PET/CT to Predict Response to Infliximab Therapy in Patients With Crohn's Disease

The costs and potential complications (side effects) of therapies currently used to treat
Crohn's disease could potentially be reduced if a non-invasive test existed that determined
which therapies benefit patients and which do not. Currently, once therapies are prescribed,
doctors rely solely on clinical parameters to gauge whether the therapies are helpful. This
includes evaluation of overall general well-being, abdominal pain, and number of liquid
stools per day. There is no established and reliable non-invasive test that can predict
whether a person is responding to therapy early in the course of treatment when these
evaluations may be inconclusive.

During this research study we will look for changes in sugar metabolism on low-dose PET/CT
before and 2 weeks after the first infusion of infliximab therapy. This is to find out if
these changes can predict clinical response and steroid-free remission at two, six and 12
months, in patients with Crohn's disease.

PET/CT can be used to detect active inflammation (reaction of a part of the body to injury
or infection) in Crohn's disease as well as complications such as ulcers, fissures, and
strictures (thinning of, breaks in, and fixed narrowing of the bowel, respectively). PET
(positron emission tomography) scans take pictures using special dyes that "light up" inside
the body. This happens because the special dyes contain radiation, which is similar to the
radiation in a standard x-ray. CT (computed tomography) uses x-rays and a computer to make
pictures.

The radioactive tracer that will be used in this study is FDG. FDG is a radioactive sugar.
FDG is approved by the U.S. Food and Drug Administration (FDA). This tracer can show early
response to chemotherapy or other cancer treatments for a variety of tumors. Changes in FDG
uptake accurately predict persistent response in as little as hours to days after therapy
has begun. These changes often happen weeks to months before anatomic changes on CT or MRI.
Sometimes the CT or MRI never changes.

One of the few FDG PET studies looking at treatment for an inflammatory condition showed
that FDG uptake decreased significantly within two weeks of starting therapy for rheumatoid
arthritis. Accurate early assessment with FDG PET/CT shortly after starting therapy with
infliximab has the potential to change the standard clinical approach to both initial and
continuing infliximab therapy in patients with Crohn's disease.

Inclusion Criteria:

- New diagnosis of symptomatic Crohn's disease or an established diagnosis of Crohn's
disease with a suspected flare.

- Appropriate clinical candidate for infliximab induction therapy, as determined by the
patient's gastroenterologist

Exclusion Criteria:

- Anti-TNF medications in the previous 6 months

- Pregnancy or plan to become pregnant

- Severe claustrophobia, sufficient to preclude PET/CT scanning