CR6086/AGEN2034 Combination in Stage IV pMMR - MSS CRC, and Other Metastatic GI Cancers

This Phase Ib/IIa study comprises a Main Study and a Study Extension.

The Main Study has been designed according to a 3+3 dose escalation/dose expansion design in MSS mCRC patients. A dose expansion will be conducted at both the intermediate and high dose levels, if tolerated, with the purpose of generating additional and more robust safety and preliminary efficacy data.

The Study Extension explores in other metastatic GI cancers the CR6086 recommended dose for expansion (RDE) obtained in the Main Study.

No control arm was included, as the target patient population of this study consists of patients in whom the overall survival is less than 6 months and treatment options are very limited and often poorly tolerated, making unlikely that the study results can be significantly biased.

In this study, the combination of the PGE2 inhibition (through the EP4 receptor antagonist CR6086) with the immune checkpoint blockade (through the anti-PD-1 AGEN2034) is being evaluated in pMMR-MSS mCRC and other metastatic GI cancers. CR6086 (vorbipiprant) is a potent and selective, orally bioavailable, targeted immunomodulator small molecule acting as an EP4 receptor antagonist. AGEN2034 (balstilimab) is a novel, fully human monoclonal immunoglobulin G4 antibody, designed to block programmed cell death 1 (PD-1) from interacting with its ligands (PD-L) PD-L1 and PD-L2, currently being developed for the treatment of advanced malignancies. EP4 receptor antagonists turn the status of the tumor microenvironment into a favourable one, i.e. immune-responsive, representing thus a rational therapeutic approach in combination with ICIs in primarily refractory cancers.

Eligibility Criteria:
Diagnosis and Main Criteria for Inclusion/Exclusion:

Inclusion Criteria

Main Study - patients with MSS mCRC

1. Signed and dated informed consent obtained before undergoing any study-specific procedure
2. Male or female aged ≥18 years
3. Histologically confirmed diagnosis of adenocarcinoma originating from the colon or rectum, with known RAS and BRAF mutational status as assessed per standard practice
4. Stage IV (according to the American Joint Committee on Cancer definition)
5. Presence of measurable disease per RECIST v1.1 (based on imaging within 28 days from first study drug administration). Patients must have at least one "target lesion" to be used to assess response, as defined by RECIST v1.1 Note: Subjects with lesions in a previously irradiated field as the sole site of measurable disease will be permitted to enroll provided the lesion(s) have demonstrated clear progression and can be measured accurately
6. Disease progression after at least two standard treatment lines for mCRC, including fluoropyrimidines, oxaliplatin and irinotecan and, if RAS and BRAF wild-type, cetuximab or panitumumab, or, intolerance or refusal of chemotherapy regimens for mCRC Note: Previous oxaliplatin-based adjuvant treatment is considered as a treatment line if disease relapse occurred within 6 months from its completion
7. Naïve to any antibody/drug targeting T-cell co-regulatory proteins (immune checkpoints inhibitors) and EP4 receptor antagonists
8. Availability of adequate and sufficient baseline tumour tissue sample (archival or newly obtained biopsy) Note: an adequate and sufficient sample is defined as formalin fixed paraffin embedded tumour tissue sample, preferably from the most recent biopsy of a tumour lesion, collected either at the time of or after the diagnosis of metastatic disease has been made AND from a site not previously irradiated. If no tumour tissue is available, a fresh tissue from needle or excisional biopsy or from resection is required
9. pMMR/MSS defined as CRC with all 4 MMR proteins intact and/or with instability at ≤1/5 locus (or 30% of loci if larger panel of markers are assayed)
10. Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1
11. Anticipated life expectancy ≥ 3 months
12. Adequate hematologic and end organ function, defined by the following laboratory results, obtained within 7 days before first dose of study drug treatment:

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1. Hemoglobin ≥ 10 g/dL, platelet count ≥100,000/mm3, ANC ≥1500/mm3
2. Creatinine clearance ≥ 50 mL/min
3. Amylase and lipase ≤ 1.5 × ULN
4. Serum bilirubin ≤ 1.5× ULN
5. AST, ALT, and ALP ≤ 2.5 × ULN with the following exceptions:

   - Patients with documented liver metastases: AST and/or ALT ≤ 5 × ULN
6. INR and PTT ≤ 1.5 × ULN.

   * Patients who are on therapeutic doses of anti-coagulants should be on a stable dose for 28 days, with stable INR and PTT values.
7. Serum albumin ≥ 3.0 g/dL

13. Ability e and willingness to participate and comply with the requirements of the entire study

Study Extension - other metastatic GI cancers

Cohorts A and B - Gastric cancer

1. Signed and dated informed consent obtained before undergoing any study-specific procedure
2. Male or female aged ≥18 years
3. Body weight \> 40kg
4. Histologically proven advanced-stage unresectable adenocarcinoma of the stomach or the GEJ
5. Stage IV (according to the American Joint Committee on Cancer definition)
6. Available CPS or available tissue to perform CPS assessment: Cohort A: CPS≥5 - Cohort B CPS\<5
7. Failure to at least one prior line of chemotherapy for metastatic disease, given with or without trastuzumab, with or without anti-PD-1. In alternative, early disease recurrence after surgery with neo-adjuvant and/or adjuvant chemotherapy (within 6 months of the last administration of chemotherapy) or progression during neo-adjuvant and/or adjuvant chemotherapy (containing fluoropyrimidine and a platinum derivative).
8. Presence of measurable disease per RECIST v1.1 (based on imaging within 28 days from first study drug administration). Patients must have at least one "target lesion" to be used to assess response, as defined by RECIST v1.1 Note: Subjects with lesions in a previously irradiated field as the sole site of measurable disease will be permitted to enroll provided the lesion(s) have demonstrated clear progression and can be measured accurately
9. Naïve to EP4 receptor antagonists
10. Availability of adequate and sufficient baseline tumour tissue sample (archival or newly obtained biopsy) Note: an adequate and sufficient sample is defined as formalin fixed paraffin embedded tumour tissue sample, preferably from the most recent biopsy of a tumour lesion, collected either at the time of or after the diagnosis of metastatic disease has been made AND from a site not previously irradiated. If no tumour tissue is available, a fresh tissue from needle or excisional biopsy or from resection is required
11. Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1
12. Anticipated life expectancy ≥ 3 months
13. Adequate hematologic and end organ function, defined by the following laboratory results, obtained within 7 days before first dose of study drug treatment:

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1. Hemoglobin ≥ 10 g/dL, platelet count ≥100,000/mm3, ANC ≥1500/mm3
2. Creatinine clearance ≥ 50 mL/min
3. Amylase and lipase ≤ 1.5 × ULN
4. Serum bilirubin ≤ 1.5× ULN
5. AST, ALT, and ALP ≤ 2.5 × ULN with the following exceptions:

   - Patients with documented liver metastases: AST and/or ALT ≤ 5 × ULN
6. INR and PTT ≤ 1.5 × ULN.

   - Patients who are on therapeutic doses of anti-coagulants should be on a stable dose for 28 days, with stable INR and PTT values.
7. Serum albumin ≥ 3.0 g/dL

14. Ability e and willingness to participate and comply with the requirements of the entire study

Cohort C - GI cancers other than CRC and GC

1. Signed and dated informed consent obtained before undergoing any study-specific procedure
2. Male or female aged ≥18 years
3. Body weight \> 40kg
4. Histologically proven advanced-stage unresectable GI cancer other than CRC and GC
5. Stage IV (according to the American Joint Committee on Cancer definition)
6. Failure to at least one prior line of chemotherapy for metastatic disease, given with or without trastuzumab, with or without anti-PD-1. In alternative, early disease recurrence after surgery with neo-adjuvant and/or adjuvant chemotherapy (within 6 months of the last administration of chemotherapy) or progression during neo-adjuvant and/or adjuvant chemotherapy (containing fluoropyrimidine and a platinum derivative).
7. Presence of measurable disease per RECIST v1.1 (based on imaging within 28 days from first study drug administration). Patients must have at least one "target lesion" to be used to assess response, as defined by RECIST v1.1 Note: Subjects with lesions in a previously irradiated field as the sole site of measurable disease will be permitted to enroll provided the lesion(s) have demonstrated clear progression and can be measured accurately
8. Naïve to EP4 receptor antagonists
9. Availability of adequate and sufficient baseline tumour tissue sample (archival or newly obtained biopsy) Note: an adequate and sufficient sample is defined as formalin fixed paraffin embedded tumour tissue sample, preferably from the most recent biopsy of a tumour lesion, collected either at the time of or after the diagnosis of metastatic disease has been made AND from a site not previously irradiated. If no tumour tissue is available, a fresh tissue from needle or excisional biopsy or from resection is required
10. Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1
11. Anticipated life expectancy ≥ 3 months
12. Adequate hematologic and end organ function, defined by the following laboratory results, obtained within 7 days before first dose of study drug treatment:

1. Hemoglobin ≥ 10 g/dL, platelet count ≥100,000/mm3, ANC ≥1500/mm3

2. Creatinine clearance ≥ 50 mL/min

3. Amylase and lipase ≤ 1.5 × ULN

4. Serum bilirubin ≤ 1.5× ULN

5. AST, ALT, and ALP ≤ 2.5 × ULN with the following exceptions:

* Patients with documented liver metastases: AST and/or ALT ≤ 5 × ULN

  6. INR and PTT ≤ 1.5 × ULN.
* Patients who are on therapeutic doses of anti-coagulants should be on a stable dose for 28 days, with stable INR and PTT values.

  7. Serum albumin ≥ 3.0 g/dL

  13. Ability e and willingness to participate and comply with the requirements of the entire study

Exclusion Criteria

Exclusion criteria 1-37 are applicable to all patients to be enrolled in the study, in both Main Study and Study Extension.

Criteria 38-40 are applicable to patients to be enrolled in Study Extension only.

Medical Condition/History:

Cancer and anti-cancer therapy:

1. Additional malignancy that progressed or required active treatment within the last 2 years. Exceptions include basal cell carcinoma of the skin, superficial bladder cancer, squamous cell carcinoma of the skin that has undergone potentially curative therapy with no evidence of recurrence for 5 years since initiation of that curative therapy, or carcinoma in situ (breast carcinoma, cervical cancer)
2. Active brain tumour, metastasis or leptomeningeal metastases. Patients with brain metastases are eligible if these have been treated and there is no magnetic resonance imaging (MRI except where contraindicated in which CT scan is acceptable) evidence of progression for at least 8 weeks after treatment is complete and within 28 days prior to first dose of study drug administration. Cases should be discussed with the Sponsor. There must also be no requirement for immunosuppressive doses of systemic corticosteroids (\>10mg/day prednisone equivalents) for at least 2 weeks prior to study drug administration
3. Major surgery within 28 days before Cycle 1 Day 1 or anticipation of needing such procedure during the trial
4. Treatment with any systemic or localized anti-cancer therapy, including chemotherapy, biological therapy, radiotherapy, or hormonal therapy within 28 days before initiation of Cycle 1 Day 1 or expected to required such a treatment during the trial
5. Persistent toxicity related to prior therapy, Grade \>1 according to NCI CTCAE Version 5.0 Note 1: Patients must have recovered from all AEs due to previous therapies, to CTCAE ≤Grade 1 or to baseline condition. Participants with CTCAE ≤Grade 2 neuropathy or alopecia may be eligible Note 2: If patients received major surgery, they must have recovered adequately from the toxicity and/or complications from the intervention prior to starting study treatment Note 3: Patients must have recovered from all radiation-related toxicities, not require corticosteroids, and not have had radiation pneumonitis. A 1-week washout is permitted for palliative radiation (≤2 weeks of radiotherapy) to non-CNS disease
6. Uncontrolled tumour-related pain. Patients requiring narcotic pain medication must be on a stable regimen at study entry
7. Uncontrolled pleural effusion, pericardial effusion or ascites requiring repeated drainage more than once every 28 days. Indwelling drainage catheters are allowed

   Cardiovascular:
8. Unstable angina
9. Myocardial infarction within 6 months before enrolment
10. History of stroke, reversible ischemic neurological defect, or transient ischemic attack within 6 months before enrolment
11. Uncontrolled ventricular arrhythmia
12. Congestive heart failure (New York Hearth Association class ≥II)
13. Poorly controlled hypertension

    Infections:
14. Confirmed infection with SARS-CoV-2 as documented by molecular testing at nasopharyngeal swab
15. HIV infection
16. Active tuberculosis
17. Acute or chronic viral hepatitis B or C infection
18. Any severe infection within 14 days before Cycle 1 Day 1

    General Medical History:
19. Active autoimmune disease in the past 2 years
20. History of allogenic tissue/solid organ transplant (including allogeneic bone marrow transplantation)
21. History of immunodeficiency
22. History or presence of interstitial lung disease or history of pneumonitis that has required oral or iv corticosteroids.
23. History of gastric/duodenal ulcers, colitis and/or gastrointestinal bleeding
24. History of severe gastrointestinal adverse reactions
25. History of hypersensitivity reactions to fully human monoclonal antibodies, Grade ≥ 3 according to NCI CTCAE Version 5.0
26. History of anaphylaxis, or uncontrolled asthma
27. Allergy/hypersensitivity/intolerance to any component of CR6086 or AGEN2034
28. Any other clinically relevant disease and condition, including psychiatric or substance abuse disorders, that, in the opinion of the Investigator, may jeopardize efficacy or safety assessments, confound the result of the trial or may compromise the patient's safety during trial participation

    Concomitant Treatments
29. Administration of a live, attenuated vaccine within 28 days before Cycle 1 D1
30. Systemic steroid therapy or any other form of immunosuppressive therapy within 7 days before screening Note: Corticosteroid use for management of immune-related adverse events, and/or as a premedication for iv contrast allergies/reactions is allowed.

    Daily corticosteroid replacement therapy is allowed: permitted therapy are daily prednisone at doses of 5 to 7.5 mg or equivalent hydrocortisone dose, and steroid therapy administered by topical, intraocular, intranasal, and/or inhalation routes
31. Regular use of any illicit drugs or recent history (within the last year) of substance abuse (including alcohol)

Others:

32. Participation in a study with an investigational drug or medical device within 28 days before Cycle 1 Day 1 Note: Participants who have entered the follow-up phase of another investigational study may participate as long as at least 4 weeks have elapsed since the last dose of the investigational agent

33. Inability to swallow medications

34. Malabsorption conditions

35. For women of childbearing potential:

* Pregnancy (i.e. positive pregnancy test at Screening) or breastfeeding
* Failure to agree to practice a highly effective method of contraception (see Section 12.4), from enrolment up to at least 120 days after the last IMP intake
* expecting to conceive within the projected duration of the trial, starting with the screening visit through 120 days after the last dose of study treatment

  36. For sexually active men with a female partner of childbearing potential: failure to agree to use condom (see Section 12.4) and refrain from donating sperm from enrolment up to at least 120 days after the last IMP intake.

  37. Patients who are legally incapacitated or has limited legal capacity

Criteria for Study Extension only

38. Presence of portal hypertension

39. Presence of oesophageal varices

40. Presence of gastric infiltration, severe gastritis, duodenal or gastric ulcer, or any other condition that may lead to bleeding or perforation, as assessed by an EGDS performed during screening period.

Criteria referring to Cycle 1 D1, should be reassessed on study D1, before starting the study treatment.