A Phase II Randomised Trial of Three Regimens of GX301 Vaccination in Castration-resistant Prostate Cancer

Prostate Cancer Clinical Trial

Official title: A Randomised, Parallel-group, Open-label Phase II Trial of the Immunological Effects of Three Regimens of GX301 Vaccination in Castration-resistant Prostate Cancer Patients Who Have Achieved Response or Disease Stability With First-line Chemotherapy

Status Completed

Clinical Trial Summary

GX301 is an experimental therapeutic vaccine directed against human telomerase, an enzyme playing an essential role in cancer cell proliferation.

This clinical trial will test three different GX301 administration regimens in castration-resistant prostate cancer patients who have achieved response or disease stability with first-line docetaxel treatment. This is aimed at identifying an optimal vaccination regimen.

The three regimens will primarily be compared for their efficacy and safety in inducing vaccine-specific immunological responses over a period of 6 months following treatment initiation. In addition, patients will be observed for the occurrence of disease progression and for their vital status up to 24 months.

Clinical Trial Description

GX301, an experimental therapeutic (anti-cancer) vaccine, is composed of four immunogenic peptides from human telomerase and two complementary adjuvants, Montanide ISA-51 VG and imiquimod.

An earlier Phase 1 study of GX301 has provided evidence of vaccine-specific immune response in a small sample of stage 4 prostate cancer patients given eight GX301 administrations over 9 weeks.

The present Phase 2, randomised, parallel-group, multicentre trial is aimed at comparing three different GX301 administration regimens in patients with progressive, castration-resistant prostate cancer who have completed a first-line docetaxel treatment and have achieved response to chemotherapy or disease stability. Primary comparisons will include regimen efficacy in inducing vaccine-specific immunological responses over a period of 6 months following randomisation; and treatment safety and tolerability over the same period.

A further study aim is to investigate whether achievement of immunological response, irrespective of the assigned GX301 regimen, is related to progression-free and/or overall survival.

Eligible patients will be randomly assigned to receive one of three GX301 vaccination regimens consisting of two, four or eight administrations, respectively, each regimen being given over a fixed 9-week period. Randomisation ratio will be 1:1:1. Randomisation will be stratified by previous cumulative exposure to docetaxel.

Following randomisation, immunological responses to GX301 will be determined over a 6-month period. However, on-study patient observation will be continued until the occurrence of one of the following end-points, whichever the earliest: (a) disease progression; (b) death; (c) completion of an 18-month observation period; or (d) patient's decision to terminate his participation in the study.

All patients discharged from the trial for reasons (a) or (c) will undergo a follow-up to ascertain survival until 24 months from randomisation.

Data analysis will be carried out in two sequential steps. The first step will focus on co-primary outcomes and will therefore take place upon completion of the study dataset up to the 6-month time-point. The second step will incorporate secondary outcomes and will therefore be conducted upon completion of the full study dataset. ;

Related Conditions & MeSH terms

• Prostate Cancer
• Prostatic Neoplasms

• NCT number: NCT02293707
• Study type: Interventional
• Source: Laboratoires Leurquin Mediolanum
• Status: Completed
• Phase: Phase 2
• Start date: November 2014
• Completion date: November 2019