Roth Capital analyst Joseph Pantginis says Aduro Biotech's LADD platform took another perception knock with a second case of a patient's treatment port testing positive for listeria. While there was no listeriosis/systemic impact to the patient and it resolved quickly, a partial clinical hold has been put in place with no new enrollment in LADD studies until protocols are modified with the FDA for increased surveillance. The analyst says his confidence remains high on the LADD platform and reiterates a Buy rating on the stock. Nonetheless, he lowered his price target on the shares to $20 from $22.