Greenwich LifeSciences reports rising immune responses in Phase III breast cancer trial

Greenwich LifeSciences (NASDAQ:GLSI) reported new open-label immune response data from its ongoing Phase III FLAMINGO-01 clinical trial evaluating its lead immunotherapy candidate, GLSI-100, in patients with HER2-positive breast cancer.

The findings, derived from the study’s non-HLA-A*02 arm consisting of 247 patients, demonstrate a statistically significant escalation in localized immune activity over the course of the primary treatment window.

The clinical-stage biopharmaceutical firm detailed that local injection site reactions (ISRs), which are used as an in vivo metric to track patient immune responses, climbed significantly between the first and subsequent immunizations.

Erythema ISRs—representing localized skin redness—surged from 20.2% after the first dose to 55.3% following the completion of doses four through six.

Concurrently, rates of induration—the structural hardening of localized tissue indicating a functional cell-mediated response—expanded from 14.9% after the initial injection to 34.6% during the later dosing sequence.

Both primary observation bars achieved high statistical significance, recording a McNemar test value of p<0.001.

Greenwich LifeSciences directly correlates these expanding localized skin reactions to the underlying therapeutic mechanism of action of GLSI-100.

The candidate is engineered to stimulate a targeted immune defense to track and eradicate residual HER2-positive cells post-surgery.

Management noted that the strengthening biological response aligns with earlier, preliminary clinical indicators from the same open-label cohort that suggested an approximate 70% to 80% reduction in overall breast cancer recurrence rates among treated participants.