Ellipses Pharma announces intent to accelerate clinical programme following ‘encouraging’ data on next generation selective RET inhibitor

Chicago June 5, 2023: Ellipses Pharma (“Ellipses”), a global drug development company focused on accelerating the development of new oncology treatments, today announces its intention to expedite further global clinical development of the next generation selective RET inhibitor (SRI) EP0031/A400 following the publication of ‘very encouraging’ clinical data.

Professor Tobias Arkenau, Global Head of Drug Development & CMO at Ellipses, commented:

“The data presented today gives everyone involved great confidence to further progress our clinical trial programme. The results have been marked in terms of significant tumour shrinkage across RET-altered tumours and importantly EP0031 had an encouraging safety and tolerability profile. This is an exciting development, and we look forward to rapidly advancing with our next phase of clinical work.”

EP0031 is being developed in partnership with Kelun-Biotech Pharmaceutical Co. Ltd. (Kelun-Biotech) and is also known as A400 when in conjunction with Kelun-Biotech’s ongoing regional development.

Trial data of the Phase 1 Study of KL590586 (EP0031/A400), presented at the American Society of Clinical Oncology (ASCO) conference in Chicago today, reported preliminary efficacy and safety for a total of 109 patients. A400/EP0031 was generally well tolerated with the majority of adverse events recorded as manageable grade 1 or 2. In the overall RET-altered tumour population, patients who received A400/EP0031 at doses between 40 and 120mg OD had an objective response rate of 60% with a disease control rate of 90%. Two specific treatment cohorts were highlighted at the meeting: i) patients, with previously untreated RET-fusion positive advanced NSCLC with an objective response rate of 80.8% (21/26 patients); and ii) patients with RET-fusion positive NSCLC who had received prior systemic treatment (median prior line 2, range 1-9), including chemo-immunotherapy, with an objective response rate of 69.7% (23/33 patients). Disease control rates of >96% were reported for each cohort. Importantly, evidence of clinical activity was also reported in cohorts of patients with brain metastases as well as patients that had received prior 1st generation SRI.

EP0031/A400 is the subject of a global, modular Phase 1/2 trial to evaluate safety, tolerability and efficacy in patients with advanced RET-altered tumours and has been under clinical investigation in China by Kelun-Biotech for patients with RET-altered cancers. Clinical dose expansion data from the latter study were reported at the ASCO conference today.

Professor Sir Christopher Evans, OBE, Chairman, Ellipses, commented: 

“From the outset of Ellipses, we have remained firmly focused on the selection of only the most promising oncology discoveries through our global network of over 200 key opinion leaders and our unbiased vetting approach. We are delighted to see EP0031 progressing so well through its clinical trial journey. It offers great potential to address a significant unmet need in oncology and extend the treatment options for patients.”  

Dr Rajan Jethwa, Chief Executive Officer, Ellipses, commented:

“EP0031/A400 is a promising next generation SRI. We welcome the very striking clinical data presented by our partners at Kelun-Biotech, which marks an important step in the development of this agent. EP0031 offers the potential to further improve patient outcomes and the rapid pace at which its clinical programme is progressing provides further evidence that our approach accelerates drug development for the benefit of patients. Data presented today will be augmented by results from our Phase1/2 trial currently underway in the US, EU and UK.”

Dr Junyou Ge, Chief Executive Officer of Kelun-Biotech, commented:

“EP0031/A400 offers a significant therapeutic potential for tumours with RET oncogene mutation/fusion and is hoped to bring new treatment options for patients. The clinical data presented today is extremely encouraging and Kelun-Biotech will continue to collaborate with Ellipses to promote the global development and subsequent potential commercialisation of this treatment to benefit more cancer patients around the world.”

About EP0031/A400

EP0031 is a potent next generation SRI with broad activity against common RET fusions and mutations, including solvent front resistance mutations. Therefore, EP0031 (A400) may have the potential to overcome resistance to first generation SRIs. An IND application for EP0031/A400 was approved by China’s National Medicinal Products Administration (NMPA) in June 2021 and a Phase 1/2 trial is ongoing in China. In March 2021, Kelun-Biotech granted Ellipses an exclusive license for EP0031/A400 in certain territories including the US and Europe, with Kelun-Biotech retaining certain rights in Greater China and part of the Asia-Pacific region. In June 2022, the US FDA approved the EP0031 IND application, and the Ellipses Phase 1/2 trial is ongoing in the US and in the EU.

About RET-altered cancers

It is estimated that RET fusions & mutations may be responsible for ~2% of all solid tumours, this includes 2% of NSCLC, 60-80% of medullary thyroid cancers (MTC) and <1-20% across a range of other cancers.¹ When patients progress on currently approved first generation SRIs there are limited treatment options and prognosis is poor.²

About Ellipses Pharma Limited

Ellipses Pharma is a global drug development company, headquartered in London, focused on accelerating the development of cancer treatments through an innovative drug development model that combines unbiased vetting to de-risk initial asset selection with an uninterrupted funding flow to minimise the time it takes to advance lead products through clinical trials and reach patients.

About Kelun-Biotech

Kelun Biotech is a holding subsidiary of Kelun Pharmaceutical, focusing on the R&D, production, marketing and international cooperation of biotechnology drugs and innovative small molecule drugs. Focusing on the unmet clinical needs worldwide and in China, the company focuses on major disease fields such as cancer, autoimmunity, inflammation and metabolic diseases, builds an international drug R&D and industrialization platform, aiming to become an international leading enterprise in the field of innovation. Significant progress has been made in the field of biotech drugs, including ADC, monoclonal antibody, dual antibodies, and hot technologies for innovative small molecule drugs with new targets. The world-renowned ADC R&D platform OptiDC has been successfully built, of which 4 ADCs are in the clinical research stage, and several are in the preclinical research stage. The company currently has 33 innovative projects for the treatment of major diseases such as cancer, autoimmunity, inflammation, and metabolism. Among them,14 projects enter clinical stage in China, of which 3 are being carried out in the United States.

For more information, please email enquiries@ellipses.life


1 Cancer Discovery 10(4), 498-505 (2020)
2 Ettinger et al. Non-small Cell Lung Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology, 497-530 (2022)
Planchard et al. Metastatic non-small cell lung cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow up (2018)