While most cancer drugs work by targeting mechanisms common to all cancers, such as cell division, PM drugs hit specific genetic mutations driving the cancer's spread.
Although the Letter is a reliable benchmark, the Division will in some cases deviate from it depending on necessities raised by specific issues in any given investigation.
"We do not comment on specific situations, " Lona Nallengara, acting director of the SEC's corporation-finance division, wrote in an email to The Wall Street Journal.