Ivonescimab Beats Pembrolizumab on OS: Landmark Signal, China-Only Data Wall

Akeso's Ivonescimab Achieves Dual OS and PFS Benefit Against Pembrolizumab in NSCLC

Akeso, Inc. announced that a pre-specified interim analysis of overall survival (OS) in its HARMONi-2 (AK112-303) Phase III trial met the key secondary endpoint. The study demonstrated that ivonescimab, Akeso’s first-in-class PD-1/VEGF bispecific antibody, showed statistically significant and clinically meaningful improvement over pembrolizumab as a first-line treatment for patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) whose tumors express PD-L1 (TPS ≥1%). This follows a May 2024 interim analysis where ivonescimab met its primary endpoint of progression-free survival (PFS), achieving a median PFS of 11.14 months versus 5.82 months for pembrolizumab, making HARMONi-2 the first randomized, double-blind Phase III trial to show a significant positive outcome against pembrolizumab in this setting.

• Akeso's ivonescimab achieved its key secondary endpoint of overall survival (OS) in the HARMONi-2 Phase III trial, as confirmed by an Independent Data Monitoring Committee. The interim analysis revealed statistically significant and clinically meaningful OS improvement compared to pembrolizumab for first-line PD-L1-positive NSCLC patients, reinforcing the drug's efficacy profile.
• The HARMONi-2 study had previously met its primary endpoint of progression-free survival (PFS) in May 2024. Ivonescimab demonstrated a median PFS of 11.14 months, significantly outperforming pembrolizumab's 5.82 months. This achievement marked HARMONi-2 as the first randomized, double-blind Phase III trial to show a significant positive outcome against pembrolizumab in this specific patient population.
• Ivonescimab, a unique PD-1/VEGF bispecific antibody, leverages a dual mechanism of action combining immunotherapy and anti-angiogenesis. This is the fourth Phase III study of an ivonescimab-based regimen to show significant benefit in both OS and PFS, strengthening confidence in its clinical value for lung cancer and its potential applicability across a broader range of solid tumors.

Ivonescimab's Landmark OS and PFS Outcomes in HARMONi-2

Two recent studies have advanced the understanding of treatment strategies in non-small cell lung cancer (NSCLC). The first, an indirect comparative meta-analysis evaluating immunotherapy-based regimens, examined patients with EGFR-mutated NSCLC who had progressed on EGFR-tyrosine kinase inhibitor (TKI) therapy. The analysis incorporated data from the Checkmate-722, Keynote-789, ORIENT-31, and ATTLAS trials, using chemotherapy as a common comparator. The key efficacy finding was that immunotherapy and bevacizumab plus chemotherapy demonstrated significantly better progression-free survival compared to immunotherapy plus chemotherapy alone (HR=0.71, 95% CI 0.55 to 0.91). Subgroup analyses identified L858R mutation (HR 0.52, 95% CI 0.37 to 0.72) and absence of T790M mutation (HR 0.50, 95% CI 0.35 to 0.71) as factors significantly associated with greater PFS benefit from immunotherapy-based regimens.

The second study is a matching-adjusted indirect comparison (MAIC) evaluating taletrectinib — a next-generation, selective ROS1 TKI — versus first-generation TKIs, crizotinib and entrectinib, in TKI-naïve patients with ROS1-positive NSCLC. Drawing on pooled data from the TRUST-I (NCT04395677) and TRUST-II (NCT04919811) studies, the analysis demonstrated that taletrectinib was associated with significantly higher odds of objective response versus both comparators. On survival outcomes, taletrectinib showed significantly longer progression-free survival versus crizotinib (HR 0.48, 95% CI 0.27–0.88) and entrectinib (HR 0.42, 95% CI 0.27–0.65), significantly longer overall survival versus crizotinib (HR 0.34, 95% CI 0.15–0.77) and entrectinib (HR 0.48, 95% CI 0.27–0.88), and significantly longer duration of response versus entrectinib (HR 0.35, 95% CI 0.21–0.60). From a safety perspective, a descriptive cross-trial comparison revealed no marked differences in treatment-related adverse event rates across taletrectinib, crizotinib, and entrectinib.

A third study, the TOGATHER trial, assessed perioperative immunotherapy in patients with primarily nonresectable NSCLC, representing a novel application of perioperative immunotherapy beyond the resectable setting. The trial is noted to have prompted re-evaluation of the frontiers of resectability, surgical approaches, and chemoradiotherapy in this population. Detailed efficacy and safety outcome data from TOGATHER are not reported in the available literature.

HARMONi-2: Designing a Head-to-Head Win Against Pembrolizumab

Several pivotal trials have evaluated diverse therapeutic strategies in NSCLC — spanning neoadjuvant/adjuvant chemotherapy and immunotherapy combinations, targeted kinase inhibition, and radiotherapy sequencing — each with distinct design parameters and endpoint hierarchies. The studies below represent a cross-section of phase II and III investigations informing current and emerging standards of care across resectable, locally advanced, and metastatic disease settings.

Reshaping First-Line PD-L1+ NSCLC Treatment with Ivonescimab

Across published randomized and meta-analytic evidence, immunotherapy-based combinations have consistently outperformed chemotherapy alone as first-line treatment for advanced NSCLC. A Bayesian network meta-analysis of 12 studies enrolling 7,490 patients found that all chemo-immunotherapy regimens significantly prolonged overall survival (OS) and progression-free survival (PFS) compared with chemotherapy, with pembrolizumab plus chemotherapy demonstrating superior PFS over nivolumab plus ipilimumab (HR 0.66). In PD-L1 ≥50% patients, pembrolizumab plus chemotherapy (HR 0.39), atezolizumab plus chemotherapy (HR 0.47), and pembrolizumab monotherapy (HR 0.67) all showed significantly better PFS than chemotherapy. An indirect comparison of tislelizumab plus chemotherapy versus pembrolizumab plus chemotherapy found no significant differences in PFS (HR 1.04, 95% CI 0.82–1.31), ORR (RR 0.79, 95% CI 0.59–1.07), or grade ≥3 adverse events (RR 0.99, 95% CI 0.87–1.12), suggesting comparable efficacy and safety between these two regimens.

In targeted therapy settings, a network meta-analysis of seven randomized controlled trials involving 3,012 patients evaluated third-generation EGFR tyrosine kinase inhibitors (TKIs) in EGFR-mutated NSCLC, finding that all third-generation agents significantly prolonged PFS versus first-generation TKIs, with no significant PFS differences among the third-generation agents themselves. Furmonertinib ranked highest for PFS (HR 0.82; 95% CrI 0.72–0.94), aumolertinib demonstrated the best intracranial control (HR 0.74; 95% CrI 0.63–0.89), and osimertinib (HR 0.90; 95% CrI 0.83–0.99) and lazertinib (HR 0.89; 95% CrI 0.79–1.00) showed OS benefits over first-generation TKIs. In ALK-positive NSCLC, a meta-analysis of alectinib across 8 studies and 626 patients reported a pooled ORR of 70% (95% CI 57%–82%), disease control rate of 88% (95% CI 82%–94%), and intracranial ORR of 52% (95% CI 45%–59%). A phase IV study of lorlatinib in patients with ALK-positive metastatic NSCLC who progressed on a prior second-generation ALK inhibitor reported an ORR of 42% (95% CI 31%–55%) and median PFS of 12.2 months (95% CI 6.9–22.1), with an intracranial ORR of 47% in patients with CNS metastases.

In later-line settings, antibody-drug conjugates (ADCs) were evaluated against docetaxel in a meta-analysis of three randomized controlled trials involving 1,597 patients. ADCs did not significantly improve PFS (pooled HR 0.91, 95% CI 0.73–1.13), and the OS benefit was borderline (pooled HR 0.88, 95% CI 0.78–1.00, p = 0.06); however, a significant OS benefit was observed in the nonsquamous subgroup (HR 0.85, 95% CI 0.74–0.98, p = 0.03). Grade ≥3 treatment-related adverse events were significantly lower with ADCs (pooled OR 0.49, 95% CI 0.26–0.90, p = 0.02). A phase 2 trial of pembrolizumab continued beyond progression in combination with next-line chemotherapy (BTCRC-LUN15-029) demonstrated a median PFS of 5.1 months (95% CI 3.6–8.0 months) and median OS of 24.5 months (95% CI 15.6–30.9 months), rejecting the null hypothesis of a 3-month median PFS (p < .05) relative to historical single-agent chemotherapy controls.

A New Era for First-Line NSCLC: Ivonescimab Outperforms Pembrolizumab

The recent announcement of ivonescimab's superior overall survival (OS) against pembrolizumab in first-line PD-L1-positive advanced non-small cell lung cancer (NSCLC) marks a pivotal moment in the oncology landscape. This achievement follows earlier data showing a significant progression-free survival (PFS) advantage, making it the first randomized, double-blind Phase III trial to achieve such a feat against a well-established standard of care.

Ivonescimab's unique mechanism as a bispecific antibody targeting both PD-1 and VEGF-A appears to be a key differentiator. Research indicates that VEGF inhibition can transform the immunosuppressive tumor microenvironment, thereby enhancing the efficacy of PD-1/PD-L1 blockade. This dual action has translated into robust clinical benefits, with median PFS nearly doubling compared to pembrolizumab (11.1 months vs 5.8 months) and now a statistically significant OS improvement. The consistency of these benefits across different PD-L1 expression levels is particularly encouraging, suggesting broad applicability within the PD-L1-positive population.

For years, pembrolizumab has been a cornerstone of first-line NSCLC treatment. Ivonescimab's head-to-head victory on both PFS and OS positions it as a formidable challenger, potentially reshaping the treatment algorithm and creating a new benchmark for efficacy. This success also validates the strategic pursuit of bispecific antibodies in oncology, potentially inspiring further innovation in multi-targeted approaches.

While the efficacy data are compelling, the safety profile warrants careful consideration. Studies have shown a higher incidence of overall Grade ≥3 treatment-related adverse events with ivonescimab compared to comparators, both as monotherapy and in combination with chemotherapy. Specifically, its VEGF-targeting component introduces risks such as hypertension and hemorrhage, which require vigilant patient monitoring. Furthermore, the primary data for HARMONi-2 and HARMONi-6 originate from trials conducted in China. While robust, the generalizability of these findings to diverse global populations will be a key area for future evaluation and real-world evidence generation. Beyond first-line PD-L1-positive NSCLC, ivonescimab has also demonstrated promising activity in challenging subgroups like advanced squamous NSCLC and EGFR-mutated, TKI-resistant NSCLC, hinting at a broader therapeutic potential that could address significant unmet needs. This comprehensive profile suggests ivonescimab is poised to become a significant new player in the evolving NSCLC treatment landscape.