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please put this to me in plain english. thank you :-)

Jan 7, 2004

Dr. Young,

I came over this article about the FDA approving protease inhibitor below. Is this a new single pill like Trizivir or something. Or is it just two agents put into one form? Will this agent help with drug resistant virus? Thank you.


FDA Approves Roche Protease Inhibitor Invirase Boosted with Norvir

Roches HIV protease inhibitor Invirase (saquinavir hard gel) won approval on January 6, 2004 for sale in the US as an HIV treatment in combination with low dose (100mg) Norvir (ritonavir) from Abbott Laboratories. This new dosing regimen boosts blood levels of saquinavir to allow for twice-daily dosing and overcomes the inadequate drug levels associated with use of Invirase alone.

In a press release, Roche said the US Food and Drug Administration approved the combination treatment that uses 1,000 milligrams of Invirase and 100mg of ritonavir twice daily.

The FDA based its decision on studies concerning Roche's other protease inhibitor, Fortovase (saquinavir soft gel), at 1,200 milligrams. Roche said the studies indicated that Invirase and Fortovase, separately combined with ritonavir, maintained similar levels of active inhibitors in a patient's blood.

A Roche spokeswoman said the use of Invirase as a combination treatment presents several advantages over combination Fortovase therapy. She said the combined use of Invirase and ritonavir led to fewer gastrointestinal side effects than Fortovase plus ritonavir. In addition, she added that twice-a-day Invirase does not require refrigeration, unlike Fortovase. In addition, Fortovase is administered three times each day.

Roche is developing a 500-milligram dose of Invirase and expects to file with the FDA for approval of that formulation sometime this year.

The approval of Invirase for boosted dosing is another important step in Roches ongoing efforts to define the optimal use of saquinavir, which was developed from our companys laboratories as the first protease inhibitor for HIV, said Kathy Presto, Vice President, US HIV Franchise, Roche. We have invested significantly in clinical trials and will continue our commitment through development of the Invirase 500 mg tablet formulation.

Following is the text of the Roche press release on the approval of combination Invirase 1000mg / ritonavir100mg:

On January 6, 2004 Roche announced U.S. Food and Drug Administration (FDA) approval of its protease inhibitor INVIRASE (saquinavir mesylate 1000 mg) for use with ritonavir (100 mg) in combination regimens for the treatment of HIV infection. This new dosing strategy increases (boosts) blood levels of saquinavir to enable twice-daily dosing and eliminates the inadequate drug levels associated with use of INVIRASE alone.

FDA approval of Roches supplemental New Drug Application (sNDA) for INVIRASE was based on data which showed that INVIRASE 1000 mg with ritonavir 100 mg twice-daily provides similar to or greater levels of saquinavir over a 24-hour period than those achieved with another formulation of saquinavir, Fortovase, 1200 mg three times per day.

Fortovase with ritonavir was studied in a heterogeneous population of 148 HIV-infected patients. Results showed that 91 of 148 subjects (61 percent) achieved and/or sustained an undetectable HIV RNA levels (<400 copies/mL) at the completion of 48 weeks of treatment. The efficacy of INVIRASE with ritonavir or Fortovase (with or without ritonavir co-administration) has not been compared against the efficacy of antiretroviral regimens currently considered standard of care.

INVIRASE with ritonavir is an attractive option for the treatment of HIV because it is designed to provide consistently therapeutic levels of saquinavir with twice-daily dosing, said Dr. Frank Palella, Assistant Professor of Medicine, Feinberg School of Medicine, Northwestern University, Chicago. With saquinavir, physicians and patients have the benefit of eight years of clinical experience on which to base treatment decisions. Todays news confirms that only low, 100 mg doses of ritonavir are needed to achieve effective levels of saquinavir when given with 1000 mg INVIRASE.

INVIRASE capsules do not require refrigeration and are smaller in size than Fortovase capsules. Roche is developing a 500 mg formulation of INVIRASE, designed to be used in the new boosted dosing regimen, that will cut daily pill count in half. A filing for the 500 mg formulation is projected for submission to the FDA for review in 2004.

It is important to note that INVIRASE and Fortovase are not bioequivalent and cannot be used interchangeably. INVIRASE may be used only if it is to be combined with ritonavir, which significantly inhibits saquinavirs metabolism and provides plasma saquinavir levels at least equal to those achieved with Fortovase. Fortovase is the recommended formulation when using saquinavir as the sole protease inhibitor in an antiviral regimen.

Dosing of Boosted INVIRASE

The FDA-approved dosing for boosted INVIRASE is 1000 mg of INVIRASE (5 x 200 mg capsules) in combination with ritonavir 100 mg, twice a day. Ritonavir should be taken at the same time as INVIRASE. INVIRASE and ritonavir should be taken within 2 hours after a meal.



US FDA approves Invirase boosted with ritonavir for use in treatment of HIV/AIDS." Press Release. January 6, 2004.

Dow Jones Newswires. January 6, 2004.

Response from Dr. Young

This note from the FDA and Roche does not represent a new coformulated pill (like Combivir, Trizivir or Kaletra), but rather the approval to use two older products (ritonavir and saquinavir) together.

In practical terms, many doctors have already been using the combination. This "change" reflects a regulatory advance, and allows both companies to promote the combination. BY

Hi from Madrid
Change from Norvir

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