Study of T Cells Targeting B-Cell Maturation Antigen for Previously Treated 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 an anti-BCMA CAR that can specifically recognize BCMA-expressing
target cells in vitro and eradicate BCMA-expressing tumors in mice.

- Anti-BCMA-CAR-expressing T cells have not been previously tested in humans.

- 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.

Secondary

- Evaluate the in vivo persistence of anti-BCMA CAR T cells

- Assess for evidence of anti-myeloma activity by anti-BCMA CAR T cells

ELIGIBILITY

- Patients must have measurable MM defined as a serum M-protein greater than or equal to
0.4 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 a normal creatinine and a normal cardiac ejection fraction.

- 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/ L, platelet count greater than
or equal to 45,000/ L, 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 be 30% or less of total bone marrow cells 30 days or less
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. If unstained, paraffinembedded 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/m2 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 of this dose-escalation trial will be 0.3x106 CAR+ T cells/kg of
recipient bodyweight.

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

for patients in which less than 50% of total bone marrow cells are plasma cells. With

Amendment C, all patients with 50% or greater bone marrow plasma cells will receive 3x10(6)

anti-BCMA CAR T cells/kg.

- Following the T-cell infusion, there is a mandatory 9-day 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.

- Repeat treatments are possible for patients with residual MM and no greater than grade 2
toxicity with an initial treatment.

- Re-enrollment will be allowed for a small number of subjects.

- INCLUSION CRITERIA:

2.1.1.1 Multiple Myeloma criteria

- Clear BCMA expression must be detected on greater than 50% of malignant plasma cells
from either bone marrow or a plasmacytoma by flow cytometry or immunohistochemistry.
These assays must be performed at the National Institutes of Health. 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. BCMA expression will need to be
documented on the majority of malignant plasma cells at some time after the original
anti-BCMA CAR T-cell infusion in all patients undergoing a second anti-BCMA CAR T-cell
infusion. 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.

- Bone marrow plasma cells must make up 30% or less of total bone marrow cells based on
a bone marrow biopsy performed within 30 days of the start of protocol treatment.

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

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

a. One or more of these abnormalities defines measurable disease:

- Serum M-protein greater or equal to 1 g/dl (10 g/l).

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

- Serum free light chain (FLC) assay: involved FLC level greater or equal to10
mg/dl (100 mg/l) provided serum FLC ratio is abnormal.

- A biopsy-proven plasmacytoma

- Patients must have multiple myeloma that meets the criteria for one of the following
Disease categories: (1) progressive disease or (2) relapse from CR as described in the
International Uniform Response Criteria for Multiple Myeloma and as listed below.

1. Progressive Disease (which requires 1 or more of the following)(A):

Increase of greater than or equal to 25% from the lowest response value (nadir)
in any one or moreof these parameters:

1. Serum M-component (the absolute increase must be greater than or equal to
0.5 g/dL) (B) and/or

2. Urine M-component and/or (the absolute increase must be greater than or
equal to 200 mg/24 h)

3. Only in patients without measurable serum and urine M-protein levels; the
difference between involved and uninvolved FLC levels. The absolute increase
must be > 10 mg/dL.

4. Bone marrow plasma cell percentage; the absolute percentage must be greater
than or equal to 10%

- Definite development of new bone lesions or soft tissue plasmacytomas or definite
increase in the size of existing bone lesions or soft tissue plasmacytomas (defined as
50% or greater increase in the sum of the products of the cross-diameters of target
lesions)

- Development of hypercalcemia (corrected serum calcium > 11.5 mg/dL or 2.65 mmol/L)
that can be attributed solely to the plasma cell proliferative disorder

2. Relapse from complete remission (A)

- Defined as one or more of the following; must be attributable to myeloma:

1. Reappearance of serum or urine M-protein by immunofixation or electrophoresis

2. Development of greater than or equal to 5% plasma cells in the bone marrow

3. Appearance of any other sign of progression (i.e., new plasmacytoma, lytic bone
lesion, or hypercalcemia)

(A)All relapse and progression categories require two consecutive assessments made at any
time before classification as relapse or disease progression and/or the institution of any
new therapy.

(B)For progressive disease, serum M-component increases of greater than or equal to 1 gm/dL
are sufficient to define progression if starting M-component is greater than or equla to 5
g/dL.

2.1.1.2 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 receiving the preparative regimen.

- Women of child bearing potential must have a negative pregnancy test because of the
potentially dangerous effects of the preparative chemotherapy on the fetus.

- 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.)

- Seronegative for hepatitis B antigen, positive hepatitis B tests can be further
evaluated by confirmatory tests, and if confirmatory tests are negative, the patient
can be enrolled.

- Seronegative for hepatitis C antibody unless antigen negative. If hepatitis C antibody
test is positive, then patients must be tested for the presence of antigen by RT-PCR
and be HCV RNA negative.

- Absolute neutrophil count greater than or equal to 1000/mm3 without the support of
filgrastim or other growth factors.

- Platelet count greater than or equal to 45,000/mm3 without transfusion support

- Hemoglobin greater than 8.0 g/dl.

- 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 1.3 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 within 6 weeks of the start of the treatment protocol.

- Patients should not take corticosteroids including prednisone, dexamethasone or any
other corticosteroid for any purpose at doses higher than 5 mg/day of prednisone or
equivalent dose of another corticosteroid 2 weeks before apheresis and within 2 weeks
prior to CAR T-cell infusion, and at any time after the CAR T cell infusion.

2.1.2 EXCLUSION CRITTERIA:

- Patients on any anticoagulants except aspirin are not eligible.

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

- Patients that have active hemolytic anemia.

- 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.

- Active systemic infections (defined as infections causing fevers or requiring
antimicrobial treatment), active coagulation disorders or other major uncontrolled
medical illnesses of the cardiovascular, respiratory, endocrine, renal,
gastrointestinal, genitourinary or immune system, history of myocardial infarction,
active cardiac arrhythmias, 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 are not allowed within 2 weeks prior to
either the required leukapheresis or the initiation of the conditioning chemotherapy
regimen.

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

- History of allogeneic stem cell transplantation

- Patients with CNS metastases or symptomatic 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.