(Reuters) - A clinical trial testing an experimental GlaxoSmithKline drug that mimics a health-boosting compound found in red wine has been suspended due to safety issues.A company spokeswoman said on Tuesday that the trial of SRT501 in patients with multiple myeloma had been suspended after a number of them developed a complication generally associated with the disease, which is a type of blood cancer.The mid-stage Phase II study, conducted in Britain and Denmark, was assessing the safety and tolerability of SRT501 with or without the established cancer drug Velcade from Takeda Pharmaceutical.