HPV DNA vaccine shows therapeutic potential in patients with cervical intraepithelial neoplasia 3
The human papillomavirus (HPV) DNA vaccine (GX-188E) is effective against HPV type 16/18–associated cervical intraepithelial neoplasia (CIN) 3, according to the results of a phase II trial.
Seventy-two CIN3 patients positive for HPV type 16/18 were randomized to receive to receive GX-188E at either 1 or 4 mg. Treatment was administered intramuscularly at weeks 0, 4 and 12. Histopathologic regression to ≤CIN1 was assessed at week 20, as well as at week 36 in an extension study. Researchers performed HPV-sequencing analysis and an ex vivo IFNγ ELISpot assay using the collected cervical biopsy and blood samples from patients.
Of the patients, 64 patients were included in per-protocol analysis and 52 in extension analysis. Histopathologic regression with GX-188E overall occurred in 33 patients (52 percent) at week 20 and in 35 patients (67 percent) at week 36.
Furthermore, HPV clearance was achieved by 73 percent and 77 percent of patients with histologic regression at weeks 20 and 36, respectively. HPV clearance was significantly associated with histopathologic regression at both time points.
Patients with HPV clearance at week 36 exhibited significantly greater changes in their IFNγ ELISpot responses relative to those without HPV clearance. The HPV type 16 E6/E7 variants D25E, V83L and N29S had an inverse association with histopathologic regression at week 36.
More studies are needed to evaluate the therapeutic effect of the GX-188E vs placebo against HPV type 16/18–associated CIN3, as well as to examine the potential of tailoring HPV therapeutic vaccine according to individual HPV variants, the researchers said.