SOUTH SAN FRANCISCO, Calif. – CASI Pharmaceuticals, Inc. (NASDAQ:CASI), a clinical-stage biopharmaceutical company developing CID-103, a potentially best-in-class, anti-CD38 monoclonal antibody, for patients with organ transplant rejection and autoimmune diseases, today announced data presented from its Phase 1 open-label study of CID-103 in adult patients with immune thrombocytopenia (ITP) at the 67th American Society of Hematology Annual Meeting and Exposition on December 7, 2025, in Orlando, Florida.
This open-label Phase 1 dose escalation study assigned patients to sequential dose-escalating cohorts of intravenous infusions of CID-103 at 30 mg (n=1), 150 mg (n=1), 300 mg (n=3), 600 mg (n=3), and 900 mg (n=3), with a priming dose of CID-103 of either 30 mg or 150 mg administered prior to the cohort dose. Primary objective is to evaluate safety and tolerability of multiple escalating doses of CID-103. Primary efficacy endpoint is the proportion of patients achieving a platelet response, defined as a platelet count ≥ 50 x 109/L and ≥ 20 x 109/L above baseline on at least 2 consecutive measurements at least 7 days apart within the first twelve weeks of treatment. Other endpoints were evaluated including pharmacokinetic and pharmacodynamic markers. As of cut-off date of November 28, eleven (11) patients have been enrolled and dosed.
Interim Results:
- CID-103 demonstrated a manageable safety profile with only two Grade 3 treatment-related events and no dose limiting toxicities observed
- All infusion-related reactions (IRR) occurred with priming dose and are due to low grade AEs
- Primary Efficacy Endpoint achieved in 8 of 11 (73%) patients
- 6 of 8 (75%) patients achieved Complete Response (CR) with platelet improvement observed as early as one week post dose
- Reduction of PD markers (decreased anti-platelet antibodies, immunoglobulins, NK and plasma cells) is consistent with the presumed CID-103 MOA resulting in the observed platelet response
“We are pleased with the safety and tolerability of CID-103 and encouraged by the 73% of patients achieving the primary efficacy endpoint,” said Alex Zukiwski, M.D., Global Chief Medical Officer of CASI. “Importantly, this study provides important clinical proof of concept supporting further development of CID-103 in autoimmune disorders, solid organ transplant rejection, and other CD38 mediated diseases with large unmet medical need.”
About Phase 1 Dose-Escalation Study
In this multicenter, open-label, Phase 1 study, an estimated maximum of approximately 30 adults between 18 and 65 with primary ITP who had received at least two previous lines of treatment and whose mean platelet count was ≤ 35 x 109/L on at least two measurements at least one week apart may be enrolled. This dose escalation study incorporated both accelerated escalation and standard 3+3 design. Patients were assigned to sequential dose cohorts of CID-103 at 30 mg, 150 mg, 300 mg, 600 mg, and 900 mg, with a priming dose of CID-103, of either 30 mg or 150 mg administered prior to the cohort dose.
Protocol incorporates multiple adaptive design elements such as intra-patient dose escalation and dose expansion as deemed appropriate by the Safety Monitoring Committee (SMC).
This study is conducted under an FDA approved IND and a Clinical Trial Application (CTA) approved by the Chinese Center for Drug Evaluation (CDE).
About CASI Pharmaceuticals
CASI Pharmaceuticals, Inc. is a public biopharmaceutical company developing CID-103, an anti-CD38 monoclonal antibody for organ transplant rejection and autoimmune diseases.
CID-103 is a fully human IgG1, potentially best-in-class, clinical stage, anti-CD38 monoclonal antibody which targets a unique epitope and has demonstrated an encouraging pre-clinical efficacy and clinical safety profile compared to other anti-CD38 monoclonal antibodies, and for which CASI owns exclusive global rights. CASI received FDA IND clearance to conduct a Phase 1 study in renal allograft antibody-mediated rejection (AMR) in the U.S. In parallel, CASI is actively recruiting and dosing patients in an ongoing Phase 1 study in immune thrombocytopenia (ITP). In addition, CASI is assessing multiple technologies for development of a stable, high concentration protein solution for subcutaneous formulation.
More information on CASI is available at www.casipharmaceuticals.com.
EVOMELA® is proprietary to Acrotech Biopharma Inc. and its affiliates. FOLOTYN® is proprietary to Acrotech Biopharma Inc and its affiliates. The Company is currently involved in disputes and legal proceedings related to certain pipeline products, including EVOMELA® and CNCT-19.Please refer to the Company’s earlier SEC filing for further information.
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