CD22CART cell

The treatment regimen will consist of lymphodepleting chemotherapy followed by CD22CART infusion: Days -4 to -2: fludarabine 25 mg/m2/dose Day -2: cyclophosphamide 900 mg/m2/dose Day 0: CD22CART infusion (starting at dose level 1 \[DL1\]: 1 x 105 transduced CAR-T cells/kg) on Day 0 participants will be evaluated for response at Day 28 post-CD22CART infusion.

Background * Hairy cell leukemia (HCL) is an indolent CD22+ B-cell leukemia comprising 2% of all leukemias. Most cases of HCL respond well to purine analog chemotherapy and harbor BRAF V600E mutation that can be considered for targeted treatment at the time of relapse.

However, there are patients with high-risk HCL such as patients with BRAF wild type IGHV4-34 unmutated HCL who respond poorly to chemotherapy and have poor survival. * HCL variant (HCLv), also brightly CD22+, resembles HCL morphologically but is more aggressive and responds poorly to standard purine analog chemotherapy. Patients have fewer options of targeted treatment partly due to wild type BRAF.

Background: CAR (Chimeric Antigen Receptor) T cell therapy is a type of cancer treatment in which a person s T cells (a type of immune cell) are changed in a laboratory to recognize and attack cancer cells. Researchers want to see if this treatment can help people with hairy cell leukemia (HCL). Objective: To test whether it is safe to give anti-CD22 CAR T cells to people with HCL.

Eligibility: Adults ages 18 and older with HCL (classic or variant type) who have already had, are unable to receive, or have refused other standard treatments for their cancer. Design: Participants will be screened with the following: Medical history Physical exam Blood and urine tests Biopsy sample Electrocardiogram Echocardiogram Lung function tests Imaging scans Some screening tests will be repeated during the study.

Live record on ClinicalTrials.gov →

• Histologically confirmed diagnosis of HCL or HCLv according to morphological and immunophenotypic criteria of WHO classification \[WHO, 2008 revised 2016\] of lymphoid neoplasm.
• Participants should have any of the following indications for therapy:
• Hemoglobin \<10g/dL,
• Symptomatic splenomegaly,
• HCL mass with short axis \> 2 cm outside or \>0.5 cm inside the CNS,
• HCL/HCLv count \>5/nL in blood or \>25/mm\^3 in CSF,

Inclusion criteria as written on the registry, trimmed. The full list, with exclusions, is on the live record.