US Stock Market Move | ZAI LAB (ZLAB.US) rises over 2%; investigational ADC Zoci shows positive Phase Ib data.

On Friday, ZAI LAB (ZLAB.US) rose nearly 10% in early trading, and as of press time, was up over 2% at $22.62. On the news front, on October 23, ZAI LAB announced data from the global Phase Ib clinical study of its investigational antibody-drug conjugate (ADC) Zocilurtatug Pelitecan (abbreviated as "Zoci," formerly code-named ZL-1310) for first-line extensive-stage small cell lung cancer. The results will be presented on October 26 at the 2026 European Society for Medical Oncology (ESMO) Congress. The data showed that at the recommended Phase III study dose of 1.6 mg/kg, Zoci combined with atezolizumab in 33 patients achieved a confirmed objective response rate (ORR) of 81.8%, with an estimated 6-month progression-free survival rate of 81.9%. Among 15 patients followed for at least 6 months, after a median follow-up of 10 months, median progression-free survival and median duration of response had not yet been reached, indicating that most patients continue to benefit from treatment. In terms of safety, among the 33 patients who received the dual-drug regimen, the incidence of Grade 3 or higher adverse events related to Zoci was 9.1%. In addition, the three-drug regimen of Zoci combined with atezolizumab and carboplatin achieved an objective response rate of 92.3% in 13 patients receiving different doses, with a median progression-free survival of 8.4 months and a median duration of response of 7.7 months. However, the incidence of Grade 3 or higher treatment-emergent adverse events for the three-drug regimen reached 76.9%, higher than the 21.2% for the dual-drug regimen. Currently, the first-line standard of care for extensive-stage small cell lung cancer is immune checkpoint inhibitors combined with chemotherapy. ZAI LAB stated that the above results support further exploration of ADC combined with immunotherapy as a replacement for traditional platinum-containing chemotherapy. The company plans to initiate a global randomized Phase III clinical study before the end of 2026 to evaluate the efficacy and safety of Zoci combined with immunotherapy for first-line treatment of extensive-stage small cell lung cancer.