TESTING A LEPTIN PRODUCT AS A NOVEL THERAPY FOR ALZHEIMER’S DISEASE J. Wesson Ashford, M.D., Ph.D. (1) Mark A. Smith, Ph.D. (2), G. Casadesus, Ph.D. (2), S.J. Greco, Ph.D. (3), J.M. Johnston, Ph.D. (3), N. Tezapsidis, Ph.D. (3)   (1) Stanford /VA Aging Clinical Research Center, VAPA-HCA, Palo Alto, CA USA   (2) Case Western Reserve University, Cleveland, OH, USA   (3) Neurotez, inc., Bridgewater, NJ, USA

Disclosures Drs. Ashford and Tezapsidis are co-principal investigators on an NIH-funded SBIR to study the effects of Leptin in Alzheimer patients

OVERVIEW Numerous factors (particularly age and APOE) are known to moderate the course of Alzheimer’s disease (AD), but the pathophysiology of AD causation is unknown. Serum Leptin levels appear to protect against cognitive decline in the elderly, and patients with AD have lower Leptin levels. Leptin injections in AD-transgenic mice protect against both the development of amyloid and tau pathology and reverse the cognitive impairments found in these animals. Therefore, Leptin may be a preventive therapy for AD

ALZHEIMER’S DISEASE COURSE There is a prolonged period during which loss of cognitive function occurs. AAMI / MCI/ early AD -- DEMENTIA Ashford et al., 1995

Ashford et al., 1998 J Neuropathol Exp Neurol.57:972

Serum Leptin levels and cognition in the elderly Data: Satoris, Inc. In elderly, higher serum leptin appears to protect against cognitive decline (5 yr prospective study, 2,871 elders, Holden et al., 2009) Patients with AD have lower serum leptin levels compared to controls, independent of BMI (Power et al., 2001) 20 AD Leptin (ng/ml) 10 MiId Normal Severe Moderate 6 6

Leptin inhibits Ab production and stimulates Ab uptake In vitro: Leptin inhibits Ab production and stimulates Ab uptake Fewlass et al., 2004

protein. It is first cleaved by one of two enzymes. extra cellular intracellular APP is a transmembrane protein. It is first cleaved by one of two enzymes. Leptin receptors can activate JAK/STAT3, stimulate lipolysis, modulatng lipid raft composition, decreasing BACE activity Lipid raft (BACE) Fewlas et al., 2004

In vitro Leptin is 270x more potent than Insulin in down-regulating tau phosphorylation Leptin, 4h Insulin, 4h IC50=46.9nM IC50=13mM Greco et al., (2008) BBRC

Animal studies Chronic s.c. Leptin in Tg2576 reduces brain Ab The effect of Leptin on Abeta homeostasis was first seen in monolayer cultures and was also recapitulated in whole animals. We treated Tg2576 mice with leptin. These animals are an extensively characterized AD mouse model that overexpress mutated human APP, the precursor of Abeta. Their brains start accumulating detectable Abeta by 9 months of age. These were fed a low or high fat diet and treated chronically by infusing ~0.5mg/kg (20 microgr) leptin daily (+) or placebo (-) through a Alzet miniosmotic pump fitted s.c. for up to 8weeks, starting at 8 months of age. Total brain Ab40 (shown by the blue bars) and Ab42 (white bars) were reduced by up to 50% under LFD and up to 40% under HFD. The highest statistically significant difference was observed between the LFD leptin-treated group and HFD placebo treated group, indicating that a LFD and leptin treatment combination may be required for the maximum effect. Fewlass et al (2004) FASEB J

Animal studies Leptin reduces phospho-tau in brain of TgCRND8 mouse Leptin reduces hippocampal Amyloid burden in TgCRND8 mouse

Animal behavior studies Memory performance was analyzed with the “novel object task” (NOT). The test is based upon the tendency of mice to investigate a novel object rather than a familiar one. In a first trial the mice were allowed to explore two similar objects presented in an open-field arena (30x 30cm) for 3 min. The five objects to be discriminated in the object recognition task consisted of a biologically neutral material such as plastic or metal, and animals could not move them around in the arena. Objects are not known to have any ethological characteristic for the mice. After 1 h the mouse was again placed into the open field now containing one object similar to both objects presented in the first trial and one novel object. The number of visits and the time spent exploring the objects were recorded using the “NOT” software and a handheld computer. To avoid object or place preferences, place and novelty-status were changed for each object at regular intervals. In order to compare groups, a recognition index was calculated for each individual by dividing the amount of time spent exploring the novel object by the total time of object exploration.

Fear conditioning after 8 weeks leptin Animal behavior studies Fear conditioning after 8 weeks leptin Greco et al., Manuscript submitted A very significant contribution towards bringing our leptin program to the clinic for AD has been achieved by the completion of animal behavioral studies. In this test, initial hippocampus-dependent memory formation was assessed by contextual and cued fear conditioning. An aversive training chamber is used for training and measurement of contextual memory. The aversive learning tasks measures fear response to an unpleasant stimulus. Here freezing is quantified in the original chamber before and after several training sessions (mild footshocks) for contextual FC or in a novel environment containing an auditory cue that was previously paired with footshock. The x –axis represents % freezing time. We observed a significant improvement in both contextual and cued FC on the CRND8 mice treated with Leptin compared to placebo as Leptin treated animals exhibited increased freezing levels to contextual and auditory cues.

Summary of preclinical data High density of Leptin receptors in the hippocampus Leptin inhibits Ab production in neurons Leptin promotes ApoE-dependent Ab neuronal uptake Leptin inhibits tau phosphorylation Leptin (chronic application) reduces brain amyloid load in AD transgenic mice Leptin (acute and chronic application) improves memory in aged AD transgenic mice. The clinical and preclinical data provide compelling evidence to support a clinical trial of Leptin for AD Leptin receptors in the hippocampus-regulation of ion channels Leptin inhibits Ab production in neurons Leptin promotes Ab uptake from neurons Leptin inhibits tau phosphorylation and is 300x more potent than insulin on this Leptin (chronic application) reduces brain amyloid load in AD transgenic mice Leptin treatment improves consolidation and retention of memory in aged AD transgenic mice.

Alzheimer’s Disease: Course, Pathology, Biomarkers Normal Pre- Symptomatic AD Mild Cognitive Impairment AD Clinical State None Amyloid Plaques, No Tangles Amyloid Plaques Few Tangles Amyloid Plaques Many Tangles Neuro pathology Normal tau Normal Ab tau? Ab? High tau Low Ab High tau Low Ab CSF Biomarkers Disease Progression 15

Biomarkers for More Valid Alzheimer Diagnosis and Precise Measurement of Severity Lancet Neurol 2007; 6: 734–46

Potential AD Biomarkers Blood, urine Aβ40? Aβ42? Neuritic threads? Most studies suggest not helpful Protein levels in blood – Proteomics, Leptin. Lower Leptin predicts MCI progression to dementia CSF: Aβ40? Aβ42? Others Aβ species? Possibly highly predictive CSF: tau, p-tau Assess active disease progression. Neuroimaging Structural (volumetric assessments) Functional (FDG-PET, SPECT) Specific protein imaging (PET) 17

CSF in Alzheimer’s Disease, both MCI and Dementia patients: Low Aβ and High Tau Concentration (pg/mL) Aβ Tau Sunderland T, et al. JAMA. 2003;289:2094-2103.

Hansson et al., Lancet Neurology 2006 CSF of subjects with MCI progressing to AD has elevated tau, decreased β-amyloid The relative risk of progression to AD substantially increased in patients with MCI who had pathological concentrations of T-tau and A42 at baseline (hazard ratio 17·7, p0·0001). The association between pathological CSF and progression to Alzheimer’s disease was much stronger than, and independent of, established risk factors including age, sex, education, APOE genotype, and plasma homocysteine. Hansson et al., Lancet Neurology 2006

ADNI Data – CSF ABeta, total tau

Power Calculations for Reduction in Rate of Decline in AD for an Experimental Treatment Number needed per arm for 50% effect size (50% reduction over 1 yr in the rate of cognitive decline ) ADAS-Cog 320 cases MMSE 241 cases hippocampal volume 21 cases temporal horn volume 54 cases ----------------------------------------------------------------------------------------------------- CSF-tau – if level returns to normal in 12 weeks, - then only 6 cases (3+3) needed for statistics!! - plan 15 in each arm due to drop-outs, etc. Neurology 2003;60:253-260

Numerous Leptin trials have been performed for several indications - no safety issues - AMGEN: obesity as a monotherapy, congenital obesity ROCHE: obesity as a monotherapy Amylin: obesity as a combination therapy with Symlin (amylin) Harvard U., Rockefeller U., Columbia U., NIH: obesity, hypothalamic amenorrhoea, lipodystrophies (i.e. aggressive anti-HIV therapies)

1 2 Clinical Trials: Design A focused clinical trial, in a group of 45 early-stage AD (MCI range to very mild dementia) individuals pre-screened for low leptin, elevated CSF-tau, low CSF-Ab42, with APOE e4 genotype and MRI enrolled for a 12 week treatment period (15 on 5mg/d; 15 on 10 mg/d; 15 on placebo) with decreased CSF-tau as the primary outcome measure and cognitive function as a secondary outcome measure. Leading to a larger, multicenter, double-blind, placebo controlled trial, for 1 year (number of patients to be determined by pilot data). 1 2

Summary Clinical Plan for Trial for Leptin Treatment in AD Recruitment Use of audience screening, genetic testing Genetics 45 APOE e4 patients Baseline diagnosis Amnesic MCI or mild dementia with AD Baseline measures Elevated CSF tau, decreased Ab Drug administration 3 groups - daily injections, placebo, 5, 10 mg SC Outcome measures Primary - CSF tau Secondary – cognitive measures, other CSF/plasma measures

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