Avacta Group has joined forces with life sciences company Selexis to help develop the Chinese hamster ovary (CHO) cell line, which will be used to manufacture Avacta’s first Affimer clinical candidate for first-time-in-human clinical trials.

The new development signals that Avacta is on track to submit an investigational new drug/clinical trial application application for an Affimer PD-L1 inhibitor by the end of next year.

Avacta’s first clinical candidate will be against clinically validated immune checkpoint PD-L1, which plays a key role in the tumour escape mechanism in cancer.

The lead molecule (AVA004) is a potent PD-L1 antagonist engineered with an Fc domain for half-life extension.

The preclinical efficacy of AVA004 has been demonstrated by Avacta in syngeneic and xenograft mouse models and it compares favourably to approved monoclonal antibodies such as Imfinzi, Tecentriq and Bavencio at the given doses.

Avacta Group CEO Alastair Smith said: “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.

“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.”

The partnership is aimed at combining the lead molecule with other Affimer checkpoint modulators in bispecific cancer immunotherapies.

AVA004 will also be combined with novel chemotherapies as drug conjugates and combination therapies using tumour microenvironment targeting chemistry.

Smith added: “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.”