An Open-label Extension to Study AVA105640, to Assess the Long-term Safety and Efficacy of Rosiglitazone (Extended Release Tablets) on Cognition in Subjects With Mild to Moderate Alzheimer's Disease.

Study start date: October 1, 2007

Inclusion criteria: * Male or female subject who has successfully completed Visit 8 of AVA105640 without safety/tolerability issues, where in the opinion of the subject /carer and of the investigator, it would be beneficial to receive RSG XR * Female subjects able to bear children must agree to use an adequate method of contraception for the duration of the study for details of highly effective methods to avoid pregnancy). Female subjects who are pre-menopausal or who have been post-menopausal for \<1 year must undertake pregnancy testing (urine test) £7 days before Visit 1, which must be negative * Subject is willing to participate in the extension study and has provided full written informed consent prior to the performance of any protocol-specified procedure; or if unable to provide informed consent due to cognitive status, full written informed consent on behalf of the subject has been provided by a legally acceptable representative (where this is in accordance with local laws, regulations and ethics committee policy) * Subject lives with (or has substantial periods of contact with) a regular caregiver who is willing to attend all visits, oversee the subject's compliance with protocol-specified procedures and study medication, and report on subject's status * Subject has the ability to comply with procedures for cognitive and other testing * Caregiver has provided full written informed consent on his or her own behalf prior to the performance of any protocol-specified procedure * Subjects considered for enrollment must have a QTc (either QTc B (Bazett's correction) or QTc F (Fridericia's correction)) \<450msec at Visit 1, with the exception of subjects with bundle branch block (for whom either QTc B or QTc F must be \<480msec) * In France, a subject will be eligible for inclusion in this study only if either affiliated to or a beneficiary of a social security category * Post-menopause \[Becker, 2001\]: Menopause is the age associated with complete cessation of menstrual cycles, menses, and implies the loss of reproductive potential by ovarian failure. This typically occurs around age 50, although it may occur earlier. A practical definition accepts menopause after one year without menses with an appropriate clinical profile, e.g., age appropriate, \>45 years, in the absence of hormone replacement therapy. In questionable cases, a blood sample with simultaneous follicle stimulating hormone (FSH) \> 40 MlU/ml and estradiol \< 40 pg/ml (\<140 pmol/L) is confirmatory (these levels are suggested guidelines and may need to be adjusted for specific laboratories/assays * Females, who are on hormone replacement therapy (HRT), and whose menopausal status is in doubt, will be required to use a highly effective method to avoid pregnancy, as outlined in the protocol, if they wish to continue their HRT during the study. Otherwise, they must discontinue HRT to allow confirmation of post-menopausal status prior to study enrollment. For most forms of HRT, at least 2-4 weeks will elapse between the cessation of therapy and the blood draw as detailed in the preceding paragraph; this interval depends on the type and dosage of HRT. Following confirmation of their post-menopausal status, they can resume use of HRT during the study without use of a highly effective method to avoid pregnancy * A non-cohabiting caregiver must spend sufficient time with the subject so that, in the opinion of the Investigator, the caregiver can reliably assess cognitive function, activities and behaviour, and report on the subject's compliance and health. As caregiver time spent with a potential subject is anticipated to be highly variable across countries and cultures, GSK will consider a variety of different measures by which this stipulation may be met, and GSK should be consulted if adequacy of a caregiver situation is in doubt. However, as guidance, the ability for a caregiver to meet his/her expected responsibilities for this study would normally be possible when the caregiver spends no less than 10 hours per week with the subject, divided over multiple days * For the purposes of these criteria, QTc B is defined as (QT interval \[msec\]) / (square root of RR interval \[seconds\]); and QTc F is defined as (QT interval \[msec\]) / (cube root of RR interval \[seconds\]) Exclusion criteria: * Subject had a serious adverse experience or clinically significant laboratory abnormality during AVA105640, which in the opinion of the investigator could have been attributable to study medication, and which is ongoing at Visit 1 * The subject is felt by the investigator to be unsuitable (on the basis of health, compliance, caregiver availability, or for any other reason) for inclusion in the study * The subject experienced a significant cardiovascular event during AVA105640 (e.g. intervention, percutaneous coronary intervention, vascular surgery, acute coronary syndrome \[non Q-wave myocardial infarction, Q-wave myocardial infarction, unstable angina\] or significant arrhythmia), unless a thorough cardiovascular evaluation has been performed which confirms that the subject does not have congestive heart failure, and is clinically stable * Clinical/investigational evidence of congestive heart failure defined by the New York Heart Association (NYHA) criteria (Class I to IV cardiac status) at the time of Visit 1 * Clinically significant peripheral oedema at the time of Visit 1 * Alanine aminotransferase (ALT), aspartate aminotransferase (AST), or alkaline phosphatase values \>2.5 times the upper limit of normal (ULN), total bilirubin values \>1.5 times the ULN, or history of severe hepatobiliary disease (e.g. hepatitis B or C, or cirrhosis, Child-Pugh Class B/C) * Subject is an immediate family member or employee of the participating Investigator, of any of the participating site staff, or of GSK * In France, a subject is neither affiliated with nor a beneficiary of a social security category * In France, a subject has participated in any study using an investigational drug during the previous 30 days (except for participation in AVA105640)