Press Release

Toronto, Canada, August 13, 2006 -- Updated treatment guidelines issued today by the International AIDS Society-USA (IAS-USA) now include the HIV protease inhibitor LEXIVA(R) boosted with ritonavir as a recommended option for protease inhibitor-based regimens in the initial treatment of adults with HIV infection. These guidelines were presented today at the International AIDS Conference (IAC) in Toronto, Canada.

LEXIVA is a protease inhibitor that was co-discovered by GlaxoSmithKline and Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX). LEXIVA is indicated in combination with other antiretroviral agents for the treatment of HIV infection in adults. LEXIVA was approved by the FDA for use in the US in 2003. (Please see the LEXIVA INDICATION STATEMENT section for the full indication language.)

Recent research has shown that LEXIVA/r offers comparable (non-inferior) efficacy and safety to lopinavir/r when both are given twice-daily as part of an HIV regimen in patients starting therapy. Based on these data, the IAS-USA included LEXIVA/r as a recommended component of initial antiretroviral therapy.

The IAS-USA commissions expert panels to issue recommendations and guidelines to provide standard approaches to patient care. The updated guidelines published in the current issue of the Journal of the American Medical Association (JAMA) stated that, "the choice of initial drug centers on acceptability; predicted tolerance; pill burden; comorbid conditions; short-term, mid-term and long term adverse event profiles."

The updated guidelines reflect the international perspectives of the panelists and are designed to serve as a tool for clinicians in countries where resources are sufficient to provide relatively unrestricted choices of drugs.

"We are pleased to see that the guidelines committee has recognized LEXIVA as an important treatment option for patients with HIV," said Mark Shaefer, Director, Clinical Development, HIV Infectious Disease Medicine Development Center at GSK.

LEXIVA Indication Statement
LEXIVA is indicated for the treatment of HIV infection in adults in combination with other antiretroviral medications. The following points should be considered when initiating therapy with LEXIVA plus ritonavir (LEXIVA/r) in PI-experienced patients: the PI-experienced patient study was not large enough to reach a definitive conclusion that LEXIVA/r and lopinavir/ritonavir are clinically equivalent. Once-daily administration of LEXIVA plus ritonavir is not recommended for PI-experienced patients.

Important Safety Information About LEXIVA
HIV medicines do not cure HIV infection/AIDS or prevent passing HIV to others.

Patients should not take LEXIVA if they have had an allergic reaction to LEXIVA or AGENERASE(R) (amprenavir). High blood sugar, diabetes or worsening of diabetes, and bleeding in hemophiliacs have occurred in some patients taking protease inhibitors. When a patient starts taking HIV medicines, his immune system may get stronger and could begin to fight infections that have been hidden in his body, such as pneumonia, herpes virus, or tuberculosis. If a patient has new symptoms after starting his HIV medicines, he should tell his doctor. Changes in body fat may occur in some patients taking antiretroviral therapy. The cause and long-term health effects of these conditions are not known at this time. Skin rashes can occur in patients taking LEXIVA. Rarely, rashes were severe or life threatening. Opportunistic infections can develop when a patient has HIV and his immune system is weak. It is very important that patients see their healthcare provider regularly while taking LEXIVA to discuss any side effects or concerns. Most common side effects in clinical studies were diarrhea, headache, nausea, rash, and vomiting. In most cases, these side effects did not cause people to stop taking their medicine.

For full prescribing information for LEXIVA, please visit http://www.treathiv.com

About GlaxoSmithKline
GlaxoSmithKline is one of the world's leading research-based pharmaceutical and healthcare companies and an industry leader in HIV research and therapies. The company is engaged in basic research programs designed to investigate new targets to treat HIV. For full prescribing information please go to http://www.LEXIVA.com.

GSK's Bridges to Access program can help provide qualified individuals with access to GSK's antiretroviral medications, as well as help identify insurance or other support for medications. Patients may be eligible for this program if they are not eligible for prescription drug benefits through any other private or public insurer, payer or program. In 2004, GlaxoSmithKline donated more than $372.5 million worth of prescription drugs to 475,000 patients. For more information, visit http://www.bridgestoaccess.gsk.com or call 1-866-PATIENT.

About Vertex
Vertex Pharmaceuticals Incorporated is a global biotechnology company committed to the discovery and development of breakthrough small molecule drugs for serious diseases. The Company's strategy is to commercialize its products both independently and in collaboration with major pharmaceutical companies. Vertex's product pipeline is principally focused on viral diseases, inflammation, autoimmune diseases and cancer. Vertex co-discovered the HIV protease inhibitor, Lexiva, with GlaxoSmithKline.

Lexiva is a registered trademark of the GlaxoSmithKline group of companies.

Vertex Contacts:
Michael Partridge, Director, Corporate Communications, (617) 444-6108
Lora Pike, Manager, Investor Relations, (617) 444-6755
Zachry Barber, Senior Media Relations Specialist, (617) 444-6470

GSK Media Contact:
Marc Meachem, (919) 483-2839