"Many question the ethics of using a placebo when studying a life threatening illness." I understand and agree.
"Many clinical trials will use the approved treatment as an alternative to placebo when a drug in the same class is studied for serious illnesses." I agree with that as well, but such a trial is not described as a "placebo-controlled trial", the language that the Company itself used. The FDA calls it an "active control (or positive control) trial".
A placebo is described by the FDA as an "inert treatment".
"Many clinical trials will use the approved treatment as an alternative to placebo when a drug in the same class is studied for serious illnesses." To your point, if memory serves, daptomycin was used in the Brilacidin trial for ABSSSI