These drugs have shown definite antitumor activity but are still classified as investigational for a variety of reasons.
• The trials seeking HPB approval may be incomplete or currently inconclusive.
• A drug sponsor has not been identified or is under negotiation.
• The circumstances in which the drug has been shown to be useful do not easily lend themselves to the drug
approval process, so approval is no longer being sought.
For oncologists registered in good standing as clinical investigators, drugs in the last two categories are often obtainable in Canada through the National Cancer Institute in the United States. Drugs are also available—rarely—from industry sponsors for "compassionate" use. In other instances, a referral to an ongoing clinical trial will allow entry into a randomized study, generally with a 50-50 chance of receiving the experimental treatment.
Azacitidine is an antileukemic agent distributed by the NCI (U.S.) for some resistant leukemias.
Edatrexate is related to the standard agent methotrexate and is under study by Ciba-Geigy. It may have a wider spectrum of activity and be more suitable for combinations than the older compound. Major disease targets are lung cancer, head and neck cancers and gynecologic cancer. Combinations with cisplatin , and with leucovorin rescue ( see "Miscellaneous Drugs" ), appear promising.
