Former Lumena Pharmaceuticals Inc. executives are at it again.

San Diego’s Reneo Pharmaceuticals emerged from stealth mode on May 20 with a $50 million Series A round to tackle metabolism and energy disorders.

Interconnected companies and talent are behind Reneo.

CEO Niall O’Donnell was the interim chief medical officer of Lumena Pharmaceuticals, a company based in San Diego that was acquired five years ago by Shire Pharmaceuticals for $260 million.

O’Donnell is also the managing director of RiverVest Venture Partners, which participated in the fundraising round, along with Lundbeckfonden Ventures and Pappas Capital. The financing was led by New Enterprise Associates.

Mike Grey, the executive chairman of Reneo, was the CEO of Lumena. The biotech veteran also leads Mirum Pharmaceuticals, which surfaced last year with a $120 million round to revitalize a Lumena drug.

Like with Reneo, New Enterprise Associates led Mirum Pharmaceutical’s funding round, with participation from RiverVest and Pappas. Other investors took part as well.

At Reneo, 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.

“We are hopeful that our approach will generate meaningful data and allow us to provide a much-needed treatment option for people suffering from these diseases,” said Alejandro Dorenbaum, chief medical officer of Reneo.