This study will examine the safety profile of SGN-CD70A. The study will test increasing doses of SGN-CD70A given every 3 weeks (or an alternate dosing schedule up to every 6 weeks) to small groups of patients. The goal is to find the highest dose of SGN-CD70A that can be given to patients without causing unacceptable side effects. The pharmacokinetics and antitumor activity of SGN-CD70A will also be evaluated.

Inclusion Criteria:

• Metastatic renal cell carcinoma, mantle cell lymphoma, or diffuse large B-cell lymphoma including Grade 3b follicular lymphoma
• Relapsed, refractory, or progressive disease following at least 2 prior systemic therapies
• Confirmed positive CD70 expression on tumor tissue
• Eastern Cooperative Oncology Group performance status 0 or 1
• Adequate baseline hematologic, pulmonary, renal, and hepatic function
• Measurable disease

Exclusion Criteria:

• Prior treatment with anti-CD70 directed therapy unless CD70 expression is confirmed on tumor tissue obtained after the treatment
• Patients <100 days since prior allogeneic stem cell transplant
• Less than 4 weeks since prior treatment; or 2 weeks if patient experienced disease progression on the prior treatment