Randomized Phase II Trial of Rituximab With Either Pentostatin or Bendamustine for Multiply Relapsed or Refractory Hairy Cell Leukemia

28 participants to pentostatin 4 mg/m\^2 days 1 and 15 of each cycle.

Rituximab 375 mg/m\^2 on day 1, 15 for 6 x 28-day cycles

1-4 participants to bendamustine 90 mg/m\^2/day, days 1 and 2 each cycle

Treatment of infusion-related symptoms with acetaminophen is recommended.

Treatment of infusion-related symptoms with diphenhydramine is recommended.

Epinephrine should be available for immediate use in the event of a hypersensitivity reaction to Rituximab.

Antihistamines should be available for immediate use in the event of a hypersensitivity reaction to Rituximab.

Corticosteroids should be available for immediate use in the event of a hypersensitivity reaction to Rituximab.

Additional treatment with bronchodilators may be indicated.

Additional treatment with intravenous (IV) saline may be indicated.