The data from Part B1 of MAVIS was published as an abstract in the Journal for ImmunoTherapy of Cancer on October 1st 2021.
By intent-to-treat (ITT) analysis, RFS was not significantly enhanced for seviprotimut-L in the overall study population but did trend slightly higher. However, strong responses were seen in two well-defined subpopulations based on disease stage and age at time of treatment. Specifically, interim efficacy analysis of subgroups based on pre-planned stratification suggested enhanced RFS for seviprotimut-L among two patient populations: those with AJCC Stage IIB/C melanoma and those under the age of 60.
Age has been identified as a cause of decreased immune competence1; thus, outcomes were assessed as a function of age as an effect modifier. Effects estimates for patients aged less than 60 years are favorable to seviprotimut-L in the overall population (Hazard Ratio= 0.61, 95% CI [0.36, 1.05]) and in the Stage IIB/IIC population (Hazard Ratio= 0.239, 95% CI [0.083, 0.69]).
Seviprotimut-L is well-tolerated with treatment-emergent adverse events (AEs) similar to placebo patients. There were no serious adverse events or Grade 4 or 5 adverse events in the 347 patients studied, and the vast majority of events were Grade 1-2 injection site reactions that were managed by topical cream/s or an over-the-counter antihistamine