Anticancer activity of a lectin-rich mistletoe extract injected intratumorally into human pancreatic cancer xenografts.

BACKGROUND

In single case observations, tumour remissions after intratumoral injections of mistletoe extracts have been described.

METHODS

We investigated the antitumour activity of intratumorally (i.t.)-injected lectin-rich mistletoe extract at different dosages and i.t.-injected mistletoe lectin I in comparison to intravenous (i.v.) Gemcitabine and i.t. treatment with placebo in a human pancreatic cancer xenograft.

RESULTS

In a preliminary dose-response experiment, the most marked tumour inhibition was induced when mistletoe extract was given at 8 mg/kg body weight (BW) and mistletoe lectin I at 5.3 microg/kg BW. In a second experiment, bi-weekly i.t. injections of mistletoe extract over 8 weeks resulted in a very high antitumour activity with an optimal T/C value (=median relative tumour volume of the test group vs. the control) of 0.4% combined with 3/8 partial and 3/8 complete remissions. Gemcitabine was less active with 2/8 partial and 1/8 complete remissions and an optimal TIC of 4.6%.

CONCLUSIONS

I.t.-injected lectin-rich mistletoe extract should be further evaluated in patients with inoperable locally advanced pancreatic cancer.