Following the recent announcement on the 2nd November 2023, the...

Following the recent announcement on the 2nd November 2023, the Vaxinia MAST trial has been extended to a 16 cohort design in both monotherapy and combination with Pembrolizumab administered by intra-tumoral injection (IT) and intravenous infusion (IV)

The progress through this trial has been exceptional and well supported by oncologists across 12 recruiting sites. We are now in the final two cohorts in the combination therapy and with only two cohorts remaining in the monotherapy with no reporting of dose limiting toxicities for the 36 patients enrolled in the 12 cohorts to date.

As this is a dose escalation study with an estimated primary completion date of 31st December 2024 there is much interest in what will be the maximum tolerable dose.

There is scope to extend the number of cohorts beyond the current design.
The combination cohorts in both IT and IV administration could progress to 3x10^8 and the monotherapy cohorts could possibly test a 1x10^9 dose.
In the preclinical animal models, a six-log therapeutic index was established between 1000 and 1 billion virus particles.

As mentioned in an earlier post, the historic record for the efficacy of CF33 in human trials has already been written in the Abstract release of results from the recent ESMO 2023 conference in Madrid.
The conclusions were that CHECKvacc induces tumor infiltration of CD4+ and CD8+ T cells.
Upregulation of PD-L1 within the tumor microenvironment further suggests immune activation by CHECKvacc.

Note these results were based on a December 2022 data read out of the first three cohorts with a maximum dose of 1x10^6 or one million virus particles.

In the context of CF33, Vaxinia being the parental virus is more potent than CHECKvacc and in my view will reveal impressive effficacy when data undergoes third party review and results are published in medical journals.

The following data of the cohorts' commencement dates, dose levels and durations have been updated from a previous post and presented in free text to improve the visibility of information.

VAXINIA MAST
Mono IT Cohort 1 - Commenced 18/05/2022 Dose 1x10^6 Duration Days 166
Mono IT Cohort 2 - Commenced 31/10/2022 Dose 1x10^7 Duration Days 94
Mono IT Cohort 3 - Commenced 02/02/2023 Dose 3x10^7 Duration Days 62
Mono IT Cohort 4 - Commenced 04/09/2023 Dose 1x10^8 Duration Days In Progress 62
Mono IT Cohort 5 - Not Commenced Dose 3x10^8

Mono IV Cohort 1 - Commenced 23/09/2022 Dose 1x10^6 Duration Days 75
Mono IV Cohort 2 - Commenced 05/12/2022 Dose 1x10^7 Duration Days 59
Mono IV Cohort 3 - Commenced 02/02/2023 Dose 3x10^7 Duration Days 62
Mono IV Cohort 4 - Commenced 09/06/2023 Dose 1x10^8 Duration Days 147
Mono IV Cohort 5 - Commenced 02/11/2023 Dose 3x10^8 Duration Days In Progress 2

Comb IT Cohort 1 - Commenced 03/03/2023 Dose 1x10^7 Duration Days 185
Comb IT Cohort 2 - Commenced 04/09/2023 Dose 3x10^7 Duration Days In Progress 62
Comb IT Cohort 3 - Not Commenced Dose 1x10^8

Comb IV Cohort 1 - Commenced 03/03/2023 Dose 1x10^7 Duration Days 98
Comb IV Cohort 2 - Commenced 09/06/2023 Dose 3x10^7 Duration Days 147
Comb IV Cohort 3 - Commenced 02/11/2023 Dose 1x10^8 Duration Days In Progress 2

As has been mentioned by other posters, patience is required as the trial seeks out the optimal tolerable dose and hence establishes the optimal biological dose for the final extension cohort.

As always there is much to look forward to as the company progresses toward its application for a fast track registrational trial for Vaxinia.

A very big congratulations to Leslie and her team for the impressive progression of CF33 through clinical trials.


GLTAH - Go Team Imugene
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