Drug-maker AstraZeneca was given a boost as a diabetes treatment was given the green light by the US regulator. Broker JPMorgan Cazenove has forecast a $600m peak in-market potential in the US for the treatment, though admitted this could prove conservative, with Morningstar analyst Damien Conover forecasting annual sales reaching around $1.5bn by 2018. Approval from the Food and Drug Administration (FDA) was largely expected but arrived quicker than anticipated. One downside is that Farxiga's labelling will include a front-page warning about the risk of bladder cancer, which rival product from Johnson & Johnson does not, putting AstraZeneca's treatment at a disadvantage, JPMorgan noted.The FTSE 100 company has developed Farxiga in a joint venture with Bristol-Myers Squibb, before agreeing to buy its US partner out of the partnership for $4.3bn in December. Shares in AZN were up 1.27% to 3,594.5p in early trading on Thursday.OH