One of the best catalysts for a stock's rise is the withdrawal of a rival. That was an important dynamic behind the double-digit-percentage rise of biotech Viking Therapeutics' (VKTX 0.32%) stock in April. Another was a looming late-stage clinical trial of a closely watched pipeline drug that's loaded with potential. A potential rival drops out For a relatively young, clinical-stage company, Viking has developed quite a high profile. That's because its leading drug candidate, VK2735, is its possible entry i ...