exhibit 10. 1 immuno - oncology discovery and development agreement by and between sanofi biotechnology sas and regeneron pharmaceuticals, inc. dated as of july 1, 2015 certain portions of this exhibit have been omitted pursuant to a request for confidentiality. such omitted portions, which are marked with brackets and three asterisks [ * * * ], have been separately filed with the commission. certain portions of this exhibit have been omitted pursuant to a request for confidentiality. such omitted portions, which are marked with brackets and three asterisks [ * * * ], have been separately filed with the commission. table of contents article 1 definitions article 2 discovery and development program2. 1io discovery program2. 2io discovery plans2. 3commercially reasonable efforts ; compliance with laws2. 4further assurances and transaction approvals2. 5exclusivity2. 6tail period and interim period2. 7program licenses ; licenses generally2. 8non - exclusive license to sanofi2. 9invention assignment2. 10combination therapy2. 11third party licenses article 3 information exchange and updates3. 1immuno - oncology steering committee3. 2alliance management3. 3obligations of the parties and their affiliates3. 4exchange of information article 4 payments4. 1payments to regeneron4. 2discovery program costs4. 3io development balance4. 4royalty payments for io royalty products4. 5royalty term and reporting4. 6payment method and currency4. 7late payments4. 8rights to offset payments4. 9taxes4. 10invoices and documentation4. 11program costs forecasts article 5 opt - in rights to license product candidates5. 1opt - in rights generally5. 2initial and deferred opt - in periods5. 3refused candidates5. 4additional development prior to opt - in5. 5additional development following opt - in article 1 definitions article 2 discovery and development program2. 1io discovery program2. 2io discovery plans2. 3commercially reasonable efforts ; compliance with laws2. 4further assurances and transaction approvals2. 5exclusivity2. 6tail period and interim period2. 7program licenses ; licenses generally2. 8non -