Avacta partners with Selexis ahead of first-in-human trials

The AIM-traded firm said the “major milestone” would keep it on track to submit an IND/CTA application for an Affimer PD-L1 inhibitor by the end of 2020.

It said its first clinical candidate would be against PD-L1 - a clinically-validated immune checkpoint that played an important role in the tumour escape mechanism in cancer.

The lead molecule - AVA004 - was described by the company as a “potent” PD-L1 antagonist that had been engineered with an Fc domain for half-life extension.

Avacta said it had demonstrated the preclinical efficacy of AVA004 in syngeneic and xenograft mouse models, explaining that it compared “favourably” to approved monoclonal antibodies such as ‘Imfinzi’, ‘Tecentriq’ and ‘Bavencio’ at the doses administered.

“The strategic partnership with Selexis allows Avacta to access the technology and know-how to develop high-expressing CHO cell lines as well as the extensive experience of developing a range of Fc fusion proteins for clinical manufacturing,” said Avacta chief executive officer Alastair Smith.

“These cell lines are the essential basis of clinical manufacturing of AVA004 and this partnership supports Avacta's strategy to demonstrate safety and tolerability of the Affimer platform in humans with a planned IND/CTA by the end of 2020.”

Smith said the ultimate aim was to combine AVA004 with other Affimer checkpoint modulators in bispecific cancer immunotherapies, and with novel chemotherapies, as drug conjugates and combination therapies utilising proprietary tumour microenvironment targeting chemistry.

“These approaches seek to combine modulation of the adaptive immune response with stimulation of the innate immune system, with the aim of improving the clinical outcome for the sizeable proportion of solid tumour patients having ‘cold’ tumours that do not respond to checkpoint inhibitors alone.”