Positive Preclinical Data Demonstrating Anti-Tumor Activity of NKTR-105 (PEG-docetaxel)...

Positive Preclinical Data Demonstrating Anti-Tumor Activity of NKTR-105
(PEG-docetaxel) Presented at 20th EORTC-NCI-AACR Conference

GENEVA and SAN CARLOS, Calif., Oct. 23 /PRNewswire-FirstCall/ -- Nektar
Therapeutics (Nasdaq: NKTR) announced today that positive preclinical data for
NKTR-105 (PEG-docetaxel) was presented at the 2008 EORTC-NCI-AACR (European
Organization for Research and Treatment of Cancer-National Cancer
Institute-American Association for Cancer Research) Symposium on Molecular
Targets and Cancer Therapeutics being held in Geneva, Switzerland. NKTR-105
is the second oncology development program derived from Nektar's innovative
small molecule PEGylation technology platform.
"These data highlight the exciting potential of NKTR-105 to treat multiple
solid tumor types," said Randall Moreadith, M.D., Ph.D., Nektar Senior Vice
President of Drug Development and Chief Development Officer. "The superior
anti-tumor activity of NKTR-105 in preclinical tumor models as compared to
docetaxel underscores the value of utilizing our proprietary PEGylation
platform with oncolytics. As we have seen with the data for NKTR-102,
PEG-irinotecan, which is advancing in Phase 2 clinical development, our
technology platform enables a substantially improved pharmacokinetic profile
that potentially enhances therapeutic efficacy."
The preclinical data presented for NKTR-105 shows significantly greater
anti-tumor activity as compared to docetaxel in colorectal (LoVo and LS174T)
and non-small cell lung (H460) mouse xenograft models of human tumors.
Partial regressions were observed in two of the cell lines (LoVo and LS174T)
for NKTR-105, while no regressions were observed for docetaxel. At maximum
tolerated doses, the percent of tumor growth delay for NKTR-105 was 2.5-,
2.0-, and 1.6-fold greater than docetaxel in H460, LoVo, and LS174T xenograft
models, respectively.
Nektar plans to file an Investigational New Drug Application (IND) for
NKTR-105 by end of 2008 to initiate a Phase 1 clinical study.
Data Presentation for NKTR-105
The poster presentation from today's session entitled 'Tubulin-interacting
agents' can be found on Nektar's website at
http://www.nektar.com/wt/page/NKTR_105
2008 EORTC-NCI-AACR Symposium - Poster # 448, "NKTR-105, A Novel PEGylated
Docetaxel, Demonstrates Superior Anti-Tumor Activity Versus Docetaxel in Human
Non-Small Cell Lung and Colon Mouse Xenograft Models"
About NKTR-105
NKTR-105 is a novel PEGylated conjugate of docetaxel, an anti-neoplastic
agent belonging to the taxoid family that acts by disrupting the microtubular
network in cells. Docetaxel is a major chemotherapy agent approved for use in
five different cancer indications: breast, non-small cell lung, prostate,
gastric and head and neck. Annual sales of docetaxel count for more than 20
percent of the global market for the top five branded chemotherapy agents.
Using Nektar's small molecule PEGylation technology, NKTR-105 was created
to improve the time-concentration profile and anti-tumor activity of
docetaxel. The drug candidate will enter Phase 1 clinical development in early
2009.
Nektar PEGylation technology can enhance the properties of small and large
molecules by increasing drug circulation time, improving pharmacokinetics,
decreasing immunogenicity and dosing frequency, increasing bioavailability and
improving drug solubility and stability. Nektar PEGylation technology has
enabled all of the PEGylated products approved over the last ten years, which
include eight approved partnered products, including UCB's Cimzia(R), Roche's
PEGASYS(R) for hepatitis C and Amgen's Neulasta(R) for neutropenia.
About Nektar
Nektar Therapeutics is a biopharmaceutical company developing novel
therapeutics based on its unique and proprietary PEGylation and advanced
polymer conjugate chemistry technology platforms. Nektar's technologies and
drug development expertise have enabled eight approved products for partners,
which include leading biopharmaceutical companies. Nektar has a robust
pipeline of high-value therapeutics in development designed to address
significant unmet medical needs.
This press release contains forward-looking statements that reflect the
company's current views regarding the potential, progress, and clinical plans
for the company's proprietary and partnered product pipeline, and the value
and potential of the company's technology platforms. These forward-looking
statements involve risks and uncertainties, including but not limited to: (i)
the company's proprietary product candidates and those of its partners are in
various stages of clinical development and the risk of failure is high and can
occur at any stage prior to regulatory approval; (ii) the timing or success of
the commencement or end of clinical trials and commercial launch of partnered
products may be delayed or unsuccessful due to slower than anticipated patient
enrollment, drug manufacturing challenges, changing standards of care,
clinical trial design, clinical outcomes, or delay or failure in obtaining
regulatory approval in one or more important markets; (iii) clinical trials
are long, expensive and uncertain processes and the risk of failure of any
product that is in clinical development and prior to regulatory approval
remains high and can occur at any stage due to efficacy, safety or other
factors; (iv) the company's patent applications for its proprietary or
partner product candidates may not issue, patents that have issued may not be
enforceable, or intellectual property licenses from third parties may be
required in the future; and (v) the outcome of any existing or future
intellectual property or other litigation related to the company's proprietary
product candidates. Other important risks and uncertainties are detailed in
the company's reports and other filings with the Securities and Exchange
Commission, including its most recent Annual Report on Form 10-K. Actual
results could differ materially from the forward-looking statements contained
in this press release. The company undertakes no obligation to update
forward-looking statements, whether as a result of new information, future
events or otherwise. For more information on Nektar Therapeutics, please
visit http://www.nektar.com
Stephan Herrera, 415-488-7699
sherrera@nektar.com

Jennifer Ruddock, 650-631-4954
jruddock@nektar.com

SOURCE Nektar Therapeutics

Stephan Herrera, +1-415-488-7699, sherrera@nektar.com, or Jennifer Ruddock,
+1-650-631-4954, jruddock@nektar.com, both of Nektar Therapeutics