Bristol-Myers Squibb, Schering-Plough Announce Promising Early Results on New Antiretroviral Drugs
Pharmaceutical companies Bristol-Myers Squibb and Schering-Plough on Wednesday at the 11th Conference on Retroviruses and Opportunistic Infections in San Francisco presented early trial data on two new experimental antiretroviral drugs showing that they are safe and effective in treating HIV, BBC News reports. Although further testing is needed before the drugs can be approved for widespread use, they could offer more options to HIV-positive people who have become resistant to existing classes of drugs. Most of the large drug companies are working on developing new classes of antiretroviral drugs because they "offer patients the best hope," according to BBC News (BBC News, 2/12).
Schering researcher Dr. Mark Laughlin said that clinical trials of the company's drug, called SCH-D, found that it was safe and well-tolerated, the Wall Street Journal reports. Researchers tested SCH-D in 48 patients over two weeks at Berlin's Charite Hospital. On average, the twice-daily pills reduced patients' viral load levels to one-fiftieth of their levels prior to treatment, Laughlin said. The drug prevents HIV from binding to the CCR5 receptor, which helps HIV break into the cells of the immune system. However, SCH-D only targets R5 viruses, a major HIV subgroup that initially infect people. The drug does not target another HIV subgroup, called X4 viruses, that appear later during infection when patients' immune systems are weakened, according to the Journal. Laughlin said that the company is planning Phase II clinical trials in about 200 patients to further examine the drug's efficacy, the Journal reports.
BMS presented "hopeful" Phase I data on another new medication called BMS-488043, the Journal reports. Twenty-four HIV-positive patients took the drug twice a day for eight days. Compared with six patients who took placebo pills, the patients who took the drug experienced viral load reductions and increases in their CD4+ T cell counts (Chase, Wall Street Journal, 2/12). The drug belongs to a new class of drugs called attachment inhibitors, which prevent HIV from attaching to healthy immune system cells (BBC News, 2/12). BMS currently has four antiretroviral drugs on the market. The newest, called Reyataz, received FDA approval last spring (Todd, Newark Star-Ledger, 2/12).
Researchers from GlaxoSmithKline announced on Wednesday at the conference that they have begun enrolling patients in a Phase II clinical trial of a new drug called 873140, after they received "promising" Phase I trial results, Reuters reports. The drug works by blocking HIV from using CCR5 receptors. The Phase I trial involved 40 HIV-negative volunteers who took varying doses of the drug twice a day for seven days. The volunteers' white blood cells were then analyzed to determine how well the drug bound to the CCR5 receptors. "Our drug pretty much completely blocked the CCR5 receptors, by 95% to 100%, regardless of the dose used," Stephen LaFon, GSK project leader for the drug, said. The company expects to announce the results of its Phase II trial later this year, according to Reuters (Pierson, Reuters, 2/11).
Researchers from Georgia-based pharmaceutical company Pharmasset and Delaware-based biotechnology firm Incyte announced clinical trial results on another new drug, called Reverset, which is a nucleoside reverse transcriptase inhibitor. The drug, which is administered once daily, was tested in 24 HIV-positive patients for 10 days. Patients taking the drug had an average 98% drop in their HIV viral load levels, compared with six patients who received a placebo pill (Wall Street Journal, 2/12).
Hepatitis C, HIV Coinfection
Researchers also presented trial results of a combination treatment for people who are coinfected with HIV and hepatitis C, BBC News reports. The APRICOT study involved more than 800 patients in 19 countries and found that patients taking a combination of Roche's Pegasys and ribavirin had the greatest probability of curing their hepatitis C infections. According to the study, 40% of patients treated with both drugs cleared the virus, compared with 12% of patients who received conventional treatment. Dr. Ed Wilkins, a consultant in infectious diseases at North Manchester General Hospital in England, said, "These groundbreaking data from APRICOT shows the greatest chance of cure ever seen" in coinfected patients (BBC News, 2/12).