Inclusion Criteria:

• Male or female patients aged 18 years or older.
• Be willing and able to provide written informed consent and any locally required authorization (eg, Health Insurance Portability and Accountability Act of 1996 [HIPAA]) prior to any protocol related procedures, including screening evaluations
• Phase 1: Patients with pathologically confirmed multiple myeloma (MM) who have progressed on or after standard therapy (relapsed/refractory [R/R] patients):
  • Must have received at least 3 prior lines of therapy, including PIs, IMiDs, and anti CD38 therapies either in combination or as a single agent; and must not be candidates for regimens known to provide clinical benefit. (Note: Patients in Australia may have received any of the therapies including PIs, IMiDs, and anti CD38 therapies either in combination or as a single agent; and must not be candidates for regimens known to provide clinical benefit ).
• Must have measurable M-protein (serum and/or 24-hr urine, or serum free light chains).
• Phase 2: Patients with pathologically confirmed MM who have progressed on or after standard therapy (R/R patients):
  • Cohort A: R/R MM
    • Must have received at least 3 prior lines of therapy, including PIs, IMiDs, and anti CD38 therapies either in combination or as a single agent;
    • Must have measurable disease defined by at least 1 of the following abnormalities (as per IMWG criteria):
      • Serum M-protein ≥ 0.5 g/L (IgA ≥ 0.5 g/L), or
      • Urine light-chain (M-protein) of ≥ 200 mg/24 hours, or
      • Serum free light chain (sFLC) assay: involved free light chain (FLC) level ≥ 10 mg/dL provided sFLC ratio is abnormal.
  • Cohort B: R/R MM Post-T-Cell Directed Therapy
    • Must have received at least 3 prior lines of therapy, including PIs, IMiDs and anti-CD38 therapies either in combination or as a single agent; and have relapsed and/or be refractory to a T-cell directed therapy including cellular therapies or T cell engagers.
    • Must have measurable disease defined by at least 1 of the following abnormalities (as per IMWG criteria):
      • Serum M-protein ≥ 0.5 g/L (IgA ≥ 0.5 g/L), or
      • Urine light-chain (M-protein) of ≥ 200 mg/24 hours, or
      • sFLC assay: involved FLC level ≥ 10 mg/dL provided sFLC ratio is abnormal
• Have a body weight ≥ 40.0 kg at screening.
• Have an Eastern Cooperative Oncology Group (ECOG) performance status score of 2 or less.
• Have life expectancy of at least 3 months (from date of informed consent signing).
• Have adequate organ function, including:
  • Aspartate aminotransferase (AST, GOT) and alanine aminotransferase (ALT, GPT) ≤3.0 × ULN; bilirubin ≤1.5 × ULN. Patients with Gilbert's syndrome may have a bilirubin level >1.5 × ULN, per discussion between the Investigator and medical monitor.
  • Estimated creatinine clearance ≥45 mL/min as calculated using the Cockcroft-Gault formula or 24-hour urine collection.
• Left ventricular ejection fraction (LVEF) ≥45% as assessed by echocardiogram (ECHO) or multiple gated acquisition (MUGA) scan.

Exclusion Criteria:

• Participants with relapsed disease where relapse is characterized only by minimal residual disease parameters (i.e., minimal residual disease positive).
• Participants with MM with disease where the only measurable parameter is plasmacytoma.
• Received treatment with anti-CD38 antibodies or CD47 targeted therapies within 1 month of C1D1; systemic anticancer treatments within 14 days before the first dose of study drug (C1D1) or any investigational products within 5 half-lives of C1D1, whichever is appropriate to last therapy received. (eg, non-IMP IMiD, proteasome inhibitor could be considered to be eligible if there is at least 14 days after last dose before C1D1. Note: Treatment with a single course of glucocorticoids is allowed (maximum dose of corticosteroids should not exceed the equivalent of 160 mg [for example, 40 mg/d for 4 days] of dexamethasone). Hormonal therapy for prostate cancer or breast cancer (as adjuvant treatment), and treatment with bisphosphonates and receptor activator of nuclear factor kappa-Β ligand inhibitors are allowed.
• Received autologous stem cell transplantation within 12 weeks of C1D1.
• Current participation in another interventional study, including other clinical trials with investigational agents (including investigational vaccines or investigational medical device for disease under study) within 4 weeks of C1D1 and throughout the duration of this trial.
• Prior radiation therapy within 14 days of C1D1; or prior irradiation to > 25% of the bone marrow. Note: Prophylactic localized ("spot") radiation for areas of pain is allowed.
• Active malignant central nervous system involvement
• Known to be refractory to platelet or RBC transfusions
• Known severe allergic or anaphylactic reactions to human recombinant proteins or excipients used in the ISB 1442 formulation.
• QTc interval > 480 msec at screening using Fredericia's QT correction formula.