Biopharmaceutical company resTORbio Inc. started an underwritten public offering of $50 million of its common shares.

Underwriters will have an option to buy up to an additional 15% of shares in the public offering to cover overallotments.

BofA Merrill Lynch, SVB Leerink and Guggenheim Securities are acting as joint book-running managers with Wedbush PacGrow acting as co-manager for the proposed offering.

Boston-based resTORbio develops and sells novel therapeutics to treat aging-related diseases.