A Phase II Trial of Regadenoson in Sickle Cell Anemia

If you are willing to participate in this research study you will be asked to undergo some
screening tests and procedures to confirm your eligibility. Many of these tests and
procedures are likely to be part of regular sickle cell anemia care and may be done even if
it turns out that you do not take part in the research study. If you have had some of these
tests and procedures recently, they may or may not have to be repeated. The tests and
procedures include: a medical history, physical examination, blood tests, blood or urine
pregnancy test (if applicable) and an electrocardiogram. If these tests show that you are
eligible to participate in the research study, you will begin the study treatment. If you do
not meet the eligibility criteria, you will not be able to participate in the research study.
At the time of screening we will also ask you about your pain level.

Because no one knows which of the study options is best, you will be "randomized" into one of
the study groups: the "study drug" group, which will receive Regadenoson, or the "control"
group, which will receive placebo. Randomization means that you are put into a group by
chance. It is like flipping a coin. Neither you nor the research doctor will choose what
group you will be in. You will have an equal (50/50) chance of being placed in either group.
Neither you nor the research doctor will know what group you are in.

You will be given a study medication and it will contain either Regadenoson or placebo
(fluids with no medicine).

You will be given one infusion of the study drug while you are admitted to the hospital for a
pain crisis. The study drug will be infused with fluids. You will stay in the hospital for at
least 3 days and 2 nights. Your infusion will be 48 hours long, followed by a 6-hour
observation period. During your infusion, you will receive standard treatment for your pain
crisis. The study drug will be given through a separate part of your body from the infusions
that are part of your standard treatment. The study drug will not be available after your
participation in the study ends.

Before the infusion: We will place a small tube in your vein called an IV, which will be used
only to infuse the study drug. It will not be used for infusions that are part of standard
treatment for your pain crisis. During the study drug infusion, standard treatment will be
given through a separate IV. We can use your standard treatment IV or a needle to draw blood
for the required blood test. If it is hard to draw blood from your veins, we may ask you if
you would like to use a peripherally inserted central catheter (PICC line) for your blood
draws. A PICC line is a small tube that is placed in a vein in your arm and goes through to a
vein in your chest. A chest x-ray is usually done to make sure it is in the right veins. It
is your choice to decide whether you would like to use a PICC line. We will record your blood
pressure and heart rate every 5-10 minutes, until they have stabilized. We will also ask you
about your pain level at the time of your blood test.

During the 48 hour infusion: Your heart rate and the amount of oxygen in your blood will be
monitored continuously using a device that fits over your finger. We will take about 2-3
teaspoons of blood at 24 and 48 hours after the beginning of your infusion for tests to try
to understand how the drug affects your body. We will ask you about your pain level at the
time of each blood test. We will take your blood pressure every 30 minutes for the first 2
hours, then every hour for the next two hours, then every 2 hours for the remainder of the
infusion.

A six hour observation period will take place immediately after the infusion. At this time
you will undergo the following: your heart rate and the amount of oxygen in your blood will
be monitored continuously with a device that fits over your finger. We will take about 5
teaspoons of blood at the end of the period to try to understand how the study drug affects
your body. We will ask you about your pain level at the time of your blood test. We will take
your blood pressure every 2 hours for the full duration of the observation period.

You may not eat or drink anything that contains caffeine, such as coffee, tea, chocolate or
sodas during the infusion and observation periods.

We would like to keep track of your medical condition for 30 days after you receive the study
drug. We would like to do this by contacting you on the telephone weekly during the 30 days
after your participation to see how you are doing.

Inclusion Criteria:

- Must have sickle cell anemia confirmed by hemoglobin analysis

- Must be admitted to hospital for pain or ACS

- Reliable IV access as determined by the study physician

- Participants must have the laboratory indices as defined below:

- Hemoglobin ≥ 5 g/dL

- Platelets > 100,000/mcL

- ALT (SGPT) < 3 X institutional upper limit of normal

- Serum creatinine ≤ 1.5 mg/dL

- INR ≤2.0, PTT ≤ 48 seconds

Exclusion Criteria:

- Pregnant or breastfeeding

- Current physician diagnosis of asthma defined by treatment with systemic
corticosteroids within the last 12 months or predicted/current use of asthma
controller medications

- 10 or more hospitalizations for pain in the last 12 months

- Receiving regularly scheduled transfusions

- Severe ACS

- Second or third degree AV block or sinus node dysfunction

- History of a bleeding diathesis

- History of clinically overt stroke within 3 years

- History of severe hypertension not adequately controlled with anti-hypertensive
medications

- Receiving chronic anti-coagulation or anti-platelet therapy

- History of metastatic cancer

- Receiving any other study agents or have received a study agent in the past 30 days

- Uncontrolled intercurrent illness

- Known HIV

- Have previously enrolled and received the investigational agent as part of this study

- Taking medications that may interact with the investigational agent

- Have previously undergone a hematopoietic stem cell transplant or solid organ
transplant