Blinatumomab (Blincyto) is a first-in-class bispecific T-cell engager (BiTE) used to treat B-cell Acute Lymphoblastic Leukemia (ALL).
Mechanism of Action
It acts as a molecular bridge between the immune system and cancer cells. One part of the antibody attaches to the CD19 protein found on the surface of B-cells, while the other part attaches to CD3 on the surface of healthy T cells. This connection tethers the two cells together, activating the T cell to recognize and destroy the leukemia cell.
Indications
- Relapsed or Refractory (R/R) ALL: Used for patients who have failed prior therapies.
- MRD-Positive ALL: Specifically indicated for patients in clinical remission who still have measurable residual disease (MRD) of $\ge 0.1%$.
- Broad Use: It is effective in both Philadelphia chromosome-negative and Philadelphia chromosome-positive (Ph+) disease.
Administration and Safety
- Continuous Infusion: Because it has a very short half-life, it is administered as a continuous intravenous infusion for 4 weeks, followed by a 2-week break.
- Key Toxicities: The most significant risks are Cytokine Release Syndrome (CRS), caused by widespread immune activation, and neurotoxicity (ICANS), which can manifest as confusion, slurred speech, or seizures.
- Hospitalization: Patients typically require hospitalization during the start of the first and second cycles to monitor for these immediate reactions.
Monitoring
- Baseline: CBC, LFTs, infection screening, neurologic assessment
- During therapy:
Supportive Measures
- Premedicate with dexamethasone before each dose
- Interrupt or discontinue for grade ≥3 neurotoxicity or CRS
- Requires inpatient initiation (Cycle 1) in many protocols
Other Notes
- Only available as continuous infusion (hospital or home-based with pump)
- CD19 expression is required on target cells
- No direct myelosuppressive chemotherapy component
- Immunogenicity is low, but hypersensitivity is possible
Synonyms
Blincyto