On April 23, 2025 Summit Therapeutics Inc. (NASDAQ: SMMT) ("Summit," "we," or the "Company") today noted that Akeso, Inc. (Akeso, HKEX Code: 9926.HK) reported that the Phase III clinical trial, HARMONi-6 or AK112-306, met its primary endpoint of progression-free survival (PFS) (Press release, Summit Therapeutics, APR 23, 2025, View Source [SID1234652085]). HARMONi-6 is evaluating ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, a PD-1 inhibitor, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous non-small cell lung cancer (NSCLC) irrespective of PD-L1 expression. HARMONi-6 is a single region, multi-center, Phase III study conducted in China sponsored by Akeso with all relevant data exclusively generated, managed, and analyzed by Akeso.

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At a prespecified interim analysis conducted by an Independent Data Monitoring Committee, ivonescimab plus chemotherapy demonstrated a statistically significant and clinically meaningful improvement in PFS by blinded independent central radiology review committee (BICR) compared to tislelizumab plus chemotherapy. The PFS benefit was demonstrated in patients with either PD-L1-positive or PD-L1-negative tumors. Akeso noted that no new safety signals were identified in this Phase III study. The full data set for HARMONi-6 is planned to be presented at an upcoming major medical conference later this year.

Prior to HARMONi-6, there were no known Phase III clinical trials in NSCLC which have shown a statistically significant improvement compared to PD-(L)1 inhibitor therapy in combination with chemotherapy in a head-to-head setting. Following the success of Akeso’s HARMONi-2 study in China where the PFS benefit was observed in a monotherapy setting for patients whose squamous or non-squamous tumors were positive for PD-L1 expression, this is the second time in which ivonescimab-based regimens have become the first known investigational therapy to demonstrate a statistically significant benefit compared to standard-of-care PD-(L)1 inhibitor-based regimens.

"Ivonescimab has the opportunity to make a significant, positive difference, potentially providing patients with the next generation of treatment options against insidious solid tumors beginning with non-small cell lung cancer," stated Dr. Maky Zanganeh, President and Co-Chief Executive Officer of Summit.

Summit is currently enrolling patients in the HARMONi-3 study. HARMONi-3 is a multiregional Phase III clinical trial sponsored by Summit which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab, an anti-PD-1 antibody, combined with chemotherapy in patients with first-line metastatic, squamous and non-squamous NSCLC. HARMONi-3 is currently enrolling patients globally and is conducted with registrational intent for the United States and other regions within Summit’s license territories.

"Our aligned mission with Akeso seeks to bring ivonescimab to as many patients around the world who can potentially benefit as quickly as possible," added Robert W. Duggan, Chairman and Co-Chief Executive Officer of Summit. "We are incredibly proud of Akeso’s accomplishment with the HARMONi-6 trial."

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 effects associated with blocking VEGF into a single molecule. Ivonescimab displays unique cooperative binding to each of its intended targets with multifold higher affinity to PD-1 when in the presence of VEGF.

This could differentiate ivonescimab as there is potentially higher expression (presence) of both PD-1 and VEGF in tumor tissue and the tumor microenvironment (TME) as compared to normal tissue in the body. Ivonescimab’s tetravalent structure (four binding sites) enables higher avidity (accumulated strength of multiple binding interactions) in the TME (Zhong, et al, SITC (Free SITC Whitepaper), 2023). This tetravalent structure, the intentional novel design of the molecule, and bringing these two targets into a single bispecific antibody with cooperative binding qualities have the potential to direct ivonescimab to the tumor tissue versus healthy tissue. The intent of this design, together with a half-life of 6 to 7 days after the first dose (Zhong, et al, SITC (Free SITC Whitepaper), 2023), is to improve upon previously established efficacy thresholds, in addition to side effects and safety profiles associated with these targets.

Ivonescimab was engineered by Akeso Inc. (HKEX Code: 9926.HK) and is currently engaged in multiple Phase III clinical trials. Over 2,300 patients have been treated with ivonescimab in clinical studies globally.

Summit has begun its clinical development of ivonescimab in non-small cell lung cancer (NSCLC), commencing enrollment in 2023 in two multi-regional Phase III clinical trials, HARMONi and HARMONi-3, and the Company has begun to activate clinical trial sites in the United States for HARMONi-7.

HARMONi is a Phase III clinical trial which intends to evaluate ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with a 3rd generation EGFR TKI (e.g., osimertinib). Enrollment in HARMONi was completed in the second half of 2024, and top-line results are expected to be announced in the middle of this year.

HARMONi-3 is a Phase III clinical trial which is intended to evaluate ivonescimab combined with chemotherapy compared to pembrolizumab combined with chemotherapy in patients with first-line metastatic, squamous and non-squamous NSCLC.

HARMONi-7 is a Phase III clinical trial which is intended to evaluate ivonescimab monotherapy compared to pembrolizumab monotherapy in patients with first-line metastatic NSCLC whose tumors have high PD-L1 expression.

In addition, Akeso has recently had positive read-outs in three single-region (China), randomized Phase III clinical trials for ivonescimab in NSCLC: HARMONi-A, HARMONi-2, and HARMONi-6.

HARMONi-A was a Phase III clinical trial which evaluated ivonescimab combined with chemotherapy compared to placebo plus chemotherapy in patients with EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who have progressed after treatment with an EGFR TKI.

HARMONi-2 is a Phase III clinical trial evaluating monotherapy ivonescimab against monotherapy pembrolizumab in patients with locally advanced or metastatic NSCLC whose tumors have positive PD-L1 expression.

HARMONi-6 is a Phase III clinical trial evaluating ivonescimab in combination with platinum-based chemotherapy compared with tislelizumab, an anti-PD-1 antibody, in combination with platinum-based chemotherapy in patients with locally advanced or metastatic squamous non-small cell lung cancer (NSCLC), irrespective of PD-L1 expression.

Ivonescimab is an investigational therapy that is not approved by any regulatory authority in Summit’s license territories, including the United States and Europe. Ivonescimab was approved for marketing authorization in China in May 2024. Ivonescimab was granted Fast Track designation by the US Food & Drug Administration (FDA) for the HARMONi clinical trial setting.