A Study to Assess Safety,and Tolerability of 2 Doses of AZD9773 (CytoFab™) in Japanese With Severe Sepsis/Septic Shock

Inclusion Criteria: * Japanese adults with a first episode of sepsis during this hospitalisation and objective evidence of infection that requires parenteral antibiotics. * At least 2 of 4 SIRS criteria in the 24 hours before organ dysfunction (must include either fever OR elevated white blood cells \[WBC\]) * Cardiovascular or respiratory dysfunction. Exclusion Criteria: * Immunocompromising comorbidities or concomitant medications: 1. Advanced human immunodeficiency virus (HIV) infection (CD4 ≤50/mm3). 2. Haemopoietic or lymphoreticular malignancies not in remission. 3. Receiving radiation therapy or chemotherapy. 4. Any organ or bone marrow transplant within the past 24 weeks. 5. Absolute neutrophil count \<500 per μL. 6. High dose steroids or other immunocompromising drugs. * Concomitant diseases: 1. Deep-seated fungal infection or active tuberculosis. 2. Severe chronic liver disease associated with portal hypertension, cirrhosis, chronic ascites or Child-Pugh class C. 3. History of chronic hypercarbia, respiratory failure in past 6 months or use of home oxygen in the setting of severe chronic respiratory disease. 4. Neuromuscular disorders that impact breathing/spontaneous ventilation. 5. Quadriplegia. 6. Cardiac arrest in the past 30 days. 7. New York Heart Association functional Class III or IV due to heart failure or any disorder. 8. Burns over \> 30% of body surface area in the past 5 days. * Medication and allergy disqualifications. 1. Treatment with anti-TNF agents within the last 8 weeks. 2. Previously received ovine derived products (CroFab™, DigiFab™). 3. Sheep product allergy or allergy to papain, chymopapain.