Background

Iscador is a preparation made from European mistletoe. When exposed to it, some tumours and T- cells commit suicide, or apoptosis. Iscador has been injected under the skin in subjects with cancer, causing some tumours to shrink and some subjects to experience remission. It is difficult to assess Iscador's usefulness as an anti-cancer agent, however, because most reports on the drug are written in German. We were unable to find articles in the English-language literature comparing the effect of Iscador with that of cancer chemotherapy.

Iscador's effect on the immune system has been the object of study. In subjects with cancer, increased levels of CD4+ and natural killer cells have been reported while, strangely, levels of CD8+ cells decrease. We now report the results from a phase I/II study of the drug in people with HIV/AIDS.

Study details

Researchers reported data on 32 HIV-positive subjects (two female, 30 male) as well as on nine non-HIV-infected subjects. The CD4+ counts of the HIV-positive subjects ranged between 50 and 600 cells; viral load measures were not provided. Some subjects used AZT, ddI or ddC as well as antibiotics to prevent PCP (Pneumocystis carinii pneumonia) during the study.

All subjects received Iscador injected under the skin twice weekly. Some subjects took the drug for up to 68 weeks. The doses used in the study ranged from 0.01 to 5 milligrams (mg) per kilogram of body weight per day.

Results - CD4+ and other cell counts

Iscador did not appear to affect levels of CD4+, CD8+ or other lymphocytes during the study.

All HIV-positive subjects experienced decreased levels of red blood cells. The decrease was greatest in those subjects receiving Iscador at doses ranging of 1 to 2 mg. At that dose, the decrease in red blood cells was statistically significant: not likely due to chance alone.

Results - side effects

Iscador did not cause any detectable liver toxicity, but slight kidney damage did occur in all HIV-positive subjects. The evidence of this damage was higher-than-normal levels of creatinine in the blood. All subjects developed a small but significant decrease in the level of protein in the blood, possibly caused by the kidney damage.

At high doses, 13 subjects developed inflammation, according to the researchers. The inflammation took the form of the following conditions:

• Worsening gum inflammation
• Flu-like symptoms
• Yeast infections
• Sinus infections
• Herpes outbreaks on the genitals

Iscador also may have caused the following symptoms:

• Headache
• Fatigue
• Fever

No subject developed a life-threatening illness during the study.

Points to consider:

1. The results of this study suggest that some people with HIV/AIDS can tolerate Iscador for as long as 68 weeks.
2. The drug may cause the loss of red blood cells, and this may be linked to the development of fatigue.
3. Iscador can cause mild kidney damage.

Major unanswered questions include the following:

• What effect does Iscador have on HIV production?
• Precisely how does Iscador affect the immune systems of people with HIV/AIDS?

We hope that answers to these questions will come from other studies.

A smaller study of Iscador looked at the drug's effect on production of interferon-gamma (IFN-gamma), a cytokine needed to help the immune system fight HIV. Iscador injections caused no increase in IFN-gamma levels. This result is not promising and may explain why an increased CD4+ cell count was not seen in the larger study of Iscador.

Another study of Iscador is currently under way. The doctors involved will measure viral load. This fact is important, because Iscador clearly stimulates the immune system, and this stimulus may increase viral load.