Senhwa Biosciences has announced positive clinical data from its Phase 1/Dose Expansion trial of Silmitasertib (CX-4945) in treating Basal Cell Carcinoma (BCC), offering new hope for patients with limited treatment options.
The completed Clinical Study Report (CSR) revealed promising outcomes for the first-in-class therapeutic, particularly in patients who had relapsed after standard therapies and had no remaining treatment alternatives.
Significant Clinical Outcomes
Among the trial's most notable findings, two patients achieved progression-free survival (PFS) exceeding 21 months (653 and 667 days, respectively). Three patients with locally advanced BCC (laBCC) experienced partial response (PR) with tumor reduction exceeding 30%, while ten patients maintained stable disease (SD).
"CX-4945 significantly prolonged survival in advanced cancer patients, marking a major milestone for both the patients and Senhwa," stated the company in their announcement from Taipei and San Diego.
The drug demonstrated superior tolerability compared to current first- and second-line therapies, with a study drug discontinuation rate of only 24% due to adverse events (AEs). This compares favorably to first-line Hedgehog pathway inhibitors (HHIs) like Vismodegib and Sonidegib.
Trial Design and Patient Population
The trial enrolled 25 patients, including 20 with locally advanced BCC (laBCC) and 5 with metastatic BCC (mBCC). The primary objective was determining the recommended Phase 2 dose (RP2D) and optimal dosing regimen for CX-4945.
Of particular significance, the study focused on patients who had already failed first-line HHIs, with 27.3% (6 patients) having also failed second-line PD-1 inhibitors such as Libtayo or Keytruda.
Among the 22 patients eligible for efficacy analysis, disease control rates reached 80% for mBCC patients and 65% for laBCC patients. Further analysis revealed median progression-free survival of 9.2 months for laBCC and 3.7 months for mBCC patients.
Median Duration of Disease Control
The median duration of disease control (DDC) was 10.3 months for laBCC patients and 7.5 months for mBCC patients, underscoring the drug's potential for disease stabilization.
In one remarkable case, a patient's primary lesion became almost undetectable by visual inspection after treatment with CX-4945.
Future Development Strategy
Based on these promising results, Senhwa Biosciences is pursuing multiple development pathways for Silmitasertib. The company is actively seeking regional licensing opportunities to accelerate commercialization through strategic partnerships.
Additionally, Senhwa is evaluating CX-4945's potential both as a monotherapy and in combination with second-line immunotherapy Libtayo. The company aims to explore additional indications and assess its potential as a first-line treatment.
Unmet Medical Need
Basal cell carcinoma is the most common form of skin cancer, with advanced cases presenting significant treatment challenges. Current therapies often have limitations in terms of efficacy and tolerability, particularly for patients with refractory or recurrent disease.
The positive outcomes from this trial suggest that Silmitasertib could potentially address a significant unmet need in the treatment landscape for advanced BCC patients who have exhausted other therapeutic options.
As Senhwa continues to advance the development of Silmitasertib, these findings represent a promising step toward providing new treatment options for patients with limited alternatives.
