ATTACHMENT AND FUSION INHIBITORS IN DEVELOPMENT

NOTE: Several fact sheets describe drugs that are being tested against HIV: These drugs have not been approved by the Food and Drug Administration (FDA) for use against HIV.
ATTACHMENT AND FUSION INHIBITORS
This is a new class of anti-HIV drugs. They are intended to protect cells from infection by HIV by preventing the virus from attaching to a new cell and breaking through the cell membrane. Researchers hope that these drugs can prevent infection of a cell by either free virus (in the blood) or by contact with an infected cell.

Because digestive acids break them down, most of these drugs are given by injections or intravenous infusion.
ATTACHMENT AND FUSION INHIBITORS IN DEVELOPMENT
Fusion and attachment inhibitors in human trials include AK602, AMD070, BMS-378806, HGS004, INCB9471, Maraviroc, PRO 140 and PRO 542, Schering C, SP01A, TAK-652, and TNX-355 and Vicriviroc (SCH 417690).

AK602 is a CCR5 blocker being developed by Kumamoto University in Japan. It is in early human trials.

AMD070 by AnorMed blocks the CXCR4 receptor on CD4 T-cells to inhibit HIV fusion. It is in phase I/II trials.

BMS-378806 is an attachment inhibitor that attaches to gp120, a part of the It is in Phase I trials.

HGS0004 by Human Genome Sciences, a monoclonal antibody CCR5 blocker, successfully completed a Phase I trial.

INCB9471 by Incyte Corporation is in Phase I trials in healthy volunteers.

Maraviroc (MVC, UK-427,857) by Pfizer blocks the CCR5 receptor. In April 2007 an FDA advisory committee recommended approval of Maraviroc.

PRO 140 by Progenics completed a Phase I trial. It blocks fusion by binding to a receptor protein on the surface of CD4 cells. PRO 140 has been granted fast-track status by the FDA.

SP01A by Samaritan Pharmaceuticals is an HIV entry inhibitor in a Phase II trial.

TAK-652 by Takeda blocks binding to the CCR5 receptor. A Phase I study has been completed.

TNX-355 by Tanox blocks the CD4 receptor. It is a genetically engineered drug, a "monoclonal antibody." It may be administered by intravenous infusion (IV) or as a twice-monthly injection. No significant side effects have shown up yet. It is in Phase II trials.

Vicriviroc (SCH417690, formerly called Schering D) by Schering Plough blocks the CCR5 receptor on CD4 cells. No serious toxicities have been seen in Phase II. However, Phase III trials in treatment-naïve patients were discontinued due to poor virologic control. The study will likely be repeated at a higher dose of vicriviroc.
DRUGS NO LONGER IN DEVELOPMENT
The following drugs are no longer being developed for use against HIV:

AMD3100 (fusion inhibitor) by AnorMed
Aplaviroc (GW873140) by GlaxoSmithKline. Development was suspended due to liver toxicity.
BMS488043 and BMS806 (attachment inhibitors by Bristol-Myers Squibb, replaced by BMS378806
FP21399 (CCR5 blocker) by Fuji Pharmaceuticals
T-1249 (fusion inhibitor) by Roche and Trimeris - development was halted in early 2004.