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 additional data from its Phase 1 open-label study of CID-103 in adult patients with immune thrombocytopenia (ITP). Initial clinical data from this study were presented at the 67th American Society of Hematology Annual Meeting and Exposition on December 7, 2025, in Orlando, Florida. Updated safety and efficacy data can be found on the CASI website here.
The update includes additional safety and efficacy data based on:
- CID-103 at 30 mg (n=1), 150 mg (n=1), 300 mg (n=3), 600 mg (n=5), and 900 mg (n=6)
- ~5 weeks of additional dosing / follow up for the ongoing patients in all cohorts
- 3 additional patients enrolled in 900 mg cohort
- 2 patients are at Week 5 of study treatment
- 1 patient is at Week 3 of study treatment
- 2 additional patients enrolled and one patient is in screening in 600 mg cohort
- 1 patient is at Week 3 of study treatment
- 1 patient is at Week 2 of study treatment
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 12 of 15 evaluable (80%) patients
- 10 of 15 evaluable (66%) 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 80% of patients achieving the primary efficacy endpoint, and plan to report additional updates as the study progresses” 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.”
Separately, the Company announced that its board of directors (the “Board”) received a preliminary non-binding proposal, dated January 7, 2026,which was further amended by an updated preliminary non-binding proposal dated January 9, 2026 from Dr. Wei-Wu He (the “Proposal”), to acquire all of the outstanding ordinary shares, par value US$0.0001 per share, of the Company (the “Ordinary Shares”), that are not already beneficially owned by Dr. He for a proposed purchase price of US$1.15 per Ordinary Share. The proposed price represents a 30% premium to the average closing price during the last 30 trading days. Full details of the proposals can be found here.
CASI Board cautions the Company’s shareholders and others considering trading the Company’s securities that no decisions have been made with respect to the Proposal. There can be no assurance that any definitive offer will be received, that any definitive agreement will be executed relating to the transaction contemplated by the Proposal, or that the transaction contemplated by the Proposal, or any other similar transaction will be approved or consummated. The Company does not undertake any obligation to provide any updates with respect to any transaction, except as required under applicable law.
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. 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 January 6, sixteen (16) patients have been enrolled and dosed.
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 studyis 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.
Company Contact
Ingrid Choong, PhD
650-619-6115
[email protected]