top of page

Kelun-Biotech Announced that A400/EP0031 has been granted Orphan Drug Designation by FDA

Kelun-Biotech announces that KL590586 (EP0031) (small molecule RET kinase inhibitor, also named A400) program, licensed to global ex-China partner Ellipses Pharma, has been granted Orphan Drug Designation (ODD) by the US Food and Drug Administration (FDA) for the treatment of RET fusion-positive solid tumors.

Orphan drugs are drugs used for the prevention, treatment and diagnosis of rare diseases. The FDA grants ODD for investigational treatments for rare diseases, such as RET fusion-positive solid tumors, defined as affecting fewer than 200,000 people in the United States. The designation is an important milestone in the development of innovative drugs, it is expected to accelerate the progress of clinical trials in the United States. ODD qualifies the developer for certain incentives with the goal of accelerating drug development for patients, including tax credits and seven years of market exclusivity in the US upon approval by the FDA.

A400 (EP0031) is a next generation selective RET inhibitor (SRI) with broad activity against common RET fusions and mutations. Therefore, A400 (EP0031) may overcome resistance mechanisms to first-generation SRIs. In preclinical studies, A400 (EP0031) demonstrated favorable inhibitory activity against key RET kinases in-vitro and in-vivo. A400 (EP0031) also demonstrated good penetration of the blood brain barrier in animal models. At present, Kelun-Biotech is conducting A400 (EP0031) pivotal clinical study in China for RET-positive non-small cell lung cancer.

In March 2021, Kelun-Biotech granted Ellipses an exclusive license for A400 (EP0031) in certain territories including the US and Europe, with Kelun-Biotech retaining certain rights in Greater China and parts of the Asia-Pacific region such as Korea, Singapore, and Malaysia.

In June 2022, the FDA approved an investigational new drug application for A400 (EP0031), and a Phase 1/2 trial is ongoing in patients with malignant tumors with RET gene alteration.

About RET altered malignancies

RET fusions and mutations are present in a wide range of tumors, including non-small cell lung cancer, medullary thyroid cancer and other types of thyroid cancer, as well as colorectal cancer, so targeting RET gene changes is promising as a treatment for all types of cancer. However, for patients with RET gene alteration, the effect of traditional chemotherapy and immunotherapy is limited, especially for patients with drug resistance after first-generation SRI treatment. The acceptable treatment options are limited, the prognosis is poor, and there are still unmet clinical needs.

About Kelun-Biotech

Kelun-Biotech(6990.HK)is a holding subsidiary of Kelun Pharmaceutical (002422.SZ), which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. The company focuses on major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, and establishing an globalized drug development and industrialization platform for the unmet medical needs in China and worldwide. The Company is committed to becoming an leading global enterprise in the field of innovation drugs.

At present, the company has 33 ongoing innovative projects in major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, including 14 projects in the clinical stage with multiple global trials conducted simultaneously in several regions including China, Europe, and the United States. The company has established one of the world’s leading in-house developed ADC platform, OptiDC, and has four ADC projects in the clinical stage (two of which are in the phase III or NDA stage, respectively) and several projects in the preclinical stage.

For more information, please visit

About Ellipses Pharma Limited

Ellipses Pharma is a global drug development company based 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 minimize the time it takes to advance lead products through clinical trials and reach patients. For more information, please visit

Business Development Team

Monday, November 27, 2023

bottom of page