Combining a therapeutic vaccine for human papilloma virus (HPV) with two standard chemotherapy drugs may extend survival in patients with advanced, recurrent cervical cancer, according to a phase 1/2 trial involving 77 patients.

The trial results suggest that integrating therapeutic cancer vaccines with traditional drug regimens could invigorate anticancer immunity and improve outcomes in patients with end-stage cervical cancer, who currently have few treatment options.

The research is published in the journal Science Translational Medicine.

Therapeutic cancer vaccines work by expanding the population of tumour-specific T cells, resulting in more robust anti-tumour immunity.

These vaccines have shown promise in treating pre-cancerous lesions caused by HPV, a virus that plays a key role in the development of cervical cancer.

However, other cell types such as myeloid cells pose a major obstacle because they can suppress the expansion of T cells, counteracting the stimulation provided by the vaccine.

Building on previous work, Cornelis Melief and colleagues administered the therapeutic HPV vaccine ISA101 to 77 HPV-positive cervical cancer patients receiving the chemotherapy drugs carboplatin and paclitaxel.

Although the patients experienced chemotherapy-related side effects, the vaccine was well-tolerated and did not cause any additional adverse reactions. Melief et al. observed that the drugs reduced the amount of suppressive myeloid cells, allowing ISA101 to better stimulate T cells.

Ultimately, 43% of the patients achieved tumour regression and another 43% showed stable disease.

Furthermore, patients who showed stronger responses to the vaccine had a longer median overall survival of 16.8 months compared with patients who displayed weaker responses (11.2 months).

The scientists plan to conduct further studies to compare the benefits of adding ISA101 to chemotherapy regimens versus receiving chemotherapy alone.

Source: American Association for the Advancement of Science