Pilot Study of Reduced-Intensity Hematopoietic Stem Cell Transplant of DOCK8 Deficiency

Background

Mutations in the Dedicator of Cytokinesis-8 (DOCK8) gene are responsible for an
immunodeficiency disease characterized by: severe cutaneous and sinopulmonary infections with
bacterial organisms; extensive cutaneous viral infections with Herpes simplex, Herpes zoster,
Molluscum contagiosum, and Human Papilloma Virus; a marked elevation in serum IgE levels and
eosinophilia; homozygous or compound heterozygous mutations in the dedicator of cytokinesis 8
(DOCK8) gene. Patients with DOCK8 deficiency die from severe infections, squamous cell
carcinomas, or hematological malignancies. Allogeneic hematopoietic stem cell transplantation
(HSCT) represents a potentially life-saving treatment for immunodeficiency diseases such as
DOCK8 deficiency. In this study we will evaluate the efficacy and safety of allogeneic HSCT
for DOCK8 deficiency. We are particularly interested in determining whether allogeneic HSCT
using different donor sources and conditioning regimens reverses the lethal disease phenotype
in DOCK8 deficiency by reconstituting normal host defense. The development of lethal squamous
cell carcinomas and lymphomas arising from the immunodeficiency in DOCK8 deficiency supports
therapeutic intervention before overt malignancy arises.

Objectives

-To determine whether allogeneic HSCT reconstitutes T-lymphocyte and B-lymphocyte cells and
myeloid cells with normal donor cells at one year post-transplant and reverses the clinical
phenotype of severe recurrent infections in patients with DOCK8 deficiency.

Eligibility

Patients 5-35 years old with DOCK8 deficiency who have suffered one or more life-threatening
infections, or who have developed lymphoma or squamous cell carcinoma, and have a 10/10
matched related donor, a 10/10 matched unrelated donor, a 9/10 matched related donor, a 9/10
matched unrelated donor, or a haploidentical related donor.

Design

- DOCK8 deficiency patients with 10/10 matched related donors and unrelated donors will
receive a pre-transplant conditioning regimen consisting of fludarabine 40 mg/m2/day on
days -6, -5, -4, and -3, and busulfan IV (dose based on pharmacokinetic levels) every
day for 4 days on days -6, -5, -4, and -3. The busulfan dosing will be adjusted based
upon a test dose of busulfan given prior to the start of the conditioning regimen. Donor
hematopoietic stem cells will be infused on day 0.

- Post-transplant immunosuppression for graft-versus-host-disease (GVHD) prophylaxis for
recipients of 10/10 matched related and unrelated donors will consist of
cyclophosphamide 50 mg/kg IV once daily for 2 days on days +3 and +4, along with
mycophenolate mofetil from day +5 to day +35 and tacrolimus from day +5 to approximately
day 180. If there is no evidence of graft-versus-host disease, tacrolimus will be
stopped at approximately day +180.

- DOCK8 deficiency patients with 9/10 matched related or 9/10 matched unrelated donors
will receive a pre-transplant conditioning regimen consisting of cyclophosphamide 14.5
mg/kg on days -6 and -5, fludarabine 30 mg/m2/day on days -6, -5, -4, -3 and -2,
busulfan IV (dose based on pharmacokinetic levels) once daily for three days on-4, -3
and -2, and 200 cGy TBI on day -1. The busulfan dosing will be adjusted based upon a
test dose of busulfan given prior to the start of the conditioning regimen. Donor
hematopoietic stem cells will be infused on day 0. Post-transplant immunosuppression for
graft-versus-host-disease (GVHD) prophylaxis for recipients of 9/10 matched related or
unrelated donors will consist of cyclophosphamide 50 mg/kg IV once daily for two days on
day s +3 and +4, along with mycophenolate mofetil from day +5 to day +35 and tacrolimus
from day +5 to day 180. If there is no evidence of graft-versus-host disease, tacrolimus
will be stopped at approximately day+180.

DOCK8 deficiency patients with a haploidentical related donor will receive a pre-transplant
conditioning regimen consisting of cyclophosphamide 14.5 mg/kg on days -6 and -5, busulfan IV
(dose based on pharmacokinetic levels) once daily for 3 days on days -4, -3,and -2,
fludarabine 30 mg/m2 on days -6, -5, -4, -3, and -2, and 200 cGy TBI on day -1. The busulfan
dosing will be adjusted based upon a test dose of busulfan given prior to the start of the
conditioning regimen. Donor hematopoietic stem cells will be infused on day 0.
Post-transplant immunosuppression for GVHD prophylaxis will consist of cyclophosphamide 50
mg/kg IV once daily for two days on day s +3 and +4, along with mycophenolate mofetil from
day +5 to day +35 and tacrolimus from day +5 to day 180. If there is no evidence of
graft-versus-host disease, tacrolimus will be stopped at approximately day+180.

- INCLUSION CRITERIA - RECIPIENT:

- Patient age of 5-35 years.

Weight greater than 12 kilograms

- DOCK8 deficiency with the two criteria listed below:

- Clinical history of one or more episodes of life-threatening or severely disfiguring
infection with opportunistic organisms, including severe recurrent cutaneous and
sinopulmonary infections with bacterial or fungal infection, or viral infections with
herpes simplex, herpes zoster, Molluscum contagiosum, or human papilloma virus.

- Homozygous or compound heterozygous mutations in the DOCK8 gene performed by a
CLIA-certified laboratory

- Available 10/10 or 9/10 HLA-matched related or unrelated donor or a haploidentical
related donor.

- Left ventricular ejection fraction > 40%, preferably by 2-D echo, obtained within 28
days of enrollment. If the patient has radiological evidence of aortic, renal artery,
or coronary artery vasculitis, a left ventricular ejection fraction >30% is
acceptable.

- Pulmonary Function Tests: FEV1 greater than or equal to 50% of expected value obtained
within 28 days of enrollment.

--Note: For children who are unable to cooperate for PFTs, the criterion is: No
evidence of dyspnea at rest, no exercise intolerance, and no requirement for
supplemental oxygen therapy.

- Creatinine: Patients: less than or equal to 2.0 mg/dl or creatinine clearance greater
than or equal to 30 ml/min/1.73 m^2. Pediatric patients (<18 years old): Creatinine
less than or equal to 1.5 mg/dl or a creatinine clearance of greater than or equal to
30 mL/min/1.73 m^2.

- Serum total bilirubin < 2.5 mg/dl; serum ALT and AST less than or equal to 5 times
upper limit of normal.

- Adequate central venous access potential.

- Patients, parents/guardian(s), legally authorized representatives (LAR), or durable
power of attorney must be able to give consent and sign the informed consent document.
Pediatric subjects will be included in age appropriate discussion and verbal assent
will be obtained for those greater than 12 years of age, when appropriate.

- Disease status: Patients with malignancy are to be referred in remission for
evaluation, except in the case of viral associated malignancies. Should a patient have
progressive disease or a donor becomes unavailable after enrollment, the patient will
be referred back to their primary hematologist-oncologist for treatment. If this
course of action is not in the best interest of the patient according to the clinical
judgment of the PI/LAI, then the patient may receive standard treatment for the
malignant disease under the current study. If under either of these settings, it
becomes apparent that the patient will not be able to proceed to transplant, then
he/she must come off study. Recipient-Subjects receiving a standard therapy will be
told about the therapy, associated risks, benefits alternatives of the proposed
therapy, and availability of receiving the same treatment elsewhere, outside of a
research protocol.

EXCLUSION CRITERIA - RECIPIENT:

- HIV infection.

- Chronic active hepatitis B. Patient may be hepatitis B core antibody positive. For
patients with a concomitant positive hepatitis B surface antigen, patients will
require a hepatology consultation. The risk-benefit profile of transplant and
hepatitis B will be discussed with the patient, and eligibility determined by the PI
and the protocol chairperson

- History of psychiatric disorder which may compromise compliance with transplant
protocol, or which does not allow for appropriate informed consent.

- Active CNS involvement by malignancy (patients with known positive CSF cytology or
parenchymal lesions visible by CT or MRI). Except in the case of viral associated
malignancies in which case the patient may benefit from the transplant to control the
malignancy.

- Pregnant or lactating. The effects on breast-milk are also unknown and may be harmful
to the infant; therefore, women should not breast feed during the interval from study
entry to one year post-transplant.

- Sexually active individuals capable of becoming pregnant who are unable or unwilling
to use effective form(s) of contraception during time enrolled on study and for 1 year
post-transplant. Effective forms of contraception include one or more of the
following: intrauterine device (IUD), hormonal (birth control pills, injections, or
implants), tubal ligation/hysterectomy, partner s vasectomy, barrier methods, (condom,
diaphragm, or cervical cap), or abstinence. Males on the protocol must use an
effective form of contraception at study entry, and for one year post-transplant. The
effects of transplant, the radiation, and the medications used after transplant may be
harmful to a fetus.

- Presence of active malignancy in another organ system other than the hematopoietic
system, except when driven by viruses in which case the immune reconstitution after
transplant may control the malignancy.

- No available 10/10 or 9/10 HLA-matched related or unrelated donor or haploidentical
related donor.

INCLUSION CRITERIA - MATCHED RELATED DONOR:

- Related donors matched at HLA-A, B, C, DR, and DQ loci by high resolution typing
(10/10 antigen/allele match) are acceptable donors. Alternatively, a 9/10 matched
related donor can be used.

- Ability to give informed consent; for donors <18 years of age, he/she must be the
oldest eligible donor, their legal guardian must give informed consent, the donor must
give verbal assent, and he/she must be cleared by social work and a mental health
specialist to participate.

- Age 2-60 years, and weight of greater than or equal to 15 kilograms.

- At least one normal DOCK8 allele demonstrated by a CLIA-certified lab.

- Adequate venous access for peripheral apheresis, or consent to use a temporary central
venous catheter for apheresis, if applicable.

- Donors must be HIV negative, hepatitis B surface antigen negative, and hepatitis C
antibody negative. This is to prevent the possible transmission of these infections to
the recipient.

- A donor who is lactating must be willing and able to interrupt breast-feeding or
substitute formula feeding for her infant during the period of filgrastim
administration and for two days following the final dose. Filgrastim may be secreted
in human milk, although its bioavailability from this source is not known.

- Matched related donors that will undergo marrow harvest with general anesthesia.
Subjects will undergo anesthesia consultation, and meet criteria for
eligibility/enrollment. CD34+ fraction will be determined.

- Matched related donors that will have their cells collected via apheresis will also
undergo the Donor Health History Screen to determine donor eligibility using standard
DTM criteria in the Dowling Apheresis Clinic by skilled staff in the Blood Services
Section for adult patients and age-appropriate questioning when indicated for
pediatric subjects.

INCLUSION CRITERIA - MATCHED UNRELATED DONOR:

1. Unrelated donor matched at 10/10 or 9/10 HLA-A, B, C, DR, and DQ loci by high
resolution typing.

2. The evaluation of donors shall be in accordance with existing NMDP Standard Policies
and Procedures. General donor inclusion criteria specified in the NMDP Standards.

INCLUSION CRITERIA - HAPLOIDENTICAL RELATED DONOR:

1. A haploidentical donor that shares one haplotype in common with the recipient such
that HLA compatibility will be a minimum of 5 out of 10 HLA loci matched. The HLA loci
to be tested will be HLA A, B, Cw, DRB1, and DQB1. A minimum number of mismatches are
desirable; however if several options are available the selection of a donor will be
based on the loci where the mismatch occurs and the relative importance of its
potential immunological function. Donor-recipient pairs will initially be typed
molecularly to provide a low resolution typing (antigen-level) to aid in the selection
of the potential donor. Upon review of the familial inheritance pattern, a qualified
HLA staff member will review haplotype inheritance. High resolution (allele-level)
typing will be performed. Final selection of a donor will be in consultation with NCI
physicians and qualified HLA personnel. If more than one haploidentical related donor
is available, we will evaluate each donor individually according to overall health,
ABO matching, CMV, etc. to select the donor

2. Age 4-60 years and weight of greater than or equal to 15 kilograms.

3. At least one normal DOCK8 allele demonstrated by a CLIA-certified lab in a sibling
donor.

4. No history of life-threatening opportunistic infections

5. Adequate venous access for peripheral apheresis, or consent to use a temporary central
venous catheter for apheresis (if applicable).

6. Donors must be HIV negative, hepatitis B surface antigen negative, and hepatitis C
antibody negative. This is to prevent the possible transmission of these infections to
the recipient.

7. Haploidentical donors will undergo marrow harvest with general anesthesia. Subjects
will undergo anesthesia consultation, and meet criteria for eligibility/enrollment.
CD34+ fraction will be determined.

8. Subjects will also undergo the Donor Health History Screen to determine donor
eligibility using standard DTM criteria in the Dowling Apheresis Clinic by skilled
staff in the Blood Services Section for adult patients and age-appropriate questioning
when indicated for pediatric subjects.

9. Adult related donors would be preferred over related donors who are minors.

10. Subjects will undergo follow-up evaluation within 1 week of donation.

EXCLUSION CRITERIA-MATCHED RELATED DONOR:

- History of severe cutaneous viral infections with herpes simplex, herpes zoster, or

molluscum contagiosum.

- HIV infection.

- Chronic active hepatitis B. Donor may be hepatitis core antibody positive.

- Other medical contraindications to stem cell donation (i.e. severe atherosclerosis,
autoimmune disease, iritis or episcleritis, deep venous thrombosis, cerebrovascular
accident).

- History of prior malignancy. However, cancer survivors who have undergone potentially
curative therapy may be considered for stem cell donation on a case-bycase basis. The
risk/benefit of the transplant and the possibility of transmitting viable tumor cells
at the time of transplantation will be discussed with the patient.

- Donors must not be pregnant. Pregnancy is an absolute contraindication under this
protocol. The effects of cytokine administration on a fetus are unknown. Donors of
childbearing potential must use an effective method of contraception. Effective forms
of contraception include one or more of the following: intrauterine device (IUD),
hormonal (birth control pills, injections, or implants), tubal ligation/hysterectomy,
partner s vasectomy, barrier methods, (condom, diaphragm, or cervical cap), or
abstinence.

- Other medical conditions that in the opinion of the PI constitute exclusion as a
donor.

- Mutation of DOCK8 on both alleles.

EXCLUSION CRITERIA - MATCHED UNRELATED DONOR:

a) Failure to qualify as an NMDP donor.

EXCLUSION CRITERIA - HAPLOIDENTICAL RELATED DONOR:

- HIV infection

- Chronic active hepatitis B. Donor may be hepatitis core antibody positive.

- History of psychiatric disorder which in the opinion of the PI may compromise
compliance with transplant protocol, or which does not allow for appropriate informed

- Other medical contraindications that in the opinion of the PI constitute exclusion as
a donor. History of prior malignancy. However, cancer survivors who have undergone
potentially curative therapy may be considered for stem cell donation on a case-bycase
basis. The risk/benefit of the transplant and the possibility of transmitting viable
tumor cells at the time of transplantation will be discussed with the patient.

- Donors must not be pregnant. Pregnancy is an absolute contraindication under this
protocol. The effects of cytokine administration on a fetus are unknown. Donors of
childbearing potential must use an effective method of contraception. Effective forms
of contraception include one or more of the following: intrauterine device (IUD),
hormonal (birth control pills, injections, or implants), tubal ligation/hysterectomy,
partner s vasectomy, barrier methods, (condom, diaphragm, or cervical cap), or
abstinence.

- Mutation of DOCK8 on both alleles in a sibling donor.