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. We showed that the
overall survival in patients progressed after cladribine-rituximab is less than
three years.
- Moxetumomab pasudotox-tdfk is an anti-CD22 recombinant immunotoxin which in 2018 was
FDA-approved for adult patients with relapsed/refractory HCL. However, there are
patients with HCL and HCLv who progress after treatments with standard purine analog
chemotherapy and moxetumomab pasudotox-tdfk, and in the case of classic HCL, even
after BRAF +/- MEK inhibition. There is still an unmet need for new treatment
options for those with relapsed/refractory disease.
- Adoptive cellular therapy with T-cells genetically modified using viral-based
vectors to express chimeric antigen receptors (CAR) targeting the CD22 molecule have
demonstrated dramatic clinical responses in patients with CD22+ acute lymphoblastic
leukemia (ALL) and non-Hodgkin lymphoma (NHL).
- Moxetumomab pasudotox-tdfk proved that CD22 is a potent target for HCL due to its
ubiquitous expression in HCL and HCLv, and cellular therapy represents a promising
target for those patients that have progressed after other treatments options with
chemotherapy, immunotherapy and targeted therapy. This will be the first trial of
anti-CD22 CAR T-cell therapy in the treatment of relapsed/refractory HCL and HCLv.
Objectives
- To assess the safety and feasibility of administering escalating doses of autologous
anti-CD22-CAR (M971BBz) engineered T-cells in participants with HCL/HCLv following a
cyclophosphamide/fludarabine lymphodepletion regimen.
- Explore whether the administration of anti-CD22-CAR engineered T-cells can mediate
antitumor effects in HCL/HCLv.
Eligibility
- HCL/HCLv, after prior treatment with, ineligible for, refusal of, or inability to
obtain 1) Rituximab given concurrently with or sequentially after purine analog, 2)
moxetumomab pasudotox-tdft, and 3) BRAF-inhibition.
- Need for treatment, either 1) absolute neutrophil count (ANC) <1/nL, 2) hemoglobin
(Hgb) <10g/dL, 3) Platelets <100/nL, 4) HCL mass with short axis > 2 cm outside or
>0.5 cm inside the central nervous system (CNS), 5) HCL/HCLv count >5/nL in blood or
>25/mm^3 in cerebrospinal fluid (CSF), 6) HCL/HCLv count doubling time <6 months and
increasing lytic or blastic bone lesions, 7) symptomatic splenomegaly.
->= 18 years of age.
- CD22 expression must be detected on greater than 80% of the malignant cells by flow
cytometry
- No uncontrolled infection, cardiopulmonary dysfunction, or secondary malignancy
requiring treatment.
- No chemotherapy, immunotherapy, or radiation therapy less than or equal to 2 weeks
prior to apheresis.
Design
- Peripheral blood mononuclear cells (PBMC) will be obtained by leukapheresis, CD3+
cells enriched and cultured in the presence of anti-CD3/-CD28 beads followed by
lentiviral vector supernatant containing the anti-CD22 (M971BBz) CAR.
- On Day -5 (cell infusion is Day 0), participants will begin lymphodepleting
chemotherapy comprising fludarabine 30 mg/m2 on Days -5, -4, -3, and -2, and
cyclophosphamide 500 mg/m2 on days -3 and -2.
- The CD22-CAR T-cells will be infused on Day 0, with up to a 7 day delay if cells are
cryopreserved, if needed for resolution of clinical toxicities, to generate adequate
cell numbers, or to facilitate scheduling.
- A Phase I cell dose escalation scheme will be performed primarily using 4 dose
levels (1 x 10^5; 3 x 10^5, 1 x 10^6, and 3 x 10^6 transduced T-cells/kg.
- After 2 participants are enrolled at dose level 1 without dose limiting toxicity
(DLT) or response, subsequent participants will each be enrolled at increasing dose
levels until either DLT or complete response (CR) is observed, after which that dose
level will be expanded. Once the maximum tolerated dose (or highest level evaluated)
is reached, with 0-1 out of 6 having DLT, an additional 4 participants will be
enrolled to provide further assessment of DLTs and for determining a preliminary
assessment of the efficacy of the therapy in this participant population.
- Participants will be monitored for toxicity, response and T-cell persistence as well
as other biologic correlates.
- Participants who achieve inadequate engraftment of transduced T-cells may receive a
2nd dose of CAR T-cells at a same or higher dose level, with the same or lower dose
of lymphodepleting chemotherapy, with results not to affect the primary endpoint of
the study.
- Accrual ceiling will be set at 27 to allow for a few inevaluable participants and
screen failures.