A Phase 1b/2, Open Label, Dose Escalation Study of Margetuximab in Combination With Pembrolizumab in Patients With Relapsed/Refractory Advanced HER2+ Gastroesophageal Junction or Gastric Cancer

This goal of this clinical research study is to learn about the safety and activity of margetuximab and pembrolizumab combination treatment in patients with HER2+ gastric and gastroesophageal junction cancer.
Cancer (Oncology) - Esophageal, Cancer (Oncology) - Stomach, Cancer (Oncology) - Gastroesophageal Junction, Cancer (Oncology)
Phillip Gold, MD
Swedish Cancer Institute
Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Signed written informed consent.
  2. Age ≥ 18 years old.
  3. Unresectable locally advanced or metastatic histologically proven HER2+ gastroesophageal junction (GEJ) or gastric adenocarcinoma.
  4. HER2+ as 3+ by IHC or in-situ hybridation (ISH) amplified.
  5. Have received prior treatment with trastuzumab.
  6. Have received treatment with at least one or more lines of cytotoxic chemotherapy in the metastatic setting.
  7. Resolution of chemotherapy, immunotherapy or radiation-related toxicities.
  8. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
  9. Life expectancy ≥ 12 weeks.
  10. Measurable disease as per RECIST 1.1 criteria.
  11. Archival or newly obtained tissue sample of a tumor lesion.
  12. Adequate organ function as determined by following laboratory parameters:

    1. Heme: Plt Ct ≥ 100 x 103/µL, ANC ≥ 1.5 x 103/µL, and Hemoglobin ≥ 9 g/dL
    2. Chemistry: ALT/AST ≤ 3.0 x ULN, TBili ≤1.5 x ULN, and Cr < 2 mg/dL
  13. Female patients of childbearing potential must have a negative pregnancy test and agree to use two forms of acceptable contraceptive measures from the time of consent through 120 days after discontinuation of study drug administration.
  14. Male patients with partners of childbearing potential must use barrier contraception.

Exclusion Criteria:

  1. Patients with symptomatic central nervous system (CNS) metastases.
  2. Patients with any history of known or suspected autoimmune disease with the specific exceptions of vitiligo, atopic dermatitis, or psoriasis not requiring systemic treatment.
  3. History of prior allogeneic bone marrow, stem-cell or solid organ transplantation.
  4. Treatment with any systemic anti-neoplastic therapy, or investigational therapy within the 3 weeks prior to the initiation of study drug.
  5. Treatment with radiation therapy within 3 weeks prior to the initiation of study drug administration.
  6. Treatment with corticosteroids (≥10 mg per day prednisone or equivalent) or other immune suppressive drugs within the 14 days prior to the initiation of study drug administration.
  7. History of clinically-significant cardiovascular disease.
  8. Clinically-significant pulmonary compromise, including a requirement for supplemental oxygen use to maintain adequate oxygenation.
  9. Presence of active pneumonitis
  10. Clinically-significant gastrointestinal disorders, such as perforation, gastrointestinal bleeding, or diverticulitis.
  11. Evidence of active viral, bacterial, or systemic fungal infection.
  12. Known positive testing for human immunodeficiency virus (HIV)or history of acquired immune deficiency syndrome (AIDS).
  13. Known history of or positive test for hepatitis B or hepatitis C infection.
  14. Second primary invasive malignancy that has not been in remission for greater than 2 years.
  15. Known hypersensitivity to recombinant proteins, polysorbate 80 or any excipient contained in the drug or vehicle formulation for margetuximab or pembrolizumab.
  16. Female patient who is breastfeeding.
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