Surface Oncology Inc. said the U.S. Food and Drug Administration granted orphan drug designation to its medicine SRF231 for treating a type of blood cancer known as multiple myeloma.

The Cambridge, Mass.-based company said investigational drug SRF231 is being evaluated in a phase 1 trial to assess safety and tolerability.

The FDA's orphan drug status is granted to drugs intended to treat rare diseases that affect fewer than 200,000 people in the U.S. The designation provides certain benefits, including a potential seven-year market exclusivity for the drug upon approval.

Surface Oncology went public in April, raising about $108 million in its IPO.