This study was an early-phase trial arranged into two phases. The Phase I portion was a dose-escalation study designed to assess the safety, tolerability and to identify the maximum tolerated dose of SB-743921 in patients with Non-Hodgkin Lymphoma and Hodgkin Lymphoma. Phase II was intended to assess the activity, safety and tolerability of SB-743921 in patients with Indolent and Aggressive Non-Hodgkin's Lymphomas exclusively. The Phase II portion of the study was not initiated.

Inclusion Criteria: Phase 1: Patients with evaluable or measurable (by MRI or CT) Hodgkin's Disease or Non-Hodgkin's Lymphoma. Phase 2: Patients with Measurable Non-Hodgkin's Lymphomas (Indolent or Aggressive) only. - Patients with Indolent NHL must be relapsed or refractory to at least one prior line of therapy (CHOP, CVP, chlorambucil or fludaribine). Prior treatment with Rituximab is required. - Patients with Aggressive NHL refractory to (or relapsed from) at least one CHOP-based therapy who have had prior treatment with Rituximab and who are not candidates for high-dose chemotherapy or autologous stem cell transplantation. - ECOG performance status 0-2 - Autologous stem cell transplant recipients are eligible if 100 days have elapsed since procedure. Exclusion Criteria: Phase 1: History of prior radioimmunotherapy (Bexxar, Zevalin); These patients ARE permitted in the Phase 2 trial. - Current active malignancy besides NHL, except excised non-melanoma skin cancer, in-situ cervical or bladder cancer or early stage prostate cancer. - Patients with leptomeningeal of CNS lymphoma - Known allergy to and/or receipt of treatments contraindicated by administration of G-CSF - Patients with active Hepatitis B or C, or patients with HIV infection. - Pregnant or breast-feeding females. - Previous treatment with a KSP inhibitor

Adverse events were collected during the 28-day treatment period and at a 14-day follow up visit.

Patients who received at least 1 dose of treatment were considered eligible for safety.