Sarah

Sarah asked for a sneak peek into the early-stage pipeline, specifically which of the four Phase 1 programs (XL309, XB010, XB628, XB371) is expected to transition next into pivotal development, and how XB371 (tissue factor topo I ADC) is differentiated from others.

Answer

Dana Aftab, EVP of Research and Development, mentioned that XL309 (USP1 inhibitor) and XB010 (5T4 targeting ADC) have been in the clinic longer and accrued more patients. XB628 (bispecific IO molecule) is enrolling well, and XB371 (tissue factor targeting ADC) is the most recent IND filing and is enrolling patients. XB371 is differentiated by a unique antibody that avoids coagulation cascade impact and a tandem mechanism release linker for payload stabilization.

Sarah asked for a sneak peek into Exelixis' early-stage pipeline, specifically which of the four phase I programs (XL309, XB010, XB628, XB371) is expected to transition next into pivotal development, and how XB371, the tissue factor topo I ADC, is differentiated from other topoisomerase I inhibitors.

Answer

Dana Aftab, Executive Vice President of Research and Development, stated that XL309 (USP1 inhibitor) and XB010 (5T4 targeting ADC) have been in the clinic longer and accrued more patients. She highlighted XB371's differentiation through a unique antibody that avoids coagulation cascade impact and a tandem mechanism release linker licensed from Catalent, which stabilizes the payload and requires dual cleavage for release.