Scancell has reported 5-year survival data in melanoma, supporting its decision to continue testing its DNA vaccine SCIB1 in combination with checkpoint inhibitors in an upcoming trial.
So far, Scancell’s ongoing Phase I/II trial has recruited 20 patients with stage III and IV melanoma, of which eight experienced recurrence of their cancer, and two of them died. Eight patients have already reached 5 years of survival, which is the gold standard to measure durable effects of a cancer therapy.
These encouraging results come from Scancell’s SCIB1, a DNA vaccine that encodes an antibody that contains four sequences from two melanoma antigens, gp100 and TRP-2. These epitopes stimulate strong immune responses in both CD4 and CD8 T cells.
Although the trial has delivered promising results, Scancell needs to bring the numbers up to provide solid statistic data. The 20 patients were treated with three different doses and those that showed recurrence were treated with additional therapies for melanoma, which brings a lot of variability to the results.
The next step for Scancell is a Phase II trial in the US that will test SCBI1 in combination with a checkpoint inhibitor. The company is planning to file an IND application this year to obtain FDA approval for the trial.
The number of clinical trials testing all kinds of therapies with checkpoint inhibitors rises over 760, raising doubts about whether there’s a proper rationale behind most them, or if the companies are just trying to jump on the bandwagon of success of checkpoint inhibitors.
Scancell, though, is working on the basis of animal studies that show SCIB1 increases PD-L1 expression on the tumor, achieving 100% survival – a number that is not observed with checkpoint inhibitors alone. On top of that, the company is developing moditopes, a technology to stimulate CD4 T cells to destroy tumors without any toxicity, that would not need the help of checkpoint inhibitors to act.
In terms of cancer vaccines, however, Scancell could be competing with other European companies with very promising approaches. One of them is BioNTech’s mRNA vaccine, a universal approach technically suitable for all types of tumors that has shown encouraging results in Phase I. Others include Vaximm, which employs live bacteria to vaccinate cancer patients; Targovax, going after new targets for peptide vaccines; and Transgene, which bids for oncolytic viruses.
Images via David Litman / Shutterstock; Scancell