San Diego’s Reneo Pharmaceuticals raised a $50 million Series A round to tackle metabolism and energy disorders.

Proceeds will flow to REN001, which is in phase 1b clinical trials for rare mitochondrial diseases, including fatty acid oxidation disorders and primary mitochondrial myopathies. The money will be used for other clinical and preclinical studies as well.

Inherited mutations in mitochondria, the power plants of the cell, impair metabolism, causing muscle pain, weakness, cramps and loss of muscle. Severe cases bring rhabdomyolysis, the death of muscle fibers that can lead to complications like kidney failure.

The round was led by New Enterprise Associates, and also participating were Lundbeckfonden Ventures, Pappas Capital and RiverVest Venture Partners.

Reneo CEO Niall O'Donnell is also the managing director of RiverVest. Mike Grey, a biotech veteran and Reneo’s executive chairman, is also the CEO of Mirum, a San Diego company tackling liver disorders.