GlaxoSmithKline Seeks U.S. Approval For Tykerb(R) (Lapatinib Ditosylate) For The Treatment Of Advanced Breast Cancer

GlaxoSmithKline plc (NYSE: GSK; London) today announced the submission of a
New Drug Application (NDA) to the United States Food and Drug
Administration (FDA) for approval to market Tykerb(R) (lapatinib
ditosylate), in combination with Xeloda(R) (capecitabine), for the
treatment of advanced or metastatic HER2 (ErbB2) positive breast cancer in
women who have received prior therapy, including Herceptin(R)
(trastuzumab). The compound has been granted Fast Track status by the FDA
in this patient population. TYKERB is a small molecule dual kinase
inhibitor developed by GSK as an oral therapy, and is currently being
investigated in breast cancer and other solid tumors. TYKERB is an
investigational drug and has not been approved for marketing by any
regulatory body.


"This filing is the result of many years of tremendous research and
development work by the scientists at GSK. It is truly an outstanding
milestone, especially for the many thousands of women who are facing the
devastating effects of advanced breast cancer," said Paolo Paoletti, M.D.,
Senior Vice President of the Oncology Medicine Development Center at GSK.
"Many of these women are desperately in need of alternative treatments, and
this filing demonstrates that we have turned the corner toward a new era of
targeted agents."


GSK plans to submit the Marketing Authorization Application (MAA) for
TYKERB in Europe during the 4th quarter of this year.


About the Data Submitted(1)


A planned interim analysis of the Phase III international, multicenter,
open-label trial randomized 324 women who had advanced or metastatic breast
cancer with documented HER2 overexpression and whose disease progressed
following treatment with Herceptin and other cancer therapies, to TYKERB
and Xeloda or Xeloda alone. In this pivotal trial, the combination of
TYKERB and Xeloda versus Xeloda alone nearly doubled median time to
progression (36.7 weeks [8.5 months] in the combination arm versus 19.1
weeks [4.4 months] with Xeloda alone, p=0.00008).


The most common adverse events (>25%) during therapy with TYKERB plus
Xeloda were gastrointestinal (diarrhea, nausea, and vomiting) or
dermatologic (palmer-plantar erythrodysesthesia and rash). The majority of
adverse events and laboratory abnormalities were mild to moderate in
severity.















The study was originally presented by trial principal investigator
Charles Geyer, M.D., Director of Breast Medical Oncology at Allegheny
General Hospital (Pittsburgh, Pennsylvania) at the 2006 American Society of
Clinical Oncology (ASCO) annual meeting in Atlanta, Georgia, in June.


In March 2006, an Independent Data Monitoring Committee (IDMC) made a
unanimous recommendation to stop enrollment of the study based on the early
success of the trial. The study met its primary endpoint of time to disease
progression, and exceeded the predetermined stopping criteria outlined in
the committee charter. GSK stopped enrollment to the study in April 2006.


About TYKERB


TYKERB, a small molecule that is administered orally, inhibits the
tyrosine kinase components of EGFR (ErbB1) and HER2 receptors. Stimulation
of EGFR and HER2 is associated with cell proliferation and with multiple
processes involved in tumor progression, invasion, and metastases.


Overexpression of these receptors has been reported in a variety of human
tumors and is associated with poor prognosis and reduced overall survival.
GSK is using advanced technologies, including pharmacogenetics, to
better define patient populations that may respond to TYKERB.


About GlaxoSmithKline


GlaxoSmithKline -- one of the world's leading research-based
pharmaceutical and healthcare companies -- is committed to improving the
quality of human life by enabling people to do more, feel better, and live
longer. For company information, visit GlaxoSmithKline at
gsk.



Cautionary statement regarding forward-looking statements



Under the safe harbor provisions of the U.S. Private Securities
Litigation Reform Act of 1995, the company cautions investors that any
forward-looking statements or projections made by the company, including
those made in this announcement, are subject to risks and uncertainties
that may cause actual results to differ materially from those projected.
Factors that may affect the Group's operations are described under 'Risk
Factors' in the Operating and Financial Review and Prospects in the
company's Annual Report on Form 20-F for 2005.


GlaxoSmithKline

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View drug information on Herceptin; Tykerb; Xeloda.