A Study of HMBD-002, a Monoclonal Antibody Targeting VISTA, as Monotherapy and Combined With Pembrolizumab, in Patients With Advanced Solid Tumors

This is a phase 1/2, open-label, multi-center study whose principal phase 1 stage objective is to determine the recommended phase 2 dose (RP2D) of the anti-VISTA monoclonal antibody (mAb) as a single agent and combined with the anti-PD-1 mAb pembrolizumab KEYTRUDA® in subjects with advanced solid malignancies.

In the phase 2 stage, the antitumor activity of HMBD-002 alone or combined with pembrolizumab KEYTRUDA® will be evaluated in patients with triple negative breast cancer (TNBC), non-small cell lung cancer (NSCLC) and a wide range of other malignancies known or documented to express VISTA.

Inclusion criteria

(Phase 1 and 2 Stages)

• Histologic or cytologic evidence of a malignant solid cancer (any histology) with advanced or metastatic disease and no available therapies known to confer clinical benefit.
• Tumor tissue, or paraffin block, ideally from the patient's most recent biopsy. A fresh tumor biopsy will be obtained if archival samples are not available.
• Measurable by Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1.
• At least 18 years old.
• An Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1.
• Adequate hematopoietic, kidney, and liver functions.
• A left ventricular ejection fraction (LVEF) ≥ 45%.
• Women of childbearing potential (WOCBP) must not be pregnant or breastfeeding. A WOCBP must agree to follow contraceptive guidance during the treatment period and for at least 120 days after the last dose of study treatment.
• Male subjects must agree to follow contraceptive guidance during the study period and for at least 120 days after the last dose of study treatment.
• Patient must give informed written consent for the study.

Inclusion criteria

for HMBD-002 Phase 2 Stage

Triple Negative Breast Cancer (TNBC)

• Histologic or cytologic evidence of TNBC that is advanced or metastatic.
• Will be requested to undergo a tumor biopsy before treatment and after 6 weeks of treatment.
• Must have received appropriate treatment with at least one prior regimen for TNBC and there are no available therapies known to confer clinical benefit.

Non-Small Cell Lung Cancer (Monotherapy and Combination)

• Histologic or cytologic evidence of NSCLC that is advanced or metastatic.
• Will be requested to undergo a tumor biopsy before treatment and after 6 weeks of treatment.
• Absence of an activating mutation of the EGFR or ALK.
• Must have received treatment with an approved therapy if there are other genomic aberrations for which targeted therapies are approved and available.
• Must have had disease progression on at least one approved or comparable standard therapy for NSCLC.
• Must have received appropriate prior treatment with a mAb to PD-1 or PD-L1.

Multiple Other Cancers (Combination Therapy Baskets)

• Histologic or cytologic evidence of an advanced or metastatic cancer aside from TNBC and NSCLC with no available therapies known to confer clinical benefit.
• Will be requested to undergo a tumor biopsy before treatment and after 6 weeks of treatment.
• Must have had appropriate treatment for their specific cancer and there is an absence of available therapy with a reasonable likelihood of conferring clinical benefit.

Exclusion criteria

• If the patient received prior therapy with an anti-PD-1 or anti-PD-L1 mAb or with an agent targeting stimulatory or co-inhibitory T-cell receptor and was discontinued from that treatment due to a Grade 3 or higher immune related adverse event.
• Received radiotherapy within 2 weeks of treatment.
• Received radiotherapy exceeding 30 Gray (Gy) to the lung within 6 months of the first dose of study medication.
• Received an allogeneic tissue/solid organ transplant.
• Received a live or live-attenuated vaccine within 30 days prior to the first dose of study medication.
• Received a VISTA targeting agent.
• The patient must have recovered from all AEs due to previous therapies to ≤Grade 1 or baseline.
• The patient has an active autoimmune disease that required systemic treatment in the past.
• Presence of an uncontrolled endocrine disorder.
• Presence of clinically significant cardiovascular disease.
• History of (non-infectious) pneumonitis or interstitial pulmonary disease that required steroids or has current pneumonitis or interstitial pulmonary disease.
• Presence of uncontrolled, clinically significant pulmonary disease.
• A previous a severe hypersensitivity reaction (≥ Grade 3) to pembrolizumab and/or any of its excipients.
• A diagnosis of immunodeficiency or is receiving chronic systemic corticosteroids at a dose that exceeds 10 mg daily of prednisone equivalent or any other form of immunosuppressive therapy within 7 days prior the first dose of study drug. Inhaled or topical steroids are permitted in the absence of active autoimmune disease.
• An uncontrolled intercurrent illness that would limit compliance with the study.
• A positive status for human immunodeficiency virus (HIV).
• A known history of Hepatitis B (defined as HBsAg reactive) or known active Hepatitis C viral (defined as HCV RNA detected) infection.
• Oxygen-dependence.
• A medical condition which, in the opinion of the Investigator, places the patient at an unacceptably high risk for toxicity.
• A positive COVID test within one week of study treatment if not fully vaccinated.
• Another active malignancy that is progressing or has required active treatment within the past 3 years.
• Known active central nervous system metastases and/or carcinomatous meningitis.