UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Delaware 42-1743430 (State or other jurisdiction of incorporation or formation) (I.R.S. employer identification number) Title of each class Trading Symbol(s) Name of each exchange on which registered Common stock, $0.001 par value per share BBLG The Nasdaq Stock Market LLC Warrants to Purchase Common stock, $0.001 par value per share BBLGW The Nasdaq Stock Market LLC Large accelerated filer ☐ Accelerated filer ☐ Non-accelerated filer ☒ ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Title of each class Trading Symbol(s) Name of each exchange on which registered Common stock, $0.001 par value per share BBLG The Nasdaq Stock Market LLC Warrants to Purchase Common stock, $0.001 par value per share BBLGW The Nasdaq Stock Market LLC FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Fo ...