Targeting the PI3K-Akt-mTOR pathway with GDC-0068, a novel selective ATP competitive Akt inhibitor

Josep Tabernero, Andrés Cervantes, Cristina Saura, Desamparados Roda, Yibing Yan, Kui Lin, Sumati Murli, Jose Baselga, and Premal Patel

Vall d'Hebron University Hospital (Barcelona, Spain), Hospital Clinico Universitario (Valencia, Spain), and Genentech, Inc. (South San Francisco, USA)

March 9, 2011

Akt pathway is frequently activated in cancer

2   Compelling evidence for targeting Akt in human malignancies

GDC-0068: Novel, specific, ATP competitive Akt inhibitor

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Enzymatic potency and selectivity of GDC-0068 Kinase IC50 (nM) Akt1/2/3 5/18/8 PKG1a/b 98/69 p70S6K 860 PKA 3100 SGK >1000* PDK1 >1000* AMPK >1000*

*No inhibition when screened at 1000 nM in a protein kinase panel

Cellular potency of GDC-0068

Cell line pPRAS40 IC50 (nM) LNCaP 157 BT474M1 208

GDC-0068: Effectively blocks Akt signaling and induces cell cycle arrest in human cancer cell lines in vitro

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(PTEN-)

High Akt activity predicts sensitivity to GDC-0068

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Sensitivity in breast cancer cell line panel: •  Strongest in HER2+ and Luminal subtypes. •  Driven by PI3K kinase domain mutations, PTEN loss and HER2 amplification. •  Negative association with KRas/BRaf mutations and EGFR expression.

GDC-0068 exhibits significant efficacy in PTEN- and PI3K mutant xenograft models

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pS6 RPPA

peIF4G RPPA

•  GDC-0068 reduces pS6 and peIF4G levels in BT474-Tr xenografts

Vehicle GDC-0068

pS6 IHC

IHC/IF and RPPA: Complementary platforms to demonstrate PD changes

Vehicle GDC-0068

peIF4G IHC

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FOXO

3A (H

-Sco

re)

GDC-0068 (mg/kg)

• Subcellular localization of FOXO3a regulated by phosphorylation by Akt • Nuclear FOXO3a controls transcription of pro-apoptotic and cell cycle inhibitory genes Vehicle

GDC-0068 nucleus

FOXO3a P

FOXO3a

P27, FASL

Cell cycle inhibition

apoptosis

AKT: ON

AKT: OFF

cytoplasm

IHC/IF: Akt Inhibitor GDC-0068 relocalizes FOXO3a to nucleus

GDC-0068 treated BT474-Tr xenografts

18d, 2h

0 12.5 25 100

Cytoplasmic FOXO

Nuclear FOXO

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RPPA analyses demonstrate feedback upregulation of HER3 and pERK induced by the Akt Inhibitor GDC-0068

GDC-0068 treated BT474-Tr xenografts

Log 2

Inte

nsity

HER3

Log 2

Inte

nsity

p-ERK1/2

@ Zimmermann and Moelling, Science, 1999 # Serra et al., Oncogene, 2011; Makhija, et al., J. Clin.

Oncol., 2010; Garrett, et al., Cancer Res., 2009

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GDC-0068 Phase I dosing strategy

•  Dose: oral daily x 21 days on/ 7days off •  Schema:

•  Single PK dose in week 1, then 21/28 day dosing •  Dose GDC-0068 in am (post O/N fast) and fast 2 hrs post dose •  Standard 3+3 design

•  PD: •  Surrogate tissue: AKT pathway evaluation in platelet-rich plasma •  pre- and on-treatment skin biopsy of all patients • Tumor biopsy when ≥ 50% pathway knockdown achieved in surrogate tissue

1 Day 8 Day 29 35

Single dose PK (days 1 – 7) DLT assessment (days 1 – 35)

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Phase I dose escalation

Trial overview:

•  FPI 3/2010

•  Currently, completing 800 mg cohort

•  No DLTs cohort 1-5

•  At least 3 patients in each cohort ≥100 mg had pre and on-treatment tumor biopsy

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GDC-0068 preliminary clinical PK summary

Preliminary summary of PK properties: •  Rapidly absorbed with tmax of 0.5-2 hours

•  Generally dose proportional increase in Cmax and AUC

•  2-3 fold accumulation following QD dosing to steady-state

•  Half-life ranges from 20.1 to 34.1 hours; suitable for once-daily dosing

•  Low (~ 20%) inter-patient variability in AUC at steady-state

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Phase Ia safety profile: All AEs related to GDC-0068*

Cohort/dose Gr/AE (# patients) 1 25mg Gr 1 Asthenia (1)

2 50mg Gr 1 Hyperglycemia (3) Gr 1 Alopecia (1) Gr 1 Dyspepsia (1) Gr 1 Decreased appetite (1) Gr 2 Asthenia (2)

3 100mg Gr 1 & 2 Asthenia (1 each) Gr 1 Rash (1) Gr 1 Nausea (1) Gr 3 Hypercholosterolemia (1)

4 200mg Gr 1 Hyperglycemia (2) Gr 1 Pneumonia (1)

5 400mg Gr 1 Hyperglycemia (1) Gr 1 Nausea (2) Gr 1 Emesis (1) Gr 1 Abdominal pain (1) Gr 1 Dysguesia (1)

* AEs up to start of 800 mg cohort are listed

GDC-0068 was well-tolerated to 400 mg; no DLTs observed

Hyperglycemia: G1 1: >ULN – 160; Gr2 >160 – 250; Gr 3 >250-500; Gr 4 >500 mg/dL

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Typical GDC-0068/insulin/glucose relationship post drug administration

GDC-0068

Insulin

Glucose GDC-0068

Insulin

Glucose •  GDC-0068 PK and glucose/insulin relationship was assessed on D1 and D15

(light meal was given at 2hrs)

•  Representative data from a patient from cohort 4 is plotted

•  Mild elevation in glucose (up to 2-3 fold), and substantial increase in insulin was observed

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Day 1

Day 15

Preliminary evidence of PD modulation in surrogate tissue Platelet Rich Plasma (PRP)assay

pGS

K3β

pGS

K3β

•  Platelet rich plasma collected on D1 and D15

•  pGSK3β level normalized to total GSK3β protein was determined

•  A dose- and time-dependent pharmacologic response was demonstrated, with a decrease in pGSK3β level of ≥ 60% at doses ≥ 200 mg

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IHC/IF

OCT FFPE

RPPA

Core Biopsies

Preliminary evidence for pathway knockdown in tumors

•  Tumor biopsies were obtained from patients during screening (baseline) and once during Cycle 1 (between Days 15 and 21).

•  Needle core biopsies were snap-frozen and evaluated by reverse phase protein array for epitopes, including pPRAS40.

•  Decreases of 60%–70% in pPRAS40 (compared with baseline) were demonstrated in all 3 patients treated at 400 mg once daily

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Conclusions

•  GDC-0068 is a novel, oral, selective ATP-competitive AKT inhibitor

•  Preclinical activity is most pronounced in models driven by PI3K kinase domain mutations, PTEN loss and HER2 amplification

•  GDC-0068 treatment resulted in pronounced PD effects in tumor xenograft models as measured by RPPA and/or IHC, including dose-dependent suppression of P-S6 and P-eIF4G, as well as induction of FOXO nuclear localization

•  In clinic, GDC-0068 has been well tolerated up to cohort 5 (400 mg once daily), with mild, manageable hyperglycemia

•  GDC-0068 has low (~ 20%) inter-patient variability for exposure and half-life (~24 hrs) suitable for once-daily dosing

•  At well-tolerated doses, GDC-0068 results in >60% pathway knockdown in surrogate and tumor tissue

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Acknowledgments

Genentech/Array GDC-0068 Akt Team

Jose Baselga’s Lab: Violeta Serra Ludmila Prudkin Celina Garcia

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