Recent studies, now reported from other laboratories, have shown that Dr. Wall's initial thoughts and persistence were justified. More details concerning Dr. Wall's contribution to the discovery of camptothecin, Taxol, and other natural products, and his research contributions on steroids and marihuana are listed below. CPT was found to have a unique structure and marked activity in rodent leukemia and tumor systems. This salt proved ineffective. Since SAR investigations by Wall and coworkers clearly showed that the intact a-hydroxy lactone moiety was required for activity, these clinical studies proved to be misleading.
Colon cancer is one of the most resistant cancers in man.
Hence the development of an active drug against this form of cancer is of great significance and is due largely to Dr. Wall and his colleagues at RTI, NCI, and elsewhere. Both of these have been approved by the FDA for marketing, the former for advanced ovarian cancer, the latter for colonic cancer. Another compound synthesized by Dr. Wall's group, 9-aminocamptothecin, has recently moved into Phase II clinical trial. The original compound, camptothecin, is now in Phase 1 clinical trial. This compound has been especially effective against resistant cells obtained from individuals who have chronic lymphocytic leukemia.