GlaxoSmithKline announces approval of Arranon® (nelarabine) Injection

New option for children and adults with treatment resistantT-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL)

Philadelphia, October 28, 2005 — GlaxoSmithKline (NYSE: GSK) today announced that the U.S. Food and Drug Administration (FDA) has approved ARRANON® (nelarabine) Injection, a chemotherapy agent, for the treatment of patients with T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) whose disease has not responded to or has relapsed following treatment with at least two chemotherapy regimens. This use is based on the induction of complete responses. Randomized trials demonstrating increased survival or other clinical benefit have not been conducted.

Approximately 1,600 adults and children are diagnosed with T-ALL or T-LBL in the U.S.each year. A subset of these patients will relapse or develop disease that is refractory to treatment. There is no standard of treatment for these patients and their prognosis is particularly poor. To facilitate the development of ARRANON for this relatively small group of patients, GSK worked closely with the National Cancer Institute (NCI) of the National Institutes of Health (NIH), the Children’s Oncology Group (COG) and the Cancer and Leukemia Group B (CALGB), in conjunction with the Southwest Oncology Group (SWOG).

“ARRANON affirms GSK’s long-term commitment to discover drugs for the treatment of cancer and to working with others in the cancer community to develop treatments for even the most difficult to treat malignancies,”said Paolo Paoletti, M.D., Senior Vice President of the Oncology Medicine Development Center, at GSK. “We are proud to meet this critical need and will continue to work closely with the oncology community to evolve the treatment paradigm.”

ARRANON received accelerated approval, granted by the FDA to medicines for treating serious or life-threatening illnesses that address an unmet medical need, based on complete response rates demonstrated in two Phase II trials in patients who had exhausted standard treatment options. Post-marketing evaluation to verify and describe the product’s clinical benefit will be pursued through a randomized, multi-center Phase III trial that will be conducted by COG and sponsored by the NCI under a Clinical Trials Agreement with GSK. The Phase III study will assess both event-free survival at four years and minimal residual disease in the post-consolidation phase for patients receiving standard therapy with or without nelarabine.

“ARRANON represents new hope for adults and children suffering from these rare and deadly cancers,” said Kevin Lokay, Vice President of Oncology and Acute Care at GSK. “As the first in a series of innovative medicines set to emerge from GSK’s robust oncology pipeline over the next few years, ARRANON is an important milestone for our oncology business and provides a glimpse of our promise for the future.”

More than 980 patients have received ARRANON as part of clinical trial protocols to date. The two multi-center pivotal Phase II clinical trials included a total of 39 adults and 151 children with T-ALL or T-LBL. These studies were conducted by cooperative groups under the auspices of the NCI. The primary efficacy results were based on 28 adults and 39 children that had multiple relapses following, or were refractory to, at least two prior induction regimens. In these groups, a total of 21 percent of the adults and 23 percent of the children achieved a complete response (CR) or a complete response without full hematological recovery (CR*) with single agent ARRANON. Remissions were generally long enough to allow for stem cell transplant procedure, often the intent following successful induction of remission. Following Arranon, patients had a median overall survival of 21 weeks for adults and 13 weeks for children.

In clinical studies of ARRANON, hematologic toxicity was the most common Grade 3 (moderate) or 4 (severe) adverse event. Consistent with various other cytotoxic agents, ARRANON is associated with neurological events, some considered severe. Close monitoring for neurologic events is strongly recommended and dosing of ARRANON should be discontinued for neurologic events of Grade 2 or greater.

About ARRANON

Discovered by GSK scientists, led by Gertrude Elion, Nobel Laureate for Medicine in 1988, ARRANON is a water-soluble prodrug of ara-G, a T-cell selective nucleoside analog. Accumulation of the active form of ARRANON (ara-GTP) in cancer cells leads to inhibition of DNA synthesis, resulting in cell death. ARRANON is toxic to T-cells with much greater potency and specificity than other types of white blood cells (B-cells, monocytes/macrophages).

In December 2003, ARRANON received Fast Track designation from the FDA, conferred on development-stage products that demonstrate a potential to address an unmet medical need for a serious or life-threatening condition. The FDA later granted ARRANON Orphan Drug Status, a designation given to products under development for a rare disease or condition (i.e. affecting fewer than 200,000 people per year in the United States). In September 2005, the agency’s Oncologic Drugs Advisory Committee (ODAC) voted to recommend that FDA grant ARRANON accelerated approval for both pediatric and adult indications.

Product Information

To find out more about ongoing clinical trials with ARRANON call the NCI’s Cancer Information Service at 1-800-4-CANCER. Information about the trialsis also available on the Internet at www.cancer.gov, a website maintained by the United States Government.

About Acute Lymphoblastic Leukemia (ALL) and Lymphoblastic Lymphoma (LBL)

Acute lymphoblastic leukemia (ALL) is a cancer of the white blood cells, the cells in the body that normally fight infections. It is an aggressive disease that is more common in children and progresses rapidly in the absence of effective therapy. ALL is the most common cancer in children, representing 23 percent of cancer diagnoses among children younger than 15 years of age[1]. T-ALL represents a minority of the ALL population and has a particularly poor prognosis after relapse.

Lymphoblastic lymphoma (LBL) is a type of non-Hodgkin’s lymphoma (NHL), a cancer of the lymphatic system, which occurs more often in children than adults. T-LBL patients represent a subset of this population.

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 2004.

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