P la te le t P D n

(4 h a fte r f ir s t d o s e o n C 1 D 1 )

[C B -8 3 9 @ 4 h ] (n g / m L )

% G

luta

min

as

e A

cti

vit

y

1 1 0 1 0 0 1 0 0 0

0

2 0

4 0

6 0

8 0

1 0 01 0 0 T ID

1 5 0 T ID

2 5 0 T ID

4 0 0 T ID

6 0 0 T ID

8 0 0 T ID

e x v iv o p la t e le t

d o s e r e s p o n s e

8 0 0 B ID

6 0 0 B ID

L L O Q

Patients: Metastatic or locally advanced solid tumors

Doses: 100-1000 mg po Regimens • TID • BID fed

Monotherapy Expansion cohorts (N > 11 pts/cohort)

A: Triple negative breast cancer (TNBC)

B: KRAS-mutant non-small cell lung cancer (NSCLC)

C: Renal cell carcinoma (RCC)

D: Mesothelioma

E: Fumarate hydratase (FH) -deficient solid tumors

F: Succinate dehydrogenase (SDH) - deficient GIST

G: Succinate dehydrogenase (SDH) - deficient non-GIST

H: Isocitrate dehydrogenase (IDH) – mutant solid tumors

Combination Expansion cohorts (Simon two-stage design)

Paclitaxel + CB-839

Erlotinib + CB-839

Everolimus + CB-839

Docetaxel + CB-839

Mo

no

the

rap

y C

om

bin

atio

ns

Monotherapy dose escalation

Combination dose escalations

Safety and Tolerability of Increasing Doses of CB-839, a First-in-class, Orally Administered Small Molecule Inhibitor of Glutaminase, in Solid Tumors Harding JJ1, Telli ML2, Munster P3, Le MH4, Molineaux CJ4, Bennett MK4, Orford KW4, Mittra E2, Burris HA5, Clark AS6, Dunphy MP1, Meric-Bernstam F7, Patel MR8, DeMichele A6, and Infante JR5

1Memorial Sloan Kettering Cancer Center, New York, NY; 2Stanford Univ. Med. Center, Palo Alto, CA; 3Univ. California, San Francisco, CA; 4Calithera Biosciences, South San Francisco, CA; 5Sarah Cannon Research Inst., Nashville, TN; 6Univ. of Pennsylvania, Philadelphia, PA; 7MD Anderson Cancer Center, Houston, TX; 8Florida Cancer Specialists, Sarasota, FL

Characteristic N=59

Age: median (range) 60 (19 — 88)

Female/Male: N (%) 39 (66%)/20 (34%)

Number of prior regimens for locally

advanced or metastatic disease

Median (range)

0-1 regimens: N (%) 2-4 regimens: N (%) ≥5 regimens: N (%)

3 (0 — 12)

11 (19%) 31 (53%) 17 (29%)

ECOG Score: N (%) 0 1

15 (25%) 44 (75%)

Partner Cancer Status Paclitaxel TNBC OPEN

Everolimus RCC OPEN

Erlotinib EGFRm NSCLC UNDER

CONSIDERATION

Docetaxel KRASm NSCLC PLANNED

Total patients: 59 Number (%) of patients

MedDRA Preferred Term All events Drug-related

Patients with any AE 56 (95) 40 (68)

Fatigue 20 (34) 13 (22)

Vomiting 11 (19) 5 (8.5)

Nausea 10 (17) 5 (8.5)

Alanine aminotransferase increased 9 (15) 8 (14)

Aspartate aminotransferase increased 8 (14) 7 (12)

Blood alkaline phosphatase increased 6 (10) 3 (5.1)

Blood creatinine increased 5 (8.5) 2 (3.4)

Constipation 5 (8.5) 2 (3.4)

Dyspnoea 5 (8.5)

Pyrexia 5 (8.5)

Abdominal pain 4 (6.8)

Anaemia 4 (6.8)

Cough 4 (6.8)

Decreased appetite 4 (6.8) 1 (1.7)

Dizziness 4 (6.8) 1 (1.7)

Oedema peripheral 4 (6.8)

Photophobia 4 (6.8) 4 (6.8)

Total patients: 59 Number (%) of patients

MedDRA Preferred Term All ≥Gr3 events Drug-related

Patients with any AE 17 (29) 8 (14)

Alanine aminotransferase increased 6 (10) 6 (10)

Aspartate aminotransferase increased 6 (10) 5 (8.5)

Blood alkaline phosphatase increased 3 (5.1) 1 (1.7)

Gamma-glutamyltransferase increased 2 (3.4) 1 (1.7)

Hyponatraemia 2 (3.4)

Pneumonia 2 (3.4)

STUDY STATUS

SAFETY AND TOLERABILITY

RCC (chromophobe) SDH-deficient GIST

NSCLC (KRAS mutant) TNBC

Mesothelioma

RCC (clear cell)

G lu ta m in a s e E x p r e s s io n ( IH C )

H S

co

re

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0h ig h es t

e x p re s s io n

lo w e s t

e x p re s s io n

T N B C

T C A c y c le

m u ta n t

R C C

N S C L C

M e s o -

th e lio m a

O t h e r

BACKGROUND AND RATIONALE

STUDY OBJECTIVES*

PHARMACOKINETICS CLINICAL OUTCOMES

SUMMARY AND CONCLUSIONS

BIOMARKER ANALYSIS

0 1 2 3 4 5 6 7 8

1 0

1 0 0

1 0 0 0

CB

-83

9 (

ng

/m

L)

T im e ( h ) : 0 1 2 3 4 5 6 7 8

B L O Q

5 0 0 0

T a r g e t :

2 0 0 n g / m L

0 1 2 3 4 5 6 7 8

1 0

1 0 0

1 0 0 0

CB

-83

9 (

ng

/m

L)

T im e ( h ) :

D a y 1 D a y 1 5

0 1 2 3 4 5 6 7 8

B L O Q

5 0 0 0

T a r g e t :

2 0 0 n g / m L

Dose (mg) 100 150 250 400 600 800 600

Schedule TID TID TID TID TID TID BID

N 3 4 10 3 7 3 8

AUC (0-8h) (ng*hr/mL)

Average 1980 7167 3852 3959 6125 5575 6201

Variation (%CV)

33% 98% 101% 46% 70% 72% 34%

Cmax (ng/mL)

Average 432 1467 778 846 1366 1019 1291

Variation (%CV)

46% 87% 89% 38% 68% 35% 23%

Cmin (ng/mL)

Average 134 585 241 306 400 457 366

Variation (%CV)

32% 108% 105% 80% 98% 92% 35%

A U C (0 -8 h )

[C 1 D 1 5 ]

CB

-83

9 E

xp

os

ure

(n

g*

h/

mL

)

0

3 0 0 0

6 0 0 0

9 0 0 0

1 2 0 0 0

1 5 0 0 0

C m a x

[C 1 D 1 5 ]

CB

-83

9 (

ng

/m

L)

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

3 0 0 0

C m in

[C 1 D 1 5 ]

CB

-83

9 (

ng

/m

L)

4 0 0

6 0 0

8 0 0

1 0 0 0

1 2 0 0

1 4 0 0

2 0 0

6 0 0 m g T ID (N = 7 ) 6 0 0 m g B ID (N = 8 )

• Glutamine is required for the growth and survival of many tumor types1,2

• Glutaminase (GLS) controls the first step in glutamine utilization in cancer cells (Figure 1), leading to the formation of glutamate, which is used to:

– generate TCA cycle intermediates

– synthesize glutathione

– generate NADPH and maintain redox balance

– synthesize anabolic building blocks, including nucleotides and fatty acids

• CB-839 is a highly selective, reversible, allosteric inhibitor of GLS3

• CB-839 has broad preclinical in vitro and in vivo anti-tumor activity in solid and hematologic malignancies3,4

• Herein we describe the initial results from CX-839-001, a first-in-man Phase 1 study of CB-839 in advanced solid tumors (ClinicalTrials.gov Identifier: NCT02071862)

Primary

• To evaluate the safety and tolerability and determine the single-agent Recommended Phase 2 Dose (RP2D) of CB-839 for locally-advanced, metastatic and/or refractory solid tumors

Secondary

• To determine the pharmacokinetics (PK) of CB-839 as a single agent

• To evaluate anti-tumor activity of the single-agent in patients with solid tumors

Exploratory

• To evaluate the pharmacodynamics (PDn) of CB-839

METHODS Study Design

• Phase 1 multicenter, open-label, dose-escalation of CB-839 as a single-agent and in combination* with standard therapies in advanced solid tumors

– Standard 3+3 dose escalation design with 3 week cycle length

– Decision to dose escalate based on review of safety data, including dose limiting toxicities (DLTs), as well as other clinical, laboratory and pharmacokinetic data following one cycle of treatment

– Pharmacodynamic assessments include measurements of GLS inhibition in peripheral blood platelets and tumors

– Disease assessments are performed every three (3) cycles

• Expansion Cohorts for monotherapy in defined patient populations (see Figure 2)

– Objectives include confirmation of safety profile and evaluation of clinical efficacy in defined patient populations

– Simon two-stage design utilized for each expansion cohort

• Minimum enrollment of 11 patients per cohort

• Further expansion of any cohort that has one confirmed response * Only single-agent data presented in this poster

Figure 2: CX-839-001 Study Design

Study Treatment

• Oral CB-839 administered in 21-day cycles using one of two regimens:

– TID: Three times daily (upon waking, at ~3 pm and at bedtime)

– BID fed: Two times daily with meals

Safety, PK, PDn and Efficacy Assessments

• Laboratory assessments performed weekly for first 1-3 cycles

• PK and PDn

– PK: Blood draws for measurement of CB-839 on Cycle 1/Day 1 (C1D1), C1D15 and D1 of each subsequent cycle

– Platelet PDn: Blood draws for collection of platelets on C1D1 predose and at 4 hr

– Tumor PDn: Tumor biopsies on C2D1 in a subset of dose escalation patients

• Computed tomography (CT) scans performed at baseline and on D1 of every third cycle (starting on C4D1)

Table 1: Baseline Characteristics

• As of April 15, 2015, 59 patients* had been treated and had data in the clinical database

• Summaries of patient enrollment and baseline characteristics are provided in Tables 1 and 2, respectively

• An MTD has not been established

– 1 DLT was observed in dose escalation

• 600 mg po BID fed was selected for expansion cohorts based on:

– PK consistently above target threshold

– Clear PK/PDn relationship in platelets

– Evidence of pharmacodynamic activity in tumors

• 13.6% (8/59) of patients experienced a G3 or Gr 4 Adverse Event (AE) suspected to be related to CB-839

• 3.4% (2/59) of patients discontinued due to an AE (one each at 100 and 250 mg TID)

• One DLT occurred on study

– Drug-related G3 creatinine elevation occurred in one patient at the 250 mg TID dose level

– Patient had Type 2 diabetes with retinopathy and nephropathy with G3 proteinuria at baseline

• Reversible, asymptomatic elevations in liver function tests (LFTs) have been the primary toxicity signal to date

– G3 ALT elevations have occurred in 6/59 patients

• G3 ALT elevations have been rapidly reversible (generally return to <G1 within 1 week)

• The frequency of ALT elevations is reduced when CB-839 is dosed BID with food (Table 5)

Table 3: Adverse Events Occurring in ≥4 Patients Table 4: Grade 3 or Higher Adverse

Events Occurring in ≥2 Patients

CB-839 Dose (mg) and Schedule 100-250 TID 400-800 TID 600 & 800 BID

Total Patients 17 15* 27

ALT Increase (Number of Patients)

Gr 1 0 0 0

Gr 2 1^ 1 1

Gr 3 0 5 1

Bilirubin Increase (Number of Patients)

Gr 1 0 0 0

Gr 2 1^ 0 0

Gr 3 0 1 0

Days on Study: Median (Range) 44 (11 - 105) 56 (14 - 286) 46 (12 - 112)

Table 5: Reduced Frequency of LFT Elevations in BID cohorts

* One subject starting at 250 mg TID and dose escalated to 600 mg TID is included in the ≥400 mg TID group

^ Extensive liver involvement (metastasis); AEs considered unrelated to drug

2015 ASCO Annual Meeting, May 29-June 2, Chicago

• CB-839 has acceptable PK properties in cancer patients

– Half-life approximately 4 hr

– Exposure generally increases with dose

– Moderate accumulation observed at steady state

• PK parameters were highly variable with the TID regimen

– AUC, Cmax and Cmin increased with dose

– All PK parameters were highly variable with the TID regimen

– Cmin dropped below target concentration of 200 ng/mL in 6/13 (46%) patients on ≥400 mg TID regimens

• PK parameters are much less variable with the BID fed regimen

– AUC, Cmax and Cmin all have lower variability (%CV) with BID fed regimen than the TID regimen (Figure 3 and Table 6)

– Cmin remained above the target concentration of 200 ng/mL for all patients that received 600 mg BID fed in the dose escalation

Figure 3: Target CB-839 Concentrations are Maintained and PK Variability is Reduced with BID Fed Dosing Regimen

Table 6: More Consistent Exposure with BID Fed Dosing Regimen

600 mg TID dose escalation cohort

600 mg BID dose escalation cohort

Target Expression

• GLS expression can be detected by immunohistochemistry (IHC) in clinical tumor samples (archival tissue or on-study biopsy) (Figure 4A).

• GLS expression in the tumor is moderate to strong in most samples tested (Figure 4B).

Pharmacodynamics • Strong inhibition of GLS was demonstrated in platelets (Figure 5A).

– GLS inhibition was measured in platelets 4 hr after dosing on C1D1. – A clear exposure-response relationship is evident in platelets. – Cmin concentrations with 600 mg BID fed regimen maintain exposures that should provide ≥90% inhibition of GLS (≥ 200 ng/mL).

• Robust GLS inhibition also demonstrated in tumor biopsies on C2D1 (Figure 5B). – GLS assay allows percent inhibition to be assayed from a single biopsy. – The magnitude of inhibition roughly correlated with CB-839 exposure on C1D15.

Tumor GIST NSCLC colon meso RCC

662^ 1384 1945 2352 11530

C1D15 AUC (0-8h) (ng*hr/mL)

^prior total gastrectomy

Figure 4: High Levels of GLS Expression in On-study or Archival Tumor Samples

Figure 5: Platelet (A) and Tumor (B) Pharmacodynamics

A B

A B

*2 patients with SD by CT scans but prior to C4D1

• This Phase 1 study has enrolled patients with a variety of tumor types across a range of doses on two different dosing regimens [TID (n=32) and BID fed (n=27)].

• Clinical data are preliminary as most patients have received a suboptimal dose/regimen of CB-839.

– 17 of 27 patients enrolled on the BID fed regimen were evaluable for response.

TID Dose Escalation: 100 – 800 mg

BID fed Dose Escalation and Expansion: 600 and 800 mg

Total subjects: 32 Total subjects: 27 (23 at 600 mg, 4 at 800 mg)

Dose level # Tumor types (Expansion cohort) #

100 mg 3 TNBC (A) 8

150 mg 4 NSCLC (B) 2

250 mg 11 RCC (C) 4

400 mg 4 Mesothelioma (D) 2

600 mg 7 FH-deficient (E) 2

800 mg 3 SDH-deficient GIST (F) 1

Tumor types: TNBC (11), RCC (4), NSCLC (4), Mesothelioma (3), TCA

cycle mutations* (2), Other (8)

SDH-deficient non-GIST (G) 1

IDH mutant (non-glioma) (H) 7

Table 2: Enrollment Summary

* IDH 1 or 2 mutant, FH-deficient, or SDH-deficient solid tumors

Table 7: Best Overall Response TID

(N=32) BID fed (N=27)

RECIST response evaluable (N) 31 17 Stable Disease 6 (19%) 7 (41%)

Progressive Disease (radiological) 19 7

Death or symptomatic deterioration 6* 3

Not evaluable (N) 1 10 On study, prior to tumor assessment 0 9

Discontinued before tumor assessment 1 1

• Overall, 13 of 48 response-evaluable patients have had Stable Disease as their best overall radiologic response (Table 7 and Figure 6).

– 6 of 31 (19%) on the TID schedule and 7 of 17 (41%) on the BID fed schedule.

– Two TNBC patients and one RCC patient had Stable Disease for >8 cycles; all three remain on study.

– One TNBC patient demonstrated a 23% reduction in target lesions.

• Clinical efficacy of monotherapy CB-839 will be best assessed in the tumor-specific Expansion Cohorts (Figure 2), which are currently enrolling.

Figure 1: Altered Glucose and Glutamine Metabolism of Cancer Cells GLUCOSE

Pyruvate

α-KG

Glutamate

GLUTAMINE

Lactate

TCA Cycle

Mitochondrion

Normal Cell

Cancer Cell

Biosynthetic intermediates

Glutathione

Glutaminase

GLUCOSE

Pyruvate

α-KG

Glutamate

GLUTAMINE

Lactate

TCA Cycle

Glutaminase

Mitochondrion

CB-839

* Objectives regarding the evaluation of CB-839 in combination with other therapies have been excluded since combinations are not addressed in this poster

Key Inclusion Criteria • Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-1 • Life Expectancy of at least 3 months • Adequate hepatic, renal and hematological function • Measurable Disease per RECISTv1.1 Key Exclusion Criteria • Prior therapies within the specified time frames (14-21 days, depending on the agent) • Any conditions that may preclude adequate absorption of study drug • Untreated or unstable brain metastases

* As of May 15, 2015, a total of 76 patients (32 on the TID dose schedule and 44 on the BID monotherapy dose schedule) have been enrolled

References

T im e o n S tu d y (D a y s , C y c le s )

0 2 1 4 2 6 3 8 4 1 0 5 1 2 6 1 4 7 1 6 8 1 8 9 2 1 0 2 3 1 2 5 2 2 7 3 2 9 4

6 0 06 0 0

6 0 08 0 0

6 0 06 0 06 0 06 0 0

6 0 06 0 06 0 06 0 06 0 06 0 06 0 06 0 06 0 06 0 06 0 0

8 0 06 0 06 0 06 0 08 0 06 0 06 0 08 0 0

1 0 01 5 02 5 01 5 02 5 01 0 02 5 08 0 0

4 0 02 5 01 0 0

6 0 02 5 06 0 04 0 0

6 0 02 5 02 5 06 0 0

2 5 06 0 0

4 0 02 5 06 0 01 5 06 0 01 5 04 0 02 5 08 0 08 0 02 5 0

****

***

**

****

**

*

*

***

S t a r t in g

D o s e ( m g )

TID

sc

he

du

leB

ID s

ch

ed

ule

O th e r

M e s o th e lio m a

N S C L C

R C C

T C A

T N B C

S D ( -2 3 % )S D ( 6 % )

S D ( -6 % )

S D ( 1 1 % )

S D ( 1 8 % )

S D ( 1 % )

S D ( -4 % )S D ( 1 3 % )

N S C L C

R C C

T C A

T N B C

M e s o th e lio m a S D ( 3 % )

T u m o r

ty p e

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4

S D : R E C IS T s t a b le d is e a s e

( b e s t % c h a n g e in t a r g e t le s io n s )

* : R a d io g r a p h ic p r o g r e s s io n

: O n s t u d y : O f f s t u d y

: S c h e d u le d t u m o r a s s e s s m e n t sS D ( 1 1 % )

**

*

*

S D ( 9 % )S D ( 1 9 % )

ID H 1F H

ID H 1F H

ID H 1ID H 1ID H 1

ID H 1ID H 1S D H

S D H

ID H 1S D H

S D ( -1 % )

**

*

Figure 6: Treatment Duration

• CB-839 is well tolerated in advanced cancer patients

– <15% of patients experienced drug-related G3 or Gr4 AEs.

– One DLT at 250 mg TID, no MTD established.

– Asymptomatic, reversible elevations in LFTs are primary safety signal.

• Robust inhibition of GLS in platelets and tumors

– Clear exposure-response relationship predicts continuous GLS inhibition with BID regimen.

– High GLS expression detected in the majority of tumor samples from patients enrolled on study

• BID dosing with meals provides optimal PK and safety profile

– Reduced PK variability maintains all patients above PK threshold at Cmin.

– Only 1 of 27 patients experienced G3 LFT elevation.

• Evaluation of clinical efficacy as monotherapy and in combination is ongoing

– Stable Disease observed in 7 of 17 (41%) patients on BID schedule (study ongoing).

– Stable Disease observed in 6 of 31 (19%) patients across a range of doses on the TID schedule (>8 cycles in 3 patients).

– Multiple tumor-specific monotherapy Expansion Cohorts are currently being enrolled (Figure 2).

– Rational combinations based on preclinical synergy observed with TKIs and mTOR inhibitors that block glucose utilization (presented at AACR 2015) are also ongoing and/or planned (Figure 2).

1. Wise and Thompson (2010) Trends Biochem Sci 35:427-433 2. DeBerardinis and Cheng (2010) Oncogene 29:313-324

3. Gross et al. (2014) Mol Cancer Ther 13:890-901 4. Parlati et al. (2013) Blood 122:4226

T u m o r P D n (C 2 D 1 )

Glu

tam

ina

se

Ac

tiv

ity

(n

mo

l/m

in/

mg

pro

tein

)

5

1 0

1 5

2 0

2 5

3 0

3 5

-8 6 %

-7 5 %

-8 4 %-5 7 %

U n in h ib ite d

In h ib ite d

-9 6 %