From Theory to Application: The Evolution of a Biotech Drug
1. 1975: SEVERE COMBINED IMMUNODEFICIENCY
Dr. Dennis A. Carson at Scripps Clinic and Research Foundation proposes an excess of deoxyadenosine, which causes Severe Combined Immunodeficiency Disease because it destroys the body’s infection-fighting white cells, as a possible cure for leukemia, which is an overabundance of white cells.
2. 1979: 2-CdA
2-Chlorodeoxyadenosine (2-CdA) is one of five chemical compounds similar to deoxyadenosine that Carson and his lab assistant, Bruce Wasson, begin to study in the lab as a possible drug therapy for leukemia.
3. 1980: MORE DRUGS ARE TESTED
The experiments are expanded to include 20 analogs (or chemically similar drugs). Lab results suggest that 2-CdA has the most potential for success. Carson and Wasson begin making their own 2-CdA for further study.
4. 1980: ANIMAL EXPERIMENTS
2-CdA is injected in mice already infected with a standard form of rodent leukemia, to see if leukemia cells are killed. Results are inconclusive.
5. 1981: VOLUNTEER PATIENTS
The first of about three dozen patients-dying from leukemia-is injected with 2-CdA to determine if the drug can kill the leukemia in his body, and to study the dosage needed to kill cancer cells without destroying all the body’s white cells. Toxicity screening makes sure the cure doesn’t kill the patient.
6. 1984: EXPANDED TESTING
Testing is expanded to other patients with different kinds of leukemias. So far, this is a potential cure looking for a disease. Carson knew it was active against some cancer cells, and wanted to find out which cancers were best slowed by 2-CdA.
7. 1986: TESTING RESULTS
In the course of this testing, first one and then another and then even more patients with hairy-cell leukemia show remarkable results with 2-CdA.
8. 1988: TESTING RESULTS
Initial results of the testing of 2-CdA on chronic lymphocytic leukemia patients are published in the journal Blood.
9. 1990: STUDY PUBLISHED
New England Journal of Medicine publishes a study reporting the effectiveness of 2-CdA: that 11 of 12 hairy-cell leukemia patients achieved complete remission from the disease after only one course of treatment, with no necessary maintenance therapy and with minimal side effects.
10. 1991: CONCLUSION
By now, about 400 patients have received 2-CdA. Results are being monitored, but are considered spectacular for nearly 200 hairy-cell leukemia patients who have received it. Scripps hopes the FDA will approve the drug by the end of 1991.
