN, Germany and BOSTON, May 3  /PRNewswire-FirstCall/ -- Bayer AG,
Bayer Pharmaceuticals Corporation (USA), and Paratek Pharmaceuticals, Inc.
announced today new pre-clinical data detailing potent in vivo and in vitro
activity of the lead compound in a new class of antibiotics, called
aminomethylcyclines (AMCs).  BAY 73-7388, which was discovered by Paratek as
PTK 0796, is a novel, semi-synthetic antibiotic compound for IV use, and is
currently being studied to target a wide range of clinically prevalent
infections, including those caused by Gram-positive, Gram-negative, atypical
and anaerobic bacteria, and those with multi-drug resistance.  Additionally,
pre-clinical research has shown that the compound did not demonstrate
cross-resistance to currently available agents.

The compound is the first in the AMC class to be selected for development. The
class was designed using innovative proprietary medicinal chemistry to
specifically address the growing problem of antibiotic resistance in the
clinical setting.

A joint team of Bayer and Paratek scientists presented data demonstrating the
compound's in vitro activity against resistant bacteria and efficacy in animal
models at the 14th European Congress of Clinical Microbiology and Infectious
Diseases (ECCMID) in Prague, Czech Republic.  Seven studies were presented at
the meeting, including:

   * "Activity of BAY 73-7388, a Novel Aminomethylcycline, and Other
     Antibiotic Classes Against Resistance Bacteria In Vitro," Poster 925

   * "Potent Activity of BAY 73-7388, a Novel Aminomethylcycline, Against
     Susceptible and Resistant Gram-Positive and Gram-Negative Organisms,"
     Poster 926

   * "BAY 73-7388, a Novel Aminomethylcycline, Exhibits Potent Efficacy in
     Pulmonary Murine Models of Infection," Poster 927

   * "BAY 73-7388 Is Highly Efficacious in Animal Models of Intra-Abdominal
     Infections Caused by a Range of Aerobic and Anaerobic Organisms,
     Including VRE," Poster 928

   * "BAY 73-7388 Demonstrates Greater Activity Than Linezolid in a Range of
     Murine Models of Skin and Soft Tissue Infection," Poster 929

   * "Superior Efficacy of BAY 73-7388, a Novel Aminomethylcycline, Compared
     with Linezolid and Vancomycin in Murine Sepsis Caused by Susceptible or
     Multiresistant Staphylococci," Poster 930

   * "BAY 73-7388, a Novel Aminomethylcycline, is Highly Active In Vivo in a
     Murine Model of Pneumococcal Pneumonia," Poster 931



"Bayer has a long history in the research of anti-infective therapies and is
committed to developing antibiotics that are active against both resistant and
non-resistant bacteria," said Martin Springsklee, Vice-President, Therapy Area
Anti-Infectives, Product Development, Bayer Healthcare.  "Pre-clinical studies
have shown that BAY 73-7388 demonstrated potent in vitro activity against a
wide range of clinical isolates.  Additionally, the compound shows no
cross-resistance to currently available classes of antibiotics.  BAY 73-7388
shows great promise as a developmental candidate from a new antibiotic class to
be investigated for treatment of patients who would otherwise have increasingly
limited treatment options."

Stuart B. Levy, M.D., Co-founder and Chief Scientific Officer of Paratek
Pharmaceuticals, explained, "Infections in hospitals are becoming increasingly
difficult to treat, in large part because of rising bacterial resistance, and
novel agents from new classes are needed.  Designed as the lead compound in a
new class, BAY 73-7388 has demonstrated broad activity against a wide variety
of important resistant Gram-positive, Gram-negative, atypical and anaerobic
bacteria.  With such a spectrum, BAY 73-7388 has the potential to address clear
needs in the clinical setting."

Bayer and Paratek signed a Collaborative Development and License Agreement in
August 2003 for the development of the novel aminomethylcycline antibiotic BAY
73-7388/PTK 0796.

About Bayer HealthCare

Bayer HealthCare is part of the worldwide operations of Bayer, a subgroup of
Bayer AG.  Bayer HealthCare is one of the world's leading innovators in the
health care and medical products industry.

Bayer HealthCare combines the global activities of the business groups of Bayer
AG in the fields of Biological Products, Consumer Care, Diagnostics, Animal
Health and Pharmaceuticals.  More than 34,000 employees support the worldwide
operations of Bayer HealthCare.

The work at Bayer HealthCare is to discover and manufacture innovative products
for the purpose of improving human and animal health worldwide. The products
enhance well-being and quality of life by diagnosing, preventing and treating
disease.

About Paratek Pharmaceuticals

Paratek Pharmaceuticals, Inc. is engaged in the discovery and commercialization
of new therapeutics that treat serious and life-threatening diseases, with a
particular focus on the growing worldwide problem of antibiotic resistance. 
Paratek's lead programs are advancing novel compounds that can circumvent or
block bacterial resistance, as well as drugs that can prevent infection by many
gram-negative bacteria by interfering with Multiple Adaptational Response (MAR)
mechanisms in bacteria.  Out of these efforts, Paratek has discovered a new
class of antibiotics, the aminomethylcyclines (including BAY 73-7388) that
target the need for new and potent antibacterials to overcome the problem of
rapidly growing bacterial resistance.

Outside the antibacterial therapeutic area, Paratek has also established an
internal effort to exploit its novel family of compounds and their unique
mechanism of action in selected anti-inflammatory and neurodegenerative
conditions.  Paratek has an active SAR driven chemical synthesis effort within
this family of compounds to produce novel and diverse small molecules, with the
goal of developing non-antibacterial products with improved activity in serious
diseases based upon a growing body of clinical and basic research supporting
this approach.

Paratek is privately held and headquartered in Boston, Massachusetts, USA. For
more information, visit Paratek's website at http://www.paratekpharm.com/.

Forward-Looking Statements

This news release contains forward-looking statements based on current
assumptions and forecasts made by Bayer Group management. Various known and
unknown risks, uncertainties and other factors could lead to material
differences between the actual future results, financial situation, development
or performance of the company and the estimates given here. These factors
include those discussed in our public reports filed with the Frankfurt Stock
Exchange and with the U.S. Securities and Exchange Commission (including our
Form 20-F). The company assumes no liability whatsoever to update these
forward-looking statements or to conform them to future events or developments.


DATASOURCE: Bayer HealthCare Pharmaceuticals; Paratek Pharmaceuticals



CONTACT:  Mark Bennett, [phone], , or

Helmut Schaefers, [phone], , both

of Bayer; or Kate Boxmeyer of Paratek Pharmaceuticals, Inc., [phone]

x238, ; or Justin Jackson, [phone] x27,

, for Paratek Pharmaceuticals, Inc.; On-site at ECCMID:

Eileen Crowley, [phone], or Sylvia Leibner, [phone], both for

Bayer Pharmaceuticals Corporation; or Ken Tanaka, Ph.D of Paratek

Pharmaceuticals, Inc., [phone] 



Web site:  http://www.paratekpharm.com/ 

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