-- Combination of LEXIVA/r and Truvada Evaluated --
RIO DE JANEIRO, Brazil, July 26 /PRNewswire/ -- An open label, single-arm
study conducted among 15 HIV-positive patients evaluated the pharmacokinetic
parameters of a once-daily combination of LEXIVA(R) (fosamprenavir calcium),
ritonavir and Truvada(R) (tenofovir and emtricitabine) after four weeks of
treatment. Results showed that plasma levels of all four drugs remained
within previously described pharmacokinetic parameters, supporting the
potential for this combination to be a useful once-daily regimen for the
treatment of HIV infection. However, further study is necessary to determine
conclusively the safety and efficacy of LEXIVA/ritonavir in combination with
Truvada.
The study, which was supported by Vertex Pharmaceuticals Incorporated, was
reported today in Rio de Janeiro, Brazil at the 3rd Annual International AIDS
Society (IAS) Conference on HIV Pathogenesis and Treatment.
LEXIVA is an HIV protease inhibitor that was co-discovered by
GlaxoSmithKline (GSK) and Vertex Pharmaceuticals Incorporated. It is the
first PI to offer flexible dosing options (for PI-naive patients) with no food
or water restrictions.
LEXIVA is indicated in combination with other antiretroviral agents for
the treatment of HIV infection in adults. The following points should be
considered when initiating therapy with LEXIVA boosted with 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.
The study examined subjects who took a combination of 1400 mg LEXIVA, 200
mg ritonavir and a fixed-dose of 300/200 mg tenofovir/emtricitabine for four
weeks. Mean baseline HIV RNA and CD4 cell counts were 129,777 (1,940-578,000)
copies/mL and 357 (156-476) cells/mm3. Median LEXIVA Cmax, Cmin, t1/2 and
AUC24 were 8.3 mg/L, 1.7 mg/L, 10.7 hr and 84.3 mg h/L, respectively. These
parameters for tenofovir were 0.2 mg/L, 0.05 mg/L, 11.9 hr and 2.4 mg h/L,
respectively. Mean (range) HIV RNA after the first four weeks of therapy was
929 (<50-3390) copies/mL.
"The identification of potent, well tolerated HIV combination regimens is
an important step forward in the improved management of HIV infection," said
David A. Parks, Medical Director, Central West Healthcare, Inc. who conducted
the study with Edward P. Acosta, Pharm.D., Assistant Professor of the
Department of Pharmacology and Toxicology at the University of Alabama at
Birmingham. "These study results are encouraging in that they support the
potential for these products to be used together in a regimen."
Important Safety Information about LEXIVA
HIV medicines do not cure HIV infection/AIDS or prevent passing HIV to
others.
LEXIVA is contraindicated in patients with previously demonstrated
clinically significant hypersensitivity to any of the components of this
product or to amprenavir. Hyperglycemia, new onset or exacerbations of
diabetes mellitus, and spontaneous bleeding in hemophiliacs have been reported
with protease inhibitors.
Redistribution/accumulation of body fat including central obesity,
dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial
wasting, breast enlargement, and "cushingoid appearance" have been observed in
patients receiving antiretroviral therapy. The causal relationship,
mechanism, and long-term consequences of these events are currently unknown.
LEXIVA should be used with caution in patients with a known sulfonamide
allergy.
Severe or life-threatening skin reactions were reported in less than 1
percent of 700 patients treated with LEXIVA in clinical studies, including one
case of Stevens-Johnson syndrome.
Skin rashes (all grades, without regard to causality) occurred in
approximately 19 percent of patients treated with LEXIVA in the pivotal
efficacy studies. This led to the discontinuation of LEXIVA in less than 1
percent of patients.
During the initial phase of treatment, patients responding to
antiretroviral therapy may develop an inflammatory response to indolent or
residual opportunistic infections.
LEXIVA is contraindicated with ergot derivatives, cisapride, pimozide,
midazolam, and triazolam. If LEXIVA is coadministered with ritonavir,
flecainide and propafenone are also contraindicated. Caution should be used
when coadministering medications that are substrates, inhibitors, or inducers
of CYP3A4, or potentially toxic medications that are metabolized by CYP3A4.
Serious and/or life-threatening drug interactions could occur between LEXIVA
and amiodarone, lidocaine (systemic), tricyclic antidepressants, and
quinidine. Concentration monitoring of these agents is recommended if these
agents are used concomitantly with LEXIVA. LEXIVA should not be
coadministered with rifampin, St. John's wort, lovastatin, simvastatin, or
delavirdine. Particular caution should be used when prescribing
phosphodiesterase (PDE-5) inhibitors for erectile dysfunction (eg, sildenafil
or vardenafil) in patients receiving LEXIVA. This list of potential drug
interactions is not complete.
Treatment with LEXIVA/r has resulted in increases in the concentration of
triglycerides. Triglyceride and cholesterol testing should be performed prior
to initiating therapy with LEXIVA and at periodic intervals during therapy.
The most common adverse events seen in clinical trials with LEXIVA were
diarrhea, nausea, vomiting, headache and rash.
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-promotes
the HIV protease inhibitor, LEXIVA(R), with GlaxoSmithKline.
Vertex Safe Harbor Statement
This press release may contain forward-looking statements including (i)
that the identification of potent, well tolerated HIV combination regimens is
an important step forward in the improved management of HIV infection and (ii)
these study results are encouraging in that they support the potential for
these products to be used together in a regimen. While management makes its
best efforts to be accurate in making forward-looking statements, such
statements are subject to risks and uncertainties that could cause Vertex's
actual results to vary materially. These risks and uncertainties include
those risks listed under Risk Factors in Vertex's Form 10-K filed with the
Securities and Exchange Commission on March 16, 2005.
LEXIVA(R) is a registered trademark of the GlaxoSmithKline group of
companies.
Vertex's press releases are available at http://www.vrtx.com.
Vertex Contacts:
Michael Partridge, Director, Corporate Communications, (617) 444-6108
Lora Pike, Manager, Investor Relations, (617) 444-6755
Zachry Barber, Specialist, Media Relations, (617) 444-6470
SOURCE Vertex Pharmaceuticals Incorporated
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Related links:
http://www.vrtx.com
Company News On-Call:
http://www.prnewswire.com/comp/938395.html
CONTACT:
Michael Partridge, Director, Corporate
Communications, +1-617-444-6108, or Lora Pike, Manager, Investor
Relations, +1-617-444-6755, or Zachry Barber, Specialist, Media
Relations, +1-617-444-6470 both of Vertex
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