Preclinical as well as clinical studies with
fibroblast interferon (IFN) are still lagging behind on those with
leukocyte interferon. Its side-effects seem to be less pronounced than those of human IFN-alpha, yet it may be slightly pyrogenic after
intravenous injection. Pyrogenicity of current impure preparations might for the larger part be due to impurities. Higher doses of HuIFN-beta than of HuIFN-alpha are required to obtain measurable blood titers by
intramuscular injections. Since there is concern about this being due to destruction of the
interferon before it has reached its target organ(s), most current clinical studies use either local (e.g. intratumoral) treatment or
intravenous infusions. A study of topical treatment for acute rhinovirus
infection has indicated that there is very little if any chance for
fibroblast interferon to be a clinically useful substance to prevent or cure
common cold. In herpetic
dendritic keratitis eye drops of
fibroblast interferon may be useful as such or in combination with
debridement. Topical treatment of
warts (multiple
intralesional injections) has been shown to yield a high success rate, especially in the case of verrucae vulgares, but less so in the case of verrucae planae juveniles. Studies on condyloma accuminatum are not so far advanced as to permit a documented conclusion. Topical (intralesional) treatment of neoplastic diseases has been investigated, especially in Japan, to demonstrate that
fibroblast interferon does have an
antineoplastic effect in vivo. While there seems to be little doubt that local delivery does indeed cause
tumor nodules to regress, the question is whether this procedure can offer a true clinical benefit to the patient. Systemic (
intravenous) administration for
chronic hepatitis B has been investigated further: given alone or in combination with
adenine-arabinoside,
fibroblast interferon seems to be able to reduce the level of viral activity. Whether this will lead to a generally accepted treatment of
chronic active hepatitis is difficult to say at this moment. In treating
herpes zoster in
cancer patients, results have been obtained which are comparable to those found for
leukocyte interferon. The practical significance of this finding must be seen in the perspective of recent developments in the
chemotherapy of
herpes zoster. In
breast cancer patients given
intramuscular injections,
metastases in the skin, but not in other organs, showed alterations suggestive of an effect on
tumor progression. Yet there was no true clinical benefit for the patient. In other
tumors, e.g. head and neck
epithelioma, no effect was seen.(ABSTRACT TRUNCATED AT 400 WORDS)