definiens: shall mean a for -profit entity that has been granted a license by M.I.T. under the PATENT RIGHTS to develop and s ell products ) . Subject to Section 6.4, COMPANY shall be responsible for a pro rata share of all Patent Expenses, whether such amounts were incurred before or after the EFFECTIVE DATE . As of the EFFECTIVE DATE, COMPANY ’s pro rata share is [ * * * ] of the total, and M.I.T. has incurred approximately [ * * * ] for such patent -related fees and costs, with respect to which M.I.T. will provide COMPANY with supporting documentation . As commercial licensees are added over time, COMPANY ’s pro rata share will decrease on a going forward basis only . No credits shall be allowed for payments due prior to each new commercial licensee . COMPANY shall reimburse [ * * * ] of all patent costs incurred prior to the EFFECTIVE DATE, that have not already been reimbursed, within thirty days of the EFFECTIVE DATE . COMPANY will reimburse the remaining [ * * * ] within [ * * * ] of the EFFECTIVE DATE of this Agreement or immediately upon termination of this Agreement if this Agreement is terminated prior to the [ * * * ] of this Agreement as long as there a re no additional commercial licensees prior to these dates . If there are additional Commercial Licensees then COMPANY will not have to pay this remaining [ * * * ] . COMPANY will be responsible for its pro rata share for all patent expenses incurred after the E FFECTIVE DATE . COMPANY shall reimburse all amounts due pursuant to this Section within [ * * * ] of invoicing, supported by appropriate documentation ; late payments shall accrue interest at [ * * * ] . In all instances, M.I.T. shall pay the fees prescribed for larg e entities to the United States Patent and Trademark Office . Subject to Section 6.4, payment of all fees and costs, including attorneys ’ fees, relating to the filing, prosecution and maintenance of the PATENT RIGHTS ( including without limitation interferen ces, reexaminations and reissues ) shall be the responsibility of COMPANY, whether such amounts were incurred before or after the EFFECTIVE DATE subject to the terms agreed upon in this section