EZ-2053 in the Prophylaxis of Acute Pulmonary Allograft Rejection

Inclusion Criteria: * Recipient of a primary single or double pulmonary allograft * Capable of understanding the purposes and risks of the study and has given written informed consent, and agrees to comply with the study requirements * Women of childbearing potential must have a negative serum pregnancy test within 4 days prior to randomization. Exclusion Criteria: * Undergoing second or living donor transplant * Prior treatment with T-cell depleting agents within the previous 5 years for the purpose of immunosuppression * Prior plasma exchange and/or treatment with IVIg within the past 5 years * Pulmonary infection with pan-resistant Pseudomonas or any Burkholderia species * Known positive blood cultures * Donor lung ischemia time \> 8 hours for first lung and \> 8 hours for the second lung * Previously received or is receiving a multi-organ transplant * Pregnant women, nursing mothers or women of child-bearing potential who are unwilling to use reliable contraception. Effective contraception must be used BEFORE beginning study drug therapy, for the duration of the study and for 6 months following completion of the study * Active, extra-pulmonary systemic infection requiring the prolonged or chronic use of antimicrobial agents or the presence of a chronic active hepatitis B or C * Active liver disease (liver function tests greater than or equal to 2 times the upper limit of normal) * Severe anemia (hemoglobin, \< 6 g/dL), leukopenia (WBC \< 2500/mm3), thrombocytopenia (platelet count \< 80,000/mm3), polycythemia (Hct \> 54% \[male\], Hct \> 49% \[female\]) or clinically significant coagulopathy * Recipient or donor is seropositive for HIV * Previous exposure or known contraindication to administration of the study drug or to rabbit proteins * Current malignancy or a history of malignancy (within the previous 5 years), except non-metastatic basal cell or squamous cell carcinoma of the skin or carcinoma in-situ of the cervix that has been treated successfully * Unstable cardiovascular disease, or a myocardial infarction within the previous 6 months * Currently participating in another clinical trial with an investigational agent and/or is taking or has been taking an investigational agent in the 30 days prior to transplant and/or has not recovered from any reversible side effects of prior investigational drug * Unlikely to comply with visits schedule in the protocol * Any current history of substance abuse, psychiatric disorder or a condition that, in the opinion of the Investigator, may invalidate communication with the Investigator.