JMP Securities analyst Jason Butler said he views the patient death in ZIOPHARM's (ZIOP) Ad-RTS-IL-12 GBM trial as "possibly or even likely due to the study drug" and acknowledges the need for caution regarding the potential safety concerns of Ad-RTS-IL-12. However, while the trial death raises questions, Butler contends it has no read through to partner Intrexon's (XON) broader oncology programs. The analyst, who notes there are multiple other programs in or entering the clinic under the collaborations between ZIOPHARM and Intrexon, keeps an Outperform rating and $42 price target on Intrexon shares.