Investigate the Effect of Different Doses of Lesogaberan (AZD3355) as add-on to PPI in GERD Patients With Partial Response to PPI

This study is being carried out to see whether AZD3355 is an effective treatment as an add-on to PPI therapy in patients with Gastroesophageal Reflux Disease (GERD) with a partial response to PPI and to compare this with Proton Pump Inhibitor (PPI) treatment alone. Another goal of the study is to examine which of the investigated doses of AZD3355 is optimal for treatment of these patients. This study will also measure levels of drug in the blood and see how well it is tolerated.

Inclusion Criteria:

• Provision of informed consent prior to any study specific procedures
• Have at least 6 months history of GERD
• Continuously treated during the last 4 weeks before enrolment with daily optimized unchanged PPI therapy for any GERD indication

Exclusion Criteria:

• Patients that have not experienced any GERD symptom improvement at all during PPI treatment
• Prior surgery of the upper gastrointestinal tract.
• Subject who have any of the following conditions or diseases: Heart disease, Angina, Seizure disorders such as epilepsy, Congestive Heart Failure (CHF), Liver disease such as Cirrhosis or Hepatitis, Kidney disease, Lung disease or lung cancer, Cancer