A Phase 1b, Dose Escalation/Dose Expansion, Multicenter, Open-Label Study to Assess the Safety and Tolerability of OPN-6602 Monotherapy and in Combination with Dexamethasone in Subjects with Relapsed and/or Refractory Multiple Myeloma

Phase 1b, open-label study evaluating the safety, tolerability, pharmacokinetics,
preliminary antitumor activity, and pharmacodynamics of OPN-6602 monotherapy and in
combination with dexamethasone in subjects with relapsed and/or refractory MM.

Inclusion Criteria:

- Confirmed diagnosis of multiple myeloma (MM)

- Relapsed or refractory to 3 or more different prior lines of therapy for MM that
included immunomodulatory agents, proteosome inhibitors, and anti-CD38 antibody and
not a candidate for or intolerant to established therapy known to provide clinical
benefit

- Adequate hematologic, renal, liver, cardiac function

Exclusion Criteria:

- Monoclonal gammopathy of undetermined significance (MGUS), smoldering myeloma,
Waldenström's macroglobulinemia, or IgM myeloma

- Active plasma cell leukemia

- Polyneuropathy, organomegaly, endocrinopathy, monoclonal protein and skin changes
(POEMS syndrome)

- Prior Stevens Johnson syndrome

- Localized radiation therapy to disease site(s) within 2 weeks of the first dose

- Prior autologous peripheral stem cell transplant or prior autologous bone marrow
transplantation within <90 days of the first dose of study drug

- Prior allogeneic stem cell transplantation or solid organ transplantation within 12
months of screening; subjects receiving immunosuppressive medication for active
graft vs host disease will be excluded.

- Prior chemotherapy, targeted anticancer or radiation therapy within 2 weeks prior to
first dose of study drug

- Concomitant high-dose corticosteroids (except subjects on chronic steroids given for
disorders other than myeloma)

- Known central nervous system involvement by multiple myeloma

- Active known second malignancy with exception of adequately treated basal cell
carcinoma, squamous cell carcinoma of the skin, or in situ cervical cancer;
adequately treated Stage 1 cancer from which the subject is currently in remission
and has been in remission for ≥2 years; low-risk prostate cancer with a Gleason
score <7 and a PSA level <10 ng/mL; any other cancer from which the subject has been
disease-free for ≥3 years

- Ongoing systemic infection requiring parenteral treatment

- Poorly controlled Type 2 diabetes