Traws Pharma announced the publication of compelling clinical efficacy data for rigosertib in patients with recessive dystrophic epidermolysis bullosa-associated squamous cell carcinoma (RDEB SCC), marking the first clinical trial of any experimental cancer therapeutic in this rare monogenic disease. The results, published in the British Journal of Dermatology, demonstrated an overall response rate of 80%, with complete responses achieved in 50% of evaluable patients.
Breakthrough Results in Rare Disease
"These data indicate that rigosertib is a potential treatment for cutaneous SCC in RDEB patients, where there is a substantial unmet need and no approved therapies," said Victor Moyo, MD, Chief Medical Officer Oncology at Traws Pharma. "The aggressive course of this disease is inadequately addressed by current treatment regimens, which produce limited response rates of mostly short duration."
The clinical trial represents a significant milestone for patients with RDEB-associated SCC, a devastating condition that serves as the primary cause of death for RDEB patients. The disease carries a cumulative risk of death of 70% and 78.7% by ages 45 and 55, respectively.
Understanding RDEB-Associated Cancer
RDEB is caused by insufficient expression of type VII collagen, which is responsible for anchoring the skin's inner layer to its outer layer. This leads to extreme skin fragility as well as chronic blistering and wound formation with recurrent infections in RDEB patients, many of whom go on to develop metastatic squamous cell carcinoma driven by overexpression of polo-like kinase 1 (PLK-1).
RDEB-associated SCC tumors show a highly aggressive and early metastasizing course, and can appear in pediatric patients or young adults. Currently available treatments such as targeted therapies and conventional chemo- and/or radiotherapy have demonstrated limited response rates and poor durability in RDEB-associated SCC.
Drug Mechanism and Development
Rigosertib is a small molecule kinase inhibitor targeting PLK-1, among other kinases. The compound is being evaluated in investigator-sponsored studies as a monotherapy for advanced squamous cell carcinoma complicating RDEB, using both oral and intravenous formulations. Rigosertib has also been evaluated in combination with other agents, including checkpoint inhibitors, for solid tumors including non-small cell lung cancer and metastatic melanoma.
Partnership Opportunities
"We are excited to report the compelling efficacy and tolerability profile of rigosertib in this devastating, difficult to treat disease, and thank the patients, sponsors and investigators for their commitment to this program," commented Iain Dukes, MA, DPhil, Interim CEO of Traws Pharma. "Rigosertib is available for further development and commercialization, and we are committed to finding an appropriate partner to advance this important medicine to approval."
Traws Pharma is actively seeking development and commercialization partners for its legacy clinical oncology programs, including rigosertib and narazaciclib, as the company focuses its primary efforts on developing novel therapies for respiratory viral diseases.
