Avrobio Inc. said Katina Dorton and Nerissa Kreher are stepping down as CFO and chief medical officer of the company, respectively.

Erik Ostrowski will replace Dorton as CFO of the company, effective January 2019. Ostrowski was previously CFO of Summit Therapeutics PLC.

Meanwhile, Kreher will continue as a clinical adviser to Avrobio in a transitional role during the first quarter of 2019.

Cambridge, Mass.-based Avrobio develops gene therapies for treating rare diseases.