Robert Driscoll

Robert Driscoll of Wedbush Securities questioned whether the CTX-8371 expansion cohorts would select for PD-L1 expression and asked about the profile of immune-related adverse events (irAEs) observed so far.

Answer

CEO Thomas Schuetz stated that the expansion cohorts will not select for PD-L1 expression, maintaining the same criteria as the dose-escalation phase. Regarding safety, he noted no dose-limiting toxicities were seen in the first four cohorts and speculated that the drug's mechanism could potentially lead to a better safety profile, though more data is needed.

Robert Driscoll of Wedbush Securities asked if the CTX-8371 expansion cohorts would select for PD-L1 expression and inquired about any observed immune-related adverse events (irAEs) in the dose-escalation phase.

Answer

CEO Thomas Schuetz stated that the company does not plan to change the selection criteria for the CTX-8371 expansion cohorts, meaning they will not select based on PD-L1 status. Regarding safety, he noted no dose-limiting toxicities were seen in the first four cohorts and speculated the drug's mechanism could potentially lead to a better safety profile by anchoring it in the tumor microenvironment.

Robert Driscoll questioned if EpCAM expression is similarly high in earlier-stage colorectal cancer (CRC), asked about the biology of EpCAM, and inquired about any plans to explore higher doses given the response rate at 10 mg/kg.

Answer

CEO Sean McCarthy confirmed that EpCAM has long been established as a CRC antigen expressed throughout the disease's natural history, making it a suitable target for earlier lines. He noted that while EpCAM's biological function isn't fully characterized, its high expression level makes it an ideal 'address' for an ADC. McCarthy also stated that while they have escalated to higher doses, they anticipate finding the maximum assessed dose there and are currently focused on the 7.2, 8.6, and 10 mg/kg expansion cohorts.