PACIFIC-5 Phase III Trial Demonstrates Significant Efficacy of Durvalumab in Unresectable Stage III NSCLC Patients Following Concurrent or Sequential Chemoradiotherapy

China Finance Network December 10th: Positive results from the PACIFIC-5 Phase III clinical trial indicate that AstraZeneca's Imfinzi (generic name: durvalumab) treatment for unresectable Stage III non-small cell lung cancer (NSCLC) patients who have not progressed following concurrent or sequential chemoradiotherapy (CRT) shows statistically significant and clinically meaningful improvement in progression-free survival (PFS), with a trend toward overall survival (OS) benefit.

The specific data were presented on December 6 at the 2024 European Society for Medical Oncology Asia Congress (ESMO ASIA) held in Singapore (Abstract #LBA6).

The results evaluated by the blinded independent central review (BICR) indicated that, compared with placebo, the estimated risk of disease progression or death was reduced by 25% in patients receiving durvalumab (based on PFS [HR] 0.75; 95% [CI] 0.578-0.986; p=0.038). Subgroup analysis showed consistent benefits in patients receiving durvalumab after concurrent chemoradiotherapy (HR 0.76; 95% [CI] 0.545-1.063; p=0.103) or sequential chemoradiotherapy (HR 0.75; 95% [CI] 0.490-1.181; p=0.213).

In the first interim analysis, the key secondary endpoint OS results showed: compared with placebo, there was a trend of decreased death risk in patients receiving durvalumab (HR 0.87; 95% [CI] 0.656-1.166; p=0.346). Approximately half (49.1%) of the patients received durvalumab treatment for at least one year, while the proportion in the placebo group was 33.6%. About one-third (29.9%) of the patients received durvalumab treatment for at least two years, while the proportion in the placebo group was about one-fifth (20.9%).

Professor Wu Yilong, the international coordinating investigator of the PACIFIC-5 clinical trial, Chief Expert of Guangdong Provincial People's Hospital, and Chairman of the Chinese Thoracic Oncology Group (CTONG), stated that the results of the PACIFIC-5 study further confirm the clinical benefits of durvalumab as the global standard treatment following concurrent chemoradiotherapy for unresectable Stage III non-small cell lung cancer. The study also indicates that patients receiving sequential chemoradiotherapy can benefit from this treatment regimen. "We look forward to the PACIFIC regimen’s indications in China being further expanded to include patients who have not progressed after sequential chemoradiotherapy. This will help prolong the lives of more patients with this disease and improve their quality of life."

Durvalumab’s safety and tolerability are consistent with its known safety profile, with no new safety concerns identified.

Data shows that lung cancer is the malignant tumor with the highest incidence and mortality rate in China, with more than a million new cases annually, accounting for over 40% of global lung cancer patients. Non-small cell lung cancer (NSCLC) accounts for approximately 80%-85% of these cases. Based on factors such as tumor size, extent of invasion, lymph node metastasis, and distant metastasis, the international TNM staging system classifies NSCLC into stages I, II, III, and IV. In China, about 30% of patients are already at stage III (locally advanced) at the time of diagnosis and have missed the optimal window for surgical treatment. The standard treatment for unresectable stage III NSCLC is chemoradiotherapy (CRT), but patient prognosis remains poor, necessitating new treatment options.

The PACIFIC Phase III clinical trial, initially presented at the 2017 European Society for Medical Oncology Annual Meeting, evaluated the efficacy of durvalumab consolidation therapy in patients with Stage III unresectable locally advanced NSCLC who did not experience disease progression after concurrent chemoradiotherapy. The trial results demonstrated a significant improvement in efficacy compared to placebo, establishing durvalumab as the standard treatment regimen. The PACIFIC-5 clinical trial includes a large number of Chinese patients and assesses the efficacy of durvalumab as consolidation therapy following sequential or concurrent chemoradiotherapy.

Dr. He Jing, Senior Vice President of AstraZeneca Global and Head of China Center for Global R&D, stated: "Based on the PACIFIC trial, durvalumab has changed the treatment standard for patients with unresectable Stage III NSCLC worldwide. We are very pleased to see that in the PACIFIC-5 clinical trial, which mainly involved Chinese patients, the benefits of durvalumab have once again been confirmed. Adhering to the concept of 'patient-centeredness,' we look forward to having in-depth discussions with Chinese regulatory authorities regarding these clinical results. We will also continue to focus on providing better treatment options for lung cancer patients in China and around the world."

AstraZeneca is conducting several clinical trials aimed at registration to evaluate the efficacy of durvalumab in early-stage lung cancer, including the PACIFIC-4 trial for inoperable or unresectable Stage I and Stage II lymph node-negative NSCLC, and the PACIFIC-8 and 9 trials for inoperable Stage III NSCLC.