The purpose of this study is to determine the effect of AZD1236 in patients with cystic fibrosis (CF) on inflammatory biomarkers in induced sputum, after a treatment period of 4 weeks.

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