Topline results from the phase III clinical trial, HARMONi, evaluating ivonescimab, successfully met the progression-free survival (PFS) primary endpoint for NSCLC/EGFR .- Summit Therapeutics

Summit Therapeutics Inc. announced topline results from the Phase III clinical trial, HARMONi, the first global Phase III study evaluating ivonescimab, successfully met the progression-free survival (PFS) primary endpoint and showed a positive trend in the other primary endpoint, overall survival (OS). HARMONi is a multiregional, double-blinded, placebo-controlled, Phase III study sponsored by Summit evaluating ivonescimab plus platinum-doublet chemotherapy compared to placebo plus platinum-doublet chemotherapy in patients with epidermal growth factor receptor (EGFR)-mutated, locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) who have progressed after treatment with a 3rd generation EGFR tyrosine kinase inhibitor (TKI). 

This is a clinical setting with a patient population where PD-1 monoclonal antibodies have previously been unsuccessful in Phase III global clinical trials in showing either a PFS or OS benefit. Approximately 38% of patients were randomized from western countries (ex-Asia), consistent with other recent multiregional Phase III studies in patients with EGFR-mutated NSCLC. At the prespecified primary data analysis, ivonescimab in combination with chemotherapy demonstrated a statistically significant and clinically meaningful improvement in progression-free survival, with a hazard ratio of 0.52 (95% CI: 0.41 – 0.66; p<0.00001). PFS was measured by blinded independent central radiology review committee (BICR) compared to placebo in combination with chemotherapy. A clinically meaningful hazard ratio was observed in both Asia and ex-Asia sub-populations. The primary analysis demonstrated the consistency of the magnitude of the PFS benefit between patients randomized in Asia and ex-Asia, as well as the consistency in a single-region study (HARMONi-A) with this multiregional study.

 Ivonescimab in combination with chemotherapy showed a positive trend in OS in the primary analysis without achieving a statistically significant benefit with a hazard ratio of 0.79 (95% CI: 0.62 – 1.01; p=0.057). This trend provides further support for its use in 2L+ EGFRm NSCLC, a setting where high unmet need continues to exist with limited approved options in the United States and other western territories. There are no current FDA-approved regimens that have demonstrated a statistically significant overall survival benefit in this patient setting. The median follow-up time for western patients was less than the median overall survival at the time of the analysis, and these patients may continue to be followed for long-term outcomes. Both Asian and North American patients demonstrated a positive trend in overall survival. The results of the primary analysis in this multiregional study 1 were consistent with that of the single-region HARMONi-A study, which demonstrated an overall survival hazard ratio of 0.80 at 52% data maturity in a similar patient population. 

There were no new safety signals noted in this Phase III study. Grade 3 or higher treatment-emergent adverse events (TEAEs) were reported for 56.9% of patients in the ivonescimab + chemotherapy arm vs 50.0% with chemotherapy alone. Fatal TEAEs (excluding disease progression) were reported for 1.8% of patients in the ivonescimab + chemotherapy arm vs. 2.8% in those patients receiving chemotherapy alone. The safety profile of ivonescimab + chemotherapy was acceptable and manageable in the context of the observed clinical benefit. 

“The evidence of a consistent benefit in PFS for both Asian and western patients, as well as the consistent overall survival results between the single-region HARMONi-A study and our global HARMONi study demonstrates the potential benefit ivonescimab has to bring to patients around the world, including the United States,” stated Robert W. Duggan, Chairman and Co-Chief Executive Officer of Summit Therapeutics. Based on the results of the HARMONi clinical trial, Summit, at present time, intends to file a Biologics License Application (BLA) in order to seek approval for ivonescimab plus chemotherapy in this setting. Based on discussions with the FDA, under our determination and subject to our review, Summit will consider the timing of the filing of this BLA. The FDA noted that a statistically significant overall survival benefit is necessary to support marketing authorization, which will weigh into Summit’s considerations regarding the timing of a potential BLA filing. A more complete data presentation from the clinical study is intended to be shared at a future major medical conference. “Our conviction in the promise that this therapy holds for patients continues to be validated: we believe that ivonescimab has the potential to make a meaningful difference for the betterment of patients’ lives,” added Dr. Maky Zanganeh, President and Co-CEO of Summit.

The positive Phase III HARMONi study results, along with the approval of ivonescimab in China in combination with chemotherapy based on the results of the HARMONi-A trial and the subsequent supplemental approval of ivonescimab monotherapy in China for first-line treatment of patients with advanced NSCLC whose tumors have positive PD-L1 expression based on the results of the HARMONi-2 trial, further substantiates the purposefully engineered, differentiated mechanism of action of ivonescimab, a PD-1 / VEGF bispecific antibody evidencing cooperative binding characteristics, and its opportunity to improve upon the existing standards of care for solid tumors, including in settings where existing immune checkpoint inhibitors are indicated. We would like to offer our heartfelt gratitude to each of the patients, physicians, nurses, and caregivers who participated in and supported this clinical study. We are grateful to the dedication of our investigators and patients who are essential in advancing innovative therapies and bringing to patients the most advanced therapies for those facing unfortunate diagnoses. About Ivonescimab Ivonescimab, known as SMT112 in Summit’s license territories, North America, South America, Europe, the Middle East, Africa, and Japan, and as AK112 in China and Australia, is a novel, potential first-in-class investigational bispecific antibody combining the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis