Prothena slides as Muddy Waters attacks.

One of the passive immunology co's going after AL amyloidosis.

"Prothena Corp. dropped after short seller Muddy Waters Capital said that the drugmaker’s lead compound doesn’t help patients much more than existing therapies.
“Our view is that at least what’s been publicly released does not show that it’s efficacious,” Carson Block, the fund’s founder, said of Prothena’s lead experimental drug in an interview on Bloomberg TV. Early results showing that patients improved could be attributed to “previous therapies,” he said.

"Prothena, which is testing the compound in a final-stage study, said last year that NEOD001 had been tied to an improvement in patients with AL amyloidosis, a rare disease driven by protein buildup in various organs.
Short sellers like Muddy Waters seek to profit by betting a stock will decline, and sometimes publish research to take their case to the public."