Expanded Phase 1 study of intratumoral Ad-RTS-hIL-12 plus oral veledimex: Tolerability and survival in recurrent glioblastoma. E. Antonio Chiocca1, John Yu2, Surasak Phuphanich2, Rimas Vincas Lukas3, Priya Kumthekar4, Yijun Yang5, Qiang (John) Zhou5, Jill Y. Buck5, Alicia Deary5, Hongliang Cai5, John A. Barrett5, Laurence JN Cooper5, Francois M. Lebel5

1Brigham and Women's Hospital, Boston, MA;

2Cedars-Sinai Medical Center, Los Angeles, CA;

3University of Chicago, Chicago, IL;

4Northwestern Memorial Hospital, Chicago, IL;

5ZIOPHARM Oncology, Inc, Boston, MA

Background: Glioblastoma (GBM) is an aggressive brain tumor affecting ~74,000 people worldwide an-

nually. Recurrent GBM patients have a median OS (mOS) of 6-7 months. OS in patients who have failed

temozolomide, bevacizumab or equivalent salvage chemotherapy, is ~3-5 months. New therapies are ur-

gently needed. Ad-RTS-hIL-12 (Ad) is a novel gene therapy expressing IL-12 under the control of an oral

activator ligand, veledimex (V), through the RheoSwitch Therapeutic System®. Intratumoral administration

of Ad results in targeted tumor cytotoxicity and induction of systemic T cell memory. Ad + V is a treat-

ment strategy to extend the IL-12 therapeutic window. Methods: In a multicenter Phase I dose escalation

trial and expansion cohort, subjects with recurrent or progressive Grade III or IV glioma undergoing resec-

tion were injected intratumorally with Ad 2 x 1011 viral particles (vp) and daily oral V for 15 doses, begin-

ning prior to surgery. The primary endpoint is safety and tolerability of Ad + V; secondary endpoints in-

clude OS. Results: 25 subjects were dosed in 3 dose escalation cohorts: 20 mg (n = 7), 30 mg (n = 4), and

40 mg (n = 6) and an expansion cohort of 20 mg (n = 8). Results show V crossed the blood brain-barrier

with 35±5% of plasma levels detected in the brain tumor. The 20 mg dose (n = 15) had better drug com-

pliance (86%) than the 30 mg (63%) or 40 mg (52%) cohorts and the 20 mg cohort shows better survival

(mOS 12.7 months) compared to other cohorts. The frequency of related ≥Grade (G)3 AEs in the 20 mg

cohort was significantly lower: 20% in 20mg, 50% in 30mg and 40 mg. In the 20 mg cohort, the most fre-

quent AEs were transient mild flulike symptoms seen in 12/15, G3 cytokine release syndrome in 2/15, G3

elevated ALT/AST in 1/15 and G3 lymphopenia in 3/15. All AEs reversed promptly upon discontinuing V.

Conclusions: Overall, Ad + 20 mg V is well tolerated; toxicities were predictable and reversible upon dis-

continuing V. There is a correlation between V dose, BBB penetration and drug related AEs. The tolerabil-

ity and encouraging survival observed to date warrant further investigation in a pivotal trial. A stereotac-

tic arm and a pediatric trial in diffuse intrinsic pontine glioma patients are planned.

RheoSwitch Therapeutic System® (RTS®) Gene Switch is a 3-Component Transcriptional Regulator

1. The Switch Components: The RTS® gene program includes 2 receptor protein fusions: VP16-RXR (co-activation partner, CAP) and

Gal4-EcR (ligand-inducible transcription factor, LTF). In the absence of ligand, the LTF binds to the inducible promoter and does not

form a stable interaction with the CAP.

2. The Inducible Promoter: A customizable promoter to which basal transcription proteins are recruited and the target gene is

transcribed.

3. The Activator Ligand (veledimex): An ecdysone analog, diacylhydrazine-based small molecule, functions as an activator. In the

presence of the ligand, a conformational change in the LTF leads to a stable, high-affinity interaction with the CAP.

Ad 2X1011 vp

20 mg Cohort

(N=15) 30 mg Cohort

(N=4) 40 mg Cohort

(N=6) Total

(N=25)

Age in Years

Mean (Min, Max) 45.93 (26, 68) 59.75 (43, 74) 47.67 (36, 58) 48.56 (26, 74)

Gender Male : Female 10 : 5 2 : 2 4 : 2 16 : 9

Recurrence (n) 1st

2nd

3rd or more

4

5

6

1

2

1

2

2

2

7

9

9

Prior Lines of Treatment (mean) 2.2 3.0 2.5 2.4

Grade at Study Entry

HGG Grade III Glioblastoma

2

13

0

4

0

6

2

23

KPS at Screening

≥ 90

≥ 70 and < 90

9

6

3

1

2

4

14

11

IDH Status

WT

mutated

TBD

8

5

2

3

0

1

5

1

0

16

6

3

Total Steroid Use in mg Day 0

Median (Min, Max) 4 (0, 10) 7 (0, 14) 10 (0, 14) 8 (0, 14)

Total Steroid Use in mg Days 1-3

Median (Min, Max) 18 (0, 44) 36 (0, 44) 8 (0, 40) 18 (0, 44)

Total Steroid Use in mg Days 0-14

Median (Min, Max) 48 (0, 140) 106 (0, 136) 35.5 (10, 102) 54 (0, 140)

Veledimex Dosing Compliance 84% 63% 58% 73%

As of 24 May 2017, 25 subjects enrolled in Group 1 Dose Escalation. Follow-up is ongoing.

Subject Characteristics

Adenovirus serotype

5 NR

Overall Survival: 20 mg vs 30 & 40 mg Cohorts

Tight transcriptional control of the RTS® gene switch by veledimex regulates recombinant IL-12 protein

expression and downstream endogenous IFN- in a dose-related manner

There is a strong correlation between veledimex dose, BBB penetration, IL-12 and IFN- production

Safety

Related AEs were tolerable, predictable, and rapidly reversible upon discontinuing veledimex

Severity and frequency of CRS correlated with veledimex dose, serum IL-12 and IFN- levels, and was always reversible upon holding veledimex

Neurologic adverse events were relatively mild and transient. The were no drug-related deaths

Efficacy

Survival appears to correlate with cellular immune modulation

Median overall survival at 20 mg of veledimex is maintained at 12.5 months and continues to compare favorably to historical controls

Concurrent steroid use during first 15 days dampens the survival benefit of IL-12 driven immune activation

20 mg N=15

30 mg N=4

40 mg N=6

Total N=25

Related Adverse Events (AEs)

Related AEs 12 (80%) 4 (100%) 5 (83%) 21 (84%)

Related ≥ Grade 3 AEs 7 (47%) 3 (75%) 4 (67%) 14 (56%)

Related Serious Adverse Events (SAEs)

Cytokine release syndrome 2 (13%) 1 (25%) 2 (33%) 5 (20%)

Thrombocytopenia 2 (13%) 0 1 (17%) 3 (12%)

LFT increased, Leukopenia, Neutropenia, Py-

rexia, and Aseptic meningitis

Each term

1 (7%)

0 0 Each term

1 (4%)

Related ≥ Grade 3 AEs That Occurred in ≥ 5% of Subjects

Lymphopenia 6 ( 40%) 3 ( 75%) 3 (50%) 12 ( 48%)

AST increased 1 ( 7%) 0 2 ( 33%) 3 ( 12.%)

Cytokine release syndrome* 2 (13%) 1 (25%) 3 (50%) 6 (24%)

Headache 2 ( 13%) 0 0 2 ( 8%)

Hyponatremia 1 ( 7%) 0 1 ( 17%) 2 ( 8%)

Thrombocytopenia 2 ( 13%) 0 0 2 ( 8%)

Related ≥ Grade 3 Neurological AEs

Headache 2 (13%) 0 0 2 (8%)

Brain edema 0 1 ( 25%) 0 1 (4%)

Confusional state 0 0 1 (16.7%) 1 (4%)

Aseptic meningitis 1 (6.7%) 0 0 1 (4%)

Cytokine Release Syndrome*

20 mg N=15

30 mg N=4

40 mg N=6

Total N=25

Grade 2 4 (27%) 2 (50%) 2 (33%) 8 (32%)

Grade 3 2 (13%) 1 (25%) 3 (50%) 6 (24%)

IL-12 (pg/mL) IFN- (pg/mL)

Mean Min Max Mean Min Max

Grade 2 60.2 3.6 198.7 43.5 <8.0 194.7

Grade 3 101.7 4.7 >200.0 213.2 <8.0 370.7

Abstract

Biological properties of IL-12 “Master Regulator”

Study Design

Patients

scheduled

for SOC

resection

Patients not

scheduled for

resection

Ad 2x1011 vp

Cohort 1: 20 mg v Cohort 2: 40 mg v Cohort 3: 30 mg v

Expansion Cohort: 20 mg v

Safety

Cytokine Release Syndrome* and Cytokine Levels

RTS® Switch Responds to the Presence/Absence and Dose of Veledimex in Recurrent or Progressive GBM Patients

Tumor veledimex levels are ~40% of plasma levels

Based on the mouse model, the 20 mg dose is projected to generate 30-fold higher level of IL-12 and IFN- in the tumor

N=25

* ZIOPHARM CRS Working Definition

Peripheral Blood CD8+/FOXP3 Ratio at 14-28 Days After Viral Injections Suggests Correlation With Survival

Centrally processed

samples. N= 11

Deceased

Alive

Phase 1 Study: Updated Results

R= 0.84

GBM

Patient With Grade 3 CRS* With Rapid Reversal

0 2 4 6 8 10 12 14 16 18 20 22 24

Time in Months from Dosing

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Sur

viva

l pro

babi

lity

Censored30 & 40 mg (N=10)20 mg (N=15)

Median OS (mOS) is at 12.5 months with a mean follow up of 9.2 months (range: 1.8, 23.4) 6 of 15 subjects alive at 20 mg veledimex as of 24 May 2017

0 2 4 6 8 10 12 14 16 18 20 22 24

Time in Months from Dosing

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Su

rviv

al p

rob

ab

ilit

y

Censored>100 mg (N=4)>10 - <=100 mg (N=7)<=10 mg (N=4)

Dexamethasone Impact on Survival at 20 mg Veledimex

Dexamethsone Use Days 0-14

Alive Deceased mOS Lower bound Upper bound

≤10 mg 4 0 Not reached Not reached Not reached

11-100 mg 2 5 12.5 Not reached Not reached

≥100 mg 0 4 8.0 1.8 12.7