Description

Loncastuximab Tesirine (Loncastuximab Tesirine-lpyl)

Brand Name

ZYNLONTA®

Generic Name

Loncastuximab tesirine-lpyl

Drug Class

CD19-directed antibody-drug conjugate (ADC)

Overview

Loncastuximab tesirine is a targeted anticancer therapy approved for the treatment of adults with relapsed or refractory large B-cell lymphoma (LBCL), including diffuse large B-cell lymphoma (DLBCL), after two or more lines of systemic therapy. It is an antibody-drug conjugate composed of a humanized anti-CD19 monoclonal antibody linked to a potent pyrrolobenzodiazepine (PBD) dimer cytotoxic payload. The drug is designed to selectively deliver the cytotoxic agent to malignant B cells expressing CD19, thereby minimizing damage to normal tissues.

Mechanism of Action

Loncastuximab tesirine targets CD19, a cell-surface antigen widely expressed on malignant B cells. After binding to CD19, the antibody-drug conjugate is internalized into the cancer cell. Within the lysosomal compartment, the linker is cleaved, releasing the PBD dimer cytotoxic payload. The released payload forms DNA interstrand cross-links, preventing DNA replication and transcription, ultimately leading to apoptosis and cell death.

Indications

Loncastuximab tesirine is indicated for the treatment of adult patients with relapsed or refractory large B-cell lymphoma, including:

• Diffuse large B-cell lymphoma (DLBCL), not otherwise specified
• DLBCL arising from low-grade lymphoma
• High-grade B-cell lymphoma

The therapy is generally used after at least two prior lines of systemic treatment have failed.

Dosage and Administration

The recommended dosing schedule is:

• 0.15 mg/kg intravenously every 3 weeks for the first two cycles
• 0.075 mg/kg intravenously every 3 weeks for subsequent cycles

The drug is administered as an intravenous infusion over approximately 30 minutes. Premedication with dexamethasone is recommended to reduce treatment-related adverse reactions.

Clinical Efficacy

Clinical studies, including the LOTIS-2 trial, demonstrated meaningful antitumor activity in heavily pretreated patients with relapsed or refractory DLBCL. The trial reported an overall response rate of approximately 48%, with durable responses observed in a subset of patients. These findings supported regulatory approval of the drug.

Common Adverse Reactions

Frequently reported adverse events include:

• Fatigue
• Nausea
• Peripheral edema
• Rash
• Musculoskeletal pain
• Neutropenia
• Thrombocytopenia
• Anemia
• Elevated liver enzymes
• Hyperglycemia

Patients should be monitored regularly for hematologic toxicity and liver function abnormalities.

Warnings and Precautions

Important safety concerns associated with loncastuximab tesirine include:

• Effusion and edema, including capillary leak syndrome
• Myelosuppression
• Serious infections
• Cutaneous reactions and photosensitivity
• Embryo-fetal toxicity

Appropriate monitoring and dose modifications may be required during treatment.

Regulatory Status

Loncastuximab tesirine received accelerated approval from the U.S. Food and Drug Administration (FDA) in April 2021 for the treatment of relapsed or refractory large B-cell lymphoma after at least two prior systemic therapies. It has also received approval in several other regions, including the European Union.

Conclusion

Loncastuximab tesirine represents an important treatment option for patients with relapsed or refractory large B-cell lymphoma. By combining the specificity of an anti-CD19 monoclonal antibody with the potency of a DNA-crosslinking cytotoxic payload, it offers a targeted therapeutic approach capable of producing clinically meaningful responses in patients with limited treatment options.