Inclusion Criteria:

- Histologically confirmed diagnosis of relapsed/refractory MCL or hematologically/bone
marrow confirmed relapsed/refractory CLL that is not amenable to cure by surgery or
other means and has failed at least 1 prior systemic therapy;

- Subjects may have been treated with up to 6 prior systemic therapies for
relapsed/refractory disease or have become intolerant to a systemic therapy

- For MCL, must have measurable disease

- At least 4 weeks since the last systemic therapy, including RT, for the treatment of
MCL/CLL;

- At least 4 weeks since taking any corticosteroids prior to the first dose of MDX-1411

- ECOG Performance Status 0 to 2;

- No known positivity for human immunodeficiency virus (HIV) and no active infection
with Hepatitis B or Hepatitis C;

Exclusion Criteria:

- History of severe hypersensitivity reactions to other monoclonal antibodies;

- Use of other investigational drugs within 30 days before study drug administration

- Prior treatment with any other anti-CD70 antibody;

- Active infection requiring i.v. systemic therapy within 4 weeks of receiving the
first dose of MDX-1411;

- Evidence of bleeding diathesis or coagulopathy;

- Active autoimmune disease requiring immunosuppressive therapy;

- Known current drug or alcohol abuse;

- Underlying medical conditions that will make the administration of MDX-1411 hazardous