Article Abstract:
There are conflicting opinions on how clinical trials testing the effectiveness of various drugs in patients with AIDS should be conducted. The data from the clinical trials must be solid. However, as many drugs as possible should be available to the patients. A possible solution to the conflict is parallel tracking, so that drugs are available to patients at the same time the clinical trials are being conducted to determine their effectiveness. The patient's physician would have to agree to reveal information about the effects of the drug in the patient to those running the clinical trials. A conference entitled ''Expected Access to Unproven Pharmaceuticals: Risk, Regulation, and Personal Autonomy'' was held in November 1990. There are various opinions on the effectiveness of parallel tracking. It is felt by some that parallel tracking raises as many questions as it answers and it is not known how much data should be collected on the parallel track. However, parallel tracking may revolutionize how drugs for life-threatening diseases are tested. Parallel tracking would make drugs available to patients who cannot participate in clinical trials because they aren't eligible under the requirements of the trial or because they live far from the trial center. Although parallel tracking has received a lot of publicity, it has not been formally accepted. The drug dideoxyinosine (ddI) has been available to patients with AIDS through expanded access, which is similar to parallel tracking, except little data is collected about the drug. This latter process is wasteful in that it does not attempt to collect data and learn what can be learned about the side effects, safety and effectiveness of the drug. One hundred patients had been taking ddI in clinical trials, but with expanded access, approximately 14,000 patients could obtain the drug. It is suggested that a type of clinical trial be held that combines parallel track and expanded access. These would be large simple trials, consisting of almost anyone who wants to participate, with simple data concerning the effectiveness being collected from the physicians. It must be remembered that drugs that are available but are not officially approved have increased risk of toxicity and side effects. (Consumer Summary produced by Reliance Medical Information, Inc.)
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Article Abstract:
The goal of antiviral therapy in AIDS is to inhibit the replication of the retrovirus, human immunodeficiency virus (HIV), in the individual (in vivo). There are many types of drugs and biological substances which inhibit the replication of HIV in vitro (in tissue culture). Every step in the replication of the virus can potentially be targeted to stop the virus from reproducing. These steps include: the binding and entry of the virus into the cell; the transcription of viral RNA (ribonucleic acid) to DNA (deoxyribonucleic acid) by the viral enzyme, reverse transcriptase; and the migration of the newly synthesized DNA to the nucleus of the cell for integration of the viral DNA into the DNA of the host. The steps that follow include: the transcription and translation of the HIV gene products into viral proteins, with inhibition of gene products involved in the regulation of viral replication; the transport and packaging of the viral proteins so that the virus can mature into virus particles that are infectious; and the budding or release of the virus from the infected cell, allowing the cycle to begin again. AZT (3'-azido-2',3'-dideoxythymidine) is a nucleoside analog which interferes with the replication of HIV by inhibiting the viral enzyme reverse transcriptase, the key enzyme involved in the replication of the genetic information of the virus. AZT is widely used to prolong survival and improve the quality of life for those with advanced stages of HIV infection, and also to delay progression in certain individuals who are infected with HIV and do not yet have any clinical symptoms. Other analogues of nucleosides also inhibit replication of HIV. New drugs, other than nucleoside analogues, that interfere with the various steps of replication are being used experimentally against HIV. It is hoped that therapies will be found which inhibit the virus but do not affect normal, uninfected cells and have minimal toxic effects on the individual being treated. (Consumer Summary produced by Reliance Medical Information, Inc.)
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Article Abstract:
Suboptimal antiretroviral therapies continue to be used in clinical trials for a variety of reasons including regulatory requirements and the financial interests of pharmaceutical companies. Recommendations for ensuring that all patients receive optimal therapies are provided.
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