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Collaborative and Other Relationships (Tables) | 3 Months Ended
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Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract] |
Summary of Activity Related to BAN2401 and Elenbecestat Collaboration |
(In millions) |  | For the Three Months Ended March 31, 2020
Total development expense incurred by the collaboration related to the advancement of BAN2401 and elenbecestat |  | $ | 43.5 |
Biogen's share of BAN2401 and elenbecestat development expense reflected in research and development expense in our condensed consolidated statements of income |  | $ | 21.8 |
Total sales and marketing expense incurred by the collaboration |  | $ | 4.9 |
Biogen's share of BAN2401 sales and marketing expense reflected in selling, general and administrative expense in our condensed consolidated statements of income |  | $ | 2.4 |
Summary of Activity Related to Aducanumab Collaboration | A summary of development and sales and marketing expenses related to the Aducanumab Collaboration Agreement is as follows:
|  | For the Three Months Ended March 31,
(In millions) |  | 2020 |  | 2019
Total aducanumab development expense |  | $ | 19.1 |  |  | $ | 162.5 |
Biogen's share of aducanumab development expense reflected in research and development expense in our condensed consolidated statements of income |  | $ | 10.5 |  |  | $ | 89.4 |
Total aducanumab sales and marketing expense |  | $ | 22.7 |  |  | $ | 20.9 |
Biogen's share of aducanumab sales and marketing expense reflected in selling, general and administrative expense in our condensed consolidated statements of income |  | $ | 12.3 |  |  | $ | 11.6 |

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