T Cells Expressing a Novel Fully-Human Anti-BCMA CAR for Treating Multiple Myeloma

Background:

- Multiple myeloma (MM) is a malignancy of plasma cells.

- MM is nearly always incurable.

- T cells can be genetically modified to express chimeric antigen receptors (CARs) that
specifically target malignancy-associated antigens.

- Autologous T cells genetically modified to express CARs targeting the B-cell antigen
CD19 have caused complete remissions in a small number of patients with leukemia or
lymphoma. These results demonstrate that CAR-expressing T cells have anti-malignancy
activity in humans.

- B-cell maturation antigen (BCMA) is a protein expressed by normal plasma cells and the
malignant plasma cells of multiple myeloma.

- BCMA is not expressed by normal cells except for plasma cells and some mature B cells.

- We have constructed a novel anti-BCMA CAR that can specifically recognize BCMA-
expressing target cells in vitro and eradicate BCMA-expressing tumors in mice.

- This CAR has an antigen-recognition domain made up of a single fully-human heavy chain
variable region.

- We hypothesize that anti-BCMA-CAR-expressing T cells will specifically eliminate BCMA-
expressing MM cells in patients

- Possible toxicities include cytokine-associated toxicities such as fever, hypotension,
and neurological toxicities. Elimination of normal plasma cells and unknown toxicities
are also possible.

Objectives:

Primary

- Determine the safety and feasibility of administering T cells expressing an anti-BCMA CAR
to patients with MM.

Eligibility:

- Greater than or equal to 18 years of age and less than or equal to age 73.

- Patients must have measurable MM defined as a serum M-protein greater than or equal to
1.0 g/dL or a urine M- protein greater than or equal to 200 mg/24 hours or an involved
serum free light chain (FLC) level greater than or equal to 10 mg/dL (provided FLC ratio
is abnormal) or a biopsy-proven plasmacytoma.

- Patients must have previously received at least 3 different treatment regimens for MM.

- Patients must have prior exposure to an IMiD such as lenalidomide, and a proteasome
inhibitor

- Patients must have a creatinine level of less than or equal to 1.4 mg/dL

- Patients must have a cardiac ejection fraction greater than or equal to 50%.

- An ECOG performance status of 0-2 is required.

- Patients on any anticoagulant medications except aspirin are not eligible.

- No active infections are allowed.

- Absolute neutrophil count greater than or equal to 1000/microliters, platelet count
greater than or equal to 55,000/ microliters, hemoglobin greater than or equal to 8g/dL

- ALT and AST less than or equal to 2.5-fold higher than the upper limit of normal.

- At least 14 days must elapse between the time of any prior systemic treatment (including
corticosteroids) and the required leukapheresis.

- At least 14 days must elapse between the time of any prior systemic treatment (including
corticosteroids) and initiation of protocol treatment.

- Bone marrow plasma cells must make up less than or equal to 50% of total bone marrow
cells less than or equal to 21 days prior to the start of protocol treatment.

- The patient s MM will need to be assessed for BCMA expression by flow cytometry or
immunohistochemistry performed at the NIH. The myeloma must express BCMA. If unstained,
paraffin-embedded bone marrow or plasmacytoma sections are available from prior
biopsies, these can be used to determine BCMA expression by immunohistochemistry;
otherwise patients will need to come to the NIH for a bone marrow biopsy or other biopsy
of a plasmacytoma to determine BCMA expression. The sample for BCMA expression can come
from a biopsy obtained at any time before enrollment.

Design:

- This is a phase I dose-escalation trial

- Patients will undergo leukapheresis

- T-cells obtained by leukapheresis will be genetically modified to express an anti-BCMA
CAR

- Patients will receive a lymphocyte-depleting chemotherapy conditioning regimen with the
intent of enhancing the activity of the infused anti-BCMA-CAR-expressing T cells.

- The chemotherapy conditioning regimen is cyclophosphamide 300 mg/m^2 daily for 3 days
and fludarabine 30 mg/m2 daily for 3 days. Fludarabine will be given on the same days as
the cyclophosphamide.

- Two days after the chemotherapy ends, patients will receive an infusion of anti-BCMA-
CAR-expressing T cells.

- The initial dose level will be 0.75x10^6 CAR+ T cells/kg of recipient bodyweight.

- The cell dose administered will be escalated until a maximum tolerated dose is
determined.

- Following the T-cell infusion, there will be a mandatory 9-day minimum inpatient
hospitalization to monitor for toxicity.

- Outpatient follow-up is planned for 2 weeks, and 1, 2, 3, 4, 6, 9, and 12 months after
the CAR T-cell infusion. Afterwards, follow-up will be every six months up to at least 5
years.

- INCLUSION CRITERIA:

Multiple Myeloma criteria:

- BCMA expression must be detected on malignant plasma cells from either bone marrow or
a plasmacytoma by flow cytometry or immunohistochemistry. A specific quantitative
level of BCMA expression for eligibility is not specified, but patients with multiple
myeloma cells that are negative for BCMA by flow cytometry and immunohistochemistry
will not be enrolled. These assays must be performed at the National Institutes of
Health (NIH). It is not required that the specimen used for BCMA determination comes
from a sample that was obtained after the patient s most recent treatment. If paraffin
embedded unstained samples of bone marrow involved with MM or a plasmacytoma are
available, these can be shipped to the NIH for BCMA staining, otherwise new biopsies
will need to be performed for determination of BCMA expression.

- BCMA expression will need to be documented on the majority of malignant plasma cells
by flow cytometry at the NIH at some time after the original anti-BCMA CAR T-cell
infusion in all patients undergoing a second anti-BCMA CAR T-cell infusion.

- Bone marrow plasma cells must make up less than 50% of total bone marrow cells based
on a bone marrow biopsy performed within 21 days of the start of protocol treatment.

- Patients must have received at least 3 different prior treatment regimens for multiple
myeloma

- Must have prior exposure to an "IMiD" such as lenolidamide and a proteasome inhibitor

- Patients must have measurable MM as defined by at least one of the criteria below.

- One or more of these abnormalities defines measurable multiple myeloma:

- Serum M-protein greater or equal to 1.0 g/dL.

- Urine M-protein greater or equal to 200 mg/24 h.

- Serum free light chain (FLC) assay: involved FLC level greater or equal to 10
mg/dL (100 mg/L) provided serum FLC ratio is abnormal.

- A biopsy-proven plasmacytoma

- Bone marrow plasma cells make up 30% or more of total bone marrow cells

Other inclusion criteria:

- Greater than or equal to 18 years of age and less than or equal to age 73.

- Able to understand and sign the Informed Consent Document.

- Clinical performance status of ECOG 0-2

- Patients of both genders must be willing to practice birth control from the time of
enrollment on this study and for four months after last day of receiving protocol
treatment.

- Seronegative for HIV antibody. (The experimental treatment being evaluated in this
protocol depends on an intact immune system. Patients who are HIV seropositive can
have decreased immune-competence and thus are less responsive to the experimental
treatment and more susceptible to its toxicities.)

- A patient with a negative blood PCR test for hepatitis B DNA test can be enrolled. If
hepatitis B DNA (PCR) testing is not available, patients with a negative hepatitis B
surface antigen and negative hepatitis B core antibody can be enrolled.

- Patients must be tested for the presence of Hepatitis C antigen by PCR and be HCV RNA
negative in order to be eligible. Only if Hepatitis C PCR testing is not available in
a timely manner, patients who are Hepatitis C antibody-negative can be enrolled.

- Absolute neutrophil count greater than or equal to 1000/mm(3) without the support of
filgrastim or other growth factors within the previous 10 days.

- Platelet count greater than or equal to 55,000/mm(3) without transfusion support
within the past 10 days.

- Hemoglobin greater than 8.0 g/dL without transfusion support within the past 10 days.

- Less than 5% plasma cells in the peripheral blood leukocytes

- Serum ALT and AST less or equal to 2.5 times the upper limit of the institutional
normal.

- Serum creatinine less than or equal to 1.4 mg/dL.

- Total bilirubin less than or equal to 2.0 mg/dL, except in patients with Gilbert s
Syndrome who must have a total bilirubin less than 3.0 mg/dL.

- At least 14 days must have elapsed since any prior systemic therapy at the time the
patient starts the cyclophosphamide and fludarabine conditioning regimen, and
patients' toxicities must have recovered to a grade 1 or less (except for toxicities
such as alopecia or vitiligo).

- Because this protocol requires collection of autologous blood cells by leukapheresis
in order to prepare anti-BCMA-CAR T cells, systemic anti-myeloma therapy including
systemic corticosteroid steroid therapy of greater than 5 mg/day of prednisone or
equivalent dose of another corticosteroid are not allowed within 2 weeks prior to the
required leukapheresis.

- Normal cardiac ejection fraction (greater than or equal to 50% by echocardiography)
and no evidence of hemodynamically significant pericardial effusion as determined by
an echocardiogram.

- For patients with past participation in gene-therapy, cryopreserved PBMC that have not
been genetically-engineered must be available.

EXCLUSION CRITERIA:

- Patients on any anticoagulants except aspirin.

- Patients that require urgent therapy due to tumor mass effects or spinal cord
compression.

- Patients that have active hemolytic anemia.

- Patients currently taking anticoagulants

- Patients with second malignancies in addition to multiple myeloma are not eligible if
the second malignancy has required treatment within the past 3 years or is not in
complete remission. There are two exceptions to this criterion: successfully treated
non-metastatic basal cell or squamous cell skin carcinoma.

- Women of child-bearing potential who are pregnant or breastfeeding because of the
potentially dangerous effects of the preparative chemotherapy on the fetus or infant.
Women of child bearing potential cannot have a positive pregnancy test. Women of
child-bearing potential are defined as all women except women who are post- menopausal
or who have had a hysterectomy. Postmenopausal will be defined as women over the age
of 55 who have not had a menstrual period in at least 1 year.

- Active systemic infections (defined as infections causing fevers or requiring anti-
microbial treatment), active coagulation disorders or other major uncontrolled medical
illnesses of the cardiovascular, respiratory, endocrine, renal, gastrointestinal,
genitourinary, neurologic, or immune system, history of myocardial infarction, active
cardiac arrhythmias, history of atrial fibrillation or other arrhythmias other than
sinus tachycardia, active obstructive or restrictive pulmonary disease.

- Any form of primary immunodeficiency (such as Severe Combined Immunodeficiency
Disease).

- Systemic corticosteroid steroid therapy of greater than 5 mg/day of prednisone or
equivalent dose of another corticosteroid (prednisone, dexamethasone, etc) is not
allowed within 2 weeks prior to either the required leukapheresis or within 2 weeks
prior to CAR T-cell infusion (and at any time after the CAR T cell infusion).

- History of severe immediate hypersensitivity reaction to any of the agents used in
this study.

- Patient unwilling to undergo intensive care unit treatment including mechanical
ventilation, cardiopulmonary resuscitation, vasoactive drugs, and hemodialysis.

- History of allogeneic stem cell transplantation

- Patients with CNS metastases or CNS involvement (including cranial neuropathies or
mass lesions and spinal cord compression).

- Patients with active autoimmune skin diseases such as psoriasis or other active
autoimmune diseases such as rheumatoid arthritis.

- Patients must not have required supplemental oxygen within the past month unless it
was for a resolved infection.

- Patient must not have received genetically modified cells except on prior NCI gene
therapy protocols.