1592 (Abacavir, or New Name Ziagen (tm)) More Widely Available March 23
On March 12 Glaxo Wellcome announced that its experimental drug abacavir (brand name Ziagen, formerly known as 1592) will become more widely available on March 23. Ziagen has already been provided to about 1,900 patients through a limited expanded access program which the company started last summer.The main changes are that the program will no longer include restrictive entry criteria (the older program required a CD4 count under 100, viral load at least 30,000, and specific drug failures), nor be restricted to physicians who had conducted clinical trials of the drug. Instead, patients must be "failing or intolerant to standard therapy and, in the judgment of the physician, unable to construct a viable treatment regimen without Ziagen." Physicians will require approval from an IRB (institutional review board) to participate in the program, and this will cause delays in some cases; Glaxo Wellcome has set up a central IRB which should be able to process applications rapidly, but many physicians are required to use their hospital or other local IRB, which may not be meeting soon or may be backed up with other work.
This program is open to patients over 13 years of age. For those 13 or younger, a pediatric program is available.
There are exclusions for pregnant or breastfeeding women, and for patients with certain medical conditions who might not be able to use the drug safely.
Background on Using Abacavir
The most important safety issue with abacavir is that patients and physicians must be aware of the risk of a hypersensitivity reaction; if it occurs the drug must be stopped and never taken again. "In approximately three percent of patients receiving Ziagen, a hypersensitivity reaction has been observed, consisting of fever with any one or all of the following: nausea (with or without vomiting), malaise, and possibly an accompanying rash. These symptoms begin from several days to six weeks after initiating therapy and resolve within one to two days following discontinuation of Ziagen. Patients experiencing this reaction must not take Ziagen again. Restarting Ziagen after a hypersensitivity reaction has resulted in cases of a life-threatening, and in one case fatal, reaction."
Abacavir (Ziagen) should only be started as part of a combination antiretroviral treatment, including at least one other antiretroviral which the patient has never taken.
In is unclear at this time who should be using abacavir. Recent studies have found that this drug is unlikely to greatly reduce viral load in those who have already developed extensive viral resistance to approved nucleoside analogs (ddI, 3TC, AZT, etc.).
Patients who are eligible and likely to enroll in an expanded-access program are those for whom standard treatments have already failed in one way or another. Therefore, for many patients it will be difficult to decide whether it is better to use abacavir now, or to wait until more is known about when and how to use it best.
For More Information
For more information on abacavir and the new expanded access program, patients and physicians can call the Abacavir Coordinating Center, 800-501-4672.
