2516 Background: A key metabolic alteration in tumour cells is an increased dependency on the glycolysis, resulting in the production of lactate, which is transported out of cells by MCTs. Inhibition of MCT-1 leads to a profound inhibition of cancer cell growth in preclinical models. AZD3965 is a FIC inhibitor of MCT-1, and we report results from the phase I study of this agent. Methods: Patients with advanced solid tumours were treated with oral (po) AZD3965 at total daily doses of 5-30mg given once (od) and twice daily (bd). Exclusion criteria included a history of retinal or cardiac disease due to preclinical toxicology findings in the eye and heart (which express MCT-1). The primary objectives were to determine the safety, dose limiting toxicities (DLT) and maximum tolerated dose (MTD) of AZD3965. Intensive pharmacokinetic (PK) profiling was performed with subsequent modelling for receptor occupancy. Pharmacodynamic profiling included imaging to detect pH changes and tumour glucose uptake; plasma/urine metabolomics and MCT-1 and MCT-4 tumour expression by immunohistochemistry. Results: 35 patients (20M:15F median age 65) were treated at dose levels 5, 10, 20, and 30mg od and 15 and 10mg bd. AZD3965 was generally well tolerated with nausea and fatigue (CTCAE Gr1-2) the most commonly reported side effects. A single DLT of cardiac troponin rise was observed at 20mg od. Asymptomatic, reversible retinal ERG changes were observed in all but the lowest dose levels, with DLTs observed at doses above 20mg od. PK data indicate exposures in the preclinical efficacy range. Metabolomic changes in urinary lactate and urinary ketones correlate with on-target activity. The increase in urinary ketones is likely to be attributable to the role of MCT1 in physiological ketone transport. Conclusions: The MCT1 inhibitor AZD3965 can be administered to patients at doses which engage the drug target, with a MTD of 20mg od po. DLTs seen were primarily dose dependent, asymptomatic and reversible changes in retinal function, which were an expected on-target effect. Investigation of the activity of AZD3965 is ongoing in tumours known to express MCT1. Clinical trial information: NCT01791595.

ABSTRACT.Purpose: Microcephaly with or without chorioretinopathy, lymphedema or intellectual disability (MCLID) is an autosomal dominant condition. Mutations in KIF11 have been found to be causative in approximately 75% of cases. This study describes the ocular phenotype in patients with confirmed KIF11 mutations. Methods: Standard ophthalmic examination and investigation including visual acuity, refraction and fundus examination was carried out in all patients. Fundus autofluorescence imaging (FAF) was performed in three patients, and four patients underwent spectral domain optical coherence tomography (OCT). Flash electroretinography (ERG) was performed in seven patients, and five underwent additional pattern electroretinography (PERG). Results: The patients ranged in age from 2 to 10 years. Most presented with visual acuity loss. Fundus examination revealed lacunae of chorioretinal atrophy. Pigmentary macular changes and optic disc pallor were present in three of seven patients. Fundus autofluorescence demonstrated hypoautofluorescence at the macula in two of three patients. The lacunae of chorioretinal atrophy were hypoautofluorescent. The OCT showed atrophic maculae in three of four patients. Follow-up in one patient showed no deterioration of the vision over a 9-year period. The lesions appear not to be progressive on the follow-up imaging. Electrophysiology showed generalized rod and cone dysfunction and severe macular dysfunction. Inner retinal dysfunction was evident in three of seven patients. Conclusions: Patients with KIF11 mutations show a specific ocular phenotype with variable expressivity and intrafamilial variability. Macular atrophy and dysfunction have not been consistently documented before. The fundus lesions appear non-progressive. The findings assist in providing an accurate diagnosis and thus improving the management and follow-up of patients with this syndrome.