GTL001 - GTL002 (HPV)
GTL001 is a bivalent immunotherapeutic candidate for women infected with HPV 16 and / or HPV 18, before the onset of cervical lesions or cancer. GTL001 was developed based on the CyaA vector.
GTL002 is a multivalent immunotherapeutic candidate for women infected with HPV 16, HPV 18 and / or 4 other types of HPV, the most most relevant in terms of epidemiology. It was developed with the Vaxiclase platform.
Today, there is no treatment to eliminate the HPV virus, the proven cause of cervical cancer. This cancer is responsible for more than 250,000 deaths each year. Over 90 million women worldwide are infected with the two most dangerous types, HPV 16 and HPV 18, but preventive vaccines are effective only among young people, before infection.
GTL001 was evaluated in a phase 2 trial. It was a randomized double-blind, placebo controlled study conducted at 33 investigational sites in 7 Western European countries. 233 patients positive for HPV 16/18 at baseline were evaluable for efficacy analysis, with a treated arm of 117 patients and a placebo arm of 116 patients. Enrolled patients were required to be HPV 16 and/or 18 positive and not have developed any high-grade lesions. All patients receiving at least one dose of vaccine or placebo were assessed for viral clearance. Compliance was excellent, with 218 subjects completing the study (112 in the treated group and 106 in the placebo group).
The final data at month 24 showed no statistical differences in viral clearance rates between the GTL001 and placebo groups. No consistent statistical differences between groups were demonstrated in any of the secondary endpoints (confirmed and sustained clearance) over the 2-year duration of the trial. The incidence of subjects progressing to high-grade lesions was identical in both groups. A significant increase in anti-CyaA antibodies following treatment was observed in the GTL001 group, but not in the placebo group. The significant increase in anti-CyaA titers in the treated group persisted during the entire course of the study.
The 12-month results announced in January 2016 showed no overall difference in viral clearance between the treatment and placebo groups, but a trend towards a significant difference in sub-group analyses was observed, most notably in the NILM sub-group. The interim analysis at 18 months demonstrated that overall viral clearance, or by sub-group, did not statistically differ from the natural clearance observed in the placebo group.
Other than the first days following each vaccination, GTL001 and imiquimod were generally well tolerated with no unexpected safety signal identified at any point during the study.These results, which do not meet expectations, led the Company to reconsider the preclinical and clinical development plans for its HPV program including GTL001 and GTL002 candidates.
Given this outcome, no further investment will be made to prepare a Phase 3 program of GTL001. Moreover, as the development plans of the Company's' two HPV candidates, GTL001 and GTL002, had much in common - such as the adjuvant or the administration protocol - the Company has decided not to pursue the preclinical development of GTL002.