Atypical or malignant meningiomas were not eligible and it was therefore not an option for our patient. Hydroxyurea is a drug used since the early to mid-1960 s in the treatment of various malignancies. It has different mechanisms of action, such as inhibition of ribonucleotide reductase, inhibition of DNA synthesis, and induction of cell death in the S-phase of the cell cycle. Experiments have recently demonstrated inhibition of primary human meningioma cell cultures and meningioma transplants in nude mice by way of this apoptosis-inducing mechanism. In addition, preliminary data in four patients demonstrated reduction in size in three recurrent, non-resectable benign meningiomas and absence of recurrence for 2.5 years in a patient with a malignant meningioma.
Additional patients are currently under study.
Another agent that has been used for its antiproliferative and immunomodulatory effects is IFNa. Its use in meningiomas has been substantiated in various in-vitro and clinical studies. Its mechanism of action includes a direct cytotoxic effect, activation of natural killer cells, modulation of antibody production, an anti-angiogenic effect and induction of major histocompatibility complex antigens on the tumor cell surface. Preliminary results are encouraging. A sixth patient with a malignant variant progressed after four months.