Study to Assess Efficacy of AZD1236 in Patients With Cystic Fibrosis

Inclusion Criteria: * Provision of informed consent prior to any study specific procedures * Have a clinical diagnosis of cystic fibrosis with an FEV1 \>40% of predicted normal * Be able to comply with induced sputum procedure * post-menopausal surgically sterile female (total hysterectomy and /or bilateral total oophorectomy) Exclusion Criteria: * Concomitant diagnosis of significant pulmonary disease other than CF-related lung disease, including symptomatic asthma and allergic bronchopulmonary aspergillosis * Treatment with any immunomodulatory agents within 8 weeks prior to Visit 2 * Known to be infected with Burkholderia cepacia