Phase II Study of Ofatumumab Plus Ifosfamide, Carboplatin, Etoposide (ICE) or Dexamethasone, Cytarabine, Cisplatin (DHAP) Chemotherapy Regimen in Relapsed/ Refractory Diffuse Large B Cell Lymphoma (DLBCL)

Inclusion Criteria:

* Subjects with CD20 positive aggressive non-Hodgkin's lymphoma (NHL) including DLBCL, transformed follicular lymphoma (FL) \& grade 3b FL.

Refractory to, or relapsed following, first-line treatment with rituximab combined with anthracycline- or anthracenedione-based chemotherapy as defined by the protocol.

* Computed tomography (CT) with involvement of 2 or more clearly demarcated lesions with a long axis \> 1.5 centimeters (cm) and short axis ≥ 1.0 cm or 1 clearly demarcated lesion with a long axis \>2.0 cm and short axis ≥1.0 cm.
* Baseline \[18F\] fluorodeoxyglucose (FDG)-positron emission tomography (PET) scans must demonstrate positive lesions compatible with CT defined anatomical tumor sites.
* Age 18 yrs or older.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2.
* Eligible for high dose chemotherapy and autologous stem cell transplant (ASCT).
* Resolution of toxicities from first-line therapy to a grade that in the opinion of the investigator does not contraindicate study participation.
* Signed written informed consent.

Exclusion Criteria:

* Previous cancer therapy for lymphoma, with the exception of required rituximab/ anthracycline- or anthracenedione-based chemotherapy, monotherapy rituximab prior to first-line therapy and / or as a maintenance therapy, or limited field radiotherapy (as defined by the protocol).
* Any anti-cancer therapy, except limited field radiotherapy, within 2 weeks prior to start of study therapy.
* Chronic Glucocorticoid use (limited acute use is allowed and defined by the protocol).
* History of significant cerebrovascular disease.
* Abnormal/ inadequate white blood cell (WBC) count, liver, and kidney function.
* Clinically significant cardiac disease, active or chronic infections, serious significant diseases, other cancer within last 5 years.
* Known or suspected hypersensitivity to study treatments.
* Prior treatment with anti-CD20 monoclonal antibodies, at any time, or treated with other monoclonal antibodies within 3 months prior to start of study therapy, with the exception of rituximab in both instances.
* Inability to comply with the protocol activities.
* Pregnant or lactating women or female patients of child-bearing potential (or male patients with such partners) not willing to use adequate contraception during and up to 1 year following dosing completion.