Targeted therapies of cancer: Lessons from EGFR mutations in lung cancer Daniel Haber MD PhD Massachusetts General Hospital Cancer Center Harvard Medical School

Trend toward molecularly targeted anti-cancer drugs ONCOLOGY PRODUCTS 32 6 27 Hormonal 49 67 Cytotoxic Targeted 18 Market Development 2001 2006 (McKinsey & Co., NY)

Molecular targeting of cancer.... finding the right fit

The Holy Grail: BCR-ABL, Imatinib and CML Philadelphia chromosome “tumor specific” kinase BCR-ABL C lobe Inhibitor Drug Gleevec Chronic Myeloid Leukemia

Receptor tyrosine kinases as drug targets growth factor Receptor Tyrosine Kinase ATP P K Intracellular kinase P P K ATP P BCR-ABL signaling cascade P P substrate P P

Iressa/Tarceva-responsive lung cancer: -- Mutations in EGFR near drug binding site EGFR Mutations Responders: 78 % ( 74/95) Nonresponders: 6% (6/106) Correlated with - Nonsmokers - Women - Asian ethnicity - Adenocarcinoma del L747-P753insS del E746-A750 del L747-A750 L858R N lobe Inhibitor C lobe

Genotype-directed therapy of lung cancer? -Genetically defined NSCLC subset (~10%).... Dramatic responses to Iressa (Gefitinib)/Tarceva (Erlotinib) - EGFR mutations - EGFR amplification (mutant + wild type allele) - too infrequent to drive survival in large US studies - 80% upfront responses and improved survival in Asia Disease stabilization with Tarceva (Erlotinib) - Other molecular markers...? - Modest survival advantage in non-genotyped studies - Drug dose (Iressa vs Tarceva) -Majority of NSCLC....

Biochemical: Structural alteration in mutant receptor Why are EGFR-mutant lung cancers exquisitely sensitive to small molecule EGFR inhibitors ? Biochemical: Structural alteration in mutant receptor -- Complete suppression of EGFR signaling at clinically relevant dosing Biological: Dependence on mutant EGFR for survival -- Altered signaling by mutant receptor -- “Oncogene Addiction” (Bernard Weinstein)

Acquired resistance to EGFR inhibitors 1. Recurrent T790M “Gatekeeper” Mutation N lobe T790M Inhibitor C lobe Irreversible EGFR inhibitors 2. Reprogramming of cellular survival signals Targeting multiple pathways? -- eg. EGFR and MET (Engelman and Janne) Cell Signaling

Monitoring genotype during cancer therapy: Isolation of circulating tumor cells by microfluidic immunocapture Mehmet Toner, Sunitha Nagrath, Shyamala Maheswaran

Appearance of T790M drug resistance mutation in CTCs Exon2 Del T790M

How common are genetically definable drug susceptible subsets of epithelial cancers ? --- MET Amplification as marker for drug susceptibility Subset of gastric/esophageal cancers with MET amplification: -- Exquisite sensitivity of Amp+ cells to MET inhibitor 2. AKT survival signals are driven by MET in Amp+ cells

High throughput drug screening How common are genetically definable drug susceptible subsets of epithelial cancers ? --- Functional screen for drug susceptibility ~1100 human cancer cell lines panel “genetic diversity of cancer” Compounds 1-8 Compounds 9-16 Compounds 17-24 Con MG-132 L-685,458 Taxol Cisplatin CL-387,785 HKI-272 AG-957 JAK2 inhibitor Low High Medium Drug Concentration High throughput drug screening Jeff Settleman

Range of tumor cell line sensitivity to kinase inhibitors McDermott et al

NSCLC lines with greatest erlotinib sensitivity are enriched for EGFR mutations Extremely sensitive Highly sensitive Moderately sensitive Insensitive Cell line Tissue Sensitivity EGFR status McDermott et al

Sensitivity to the MET inhibitor correlates with MET amplification * McDermott et al

Molecular targeted therapy of cancer Challenges.... Identifying an “Achilles heel” for different subsets of cancers in preclinical studies ? Designing early phase clinical trials for genotype-directed therapies? Expectations from targeted therapies ?

Acknowledgements Jeff Settleman Tom Lynch Daphne Bell Shyamala Maheswaran Sree Sharma Mehmet Toner Lecia Sequist Raffaella Sordella Eunice Kwak The “Iressa Team” Ultan McDermott Gromek Smolen Nadia Godin- Heymann