* AstraZeneca to run new global trial of COVID-19 vaccine - report * JD Sports among worst performing bluechips this week * Drugmaker Indivior underperforms midcaps for the week (Updates to close) Nov 27 (Reuters) - Domestically-oriented British midcap stocks rose slightly on Friday, but marked their first weekly loss this month as frictions in the Brexit process and a gloomy economic outlook due to the coronavirus weighed on sentiment. The mid-cap FTSE 250 rose 0.3% and lost 0.2% for the week, while the blue-chip FTSE 100 ended the day and the week a touch higher. The European Union and Britain said there were still substantial differences over a Brexit trade deal, with three main issues of contention - fishing, state aid and how to resolve any future disputes. The EU chief negotiator prepared to travel to London in a last-ditch attempt to avoid a tumultuous divorce, with just five weeks left until the deadline for UK’s exit. “Mask-to-mask talks will be held over the weekend—but this is not yet the last possible moment for a deal, and a deal can (by EU tradition) only occur at the last possible moment,” Paul Donovan, chief economist of UBS Global Wealth Management said. Appetite for locally-focussed stocks was battered through the week by updates from the finance and health ministers over the COVID-19 pandemic’s economic impact, while doubts over the efficacy of a leading vaccine candidate also weighed. A Bloomberg report said AstraZeneca was likely to run an additional global trial to assess the efficacy of its COVID-19 vaccine using a lower dosage, amid questions over the results of its late-stage study. Among individual stocks, retailer JD Sports Fashion was among the worst performing blue-chip stocks for the week in the face of strict restrictions on activity even after the end of a nationwide lockdown. Drugmaker Indivior underperformed its midcap peers for the week with a 23.9% loss after it was slapped with a 1.07 billion pound ($1.43 billion) claim by its former owner Reckitt Benckiser. (Reporting by Devik Jain in Bengaluru; Editing by Shounak Dasgupta and Shailesh Kuber)