High-risk HPV infection is the primary cause of cervical cancer. Preventive HPV vaccines are highly effective when given before exposure to the virus, but there are currently no approved vaccines designed to treat people who already have a persistent HPV infection.
In many cases, the immune system clears HPV naturally without treatment. However, when infection persists, it can lead to cervical cell abnormalities and, over time, increase the risk of cancer. Clearance of high-risk HPV has been associated with strong immune responses, leading researchers to explore whether therapeutic vaccination could enhance the body’s ability to eliminate the virus. The VTP-200 programme, led by Associate Professor Karin Hellner (Nuffield Department of Women's and Reproductive Health) was developed to stimulate targeted immune responses against multiple high-risk HPV types in women with persistent infection and low-grade cervical changes.
Study design
The study, published in Clinical Infectious Diseases, assessed the safety, tolerability, immune response and preliminary efficacy of VTP-200, a two-component vaccine that uses modified viruses to deliver HPV-specific instructions to the immune system. The trial enrolled 108 women with persistent high-risk HPV infection and low-grade cervical lesions. After an initial lead-in phase, participants were randomly assigned to receive one of several vaccine dose regimens or a placebo, administered 28 days apart.
Safety and immune response
The vaccine regimens were well tolerated. No serious treatment-related adverse events were reported. All active dose groups generated strong HPV-targeted immune responses, confirming that the vaccine successfully stimulated the intended immune mechanisms.
Clinical outcomes
At 12 months, clearance of high-risk HPV was observed in both vaccinated and placebo groups at similar rates. The study did not demonstrate a statistically significant difference in HPV clearance or lesion resolution between the combined vaccine groups and placebo.
A trend toward higher HPV clearance was observed in participants receiving the highest vaccine dose, though this finding requires further investigation. No clear association was identified between the measured immune responses and clinical clearance outcomes.
Interpretation and next steps
This early-phase study demonstrates that the VTP-200 therapeutic vaccine is safe and can induce HPV-specific immune responses in women with persistent infection. However, the trial did not show a statistically significant improvement in HPV or lesion clearance compared with placebo in this study population.
Building on the trial results, Karin Hellner received substantive research funding through Cancer Research UK’s prestigious ‘Biology to Prevention Award’ to develop an improved therapeutic HPV vaccine to improve its clinical benefits. This work is currently ongoing.
For more information please see the Nuffield Department of Women's and Reproductive Health website.