Credit Suisse analyst Alethia Young does not think the clinical holds placed by the FDA on Celgene's (CELG) PD1 trials for durvalumab have anything to do with the safety issue of the trials, but are more of a class-wide review taken after the hold on Merck's (MRK) Keytruda, she tells investors in a research note. Celgene said it has not seen a risk/benefit imbalance in the over 500 patients treated in the FUSION program, she added. Young, who currently doesn't include durvalumab in her valuation of Celgene, keeps an Outperform rating and $156 price target on the stock.