In my clinical practice I use FDG-PET for the following 1- Staging 2- Therapeutic monitoring 3- Staging and therapeutic monitoring 4- I do not use FDG-PET; no access 5- I do not use FDG-PET; not cost effective

“PET scans to image pharmacodynamic effects of vemurafenib” Grant McArthur MB BS PhD Peter MacCallum Cancer Centre Melbourne, Australia

Disclosure Information I have the following financial relationships to disclose – Research support from: Pfizer, Millennium & Novartis

Talk Outline FDG-PET response as a clinical tool in oncogene addiction – lessons from gastrointestinal stromal tumors (GIST). Responses on FDG-PET in patients treated with the BRAF inhibitor vemurafenib. Clinical and biological implications. FDG-PET as an early marker of response in patients with rare BRAF mutations. Could inhibition of glucose metabolism be important in response to BRAF inhibitors?

Oncogene Addiction GIST CML Mut EGFR APML p210 Bcr-Abl

FDG-PET to assess response- Re-Evaluating the Conventional Treatment Paradigm GIST Before Imatinib 24 hours after starting Imatinib

The Limitations of Structural Imaging 6 months after commencing imatinib

Monitoring response to imatinib in GIST Survival Adapted from Stroobants et al, EJC, 2003 Time (Days) PET responders n=13 PET non-responders n= p=0.001

Talk Outline FDG-PET response as a clinical tool in oncogene addiction – lessons from gastrointestinal stromal tumors (GIST). Responses on FDG-PET in patients treated with the BRAF inhibitor vemurafenib. Clinical and biological implications. FDG-PET as an early marker of response in patients with rare BRAF mutations. Could inhibition of glucose metabolism be important in response to BRAF inhibitors

Vemurafenib: a novel, small molecule inhibitor Selectivity for BRAF V600E in vitro and in vivo Phospho-ERKIC 50 (nM) A375 COLO829 COLO205 SW620 SKMEL >40,000 14,000 Selective in cellular assays V600E WT Selective for BRAF V600E kinase among 70 kinases screened 10–100 IC 50 (nM) 100– –10000 Kinase domain binding Bollag et al, Nature, 2010 BRAF Bollag et al, Nature, 2010 Dose dependent regression of V600E tumors

CT Response- Phase 1 PLX06/02 Study Flaherty et al, NEJM. 2010Flaherty et al, NEJM, 2010

Progression-free survival (%) No. of patients in follow up Dacarbazine Vemurafenib Hazard Ratio 0.26 (95% CI; ) Log-rank P< Months Dacarbazine (N=274) Vemurafenib (N=275) Progression-free survival (30 Dec 2010, final pre-planned analysis at IA) Median 1.6 mos Median 5.3 mos McArthur et al, ESMO, 2011

Heterogeneity of ERK phosphorylation at progression Recovery of ERK and MEK phosphorylation at disease progression was observed in some but not all patients H-Score BaselineDay 15PD pERK1/2 cytoplasmic H-Score H-Score BaselineDay 15PD pMEK1/2 cytoplasmic H-Score McArthur ASCO, 2011

Patterns of Progression Baseline Response Progression

Design of Clinical Study Day1 VemurafenibScreening Procedure FDG-PET CT 15 FDG-PET CT

FDG-PET Response Baseline Day 15 Kim, MD Anderson

FDG-PET Response McArthur….Hicks, J Clin Oncol, 2012

Response Assessment -quantitative analyses PLX4032 ≥320mg bid (n=27) Controls (n=4)p Mean±SD Drug Exposure day 15 µM.hr 1683±15369± Change Target Lesions SUVmax (%) 80±178±19< Change Whole Body Lesions % Injected Dose(%) 84±151±41< Metabolic Disease Volume ml (range) 816±423 (7-6945) 597±1012 ( )

Response Assessment -summary PLX4032 ≥320mg bid (n=27) Controls (n=4) Overall Assessment of FDG-response (N, %) Complete Metabolic Response 3 (11%)0 Partial Metabolic Response 41(89%)1 No Response03 Overall Assessment of response RECIST (N, %) CR2 (7%)0 PR21(78%)0 SD3 (11%)0 100% of patients with BRAF V600E melanoma achieved an FDG-PET response An example of precision medicine McArthur….Hicks, J Clin Oncol, 2012

Homogeneity of Molecular Response A B McArthur….Hicks, J Clin Oncol, 2012

Conclusions FDG-PET is a useful marker of early biological response to a vemurafenib with 100% of patients achieving partial or complete metabolic response. FDG-PET responses were obtained in patients with high volumes of disease.

Conclusions Limited heterogeneity in FDG-PET response was found between lesions in individual pts suggesting minimal intrapatient molecular heterogeneity. In this small patient cohort, very early FDG-PET response does not appear to be correlated with conventional clinical endpoints of PFS, Best Overall Response by RECIST, time to PR, or Duration of Response.

Talk Outline FDG-PET response as a clinical tool in oncogene addiction – lessons from gastrointestinal stromal tumors (GIST). Responses on FDG-PET in patients treated with the BRAF inhibitor vemurafenib. Clinical and biological implications. FDG-PET as an early marker of response in patients with rare BRAF mutations. Could inhibition of glucose metabolism be important in response to BRAF inhibitors?

BRAF K601E treated with the MEK-inhibitor trametinib A B Day 17 K601E represents 1-2% of all BRAF mutations in melanoma Day 0

BRAF T599 ins I V601 treated with the vemurafenib A B Day 0 Day 18

BRAF L597R treated with the vemurafenib A B Day 0 Day 14

Talk Outline FDG-PET response as a clinical tool in oncogene addiction – lessons from gastrointestinal stromal tumors (GIST). Responses on FDG-PET in patients treated with the BRAF inhibitor vemurafenib. Clinical and biological implications. FDG-PET as an early marker of response in patients with rare BRAF mutations. Could inhibition of glucose metabolism be important in response to BRAF inhibitors?

Baseline Day 15 Kim, MD Anderson Could inhibition of glucose metabolism be a driver of response?

A B Day 0 Day 15 McArthur….Hicks, J Clin Oncol, 2012 Could inhibition of glucose metabolism be a driver of response?

Conclusions Mechanistic preclinical studies and correlations with reactivation of the MEK/ERK pathway suggest FDG- PET is pharmacodynamic marker activity of MEK/ERK. Inhibition of glycolytic metabolism with siRNAs phenocopies the effects of vemurafenib on cell viability, suggesting inhibition of glycolytic metabolism maybe one component of the anti-tumor activity of BRAF inhibitors

Acknowledgements Keith Flaherty Antoni Ribas Paul Chapman Keith Nolop Jeff Sosman Kevin Kim Igor Puzanov Joe Grippo Richard Lee Gideon Bollag Tiffany Parmenter Rod Hicks Jason Callahan Fergal Kelleher Alex Dobrovic Cliff Meldrum PET-imaging colleagues Study Coordinators Patients & their families