Primary trial objective in this three arm trial is to assess the safety and tolerability of EMD 521873, and to determine whether the maximum tolerated dose (MTD) is reached with EMD 521873 doses of up to 1.5 mg/kg given alone or in combination with fixed, low-dose cyclophosphamide (CPA) in patients with metastatic or locally advanced solid tumors or B-cell non-Hodgkin lymphoma.

Secondary objectives are to evaluate pharmacokinetic, immunogenicity, overall and best clinical response, changes in tumor marker levels, survival and biological/immune responses to EMD 521873. A total of 78 patients are planned. Patients will remain on the dose throughout the trial. It is intended to administer 3 cycles (21 d each, or until progression or a xxx line therapy becomes necessary.

Inclusion Criteria:

1. Signed written informed consent
2. Male or female, aged ≥ 18 years, inpatient for treatment phase of cycle 1 and 2, outpatient treatment possible for subsequent cycles
3. Histologically or cytologically proven metastatic or locally advanced solid tumors (epithelial or mesenchymal cancers) or B-cell non-Hodgkin lymphoma for which no standard therapy exists or after failure of standard therapy
4. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 at study entry and an estimated life expectancy of at least 3 months
5. Adequate hematological function defined by WBC count ≥ 3 x 109/L with absolute neutrophil count (ANC) ≥ 1.5 x 109/L and lymphocyte count ≥ 0.5 x 109/L; platelet count ≥100 x 109/L; hemoglobin ≥9 g/dL ( If the laboratory values for hemoglobin are outside the required entry level at Screening, a patient may receive a transfusion of RBC. A stable hemoglobin level of ≥9 mg/dL for at least 7 days must be achieved prior to receiving the first dose of study medication.)
6. Adequate hepatic function defined by a total bilirubin level ≤ 1.5 times the upper limit of normal (ULN) and aspartate-aminotransferase (AST) and alanine-aminotransferase (ALT) levels ≤ 2.5 x ULN or, for patients with documented metastatic disease to the liver, AST and ALT levels ≤ 5 x ULN
7. No history of acute or chronic kidney disease and adequate renal function defined by an estimated creatinine clearance above 50 mL/min determined by 24-hour urine sampling or by the Cockcroft-Gault formula
8. Effective contraception for both male and female subjects if the risk of conception exists

Exclusion Criteria:

1. Prior IL-2 therapy within the last 6 months
2. Requirement for concurrent anticancer treatment (chemotherapy, radiotherapy, immune therapy, cytokine therapy except erythropoietin) or for concurrent systemic therapy with steroids or other immunosuppressive agents. Short-term administration of steroids (i.e. for allergic reactions) is allowed.
3. Radiotherapy, chemotherapy, surgery (excluding prior diagnostic biopsy) or any investigational drug in the 30 days before the start of treatment in this study
4. Acquired immune defects such as human immunodeficiency virus (HIV)
5. Systemic autoimmune disease (e.g. lupus erythematodes, rheumatoid arthritis, Addison's disease, autoimmune disease associated with lymphoma)
6. Organ transplant recipients
7. History of or active inflammatory bowel disease (e.g. Crohn's disease, ulcerative colitis)
8. Chronic viral infections (e.g. hepatitis B virus [HBV], hepatitis C virus [HCV])
9. Uncontrolled hypertension (systolic >180 mmHg, diastolic >100 mmHg)
10. Known hypersensitivity reactions to any of the compounds of the study medication
11. Confirmed or clinically suspected brain metastases
12. Pregnancy (absence to be confirmed by beta-human chorionic gonadotropin [β-HCG] test) or lactation period
13. Clinically significant (i.e. active) cardiovascular disease: Cerebral vascular accident /stroke (< 6 months prior to enrolment), myocardial infarction (< 6 months prior to enrolment), unstable angina, congestive heart failure or serious cardiac arrhythmia requiring medication.
14. Pulmonary disease which, in the opinion of the investigator, might impair the patient's respiratory tolerance to moderate pulmonary fluid overload (e.g. interstitial lung disease, severe chronic obstructive pulmonary disease)
15. All conditions which are associated with significant necroses of non tumor-bearing tissues like e.g. esophageal or gastroduodenal ulcers (< 6 months prior to enrolment), organ infarctions (< 6 months prior to enrolment) or active ischemic bowel disease
16. Presence of medically significant third space fluid (pericardial effusion or ascites/ pleural infusion requiring repetitive paracentesis)
17. Known alcohol or drug abuse
18. Participation in another clinical trial within the past 30 days before start of study treatment
19. All other significant diseases which, in the opinion of the investigator, might impair the patient's tolerance of study treatment.
20. Dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent