Green light for Seagen's pivotal integrin beta-6 trial

When Seagen starts enrolment into SGN-B6A’s phase 3 study, which went up on clinicaltrials.gov last week, it will cement the ADC’s status as the industry’s most advanced inhibitor of integrin beta-6. Not that there’s much competition. OncologyPipeline identifies just two other active projects broadly with this target: BJ Bioscience’s BJ-001 targets a range of integrins, including αvβ6 (which includes the beta-6 subunit), while Harpoon presented preclinical data on HPN-ITGB6 at this year’s AACR. SGN-B6A had featured at ASCO in a dose-escalation study in head and neck cancer and NSCLC, yielding a 33% ORR in the latter. However, with a 45% rate of severe treatment-related adverse events, Seagen indicated that it had yet to pin down an optimal dose. Moving straight into phase 3 means either that this has now been done or that Seagen is rushing, Evercore ISI’s Umer Raffat suggested on a webinar. The pivotal trial is in second-line NSCLC, and measures overall survival and ORR versus docetaxel as co-primary endpoints. Pfizer’s $43bn Seagen buyout is to close late this year or early next. Pfizer had called SGN-B6A, until then a relatively low-key asset, one reason for buying Seagen, and it will soon have full control over it.

Industry projects said to have activity on integrin beta-6

Note: *comprises an integrin-binding RGD-4C motif, linked with a human IgG1 Fc, and then a modified sushi domain of human IL-15Rα unit and a human IL-15; the RGD-4C motif binds αvβ3, αvβ5 & αvβ6 integrins commonly overexpressed in solid tumours. Source: OncologyPipeline.