exhibit 10. 63 ( a ) eighth amendment to research and licence agreement ( this “ amendment ” ) effective date : december 2, 2021 by and between yeda research and development company limited a company duly registered under the laws of israel of p o box 95, rehovot # # # - # # # - # # # #, israel ( hereinafter, “ yeda ” ) and cell source limited a company duly registered under the laws of israel of 5 kineret street, bnei brak # # # - # # # - # # # # ( hereinafter, “ cell source ” ) whereasyeda and cell source are parties ( the “ parties ” ) to a research and licence agreement dated october 3, 2011, as amended by a first amendment thereto dated april 8, 2014, a second amendment thereto dated november 28, 2016, a third amendment thereto dated march 29, 2018, a fourth amendment thereto dated march 30, 2018, a fifth amendment thereto dated june 30, 2019, a sixth amendment thereto dated december 31, 2019 and a seventh amendment thereto dated november 15, 2020 ( together, “ the r & l agreement ” ) ; and whereasyeda and cell source are parties ( the “ parties ” ) to a research and licence agreement dated october 3, 2011, as amended by a first amendment thereto dated april 8, 2014, a second amendment thereto dated november 28, 2016, a third amendment thereto dated march 29, 2018, a fourth amendment thereto dated march 30, 2018, a fifth amendment thereto dated june 30, 2019, a sixth amendment thereto dated december 31, 2019 and a seventh amendment thereto dated november 15, 2020 ( together, “ the r & l agreement ” ) ; and whereas yeda and cell source are parties ( the “ parties ” ) to a research and licence agreement dated october 3, 2011, as amended by a first amendment thereto dated april 8, 2014, a second amendment thereto dated november 28, 2016, a third amendment thereto dated march 29, 2018, a fourth amendment thereto dated march 30, 2018, a fifth amendment thereto dated june 30, 2019, a sixth amendment thereto dated december 31, 2019 and a seventh amendment thereto dated november 15, 2020 ( together, “ the r & l agreement ” ) ; and whereascell source wishes revise the milestones associated with the agreement as set out