Tykerb Phase III Trial Update

GlaxoSmithKline PLC
03 April 2006



Issued - Monday 3 April 2006



GlaxoSmithKline Receives Positive Data and Halts Enrolment in Phase iii Trial of
Tykerb(R) (Lapatinib) in Advanced Breast Cancer


            First Regulatory Filings now Planned for 2nd Half of 2006



Based on the unanimous recommendation of an Independent Data Monitoring
Committee (IDMC),  GlaxoSmithKline (GSK) announced today that it has halted
enrolment in its Phase III clinical trial evaluating the combination of Tykerb
(lapatinib ditosylate) and capecitabine (Xeloda(R)) versus capecitabine alone.
The trial evaluated women with refractory advanced or metastatic breast cancer
who have documented ErbB2 (HER2) overexpression and whose disease progressed
following treatment with trastuzumab (Herceptin(R)) as well as other cancer
therapies.  A pre-planned interim analysis of 321 patients in the study yielded
statistically significant results, exceeding the primary endpoint.


According to the study protocol, the pre-planned interim analysis was reviewed
by the IDMC, which is comprised of medical oncology experts and a statistician.
The IDMC unanimously recommended halting enrolment in the study because it
exceeded its primary endpoint of time to disease progression, or TTP, for women
receiving the combination of Tykerb and capecitabine.  The IDMC made their
recommendation based on pre-specified stopping rules outlined in their charter.
All women currently enrolled in the trial will continue to be followed and those
who are receiving capecitabine alone will be offered the option of switching to
the combination therapy of capecitabine and Tykerb in consultation with their
physician.


"We are extremely encouraged by these data which suggest that Tykerb may offer
significant benefit as an oral medication in combination with chemotherapy for
patients with advanced or metastatic ErbB2 positive breast cancer, and whose
disease has progressed on previous treatment regimens, including Herceptin,"
said Paolo Paoletti, M.D., Senior Vice President of the Oncology Medicine
Development Center, at GSK.  "On the basis of this and other data we now plan to
file in the US and Europe during the second half of 2006."


The Phase III trial (EGF100151) is an international, multicentre, randomised,
open-label study to evaluate and compare TTP in patients with documented ErbB2
(HER2) overexpressing refractory advanced or metastatic breast cancer treated
with Tykerb in combination with capecitabine versus capecitabine alone.  The
primary endpoint of the study was to detect a 50 percent increase in TTP in the
combination arm compared with the capecitabine alone arm. 392 patients have been
enrolled in the study of which 321 were included in the analysis (160 in the
combination arm and 161 in the monotherapy arm). The most common drug-related
adverse events in the combination arm of the study were diarrhea and nausea.


Tykerb is an experimental drug that does not have regulatory approval in any
country for any use outside of clinical trials.


S M Bicknell

Company Secretary


3 April 2006


About Metastatic Breast Cancer

The World Health Organization reports that just over one million cases of breast
cancer are diagnosed annually. Breast cancer is the most common non-cutaneous
malignancy in women and one of the leading causes of cancer death.



Approximately 10-20 percent of newly diagnosed breast cancer patients have
locally advanced and/or metastatic disease; 20 to 85 percent of patients
(depending on initial stage, tumor biology, and treatment strategy) diagnosed
with early breast cancer will develop recurrent and/or metastatic disease.1 The
median survival time for women treated for metastatic breast cancer is two
years.2



About Tykerb

Tykerb, a small molecule that is administered orally, inhibits the tyrosine
kinase components of ErbB1 and ErbB2 receptors. Stimulation of ErbB1 and ErbB2
is associated with cell proliferation and with multiple processes involved in
tumor progression, invasion, and metastasis. 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.



Tykerb is being developed by GSK as an orally administered therapy for breast
cancer and other solid tumors.


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 http://www.gsk.com.


Cautionary statement regarding forward-looking statements

Under the safe harbor provisions of the US 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.


Notes to editors:

Tykerb(R) (lapatinib) is also designated as GW572016.

Tycerb(R) (lapatinib) is the registered trade name of lapatinib in Europe.

Herceptin(R) is a registered trademark of Genentech, Inc. in the United States
and Roche Pharmaceuticals in Europe.

Xeloda(R) is a registered trademark of Roche Pharmaceuticals.


 References:


1     C. Bernard-Marty et al. Facts and Controversies in Treatment of Systemic
      Metastatic Breast Cancer. The Oncologist. 2004:9:617-632.

2     ibid.



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