3038 Background: 5T4, a Type I transmembrane glycoprotein, is over expressed in a broad spectrum of solid tumors. It modulates the CXCR4 n = 41 in cohort expansions) have been treated, median age of 60 yrs, >70% treated with ≥ 3 prior lines of therapy, including >75% of treated pts with prior taxane exposure. Treatment has been well-tolerated with predominantly low-grade treatment-related adverse events (TRAEs) (Gr 1 no Gr 4 JK06-related AEs have been observed to date. Four pts underwent dose reductions, and five additional pts were discontinued due to TRAEs. Among 19 response-evaluable NSCLC pts to date, a 32% ORR has been observed, with 1 confirmed complete response (cCR), 4 confirmed partial responses (cPR) (one with CNS response) & 1 with unconfirmed partial responses (uPR), with the longest continuing therapy for 51 wks. Responses have been observed in adenomatous, squamous & EGFR mutant NSCLC pts. One of seven evaluable breast cancer pts (14% ORR) achieved a cPR and remained on treatment for >27 wks. Conclusions: To date, JK06 demonstrates promising emerging clinical activity in refractory NSCLC & breast cancer at multiple dose levels while being well tolerated without significant drug-related toxicities. Updated safety & clinical activity data from both dose escalation & expansion cohorts, including the initial assessment of dose randomization, will be presented. Clinical trial information: NCT06667960 .
Saavedra et al. (Wed,) studied this question.