Stages of drug development
1. Molecular target
2. Screen for inhibitor or activators
3. Drug formulation is optimization
4. Drug tested in pre-clinical studies
5. Clinical trials
a. Phase 0: drugs are tested during a short period (<7 days) for
metabolism, targeting and pharmacokinetics
b. Phase I: dose of the drug is escalated (verhogen) and new
combinations are tested. Primary endpoint: safety and tolerability
3+ 3 design: first 3 patients treated at dose K
- 0 patients experience dose-limiting toxicity K + 1
- 1 patient experience dose-limiting toxicity K
o In 1 of 6 experiences K+1
o In 2 or more of 6 experiences K-1
- 2 patients experience dose-limiting toxicity K-1
c. Phase II: one dose is tested in specific cancer type. Primary endpoint:
efficacy
d. Phase III: randomized studies in specific cancer types. Primary
endpoint: superiority or non-inferiority to standard treatment
e. Phase IV: one does is tested in specific cancer type. Primary endpoint
safety in larger group of patients
6. Drugs gets regulatory approval
Development of Gleevac (trademark) – first targeted therapy
o Drugs: imatinib inhibiting tyrosine phosphorylation
o Description: small-molecule inhibitor
o Target: BCR-ABL + Kit
o Cancer: chronic myeloid leukemia (CML) + Gastro-
intestinal stromacell tumor (GIST)
CML
CML has an abnormality is Philadelphia chromosome: result
from translocation of chromosomes 9 and 22 Generation of
the fusion protein BCR-ABL activate tyrosine kinase (ATP)
increase of leukemic cells
Treatment for CML: inhibitor of BCR-ABL tyrosine kinase
1. Molecular target: inhibitor of BCR-ABL tyrosine kinase
2. Screen for these
3. Drug formulation is optimization: potency and specificity was low by adding
different molecules it was able to optimize kinase inhibitory activity, specificity
and solubility resulting in the final compound imatinib
4. Drug tested in pre-clinical studies: tested in animal models
5. Clinical trials
a. Phase I: escalated the dose and monitor the side effects
b. Phase III: compare imatinib with standard treatment