Libtayo May Treat Advanced Skin Cancer in RDEB Patients, Case Report Shows

The immunotherapy Libtayo (cemiplimab-rwlc) may be a promising treatment for the skin cancers that sometimes appear in people with recessive dystrophic epidermolysis bullosa (RDEB) as a result of chronic wounds, a case report shows.

The study, “Induced Remission of Metastatic Squamous Cell Carcinoma with an Immune Checkpoint Inhibitor in a Patient with Recessive Dystrophic Epidermolysis Bullosa,” was published in Case Reports in Oncology.

Epidermolysis bullosa (EB) refers to a group of rare and inherited skin disorders that make the skin fragile and prone to blistering. RDEB, which accounts for approximately 25% of EB cases, is caused by mutations in the COL7A1 gene, which contains the instructions for making type VII collagen (COL7), a key protein for skin integrity.

The chronic wounds that result from RDEB are common sites for the development of cutaneous squamous cell carcinoma (SCC), a form of skin cancer that is often resistant to treatment and associated with poor survival rates. Patients usually live a median of 2.4 years after their SCC diagnosis, according to researchers from Washington and Stanford universities.

Yet, no standard care exists for treating SCC in people with RDEB, particularly when the cancer becomes more aggressive and spreads to distant organs. In such cases, treatment is based on rare reports and expert opinions.

“There is no optimal therapy for advanced or metastatic SCC in this patient population given the partial short-lived response with conventional chemotherapy and the absence of controlled trials,” the investigators wrote.

These researchers now reported the case of a 32-year-old man with RDEB and metastatic SCC who attained a durable response — lasting at least 14 months — with Libtayo.

The man had severe RDEB, and a history of multiple SCCs on his lower back and right hand. Despite multiple surgeries to remove the localized cancer lesions, the cancer kept returning and eventually progressed into the right forearm and and axillary lymph node — one in the armpit.

The patient had previously received skin grafts and injections of skin cells, in which viral vectors were used to correct the mutated COL7A1 gene, but SCC samples were negative for the presence of such virus.

Before starting treatment, the man underwent a positron emission tomography/computed tomography (PET/CT) scan to detect the full extent of his cancer. As per the physical exam, several lesions were detected in the right underarm, right forearm, and right hand.

Since chemotherapy comes with several risks for RDEB patients, including bone marrow suppression with an increased risk of infection in chronic wounds, the patient was started on Libtayo.

Developed by Regeneron and Sanofi Genzyme, Libtayo belongs to a class of medications called immune checkpoint inhibitors, which block proteins used by cancer cells to avoid being targeted and destroyed by immune cells.

Libtayo specifically blocks a protein receptor found on the surface of immune T-cells, called PD-1, preventing it from interacting with PD-L1 and PD-L2 on cancer cells. This allows immune cells to recognize and eliminate cancer cells more effectively.

This therapy is approved for people with locally advanced and metastatic cutaneous SCC, and appears to lead to mild and minimal skin-adverse events. However, no existing report describes Libtayo’s safety and efficacy in RDEB patients.

The man received Libtayo directly into the bloodstream (intravenously) at a 350 mg dose every three weeks, along with a single radiotherapy treatment to the underarm and forearm. Two months later, repeat imaging scans showed a dramatic reduction in cancer lesions. Skin lesions were no longer detected at this point, and scans every three months continued to come back negative.

Notably, the patient reported mild nausea and fatigue, but no worsening of his RDEB wounds, nor immune-related events.

Importantly, the response to Libtayo was lasting for 14 months at the time of the report.

“Our patient demonstrated a sustained radiological response for 14 months, with minimal side effects and no immune-related adverse effects, which is promising,” the investigators wrote.

“However, additional larger case studies and controlled trials are needed to confirm the safety and efficacy of cemiplimab in RDEB patients with cutaneous metastatic SCC,” they added.