Efficacy of Ferric Carboxymaltose in Gastrointestinal Stromal Tumor (GIST) Patients With Iron Deficiency Anemia (IDA) Receiving Systemic Therapy

The goal of this clinical research study is to compare Injectafer® (ferric carboxymaltose) with an iron supplement to learn which may be more effective in improving red blood cell counts in patients who have iron-deficiency anemia (a low red blood cell count) because of a gastrointestinal stromal tumor (GIST) and/or systemic therapy.

The safety of ferric carboxymaltose will also be studied.

This is an investigational study. Ferric carboxymaltose is FDA approved and commercially available to treat iron deficiency anemia; however, it is considered investigational to use in patients who have cancer-related or systemic therapy-related anemia.

Up to 50 participants will take part in this study. All will be enrolled at MD Anderson.

Study Groups and Study Drug Administration:

If you are found to be eligible to take part in this study, you will be randomly assigned (as in the flip of a coin) to 1 of 2 study groups. This is done because no one knows if one group is better, the same, or worse than the other.

* If you are in Group A, you will receive ferric carboxymaltose injection by vein over about 15 minutes. You will receive 2 injections about 7 days apart (for example, on Days 0 \[the day you are assigned to a study group\] and 7).
* If you are in Group B, you will take iron supplements by mouth every day. This is considered standard of care for iron deficiency anemia and the study staff will discuss with you which iron supplements you will take and their risks.

You and the study staff will know to which group you are assigned.

Length of Study:

You may receive up to 2 injections of ferric carboxymaltose (if you are in Group A) or up to 3 months of oral iron supplements (if you are in Group B). You will no longer be able to take the study drug if intolerable side effects occur or if you are unable to follow study directions.

Your participation on the study will be over after you have completed the Week 24 visit.

Study Visits:

Baseline (within 1 week after you have been assigned to a study group):

* You will have a physical exam.
* You will complete a questionnaire about your health. It should take about 5 minutes to complete.
* Blood (about 1 tablespoon) will be drawn for routine tests and to test the level of iron in your blood.

One (1) time every week during Months 1-3, blood (about 1 tablespoon) will be drawn for routine tests.

At about Weeks 4, 8, 12, and 24 (the end-of-study visit):

* You will have a physical exam (Weeks 12 and 24 only).
* You will complete the same questionnaire you did at baseline.
* Blood (about 1 tablespoon) will be drawn for routine tests and to test the level of iron in your blood.

During Weeks 16 and 20, blood (less than 1 tablespoon) will be drawn to test the level of iron in your blood.

If you leave the study before Week 24, you will have the Week 24 study visits as soon as possible after you leave the study.

Eligibility Criteria:
Inclusion Criteria:

1. GIST patients with IDA planned to start or are receiving systemic therapy with TKIs.
2. Evidence of iron deficiency anemia including, Hgb \< 11 g/dL, but \> 8 g/dL; and transferrin saturation (TSAT) \< 20%.
3. No H/O allergic reaction to iron therapy.
4. No clinical signs active of bleeding.
5. Adequate hematologic (ANC \> 1500/mm\^3, platelet count \> 100,000/mm\^3), renal (serum creatinine \< 1.5mg/dL), and hepatic (serum bilirubin count \< 1.5 x normal and serum glutamic-oxaloacetic transaminase (SGOT) or serum glutamic pyruvic transaminase (SGPT) \< 3 x normal) functions.
6. Patients must have Eastern Cooperative Oncology Group (ECOG) performance status of 0 - 2.
7. Signed informed consent to the study.
8. Male and Females of child bearing potential must use acceptable methods of birth control which include oral contraceptives, spermicide with either a condom, diaphragm or cervical cap, use of an intrauterine device (IUD) or abstinence.
9. Patients are required to read and understand English to comply with protocol requirements.
10. Age \>=18 years old.
11. Life expectancy of at least 6 months.

Exclusion Criteria:

1. Pregnant or lactating women.
2. Patients with any co-morbid condition which renders patients at high risk of treatment complication.
3. Patient has uncontrolled angina, congestive heart failure (New York Heart Association \> class II or known ejection fraction \< 40%), uncontrolled cardiac arrhythmia or hypertension, or acute myocardial infarction within 3 months.
4. Patient has an active seizure disorder. (Patients with a previous history of seizure disorders will be eligible for the study, if they have had no evidence of seizure activity, and they have been free of antiseizure medication for the previous 5 years).
5. Psychological, social, familial, or geographical reasons that would prevent scheduled visits and follow-up.
6. Prior surgery or radiotherapy (RT) within 2 weeks of study entry.
7. Known hypersensitivity reaction to any component of ferric carboxymaltose.
8. Any anemia treatment within 4 weeks before inclusion (oral iron, IV iron, or erythropoiesis-stimulating agents), or transfusion of PRBCs in 2 weeks.
9. Hemochromatosis or other iron storage disorders.
10. Known positive hepatitis with evidence of active disease.
11. Patients with overt bleeding.
12. Ferritin \>/= 800 ng/mL.