- B-CLL patients with refractory or relapsed disease who have received one or more (≥ 1) prior lines of treatment which must have included either a fludarabine based regimen or an alkylator based regimen. Refractoriness is defined as any patient who has failed to achieve a CR, nPR or PR according to the National Cancer Institute (NCI) working group guidelines for CLL. Fludarabine refractoriness will also include patients who achieved a CR, nPR or PR of ≤ 6 months duration.