Inclusion Criteria:

          1. Male or female age 18 years or older.

          2. Refractory or relapsed lymphoma (per World Health Organization (WHO) Classification
             system)

          3. Pathologically confirmed relapsed or refractory lymphoma

          4. Availability of formalin-fixed paraffin-embedded (FFPE) tumor tissue block.

          5. Measurable disease, defined by the 2014 Lugano Classification Criteria

          6. Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2.

          7. Absolute neutrophil count ≥1500/µL.

          8. Platelet count of ≥75000/µL.

          9. Hemoglobin ≥9.0 g/dL without transfusion within the 2 weeks prior to Day 1.

         10. Creatinine ≤1.5mg/dL

         11. Serum alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase
             ≤2 times the upper limit of normal (ULN); ≤ 5 times ULN if there is liver or bone
             involvement.

         12. Total serum bilirubin ≤1.5 times ULN

         13. Women of childbearing potential must have a negative serum beta-human chorionic
             gonadotropin pregnancy test within 7 days prior to Day 1.

         14. Women of childbearing potential must agree to use a highly effective method of
             contraception. Men with female partners who are of childbearing potential must agree
             that they or their partners will use a highly effective method of contraception.

        Exclusion Criteria:

          1. Patients who have an option for any treatment with proven clinical benefit for their
             lymphoid malignancy at current state of disease.

          2. Active graft-versus-host disease.

          3. Autologous or allogenic transplant within the 60 days prior to Cycle 1 Day 1.

          4. Evidence of myelodysplasia or myeloid leukemia by morphology, immunostains, flow
             cytometry, or cytogenetics on a bone marrow aspirate or biopsy.

          5. Known history of positive serum human anti-drug antibody (ADA), or known allergy to
             any component of ADCT-301

          6. History of symptomatic autoimmune disease

          7. Known seropositive for human immunodeficiency (HIV) virus, hepatitis B surface antigen
             (HbsAg), or antibody to hepatitis C virus (anti-HCV)

          8. History of Steven's Johnson's syndrome or toxic epidermal necrolysis syndrome.

          9. Pregnant or breastfeeding women.

         10. Significant medical comorbidities, including uncontrolled hypertension (diastolic
             blood pressure greater than 115 mm Hg), unstable angina, congestive heart failure
             (greater than New York Heart Association class II), severe uncontrolled ventricular
             arrhythmias, or electrocardiographic evidence of acute ischemia, poorly controlled
             diabetes, severe chronic pulmonary disease, coronary angioplasty, or myocardial
             infarction within 6 months prior to screening, or uncontrolled atrial or ventricular
             cardiac arrhythmias.

         11. Use of any other experimental medication(s) within 14 days prior to start of the study
             treatment.

         12. Major surgery, radiotherapy, chemotherapy, or other anti-neoplastic therapy (including
             prednisone ≥ 40 mg/day or equivalent) within 14 days or 5 half-lives (whichever is
             shorter) prior to Cycle 1, Day 1 treatment.

         13. Failure to recover (to Common Terminology Criteria for Adverse Events [CTCAE Version
             4.0] Grade 0 or Grade 1) from acute non-hematologic toxicity (except alopecia or Grade
             2 or lower neuropathy), due to previous therapy, prior to Screening.

         14. Congenital long QT syndrome or a corrected QTc interval ≥ 470 ms at screening

         15. Active second primary malignancy other than non-melanoma skin cancers, nonmetastatic
             prostate cancer, in situ cervical cancer, ductal or lobular carcinoma in situ of the
             breast, or other malignancy

         16. Any other significant medical illness, abnormality, or condition