UBS has cut its target price for GlaxoSmithKline after trimming its estimates for the pharmaceutical company, and said that its dividend "still looks unsustainable".The bank has reduced its target for the shares from 1,380p to 1,250p and kept a 'sell' rating.Following Glaxo's recent third-quarter results, UBS said it was lowered its forecasts on the back of lower sales and profit estimates, partly offset by the newly-announced cost-cutting programme.The bank said: "The critical questions for the investment case are: (1) have earnings estimates finally bottomed? We think they may still not, as visibility of gross profitability remains low; (2) (When) will respiratory return to growth? We do not project a near-term-recovery and forecast respiratory sales to decline to 2019."As for shareholder returns, a flat dividend of 80p per share out to 2020 would equal a payout of over 100% of free cash flow, the bank estimates."We believe the current dividend level beyond 2015 is only safe if we see strong and sustained recovery of respiratory sales, for which we have no indication yet, UBS said.The bank also suggested that Glaxo could continue to use proceeds from selling assets to cover the dividend beyond 2015, "though we find this a questionable strategy that further reduces the scope for earnings growth".The stock was down 0.2% at 1,413p by 11:31.