The group's tumour microenvironment activated drug conjugates (TMAC) are a ground-breaking new form of cancer immunotherapy.
Co-invented with Tufts University Medical School of the US, TMAC brings together Avacta’s Affimers with chemotherapies in a single drug using a linker that is designed to only release the chemo in the tumour.
The plan is to gain permission for phase I trial in early 2020 to test the potential new treatment in people with certain types of solid tumours.
The company called the first-in-man study “a major de-risking milestone for the programme”.
"What is so attractive about Avacta's Affimer TMAC programme is that it offers a way to combine chemotherapy with immune checkpoint inhibitors without exposing the whole body to the same level of the chemo-toxin,” said chief executive Alastair Smith.
“Whilst immunotherapies offer great promise for cancer patients, it is well established that only a relatively small sub-group of patients see durable responses to single immune checkpoint therapies. Avacta is directly addressing this urgent clinical need with its novel Affimer TMAC and bispecific programmes,” he added.
In order to test the TMAC linker in humans for the first time, a chemo treatment called doxorubicin will be modified with the Avacta linker, rendering it inactive and harmless until the linker is split in the tumour, releasing an active cancer-killing agent.
Doxorubicin has well-documented safety issues limiting its dosing, and also putting a cap on the number patients that can be treated with it.
The shares rose 8% on the news, to change hands for 32.12p. Broker finnCap’s target price is 125p.
Analyst Mark Brewer told investors: “Not only is this testing of the TMAC linker well ahead of original plans, but it potentially creates additional sources of non-dilutive funding from licensing the linker to create effective chemotherapeutic pro-drugs that are currently limited by dose-limiting systemic toxicities.
“Proving the enzyme-sensitive linker works in humans also increases the prospect of licensing the Affimer TMAC platform before clinical data are generated from its first Affimer TMAC.”
Avacta's TMAC linker has been shown to increase the maximum tolerated dose by a factor of six in a pre-clinical study in mice.
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