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Collaborative and Other Relationships (Tables) | 6 Months Ended
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Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract] |
Summary of Activity Related to BAN2401 and Elenbecestat Collaboration | A summary of development expense related to the BAN2401 and Elenbecestat Collaboration is as follows:
| For the Three Months Ended June 30, |  | For the Six Months Ended June 30,
(In millions) | 2019 |  | 2018 |  | 2019 |  | 2018
Total development expense incurred by the collaboration related to the advancement of BAN2401 and Elenbecestat | $ | 68.6 |  |  | $ | 54.6 |  |  | $ | 136.6 |  |  | $ | 111.1 |
Biogen's share of BAN2401 and Elenbecestat development expense reflected in research and development expense in our condensed consolidated statements of income | $ | 34.3 |  |  | $ | 27.3 |  |  | $ | 68.3 |  |  | $ | 55.5 |
Summary of Activity Related to Aducanumab Collaboration | A summary of development and sales and marketing expense related to the Aducanumab Collaboration Agreement is as follows:
| For the Three Months Ended June 30, |  | For the Six Months Ended June 30,
(In millions) | 2019 |  | 2018 |  | 2019 |  | 2018
Total aducanumab development expense | $ | 3.2 |  |  | $ | 76.5 |  |  | $ | 165.8 |  |  | $ | 140.0 |
Biogen's share of aducanumab development expense reflected in research and development expense in our condensed consolidated statements of income | $ | 1.7 |  |  | $ | 65.0 |  |  | $ | 91.2 |  |  | $ | 128.5 |
Total aducanumab sales and marketing expense incurred by the collaboration | $ | 0.2 |  |  | $ | 14.0 |  |  | $ | 21.2 |  |  | $ | 21.2 |
Biogen's share of aducanumab sales and marketing expense reflected in selling, general and administrative expense in our condensed consolidated statements of income | $ | 0.1 |  |  | $ | 9.2 |  |  | $ | 11.7 |  |  | $ | 13.9 |

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