Keymed Biosciences’ CM336 shows sustained remission in AIHA patients after CAR-T failure

Keymed Biosciences Inc. (HKEX: 02162) has achieved a clinical milestone with its investigational bispecific antibody CM336, after results published in the New England Journal of Medicine demonstrated durable remission in patients with autoimmune hemolytic anemia (AIHA) who had previously failed CD19 CAR T-cell therapy. The study, led by Professor Jun Shi of the Chinese Academy of Medical Sciences’ Institute of Hematology, marks the world’s first published data on a BCMA x CD3 bispecific T-cell engager in relapsed or refractory AIHA.

The findings detail how two patients with treatment-resistant AIHA—both of whom had previously undergone multiple lines of therapy including glucocorticoids, anti-CD20 monoclonal antibodies, BTK inhibitors, splenectomy, and CD19-targeting CAR T-cell therapies—achieved rapid and sustained disease control following a single course of CM336. Partial remission was documented on days 13 and 19, with hemoglobin levels normalized by days 17 and 21, respectively. Additionally, surrogate markers of hemolysis, including reticulocyte counts, lactate dehydrogenase (LDH), and indirect bilirubin, all showed substantial improvement.

Most notably, both patients remained in complete remission six months after treatment, without requiring further immunosuppressive drugs or transfusions. The safety profile was equally significant—no cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), or infections were reported during the treatment or follow-up periods.

What is autoimmune hemolytic anemia (AIHA)?

Autoimmune hemolytic anemia is a rare blood disorder in which the body’s immune system mistakenly targets and destroys its own red blood cells. This destruction causes a shortage of circulating red cells, leading to fatigue, shortness of breath, paleness, jaundice, and in severe cases, organ dysfunction. AIHA can be classified into “warm” and “cold” types based on the temperature at which autoantibodies are active, with warm AIHA being more common.

Standard treatment typically begins with corticosteroids such as prednisone, which suppress immune function. In more resistant cases, immunosuppressive drugs like rituximab (anti-CD20), splenectomy, or even BTK inhibitors may be used. However, 10–20% of patients progress to a chronic relapsing or refractory form where treatment options are limited. Newer modalities like CD19 CAR T-cell therapy are emerging, but even these may not offer durable responses for all patients. In this context, CM336’s reported efficacy in two such post-CAR-T cases is especially noteworthy.

What makes CM336 a novel treatment candidate?

CM336 is a BCMA x CD3 bispecific antibody designed to engage T cells and redirect their cytotoxic activity toward BCMA-expressing B cells. The molecule achieves this by simultaneously binding CD3 on T cells and BCMA on pathogenic B cells, triggering T-cell dependent cellular cytotoxicity (TDCC). While this therapeutic logic has been validated in multiple myeloma, the AIHA trial is the first to demonstrate its application in autoimmune indications where aberrant B cells drive pathology.

Keymed Biosciences’ successful redirection of this bispecific platform into AIHA represents not only an innovation in disease management but also a strategic pipeline evolution that widens its competitive footprint beyond oncology.

Why the results matter for post-CAR-T patients

AIHA is a rare but debilitating autoimmune disease where the immune system destroys red blood cells. While conventional treatment includes steroids, rituximab, and immunosuppressants, a subset of patients remains unresponsive or relapses after advanced interventions like CAR-T therapy. These patients often face cumulative toxicity and limited therapeutic options. The CM336 study offers a rare glimpse of durable efficacy and manageable safety in this population, positioning the molecule as a potential breakthrough in autoimmune hematology.

The study’s publication in the New England Journal of Medicine, considered one of the most authoritative medical journals globally, further validates the strength of the clinical evidence and Keymed Biosciences’ credibility in high-impact innovation.

What is the regulatory status of CM336?

In parallel with the AIHA trial, Keymed Biosciences has received clearance from the National Medical Products Administration (NMPA) of China to initiate a Phase II trial for CM336 in the treatment of primary light-chain (AL) amyloidosis. The company is expected to commence patient recruitment for this indication shortly, marking its expansion into rare, B-cell–driven proteinopathies. Should efficacy in AL amyloidosis mirror the AIHA findings, CM336 could evolve into a broad-spectrum therapy for B-cell–mediated diseases.

The dual-path development strategy—targeting both hematologic malignancies and autoimmune diseases—places Keymed Biosciences among the few Chinese biotech firms pursuing differentiated bispecific antibody programs with international clinical relevance.

What do analysts and institutions think about Keymed Biosciences stock?

While CM336 forms the clinical core of this announcement, the market has also responded to Keymed Biosciences’ broader pipeline momentum. As of June 12, 2025, Keymed Biosciences stock trades at approximately HK$48.65, up nearly 80% from its 52-week low of HK$27.05. The rally began in late Q1 following strong FY2024 results and an upsized share placement that raised over HK$850 million, enabling robust pipeline funding.

Technical indicators suggest support above HK$47.50, with potential resistance near the recent high of HK$50.30. Analyst consensus, including sentiment from firms like CLSA and Citi, leans toward a “moderate buy” with an average target price of HK$60.00, suggesting a 23% upside potential.

Institutional ownership, though relatively modest at 3.3%, includes notable investors such as Vanguard and iShares. Retail participation remains significant, reflecting growing interest in Hong Kong-listed biotech growth stories. Analysts monitoring institutional flows suggest steady accumulation across Q2, especially following peer-reviewed validation of CM336 data.

From an investor positioning standpoint, Keymed Biosciences offers long-term upside for those focused on first-in-class immunotherapy platforms. While the stock has appreciated substantially, analysts advise a Buy/Hold stance for long-duration biotech portfolios, with short-term profit-taking warranted only if the price approaches upper resistance without additional clinical catalysts.

Future outlook: what comes next for CM336?

Keymed Biosciences is now strategically positioned to accelerate CM336’s development both within China and potentially through global licensing. With one foot in oncology and another in immunology, the bispecific platform’s versatility will likely dictate its future market access and valuation multiples.

The publication of AIHA results in a globally recognized journal not only opens doors for new indications but also enhances Keymed’s scientific standing. The next major catalyst will likely be the readout from the Phase II AL amyloidosis trial. If positive, it could validate the expansion of CM336 into a broader range of rare B-cell–mediated disorders, bolstering both pipeline depth and investor confidence.

Industry experts note that Chinese biotechs like Keymed are increasingly mirroring Western platform strategies—repurposing bispecifics, leveraging rare disease entry points, and aligning with global publication standards. In this context, CM336 may represent more than a clinical success; it could be a symbol of China’s evolving biotech innovation model.