FDA OKs Nelarabine Larger Vial Size for T-ALL and T-LBL: Data and Dosing

The FDA approved a larger vial size of 375 mg/75 mL for nelarabine (Arranon) for the treatment of adult and pediatric patients with T-cell lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL), according to a news release from Shorla Oncology, the developer of the agent.¹

This approval provides a second option alongside the existing 250-mg/50-mL formulation. Nelarabine is a nucleoside metabolic inhibitor with indications for patients whose disease has relapsed or failed to respond to 2 or more prior chemotherapy regimens.

The introduction of the 375-mg vial is designed to offer greater dosing flexibility and more precise volume management based on the individual’s body surface area (BSA). With an average BSA of 1.7 m² generally require a dose of approximately 2550 mg, potentially making the 375-mg option more efficient for high-volume preparation.

Further, pediatric patients with T-ALL have a median age of diagnosis of 9 years with an average BSA of 1.07 m², typically requiring a 696-mg dose. For these patients, the larger vial size can facilitate dosing with fewer vials.

“Both adult and pediatric patients have differing dose needs, which can make treatment preparation complex,” said Sharon Cunningham, the CEO and co-founder of Shorla Oncology. “With this FDA approval, we hope to support healthcare providers in delivering care more efficiently, reducing waste, and improving precision in managing these types of aggressive blood cancers.”

Nelarabine Safety Data

Nelarabine carries a boxed warning regarding severe neurologic adverse events (AEs), which may include altered mental states such as severe somnolence, central nervous system effects like convulsions, and peripheral neuropathy, symptoms of which may include paresthesia, numbness, motor weakness, and paralysis. Reports have also identified ascending peripheral neuropathies similar to Guillain-Barré syndrome and AEs associated with demyelination. Critically, full recovery from these neurologic events does not always occur when therapy is discontinued.

Clinicians are advised to monitor patients frequently for signs of toxicity and must discontinue nelarabine for any neurologic AEs that reach CTCAE grade 2 or worse. Beyond neurologic concerns, other common AEs vary slightly by age group. In adults, reactions occurring in 20% or more patients include anemia, thrombocytopenia, neutropenia, nausea, diarrhea, vomiting, constipation, fatigue, pyrexia, cough, and dyspnea. In pediatric patients, the most common reactions are primarily hematologic, including anemia, neutropenia, thrombocytopenia, and leukopenia.

For adults, the most common neurological AEs, occurring in at least 10%, included somnolence, dizziness, peripheral neurologic disorders, hypoesthesia, headache, and paresthia. Likewise, the most common in pediatric patients were headache and peripheral neurologic disorders.

The drug’s mechanism involves its rapid conversion into the active deoxyguanosine analog, ara-G, which is then converted to ara-GTP within T-lymphoblasts. This accumulation leads to both the inhibition of DNA synthesis and cell death.

Nelarabine Administration Insights

According to the prescribing information for nelarabine, adults should receive 1500 mg/m² administered intravenously over 2 hours days 1, 3, and 5 in a 21-day cycle, and children should receive 650 mg/m² over 1 hour daily for 5 consecutive days in a 21-day cycle.² Dosage may also be delayed due to hematologic reactions.

It is also noted in the prescribing information that the recommended duration of treatment for patients in either age group is not established: in clinical trials of nelarabine, the drug was continued until evidence of disease progression or unacceptable toxicity occurred, if the patients became a candidate for hematopoietic stem cel transplantation, or if the patient would no longer derive benefit from therapy.

It should be noted that nelarabine should not be administered in combination with adenosine deaminase (ADA) inhibitors.

Reference

1. Shorla Oncology® announces U.S. FDA approval of larger vial size for nelarabine intravenous administration for the treatment of T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma. News release. Shorla Oncology. January 28, 2026. Accessed January 29, 2026. https://www.businesswire.com/news/home/20260127385856/en/Shorla-Oncology-Announces-U.S.-FDA-Approval-of-Larger-Vial-Size-for-Nelarabine-Intravenous-Administration-for-the-Treatment-of-T-cell-Acute-Lymphoblastic-Leukemia-and-T-cell-Lymphoblastic-Lymphoma
2. Arranon. Prescribing information. Novartis; 2019. Accessed January 29, 2026. https://www.novartis.com/us-en/sites/novartis_us/files/arranon.pdf