Novel Topical Therapy Shows Promise in Basal Cell Carcinoma

A topical therapy known as remetinostat, may help reduce the need for the surgical removal of certain basal cell carcinoma (BCC) legions, according to a recent study published in Clinical Cancer Research.¹

The current standard of care for BCC is surgical excision. However, the procedure is often time consuming, expensive, and may lead to cosmetic and functional morbidity.

“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, MD, PhD, senior author of the study and an associate professor of Dermatology at Stanford University, in a press release.²

The phase 2 study (NCT03180528) had an actual enrollment of 30 participants. The primary end point was overall response rate (ORR). Secondary end points include adverse events (AEs) and treatment discontinuation or interruption. Patients were recruited between May 2018 and June 2020. Patients must have had at least one cutaneous tumor greater than or equal to 5 mm in diameter and amendable to surgical resection. Patients with a tumor greater than 25mm, cosmetically sensitive, inoperable, locally advanced, or had metastatic lesions were excluded.³

The refrigerated medication was applied 3 times daily for 6 weeks. Monitoring was conducted at 4 and 8 weeks. At week 8, any remaining tumor was surgically excised. Follow-up treatment was conducted between weeks 10 and 12.

The median age of participants was 59 (range, 38-86) and 63% were male. Ninety percent were non-Hispanic/Latinx white. Over half, 53%, had no personal history of skin cancer. The majority of participants had 1 tumor (73%), while 13% had 2 tumors, 3% had 3 tumors, and 10% had 4 or greater. HCC histological subtypes included nodular (35%), superficial (14%), infiltrative (2%), pigmented nodular (2%), superficial and nodular (22%), nodular and micronodular (4%), nodular and infiltrative (4%), and not determined (16%). Most tumors, 59.2%, were larger than 10 mm in diameter. Anatomic locations included forearm and elbow (6%), upper arm (4%), shoulder (10%), clavicle (4%), chest (12%), back (24%), abdomen (4%), flank (2%), thigh (8%), shin (6%), neck (6%), face (6%), and ear (6%).

Of the 30 participants initially accrued, 25 were included in the analysis. Those 25 patients had 33 tumors between them. One patient was excluded due to lack of compliance, 1 was excluded due to the lack of medication refrigeration, 1 was excluded from treatment due to abnormal baseline safety labs, 1 withdrew from the trial due to AEs, and 1 withdrew due to time commitments.

The ORR 69.7%(90% CI, 54%–82.5%). The average change in the longest tumor diameter was 62.3%. No reported tumors increased in diameter. Superficial BCC responded best to treatment, with an ORR of 100%. The ORR for nodular BCC was 68.2% and 66.7% for infiltrative BCC. Micronodular BCC did not respond to treatment. ORR also depended on if the site was sun-exposed. For example, the ORR for non-sun-exposed sites was 63.6% compared to 81.8% for those that were sun-exposed. Initial tumor diameter had no effect on ORR.

Nearly 55% of tumors demonstrated complete histologic resolution of BCC while 45.2% contained microscopic residual tumor. The mean compliance per tumor was 95%. The change in tumor longest diameter ORR was 51.1% (90% CI, 38%–64.1%; five partial responses and 18 complete responses. The average decrease was 52.5%. Twenty-one of 35 evaluable tumors demonstrated complete histologic resolution. The mean tumor compliance was 85%.

In terms of safety, no serious or symptomatic AEs were reported. The most common AE was a localized eczematous reaction at the application site. In total, 27 episodes were reported, with a mean duration of 64.4 days. Most of these reactions were grade 2, with 5 grade 1 events, and 1 grade 3 event. Four patients suspended treatment between 1 day to 2 weeks due to the reaction. Six episodes of pain at the site of drug application were reported. Four of these events were grade 1 and 2 ere grade 2. Two patients were required to temporarily suspend treatment. The rate of any-grade AEs was 90%. Of the 3 participants who did not experience any AEs, 1 had not been given treatment and 1 was less than 70% compliant.

“Our study also showed remetinostat’s clinical efficacy against nodular BCC, one of the more common BCC subtypes,” Sarin added. “An ideal therapeutic for BCC should treat both nodular and superficial BCCs, and ideally the other subtypes as well.”

_REFERENCES:

_{1. Kilgour J, Shah A, Urman N, et al. Phase II open-label, single-arm trial to investigate the efficacy and safety of topical remetinostat gel in patients with basal cell carcinoma. Clin Cancer Res. 2021; 27(17):4717-4725. DOI: 10.1158/1078-0432.CCR-21-0560.}

_{2. Topical remetinostat in treating patient with cutaneous basal cell cancer. ClincalTrials.gov. Accessed September 13, 2021. https://bit.ly/3C7duQT.}

_{3. Remetinostat, a topical therapy that works by inhibiting the expression of cancer-promoting genes, could reduce the need for surgical removal of many subtypes of basal cell carcinoma lesions. News release. American Association for Cancer Research. Accessed September 13, 2021.}