Sanaria PfSPZ Challenge With Pyrimethamine Chemoprophylaxis (PfSPZ-CVac Approach): Phase 1 Trial to Determine Safety and Protective Efficacy of Sanaria PfSPZ Challenge With Concurrent Pyrimethamine Treatment That Inhibits Development of Asexual B...

Human studies have shown that immunization by the bite PfSPZ-infected mosquitoes under drug
coverage with chloroquine, an approach called chemoprophylaxis with sporozoites (CPS),
infection treatment vaccination (ITV), or chemoprophylaxis vaccination (CVac) can provide
high level, long term protection against homologous controlled human malaria infection
(CHMI). The Sanaria PfSPZ-CVac approach duplicates this with an injectable sporozoite (SPZ)
regimen (aseptic, purified, cryopreserved SPZ). In both approaches, whether mosquitoes or a
syringe are used for SPZ administration, when chloroquine is used as the chemoprophylactic
agent, transient, limited, asexual erythrocytic stage (AES) parasitemia develops. However,
exposure to liver stage parasites only, without having any parasites completing liver stage
development and entering the blood, thereby reducing the potential to induce blood stage
immunity, likewise has been shown in animal studies to induce protective immunity upon
subsequent challenge with homologous parasites, indicating that the transient parasitemia is
not integral to inducing protection. To achieve this requires a different partner drug
regimen that includes activity against liver stage parasites.

Our approach, using PfSPZ-CVac with pyrimethamine (PYR), will assess this in humans. This
phase 1 study will investigate the safety, tolerability, immunogenicity, and protective
efficacy following liver stage only parasite exposure of direct venous inoculation (DVI)
with aseptic, purified, cryopreserved Plasmodium falciparum (Pf) sporozoites (Sanaria PfSPZ
Challenge), under chloroquine and pyrimethamine chemoprophylaxis, to induce stage specific
sterile protection. By adding pyrimethamine chemoprophylaxis to chloroquine, liver stages
will develop but should be killed before merozoites are released into the blood stream. The
subjects will thus be exposed only to liver stage parasites (qPCR and blood smear negative).
With this strategy, we will determine if protective immunity can develop without exposure to
AES parasites and additionally whether it will minimize clinical symptoms associated with
blood stage exposure. The timing of the pyrimethamine dose is critical to ensure the
efficacy of pyrimethamine as causal prophylaxis, yet still allow for maximal antigenic
exposure of liver-stage parasites to the host. An additional potential benefit of preventing
AES parasitemia is the elimination of the immunosuppression associated with AES parasitemia.

This trial will be the first step in establishing a new regimen for the PfSPZ-CVac approach,
exposure to liver stage parasites without subsequent blood stage parasites, assessing
protection against homologous CHMI. In future trials, the two-drug regimen can be assessed
for protection against heterologous Pf infection and longevity of protection. The results of
the study will contribute to understanding the targets and mechanisms of immunity against Pf
malaria infection.

- INCLUSION CRITERIA:

All of the following criteria must be fulfilled for a subject to participate in this
trial:

1. Age greater than or equal to 18 and less than or equal to 50 years.

2. In good general health and without clinically significant medical history

3. Malaria comprehension exam completed, passed (a score of greater than or equal to 80%
or per investigator s discretion) and reviewed prior to enrollment

4. Reliable access to the clinical trial center and availability to participate for
duration of study

5. Females of childbearing potential must be willing to use reliable contraception (as
defined below) from 21 days prior to study day -2 to 28 days following last Sanaria .

- Subject to the judgment and discretion of the PI, female participants who meet
ANY ONE of the criteria listed immediately below, may not be required to take
any additional measures to avoid pregnancy. Such participants will be counseled
on risks at the time of consent and at appropriate points (e.g. when pregnancy
testing occurs) during the study:

- Females who have had their uterus, and/or BOTH ovaries removed

- Females who have had BOTH fallopian tubes surgically tied or removed

- Females who are above the age of 45 and have spontaneously had no menses at
any point during the past 12 or more consecutive months (i.e. have reached
menopause)

- Females who, in the conservative and reasonable judgment of the PI (e.g.
due to sexual orientation or serious life choice (such as being celibate
clergy or transgender), during the entire trial will NOT participate in any
potentially reproductive sexual contact

- Females who, in the conservative and reasonable judgment of the PI, are in
a monogamous stable relationship with a male who has undergone vasectomy at
least 4 months prior or another procedure/medical condition that deems the
male sterile

- Subject to the judgment and discretion of the PI, female participants who DO NOT
meet ANY of the criteria listed above, will be appropriately counseled on
reproductive risks and pregnancy avoidance, and will be required to adhere to
the following measures and agree to 2 methods of pregnancy prevention as noted
below:

CATEGORY 1:

- a highly effective hormonal method to prevent pregnancy [e.g. CONSISTENT, CONTINUOUS
use of contraceptive pill, patch, ring, implant or injection], and/or

- IUD or equivalent

IN ADDITION TO

CATEGORY 2:

-a barrier method to be used at the time of potentially reproductive sexual activity (e.g.
[male/female condom, 'cap,' or diaphragm] plus spermicide).

EXCLUSION CRITERIA:

A subject will be excluded from participating in this trial if any one of the following
criteria is fulfilled:

1. Currently is breast-feeding (if female).

2. Pregnancy as determined by a positive urine or serum human choriogonadotropin
(beta-hCG) test at any point during the study (if female).

3. Recent travel to a malaria endemic area within 5 years of enrollment

4. Planned travel to a malaria endemic area during the study period

5. History of confirmed malaria diagnosis on peripheral blood smear or by clinical
history in the past 10 years.

6. Hemoglobin, WBC, platelets, ALT, and creatinine outside of local lab normal range
(subjects may be included at the investigator s discretion for not clinically
significant values outside of normal range)

7. Abnormal urinalysis as defined by positive urine glucose, protein, and hemoglobin.
Subject can be included if investigator determine the abnormality is not clinically
significant .

8. Anticipated use during the study period, or use within the following periods prior to
enrollment:

1. Investigational malaria vaccine within the last five years

2. Malaria chemoprophylaxis within 6 months

3. Chronic systemic immunosuppressive medications (>14 days) within 6 months
(e.g.cytotoxic medications, oral/parental corticosteroids >0.5 mg/kg/day
prednisone or equivalent). Corticosteroid nasal spray for allergic rhinitis and
topical corticosteroids for mild, uncomplicated dermatitis are allowed.

4. Blood products or immunoglobulins within 6 months

5. Systemic antibiotics with antimalarial effects within 30 days (such as
clindamycin, doxycycline)

6. Investigational or non-registered product or vaccine within 30 days

7. Receipt of a live vaccine within 28 days or a killed vaccine within the 14 days
prior to Sanaria PfSPZ Challenge

8. Medications known to interact with pyrimethamine, chloroquine, atovaquone,
proguanil (during the study period only)

9. History of:

1. Sickle cell disease, sickle cell trait, or other hemoglobinopathies

2. Splenectomy or functional asplenia

3. Systemic anaphylaxis

4. Any allergic reactions to study drugs

5. Documented history of chronic or active neurologic disease (including seizures,
uncontrolled migraine headaches)

6. Psoriasis or porphyria

7. Ocular diseases including retinopathy or visual field defects

10. Clinically significant medical condition, physical examination findings, other
clinically

significant abnormal laboratory results, or past medical history that may have
clinically significant implications for current health status and participation in
the study in the opinion of the Investigator. A clinically significant condition or
process includes but is not limited to:

1. A process that would affect the immune response, or requires medication that
affects the immune response

2. Any contraindication to repeated phlebotomy

3. A condition or process in which signs or symptoms could be confused with
reactions to malaria challenge and/or infection, including dermatologic
abnormalities at the site of sporozoite inoculation

4. A chronic or subclinical condition which could be exacerbated by administration
of any of the PfSPZ-CVac components or malaria infection

11. Weight > 77.2 Kg at the time of screening (this will result in a minimum dose of
pyrimethamine of approximately 0.7mg/Kg for a 50mg daily dose). (Note not required
for Arm 4 CHMI controls)

12. History of, or known active cardiac disease including: (1) prior myocardial
infarction (heart attack); (2) angina pectoris; (3) congestive heart failure; (4)
valvular heart disease; (5) cardiomyopathy; (6) pericarditis; (7) stroke or transient
ischemic attack; (8) exertional chest pain or shortness of breath; or ( 9) other
heart conditions under the care of a doctor

13. Clinically significant ECG findings, as determined by the expert study cardiologist

14. Moderate or high risk for coronary heart disease (CHD) based on NHANES I
cardiovascular risk assessment

15. Acute illness at the time of enrollment

16. Infection with HIV, Hepatitis B, Hepatitis C

17. Psychiatric condition that precludes compliance with the protocol including but not
limited to:

1. Psychosis within the past 3 years

2. Ongoing risk for suicide, or history of suicide attempt or gesture within the
past 3 years

18. Suspected or known current alcohol or drug abuse as defined by the American
Psychiatric Association in the DSM V at the discretion of the PI

19. Clinical trial staff and/or Sanaria employees with direct involvement in the conduct
of the trial are excluded from participation.

20. Participating in other clinical trials involving investigational interventions or off
label medication use during the study period (excluding participation in the optional
long term follow up visits). Participation in other trials such as observational or
imaging studies will be discussed with the investigators.

21. Any other finding that, in the judgment of the Investigator, would interfere with, or
serve as a contraindication to, protocol adherence, assessment of safety or
reactogenicity, or a subject s ability to give informed consent, or increase the risk
of having an adverse outcome from participating in the study