Avacta Therapeutics presented two new developments at its Science Day 2026 event. The Company is presenting comparative analyses of pre|CISION payload delivery via one of its programs, AVA6103, compared with now two approved Antibody-Drug Conjugates (ADCs). It is also presenting updated in vivo studies of the dual payload delivery system in another program, AVA6207.
AVA6103: The new data analyses in the AVA6103 program comparing pre|CISION FAP-cleavable exatecan delivery with those of marketed ADCs have been extended to Datroway, an ADC targeting the TROP2 antigen, as well as Enhertu an ADC targeting the HER2 antigen. All three of these drugs (AVA6103, Enhertu and Datroway) feature tumor-targeted delivery of topoisomase I inhibitors (exatecan or deruxtecan) and these comparisons are designed to address the differences in the payload delivery and control for the differences in cancer models. The delivery kinetics of exatecan (derived from AVA6103) and deruxtecan (derived from Enhertu or Datroway) demonstrate more rapid tumor penetration of released exatecan from AVA6103 (Tmax of minutes, AVA6103 versus Tmax >24 hours, Enhertu or Datroway) and higher maximal concentration (Cmax) of released payload in the tumor with differences observed of over 1-log.
The tumor selectivity index (TSI) is a measure of the overall exposure (area under the curve, AUC) in the tumor vs. the bloodstream (TSI = AUC[tumor/plasma]) which is at least 3 times higher with released exatecan from AVA6103 than either released deruxtecan from Enhertu or Datroway. The Company is planning to publish these findings at an upcoming academic meeting and in a peer-reviewed journal.
AVA6207: The in vivo data in the AVA6207 program show the dual payload delivery demonstrating prolonged deep complete responses despite tumor regrowth with the conventional cytotoxic drugs. Initial data was published at AACR 2026 last month and has been updated. Results indicate that deep and durable complete responses are observed in the FAP-high model, HEK-FAP where tumors regrow with conventional therapy.
In the FAP-low/HER2-positive patient derived xenograft model of gastric cancer, durable responses with AVA6207 are observed where tumor regrowth is observed with Enhertu. These results suggest optimal treatment with the combination is more effective in this model than the deruxtecan-based ADC. The investor Science Day 2026 event is being held at the Royal Society of Chemistry, Burlington House, Piccadilly, London W1J 0BA, starting at 10.30am.
Attendance capacity is limited, so attendance is limited to those who have received confirmation of registration previously. The presentations will be recorded and published on the Company website in due course.
