Senhwa Biosciences Announces Positive Clinical Data from Phase 1/Expansion Trial of Silmitasertib (CX-4945) in the Treatment of Basal Cell Carcinoma

Basal Cell Carcinoma CSR Highlights

• CX-4945 Monotherapy: Progression-free survival (PFS) exceeded 21 months in two patients.
• Optimal Treatment Response: Three patients achieved partial response (PR), while ten patients had stable disease (SD).
• Tolerability & Disease Control Rate: Shows potential superiority over current first- and second-line therapies.
• Unmet Medical Need: Enrolled patients with refractory or recurrent disease who had no remaining treatment options.

TAIPEI and SAN DIEGO, April 2, 2025 /PRNewswire/ -- Senhwa Biosciences, Inc. (TPEx: 6492), a new drug development company focusing on first-in-class therapeutics for oncology, rare diseases, and infectious diseases, today announced that the completion of Clinical Study Report (CSR) for Phase 1/Dose Expansion Trial of Silmitasertib (CX-4945) in the Treatment of Basal Cell Carcinoma(BCC), with positive data outcomes. The study included patients who had relapsed after standard therapies and had no other treatment options. Among them, three patients experienced over 30% tumor reduction (PR), and two patients had a progression-free survival (PFS) exceeding 21 months. CX-4945 significantly prolonged survival in advanced cancer patients, marking a major milestone for both the patients and Senhwa.

Compared to current first- and second-line therapies, CX-4945 demonstrated superior tolerability and disease control potential. Therefore, Senhwa will actively pursue licensing possibilities while carefully evaluating CX-4945's potential as a monotherapy or in combination with the second-line immunotherapy Libtayo. The company aims to explore further indications and potential as a first-line treatment, offering better options for patients.

Clinical Trial Overview

The trial enrolled 25 patients with locally advanced BCC (laBCC, 20 patients) and metastatic BCC (mBCC, 5 patients). The primary objective was to determine the recommended Phase 2 dose (RP2D) and optimal dosing regimen for CX-4945.

Among 22 patients eligible for efficacy analysis:

• Three laBCC patients achieved partial response (PR).
• Ten patients had stable disease (SD), including 2 mBCC and 8 laBCC patients.
• Disease control rates:
  • mBCC patients: 80% (4 patients with complete/partial response or stable disease).
  • laBCC patients: 65% (11 patients with complete/partial response or stable disease).

Further data analysis showed that:

• Median progression-free survival (PFS):
  • laBCC: 9.2 months
  • mBCC: 3.7 months
• Median duration of disease control (DDC):
  • laBCC: 10.3 months
  • mBCC: 7.5 months

CX-4945 exhibited promising anti-tumor efficacy and disease stabilization potential in this indication. Additionally, CX-4945 has a lower study drug discontinuation rate of 24% due to AEs, compared to first-line treatments including Vismodegib and Sonidegib, suggesting superior tolerability.

Future Prospects

This trial is particularly noteworthy as it evaluated CX-4945 monotherapy in patients who had already failed first-line HHIs. Notably, 27.3% (6 patients) had also failed second-line PD-1 inhibitors such as Libtayo or Keytruda.

Among the enrolled patients, two advanced-stage patients achieved a progression-free survival (PFS) of over 21 months, lasting 653 days and 667 days, respectively. Notably, the primary lesion of the former patient was almost undetectable by visual inspection.

Given the significant potential of CX-4945 as a monotherapy, Senhwa is now actively pursuing regional licensing to accelerate commercialization through strategic partnerships, ultimately benefiting more patients.

SOURCE Senhwa Biosciences, Inc.