Human papillomavirus causes around 5% of all cancers, including most cancers in the anogenital tract. Once cancer develops, the treatments for HPV-associated anal cancers are not well tolerated and toxic. However, pre-cancerous lesions are detectable prior to the development of cancer, and treatment of the lesions at this early stage may prevent cancer development. Cancer progression is highest for severe (“high grade”) lesions and lesions that persist over time. At the moment, there is no proven, effective treatment for anal HPV-associated lesions to prevent progression to cancer.
In this study, we are evaluating whether treatment with pomalidomide clears HPV-associated lesions in people with high grade, persistent lesions. Pomalidomide is a medication that modulates the body’s immune system and so may help control the HPV infection and lesions and prevent development of cancer. Pomalidomide has been approved for certain blood cancers. This is the first study testing whether it is useful to treat HPV-associated anal cancer precursors and the only study of immune modulation in this disease.
SPACE is an open-label study; all participants receive oral pomalidomide for 6 months together with aspirin or a similar medication. At baseline, participants undergo High Resolution Anoscopy (HRA) to confirm the presence of persistent severe (“high grade”) HPV-associated lesions. HRA is repeated to evaluate clearance of these lesions upon completion of pomalidomide treatment and again 6 months later to determine whether any treatment effect is persistent. Participants are being recruited from St. Vincent’s Hospital, where the highly specialised anoscopy services to detect and follow these anogential lesions has been developed.
The goals of the SPACE study are to determine the efficacy of pomalidomide to clear “high grade” lesions, the tolerability and feasibility of treatment in a clinical setting and the impact on quality of life of participants.
At the moment, there is not proven effective treatment for HPV-associated anal lesions. Given the problems with current cancer therapies, early intervention and prevention would be clinically significant for affected communities, offering an entirely new approach to cancer prevention.