Should Amgen's T-Vec Results Be Questioned?

In a report published Tuesday, BofA Merrill Lynch analysts maintained a Neutral rating on

, with a price objective of $183. "Documents for the FDA advisory panel for AMGN's T-Vec (talimogene laherparepvec) on April 29th were just released and raised several questions on the study design and results," the analysts mentioned. They estimate T-Vec sales at about $200 million in 2020. In the report BofA Merrill Lynch noted, "The control for therapeutic activity and adverse events, GM-CSF, is a component of T-Vec and was in clinical trials for the treatment of melanoma at the time of the study. Therefore, if investigators viewed the control as unlikely to have any therapeutic effect, they could have been biased in favor of the T-Vec arm." Dropout rates were high, with 172 patients, comprising of more than half the patients, withdrawing from the T-Vec arm before the 24-week study ended. Moreover, 106 patients, or 75.1 percent, withdrew from placebo. Due to this, the Endpoint Assessment Committee (EAC) could not evaluate the patients for durable response (DRR), which was the primary endpoint. Moreover, the study only included "patients with small or very small lesions, raising concerns about the reliability of injections and particularly the measurement of response," the analysts explained. "T-Vec's proposed mechanism of action and clinical data suggest the possibility of systemic effects, though the FDA views the supporting evidence as limited. The secondary endpoint of overall survival (OS) would have provided additional evidence but the treatment benefit was only 4.4 months and did not reach statistical significance," the report added.