Phase 1a and Phase 2 Study for Safety, Preliminary Efficacy, PK and PD of ST-067

Official title

A First-In-Human Phase 1/2 Open-Label Study of Intravenous ST-067, Subcutaneous ST-067 with or Without Obinutuzumab Pre-Treatment, and ST-067 in Combination with Pembrolizumab in Subjects with Advanced Solid Malignancies

Overview

This is a multiphase, multicenter study, which includes a Phase 1a open-label, dose escalation monotherapy study of ST-067 given as an SC injection with or without obinutuzumab \[Gazyva®\] pre-treatment, by IV infusion, and in combination with pembrolizumab. A Phase 2 monotherapy arm is also planned; the exact design of the Phase 2 study elements with respect to formulation and pre-treatment will be determined after completion of the Phase 1 study portion of the trial.

Detailed description

Phase 1a is designed to determine the maximum tolerated dose (MTD) and recommended Phase 2 dose (RP2D) of ST067, administered by subcutaneous (SC) or intravenous (IV) dosing, in subjects with relapsed or refractory solid tumors, as well as to determine the MTD and recommended Phase 2 dose of ST067, administered SC with obinutuzumab (Gazyva®) as pretreatment in subjects with relapsed or refractory solid tumors using a modified toxicity probability interval (mTPI) design. There will be evaluations of ST-067 PK and PD effects.

Phase 2 will evaluate the preliminary efficacy of ST-067 administered at the RP2D to patients with the following tumor types. A Simon 2 stage design is used to calculate the sample size and early stopping rules will be employed in the event of lack of efficacy in any of the cohorts. RECIST 1.1 will be used to assess tumor response every 8-12 weeks.

* Melanoma (n=28) * Renal cell carcinoma (n=25) * Triple-negative best cancer (n=25) * Non-small cell lung cancer (n=25) * squamous cell carcinoma of the head and neck (n=28) * MSI-Hi tumors (n=25)

A Simon 2 stage design is used to calculate the sample size and early stopping rules will be employed in the event of lack of efficacy in any of the cohorts. RECIST 1.1 will be used to assess tumor response every 8-12 weeks.

Safety will be assessed for each patient throughout the study.

Interventions

• Biological ST-067
  ST-067 is an engineered variant of human interleukin-18.
• Biological Obinutuzumab 25 MG/1 ML Intravenous Solution [GAZYVA]
  Obinutuzumab is a humanized anti-CD20 monoclonal antibody of the IgG1 subclass. It recognizes a specific epitope of the CD20 molecule found on B-cells.
• Biological pembrolizumab
  Pembrolizumab is a potent humanized immunoglobulin G4 monoclonal antibody.

Primary outcome measures

• Determine the maximum tolerated dose of ST-067 in phase 1a monotherapy [Time frame: Day 29]
• Evaluate the overall safety and tolerability of ST-067 in combination with pembrolizumab [Time frame: Day 29]
• Number of Participants With Treatment-Related Adverse Events [Time frame: Day 29]
• Initial assessment of efficacy in phase 2 [Time frame: At 8 weeks]

Secondary outcome measures (2)

• PK [Time frame: Day 29]
• ADA [Time frame: Day 29]

Eligibility criteria

Inclusion criteria

• Male and female patients aged ≥18 years
• Must provide written informed consent and any authorizations required by local law
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Have histologically or cytologically confirmed diagnosis of advanced/metastatic solid tumor

For Phase 1a, the following solid tumors are allowed: Melanoma, Merkel cell, RCC, urothelial, NSCLC,TNBC, SCCHN, microsatellite instability high, high tumor mutation burden (Hi TMB) or mismatch repair deficient, gastric, cervical, endometrial, cutaneous squamous, small cell lung, esophageal, hepatocellular carcinoma and platinum resistant ovarian cancer.

• For patients who have developed disease progression through standard therapy, or
• For patients whom standard of care therapy that prolongs survival is unavailable or unsuitable (according to the investigator and after consultation with the Medical Monitor) For Phase 1 combination therapy dose escalation, the following solid tumors are allowed: Melanoma, Merkel cell, RCC, urothelial, NSCLC (with no EGFR, TRK receptor, or ALK positive mutations/fusions), TNBC, SCCHN, MSI-Hi tumors, Hi TMB or mismatch repair deficient, gastric, cervical, endometrial, cutaneous squamous, small cell lung, esophageal, and HCC

• TNBC is diagnosed in a tumor which does not express estrogen receptor or progesterone receptor, is not human epidermal growth factor receptor 2 (HER2) 3+ on IHC or is negative by fluorescence in situ hybridization (FISH).
• MSI high tumor should have mutations in 30% or more microsatellites by PCR or be negative for MSH1/2/6 or PMS-2 by IHC.
• Hi-TMB high tumor has 10 mut/Mb or greater calculated from whole genome sequencing or whole exome sequencing

For Phase 2, the following solid tumors are allowed:

Melanoma, RCC, TNBC, NSCLC, SCCHN, and MSI-Hi tumors

• Has at least 1 measurable lesion per RECIST 1.1 criteria which has not been biopsied or received prior irradiation
• Has an accessible tumor for biopsy pre- and on-treatment (mandatory).

Exclusion criteria

• History of another malignancy
• Known symptomatic brain metastases requiring >10 mg/day of prednisolone or equivalent
• Significant cardiovascular disease (MI, thrombotic events,) within 6 months prior to study treatmentSignificant ECG abnormalities (Phase 1a and 2 monotherapy only) including unstable cardiac arrhythmia requiring medication, second-degree atrioventricular block type II, third degree AV
• Any degree of respiratory compromise (from either malignant or non-malignant disease)
• Evidence of an ongoing systemic bacterial, fungal, or viral infection
• Has received a live vaccine within 30 days
• Major surgery within 4 weeks
• Prior solid organ or bone marrow progenitor cell transplantation
• Prior high dose chemotherapy requiring stem cell rescue
• History of active autoimmune disorders
• Ongoing immunosuppressive therapy, including systemic or enteric corticosteroids.
• Treatment with an approved, systemic anticancer therapy or an investigational agent within 4 weeks of Day 1
• A positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral test within 28 days prior to dosing, unless there is Investigator-confirmed clinical recovery on or before C1D1
• Subjects with adrenal insufficiency
• Subjects with any chemistry or hematology laboratory values that are ≥Grade 2

Additional exclusion criteria for Phase 1 combination therapy only:

• Presence of known active CNS metastases and/or carcinomatous meningitis. Subjects with previously treated brain metastases may participate provided they are radiologically stable, i.e., without evidence of progression for at least 4 weeks by repeat imaging, clinically stable, and without requirement of steroid treatment for at least 14 days prior to first dose of study treatment.
• Prior radiotherapy within 2 weeks of start of study treatment or history of radiation pneumonitis.
• Presence of an active documented autoimmune disease that has required systemic treatment in the past 2 years (i.e., with use of disease modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy (e.g., thyroxine or insulin) is not considered a form of systemic treatment and is allowed. Subjects may use topical and/or inhaled corticosteroids. However, subjects with adrenal insufficiency on replacement doses of steroids are not allowed.
• Prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., CTLA-4, OX40, CD137), and was discontinued from that treatment due to a Grade 3 or higher irAE
• Severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients. Subjects who have been retreated after such a reaction may be allowed after discussion with the Simcha Medical Monitor
• History of (non-infectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease
• Subjects that have received radiation therapy to the lung that is >30Gy within 6 months of the first dose of study treatment

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Non-randomized

Model

Sequential

Masking

Open label

Primary purpose

Treatment

Study locations

United States · 6 centers

• HonorHealth Research Institute — Scottsdale
• Sarah Cannon Research Institute at HealthONE — Denver
• Yale Cancer Center — New Haven
• Moffitt Cancer Center — Tampa
• Massachusetts General Hospital — Boston
• Roswell Park Cancer Institute — Buffalo

Identifiers

NCT: NCT04787042 · ST-067-001 · KEYNOTE-E64 · MK-3475-E64

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗