A topical cream known as remetinostat has demonstrated the ability to effectively treat basal cell carcinoma, the most common form of skin cancer in the world.
The results of the Phase II clinical trial, which were published in the journal Clinical Cancer Research, showed the cream is a first-in-class inhibitor of histone deacetylase (HDAC) — meaning it can arrest tumour development — that may present a safe alternative to the surgical intervention typically necessary for patients. While systemic HDAC inhibiters have previously shown promise as a method of treatment, concerns over toxicity have impeded development. Remetinostat, on the other hand, was engineered to lose potency once absorbed into the skin, confining its cancer-fighting abilities to the specific area treated by the cream.
“While further research is needed, our results suggest that remetinostat could be a safe and promising alternative to surgical treatment of BCC due to the high rate of complete responses we observed,” said Kavita Sarin, senior author of the study and an associate professor at Stanford, according to the European Pharmaceutical Review. “However, if a therapy is to replace surgical treatment, it needs to not only induce a complete response, but also a durable one.”
Non-melanoma skin cancer accounts for around 28 per cent of all new cancer cases in the country, according to the Public Health Agency of Canada. Around 75 to 80 per cent of these cases originate in the basal cells lining the top layer of the skin and are known as basal cell cancer (BCC). The remaining 20 to 25 per cent form in the squamous cells and are known as squamous cell cancer, or SCC. Because non-melanoma cancers are often successfully treated by dermatologists and do not require hospitalization, other statistics surrounding the disease are often estimates. It is thought that one in eight Canadians will develop BCC in their lifetime and one in 20 will experience SCC. Both forms of the disease have a higher five-year survival rate than melanoma, a less common but deadlier form of skin cancer.
Sarin’s study recruited 30 patients, all with at least one BCC of at least 5 millimetres in diameter at the time they were diagnosed. The patient pool was 90 per cent non-Hispanic white, almost half of whom reported a prior encounter with skin cancer. Eight of the participants had multiple tumours — some exposed to the sun, some not — adding up to a total of 49 eligible tumours available for treatment.
Patients were required to rub remetinostat gel on their tumours three times a day for a month and a half, with any remaining tumour removed surgically for examination at the two-month mark. Researchers found that 69.7 per cent of the 33 tumours included in the study responded to the cream, with 17 demonstrating “complete resolution” and six partially responding. The diameter of the tumours in the study, on average, shrunk by 62.3 per cent. Tumour area dropped by 71.5 per cent.
Researchers found a 100 per cent response rate across the six superficial BCC tumours included in the study (five complete, one partial), a 68.2 per cent response rate among the 22 nodular BCC tumours (10 complete, five partial) and a 66.7 per cent response rate among three infiltrative BCC tumours (two complete responses). The team did not observe any response in the two micronodular tumours included in the study. The only notable adverse reaction reported was an eczema-like rash that appeared in some cases where the cream was applied.
While future trials will be necessary to ensure the encouraging results are long-lasting, the potential of a skin-cancer therapy that minimizes or eliminates the need for surgery is hard to overstate. “Our study also showed remetinostat’s clinical efficacy against nodular BCC, one of the more common BCC subtype,” Sarin said. “An ideal therapeutic for BCC should treat both nodular and superficial BCCs and ideally the other subtypes as well.”
Dave Yasvinski is a writer with Healthing.ca