Avacta Group Share News (AVCT)

(Sharecast News) - Avacta Therapeutics said on Tuesday that new preclinical analysis indicated its proprietary 'preCISION' tumour-activated delivery platform could offer pharmacokinetic advantages over the marketed antibody drug conjugate Enhertu, as it prepared to begin a phase one trial of its lead programme AVA6103 in the first quarter of 2026.

The AIM-traded clinical-stage group published data comparing its FAP-cleavable payload candidate FAP-Exd, or AVA6103, with Enhertu, an AstraZeneca and Daiichi Sankyo product approved for breast and gastric cancers.

Enhertu, also known as trastuzumab-deruxtecan (T-Dxd), is an exatecan-derivative antibody drug conjugate.

Avacta said the analysis used an artificial intelligence-generated synthetic comparator arm to recreate a published AstraZeneca dataset and compare it with experimental data generated with AVA6103 in a similar FAP-high animal model using comparable payloads.

The company said the approach enabled a direct comparison with published Enhertu data without repeating experiments in-house.

According to the company, the data demonstrated three key pharmacokinetic advantages for AVA6103.

First, maximal tumour concentration was observed within minutes of dosing, compared with 24 hours for T-Dxd.

Second, the absolute maximum concentration in tumour tissue was more than one log higher than that observed with T-Dxd.

Third, the tumour selectivity index, defined as the ratio of the area under the curve in tumour versus plasma over 14 days, was nearly three times higher with 'preCISION' delivery than with the ADC comparator.

Avacta added that in animal efficacy models the pharmacokinetic differences translated into higher activity in tumours with low FAP expression, compared with variable activity for T-Dxd at low HER2 expression levels, and deep, durable responses persisting for many weeks after a three-dose regimen with FAP-Exd.

"Our analysis demonstrates three potential advantages of our proprietary 'preCISION' delivery mechanism when compared to the marketed ADC, Enhertu - more rapid drug penetration into the tumour, a one log higher absolute maximum drug concentration in the tumour and the tumour selectivity index - a critical safety and effectiveness measure - being nearly three-fold higher," said chief executive Christina Coughlin.

"We believe the observations in this dataset have significantly increased the probability of success with FAP-Exd, given both the ability of FAP-Exd to deliver more payload selectively to the tumour in the preclinical setting and success of Enhertu in the clinic.

"We look forward to the start of the clinical trial."

Avacta said it planned to present the data at an upcoming scientific congress and submit the findings to a peer-reviewed journal.

The company expected to start the phase one clinical trial of AVA6103 in the first quarter of the year.

At 1236 GMT, shares in Avacta Group were up 6.81% at 60.35p.

Reporting by Josh White for Sharecast.com.