International Congress of Chemotherapy Meeting: Sydney, Australia

CONFERENCE COVERAGE

Note: The conference, held in Sydney June 29-July 3, was well attended by people from around the world—particularly the Pacific Rim.—Alan Tice

Some of the highlights of the interesting developments reported in the Congress included reports of the use of quinupristine/dalfopristine (Synercid) for gram-positive bacteria. The clinical studies suggested efficacy comparable to standard therapy in randomized trials and reasonable tolerance, although there seeemed to be a problem with phlebitis. Dr. Moellering’s group reported a bacterial and clinical response rate of more than 70% in more than 400 severely ill patients with vancomycin-resistant Enterococcus faecium.

There were reports on the new wave of quinolones that have already been released in many countries. Levofloxacin, sparfloxacin, and grepafloxacin all seem useful in a variety of infections, particularly respiratory. These quinolones may find a market because of increasing development of resistance to other antibiotics among organisms infecting the uninary tract, sinuses, and respiratory tract. Levofloxacin appears to have some activity against methicillin-resistant Staphylococcus aureus. There were data to indicate that trovafloxacin and levofloxacin have increased anti-pneumococcal activity as well, including some of the penicillin-resistant strains.

There was an interest in pharmacoeconomics, particularly in regard to the cost of drugs. There were reports of successful therapy of respiratory infections with clarithromycin using a dose of 500 mg per day.

Hepatitis

There was also an interest in viral hepatitis with reports of the usual response of hepatitis B and C to interferon, but with suggestions that oral drugs such as famciclovir and lamivudine may also be useful for hepatitis B. There were Phase I and II trials for adefovir and labucivir for hepatitis B reported by Dr. Locarinini.

Hepatitis G was also reported on, with information suggesting that it is a worldwide problem. It appears to be spread parenterally through drug abuse, transfusions, and reuse of needles. It runs with hepatitis C, but it is not clear whether it contributes to liver disease. What damage it may do is not yet clear.

There was considerable interest in vaccines as cost- effective tools for managing infections in underdeveloped countries. Some of the particular areas of interest included pneumococcal conjugate vaccine and a combined hepatitis A and B vaccine. There also seemed to be progress with immunization against human papilloma viruses, while there is continued high interest in a vaccine for HIV.

There was particular interest in a paper that suggested a benefit of roxithromycin in the treatment of patients who had just had an acute myocardial infarction. The chances of a second infarct and ischemic death were significantly reduced in the treatment group compared to a placebo. While it has be speculated that this is related to the role of chlamydia in coronary artery disease, serologic results were not presented. An article with the results has just been published in Lancet and reviewed in Infectious Disease Alert (Garfinkel E, et al. Randomized trial of roxithromycin in non-Q-wave cooronary syndromes: ROXISpilot study. Lancet 1997;350:404-407; Infectious Disease Alert 1997;16:187-188.)

Antimicrobials

The problems with antimicrobial resistance seem to be universal, with increasing resistance being reported by centers around the world in regard to pneumococcus. Established surveillance systems were reviewed by Ron Jones. A number of systems are present in the United States and are being expanded internationally when resources are available in other countries.

Increased antimicrobial resistance problems around the world were also noted with the presentation of a Japanese child infected with Staphylococcus aureus with only intermediate sensivity to vancomycin. Pre-prints were issued from the Journal of Antimicrobial Chemotherapy (Hiramutsu K, et al. 1997;40:135-146). The case was of a child in Japan who developed a wound infection with S. aureus that was only "intermediate" in sensitivity to vancomycin with MTC at 8 mg/L by broth microdilution. The infection responded to arbekacin and ampicillin/sulbactam. Since the conference, there have been other cases of S. aureus with intermediate resistance to vancomycin reported in Michigan and New Jersey.

Another area of interest was that of surgical prophylaxis. SmithKline Beecham presented a symposium on the use of mupirocin, which may be particularly cost-effective in underdeveloped countries. Reports suggest that intranasal mupirocin (Bactroban) was able to prevent post-operative S. aureus infections as well as does parenteral antibiotic prophylaxis. The usual regimen would start with nasal application twice daily for three days before surgery. There appear to be benefits in suppressing staphylococcal infections in dialysis units as well. There is some concern about developing mupirocin resistance, but it is sporadic.

HIV

In HIV care, experts from the United States suggested early therapy for HIV infection with two reverse-transcriptase inhibitors plus a protease inhibitor—a combination that usually raises the CD4 count by 150-200 cells. There was little new information.

There was, however, some new information about the Kaposi’s sarcoma herpes virus (KSHV). The etiologic agent appears to be human herpes virus 8 (HHV-8). It has a sero-prevalence in North America of about 20% in HIV-positive gay men without skin lesions, but of 80-90% in those who do. It also has a sero-prevalence of about 70% in East Africa. The best documented manifestation of HHV-8 appears to be Kaposi’s sarcoma, but there may be a role in other malignancies as well. It was also noted that persons with Kaposi’s sarcoma often have high antibody titers for Epstein-Barr virus as well.