1. Can cancer brain metastases be treated using humanized monoclonal antibodies: a pilot pharmacological study Guilhem BOUSQUET, Anne JANIN University Paris VII, UMR_S1165

2. Brain metastases Most frequent brain tumors 15-40% patients with metastatic cancer – even more in autopsy series Lung, breast, melanoma Low median survival Increased incidence in the last 10 years because…

3. better control of localisations outside the central nervous system an inadequate transfer through the blood brain barrier (BBB) of most chemotherapeutic agents …of

4. Blood Brain Barrier Tight continuous junctions Prevent the free paracellular diffusion of water-soluble molecules, >150Da Murin models: BBB permeable, but concentrations pharmacologically inactive Reese, J Cell Biol 1967 Wilhelm, Acta Neurobiol Exp 2011 Lockman, Clin Cancer Res 2010

5. Brain metastases and breast cancer 5-15% Risk factors: –Young age –Black women –Triple negative and HER2-overexpressed phenotypes Median survival: less than 12 months

6. HER2 and brain metastases After treatments for localized breast cancer –Meta-analysis on 6738 patients –Trastuzumab-based chemotherapy –RR of brain metastases=1.57 In case of metastatic disease –Incidence of brain metastases: 20-48% Leyland-Jones, JCO 2009 Bria, Breast Cancer Res Treat 2008

7. Chemocurability … … with anti-HER2 antibodies Brain metastases are challenging our daily practice From Swain SM et al. N Engl J Med 2015.

8. Trastuzumab After intra-veinous injection –Very low passage from blood to brain –Ratio 300/1 à 1000/1 –148 kDa After intra-thecal injection –Proof of concept in case of carcinomatous meningitidis –Empirical doses ranging from 25 to 100mg Pestalozzi, 2000 Stemmler, 2006 Mir, 2008

9. Trastuzumab After intra-veinous injection –Very low passage from blood to brain –Ratio 300/1 à 1000/1 –148 kDa After intra-thecal injection –Proof of concept in case of carcinomatous meningitidis –Empirical doses ranging from 25 to 100mg Pestalozzi, 2000 Stemmler, 2006 Mir, 2008

10. 36-year-old woman HER2-overexpressing breast cancer Liver metastases, complete response under trastuzumab treatment Resistant brain metastases Ventricular and lumbar reservoirs Intra-thecal injections of trastuzumab A sequential pharmacological pilot study

12. Overexpression of HER2 Cerebellous metastasis

13. Treatments Sampling Pharmacology

14. Pre-C1 Pre-C7Post-C10 Bousquet G, Darrouzain F, Janin A. J Clin Oncol 2015

16. A rapid clearance of the drug from the cerebro-spinal fluid

17. Cynomolgus monkeys –Trastuzumab, lumbar catheter, –6 males and 6 females received weekly intrathecal injections. –A rapid decrease in CSF concentration of trastuzumab. –A long terminal half-life of about 10 hours, independent from the dose administered Phase I intra-thecal administration of rituximab (anti-CD20) –Rapid clearance from the CSF Braen, Int J Toxicol 2010 Rubenstein, Blood 2013

18. Receptors FcRn = efflux Rat model, after direct intra-cranial administration of a monoclonal IgG1 Cooper, Brain Res 2013

19. Perspectives Chemical modification of the Fc fragment Engineered Fab fragment antibodies