This is a 2 part study for patients with solid tumours. The purpose of Part A is to measure the amount of olaparib or its breakdown products in the bloodstream for up to 72 hours after eating 3 different breakfasts (high calorie, regular and none). In Part B Patients can take olaparib capsules daily and study assessments will be recorded for 6 months (minimum). Treatment can continue for as long as the patient is benefitting. Throughout the study patients will be monitored for any side effects.

Inclusion Criteria:

• Patients aged ≥18 years, male and female
• Able to eat a high-fat breakfast within a 30-minute period, as provided by the study site
• Histologically or, where appropriate, cytologically confirmed malignant solid tumour refractory or resistant to standard therapy and for which no suitable effective standard therapy exists
• ECOG performance status ≤2
• Normal organ and bone marrow function measured within 28 days prior to administration of IP as defined in protocol

Exclusion Criteria:

• Participation in another clinical study with an IP during the last 14 days (or a longer period depending on the defined characteristics of the agents used)
• Patients receiving any systemic chemotherapy or radiotherapy (except for palliative reasons) within 2 weeks prior to study treatment (or a longer period depending on the defined characteristics of the agents used).
• Toxicities (≥CTCAE Grade 2) caused by previous cancer therapy, excluding alopecia
• Patients unable to fast for up to 14 hours or who have type I or type II diabetes
• Patients who have gastric, gastro-oesophageal or oesophageal cancer