NIJMEGEN, the Netherlands – 10 January 2022: Khondrion, a clinical stage biopharmaceutical company discovering and developing therapies targeting primary mitochondrial diseases, today announced that the last patient has been dosed with sonlicromanol in the KHENERGYZE Phase IIb clinical study. Sonlicromanol is Khondrion’s wholly-owned, lead asset being developed to treat a range of mitochondrial diseases in children and adults. Topline data from KHENERGYZE is expected in the third quarter of 2022.

The study’s primary objective is to evaluate the dose-effect of sonlicromanol on the attention domain score of cognitive functioning, as assessed by the computerised Cogstate visual identification test. Cognitive impairment is becoming increasingly recognised in mitochondrial disease patients and can have a significant and debilitating impact on many aspects of their lives. Sonlicromanol’s potential to counteract cognitive decline is supported by preclinical research and results from a completed Phase IIa study, which showed a significant improvement in attention and mood related outcomes in patients treated with sonlicromanol compared to placebo.

Prof. Dr. Jan Smeitink, Chief Executive Officer at Khondrion, said: “Completing enrolment in our Phase IIb study is an important milestone and brings us another step closer to providing an urgent and much needed disease-modifying therapy to patients with severe and debilitating mitochondrial diseases. I would like to express my gratitude to all the patients and their families for their participation in this trial, and to the investigators and wider team, whose dedication has been vital in advancing this important clinical programme. We look forward to receiving results from the trial later in the year.” 

Sonlicromanol is a first-in-class, oral small molecule targeting key underlying mechanisms of mitochondrial disease based on its unique triple mode of action: redox modulation to help restore the cell’s metabolism, radical trapping preventing ferroptotic cell death, and mPGES-1 inhibition resulting in anti-inflammatory effects. In Phase I and Phase IIa studies, sonlicromanol showed a good safety and tolerability profile well beyond target therapeutic dosing levels.

KHENERGYZE is a double-blind, randomised, placebo-controlled, multi-centre, three-way cross-over study examining cognitive function in adult patients with a specific genetically confirmed DNA mutation in the mitochondrial transfer RNALeu(UUR) (MT-TL1m.3243A>G). This mutation is responsible for MELAS spectrum disorders, including MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes), MIDD (maternally inherited diabetes and deafness) syndromes, and mixed phenotypes.

Sonlicromanol’s development programme also includes two other ongoing clinical studies: the KHENEREXT Phase IIb open label extension study, examining the long-term safety and efficacy of sonlicromanol in adult patients who have completed the KHENERGYZE study, and the KHENERGYC Phase II study in children.

Further details of the KHENERGYZE study are available on