Updated Clinical Data from the SCCHN Expansion Cohort of an Ongoing Ph1/1b Study of Eganelisib (IPI-549) in Combination with Nivolumab

Ezra E. W. Cohen, MD1, Michael Postow, MD2, Ryan Sullivan, MD3, David S. Hong, MD4, Heather Yeckes-Rodin, MD5, Jerry McCarter, RN, BSN 6, Nora Zizlsperger, PhD6, Jeffery Kutok, MD, PhD7, Brenda O'Connell, PhD6, Kara Page6, Jennifer Roberts6, Halle Zhang, PhD6, Bartosz Chmielowski, MD, PhD8

  1. University of California San Diego, 2 Memorial Sloan Kettering Cancer Center, 3 Massachusetts General Hospital,
  1. MD Anderson Cancer Center, 5 Hematology Oncology Associates of Treasure Coast, 6 Infinity Pharmaceuticals,
  1. Epizyme, 8 University of California, Los Angeles

Background

Significant unmet need for head and neck cancer patients (SCCHN)

Current checkpoint inhibitors are only active in ~16% of patients and there are limited treatment options for those that don't respond*

Eganelisib (IPI 549) is a selective PI3Kγ inhibitor that reprograms pro-tumor macrophages to relieve immune suppression and activate anti-tumor T cells

The activity of T cells by eganelisib can be maintained, despite IFN-γ mediated upregulation of PDL1, with checkpoint inhibitors providing synergistic anti-tumor effects

We are currently evaluating safety and antitumor activity of eganelisib in combination with CPIs in:

• Patients who progressed on immediate prior CPI therapy in the MARIO-1 Phase1/1b clinical trial

  • CPI naive 2L urothelial cancer patients in the MARIO-275 Phase 2 clinical trial
  • CPI naive 1L TNBC and RCC patients in the MARIO-3 Phase 2 clinical trial

*J Clin Oncol. 2016;34 (suppl; abstr 6011)

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PI3K-γ Inhibition Reprograms Macrophages: Turns Tumor

Microenvironment (TME) from Immune Suppressed to Immune Activated

Tumor

Cells

Suppressed

T cells

M2

PI3Kγ i

Eganelisib

1 Eganelisib Inhibition of PI3K-γ Reprograms Pro-tumor (M2) Macrophages/ MDSCs to Anti- Tumor (M1) Function

Anti-tumor (M1)

Macrophages/Activated Myeloid Cells

M1

2

Relieves Macrophage Suppression, Expands Activated

T cells and Generates IFN-γ Mediated Immune Response

3

Expansion of Activated

4

Anti-Tumor Activity of Expanded T

T Cells Up-Regulates PDL1 to

Cells Maintained with Addition of CPI

Blunt T Cell Response

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PI3K-γ Inhibition Reprograms Macrophages: Turns Tumor

Microenvironment (TME) from Immune Suppressed to Immune Activated

RNA Seq peripheral blood across all dose levels

IFN-γ -responsive

Fold increase

P value

C1D1-monotherapy

C2D1-monotherapy

genes

at C2D1

CD274 (PDL1)

2.4

3.5 x 10-5

CD274 (PDL1)

FCGR1B

1.8

1.5 x 10-3

FCGR1B

GBP2

1.5

5.6 x 10-4

GBP2

GBP5

2.3

1.3 x 10-4

GBP5

GBP1

2.0

1.9 x 10-4

GBP1

GBP4

1.7

9.4 x 10-4

GBP4

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MARIO-1: Eganelisib Phase 1/1b Trial in Patients with Solid Tumors

Cohort E: Combination Therapy in Patients Who Progressed on Immediate Prior CPI therapy

MARIO-1 Study Start***

Combination Dose

NSCLC

Stable Disease

PD

Melanoma

Escalation/Expansion

Eganelisib*+ Nivolumab**

SCCHN

Benefit Eganelisib

A key objective of the study is to mount an effective anti-tumor immune response in combination with CPI to generate clinical responses in patients who would not be expected to respond to checkpoint inhibitor therapy alone, including those having progressed on immediate prior CPI therapy

* 28 day cycles, continuous 40mg QD dosing

** Flat-dose 240 mg Q2WConfidential 5

*** Must have de novo or acquired resistance to immediately prior anti-PD-1/anti-PD-L1 therapy

SCCHN Patient Baseline Characteristics, Disposition and Exposure

All Patients had Previously been Refractory to or Relapsed Following Treatment with Anti-PD1/PDL1 Therapies; 85.7% had Progressed on Immediate Prior Anti-PD1/PDL1 Therapies

Characteristics

N = 21

Age median years, (range)

62.0 (29, 80)

Sex, n (%)

Male

16 (76.2)

Female

5 (23.8)

ECOG, n (%)

0

9 (42.9)

1

12 (57.1)

2

0

HPV, n (%)

Y

8 (38.1)

N

4 (19.0)

unknown

9 (42.9)

Best Response to Prior anti-

n (%)

PD1/PDL1, N = 21

PR

5 (23.8)

SD

4 (19.0)

PD

9 (42.9)

Unknown

3 (14.3)

Prior Therapies, N = 21

n (%)

Prior therapies, n (%)

1

2

(9.5)

2

3 (14.3)

3

6 (28.6)

4 or more

10

(47.6)

Anti-PD1/PDL1

21 (100)

Chemotherapy

14

(66.7)

Anti-EGFR

12

(57.1)

Anti-CTLA4

3 (14.3)

Anti-CD20

2

(9.5)

Immune stimulatory

2

(9.5)

Last Line of Therapy Prior to Study

n (%)

Anti-PD1/PDL1

18

(85.7)

Anti-CD20

2

(9.5)

Anti-EGFR

1

(4.8)

Immune stimulatory

1

(4.8)

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Eganelisib + Nivolumab was Generally Well-Tolerated and Associated with a Favorable Safety Profile

Most Common TEAEs (All Grade) in ≥15% of Patients (N=21)

Tx-Related

Immune-

Preferred Term

TEAE (All)

related Tx-

TEAE (All)

Related TEAE

(All)

Fatigue

13 (61.9)

8 (38.1)

0

Pyrexia

9 (42.9)

3 (14.3)

0

Decreased Appetite

9 (42.9)

3 (14.3)

0

Pruritus

6 (28.6)

3 (14.3)

3 (14.3)

Weight Decreased

6 (28.6)

0

0

Nausea

6 (28.6)

4 (19.0)

0

Diarrhea

6 (28.6)

0

0

Dyspnea

5 (23.8)

1 (4.8)

0

Abdominal Pain

5 (23.8)

2 (9.5)

0

Vomiting

4 (19.0)

2 (9.5)

0

Myalgia

4 (19.0)

2 (9.5)

0

Dizziness

4 (19.0)

1 (4.8)

0

Headache

4 (19.0)

0

0

Grade 3 and above TEAEs in ≥ 5% of Patients (N=21)

Preferred Term

TEAE

Tx-Related

Immune-related

TEAE

Tx-Related TEAE

(≥ Grade 3)

(≥ Grade 3)

(≥ Grade 3)

Anemia

3 (14.3)

1 (4.8)

0

Disease Progression

3 (14.3)

0

0

Sepsis

2 (9.5)

0

0

Nausea

2 (9.5)

1 (4.8)

0

Abdominal Pain

2 (9.5)

1 (4.8)

0

Data Snapshot

1 June 2020

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Eganelisib + Nivolumab Demonstrates Evidence of Clinical Activity in Patients Not Expected to Respond to CPI Monotherapy having Progressed on Immediate Prior CPI Therapy

Total

≤ 2 Prior

≥ 3 Prior

Lines

Lines

N = 21

N = 11

N = 10

Evaluable Patients*, n

20

10

10

Best Overall Response**

Partial Response (PR), n

Stable Disease (SD), n

Progressive Disease (PD), n

11

6

5

Unknown, n

0

0

0

Overall Response Rate (ORR) (PR), n

(%)

Disease Control Rate (DCR) (PR + SD), n (%)

Progression Free Survival (PFS in

Weeks), Median (95%)

Disposition and Exposure

N = 21

Patient Disposition

Continuing on Treatment, n (%)

0

Discontinued from Treatment, n (%)

21 (100)

Discontinued for Disease Progression, n (%)

15

(71.4)

Adverse Event, n (%)

2

(9.5)

Other, n (%)

2

(9.5)

Death, n (%)

1

(4.8)

Investigator Decision, n (%)

1

(4.8)

Summary of Exposure

Duration of Exposure, Median wks (min, max)

11.3 (2.6, 48.7)

# Cycles Completed, Median (min, max)

3 (1, 14)

IPI-549 dose compliance, Median

91.5%

Data Snapshot 5 October 2020

  • Response-EvaluableIs defined as having at least 1 post-baseline response assessment or discontinued the treatment phase due to disease progression (including death caused by disease progression) within 16 weeks (+ 2-week window) of the first dose of study treatment.
  • Per investigator assessment (RECIST 1.1)

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Eganelisib + Nivolumab Combination Therapy Demonstrates Clinical Benefit in Patients Not Expected to Respond to CPI Monotherapy having Progressed on Immediate Prior CPI Therapy

Size from Baseline

Best Change From Baseline in Target Lesions

140

120

100

80

60 2 or fewer prior therapies

Duration on Treatment

(2 or Fewer Lines of Therapies)

Duration on Treatment (Months)

Best % Change in Target Lesion

40

20

0 -20-40-60-80

3 or more prior therapies

PR SD PD

Based on Investigator Assessment per RECIST v1.1

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Eganelisib + Nivolumab Combination Therapy Elicits Partial Response in Patients Not Expected to Respond to CPI Monotherapy having Progressed on Immediate Prior CPI Therapy

Patient Case Studies:

Start of MARIO-1 Therapy

After Progression on Immediately Prior CPI

  • Patient A: stage IV disease at study entry
  • Refractory to pembrolizumab after 15 months (best response PR)
  • 63% tumor reduction
  • PFS: 11 months

Start of MARIO-1 therapy

After Progression on Immediately Prior CPI

  • Patient B: stage IV disease at study entry
  • Refractory to pembrolizumab after 5 months (best response SD)
  • 36% tumor reduction
  • PFS: 7 months

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Targeted Inhibition of PI3Kγ Pathway with Eganelisib has Potential to Benefit HPV+ Patients with T Cell Inflamed SCCHN Tumors

Previous Studies*

MARIO-1

Clinical Activity Associated with T Cell Inflamed SCCHN Tumors

  • In pre-clinical models, targeted inhibition of the PI3Kγ pathway in combination with anti-PD1 suppresses growth and improves survival of HPV+ SCCHN tumors
  • In HPV+ SCCHN patients, low PI3Kγ expression profile associated with survival benefit

Cancer Genome Atlas (n=97) Human HPV+ SCCHN Tumors

Log rank test p<0.001

1200

1000

(cells/mmsq)

PR

800

SD

PD

CD8+

600

Tumoral

400

200

0

Observed Benefit in HPV+ Patients

50% of HPV positive patients (n=8) achieved stable disease, as compared to 0% of HPV negative patients (n=3)

*Kaneda et al, Nature (2016) 539:437

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Combination Therapy Shows Evidence of Clinical Activity in Patients Who Would Not be Expected to Respond to Checkpoint Inhibitors Therapy Alone

Key Findings:

Treatment with

Results in Clinical Activity in

Combination Eganelisib +

SCCHN Patients with 2 or

Nivolumab is Generally

Fewer Prior Lines of Therapy,

Well-Tolerated

Including Those having

Progressed on Immediate Prior

CPI Therapy

Eganelisib has Potential to

Benefit HPV+ Patients with T cell

Inflamed SCCHN Tumors

Further Exploration in This Combination is Warranted:

Phase 2 Window of Opportunity

Study Underway

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Next Step: Phase 2 Window of Opportunity Study of IPI-549 in Patients with Locally Advanced HPV+ and HPV- Head and Neck Squamous Cell Carcinoma

Protocol 172058: UCSD Moores Cancer Center Investigator Initiated Trial

Objectives:

1

To detect a change in the PI3Kgamma regulated

Patients with Locally

Advanced, Previously

Untreated HNSCC

Amenable to Surgical

Resection

  • Baseline tumor measurement
  • Tumor biopsy (non-surgical)

gene expression signature of immune suppression

To detect change in myeloid, T cell composition

• RNA profiling

Therapy:

eganelisib 40 mg QD PO days 1-21

2

and immune activation markers by IHC as well as

TCR sequencing

3

To determine safety and tolerability of eganelisib

and change in tumor size in patients with locally

advanced HNSCC

• Multiplex IHC

• DNA isolation/TCR sequencing

3 weeks

Surgical Tissue

Specimen

Standard Therapy, Survival, Toxicity Follow-Up

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Acknowledgments

We thank the patients for

The investigators and

Study Sponsor - Infinity

participating in this clinical

their staff at the

Pharmaceuticals in collaboration

trial and their families

clinical trial sites

with Bristol Myers Squibb

For additional information please contact info@infi.com

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Infinity Pharmaceuticals Inc. published this content on 09 November 2020 and is solely responsible for the information contained therein. Distributed by Public, unedited and unaltered, on 27 November 2020 22:50:00 UTC