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        |  |  | Important Notice Regarding the Availability of Proxy Materials for the Stockholders’ Meeting to Be Held Virtually, Via Live Webcast at www.virtualshareholdermeeting.com/CARA2024, at 12:00 p.m., Eastern Daylight Time on Tuesday, June 4, 2024. |  |  | 
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                The proxy statement and the annual report to stockholders are available at www.proxyvote.com.
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|  |  | You are cordially invited to attend the virtual Annual Meeting. Whether or not you expect to attend the Annual Meeting, PLEASE VOTE YOUR SHARES. As an alternative to voting online at the Annual Meeting, you may vote via the internet, by telephone or, if you receive a paper proxy card, by mailing the completed proxy card. Voting instructions are provided in the Notice of Internet Availability of Proxy Materials, or, if you receive a paper proxy card by mail, the instructions are printed on your proxy card. |  |  | 
|  |  | Even if you have voted by proxy, you may still vote online if you attend the Annual Meeting. Please note, however, that if your shares are held of record by a broker, bank or other agent and you wish to vote at the Annual Meeting, you must follow the instructions from such organization and will need to obtain a proxy issued in your name from that record holder. |  |  | 
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| Questions and Answers about these Proxy Materials and Voting |  |  |  |  | 1 |  |  | 
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| Board of Directors and Corporate Governance |  |  |  |  | 12 |  |  | 
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| Executive Compensation |  |  |  |  | 23 |  |  | 
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| Securities Authorized For Issuance Under Equity Compensation Plans |  |  |  |  | 34 |  |  | 
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| Independent Registered Public Accounting Firm’s Fees |  |  |  |  | 37 |  |  | 
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| Security Ownership Of Certain Beneficial Owners and Management |  |  |  |  | 38 |  |  | 
| Transactions With Related Persons |  |  |  |  | 40 |  |  | 
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| Householding Of Proxy Materials |  |  |  |  | 55 |  |  | 
| Other Matters |  |  |  |  | 55 |  |  | 
|  |  |  |  | A-1 |  |  | |
|  |  |  |  | B-1 |  |  | |
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                Internet proxy voting is provided to allow you to vote your shares online, with procedures designed to ensure the authenticity and correctness of your proxy vote instructions. However, please be aware that you must bear any costs associated with your internet access, such as usage charges from internet access providers and telephone companies.
               |  |  | 
|  |  |  | 
                Female 
               |  |  | 
                Male 
               |  |  | 
                Non-Binary 
               |  |  | 
                Did Not 
                 Disclose Gender |  | ||||||
| Part I: Gender Identity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Directors |  |  |  |  | 3 |  |  |  |  |  | 3 |  |  |  |  |  |  |  |  | 
| Part II: Demographics Background |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| African American or Black |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Alaskan Native or Native American |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Asian |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Hispanic or Latino |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Native Hawaiian or Pacific Islander |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| White |  |  |  |  | 2 |  |  |  |  |  | 3 |  |  |  |  |  |  |  |  | 
| Two or More Races or Ethnicities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| LGBTQ+ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Did Not Disclose Demographic Background |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| 
                Name 
               |  |  | 
                Audit 
               |  |  | 
                Compensation 
               |  |  | 
                Nominating 
                 and Corporate Governance |  | |||||||||
| Harrison M. Bains, Jr.(1) |  |  |  |  | X |  |  |  | 
                     |  |  | 
                     |  | ||||||
| Jeffrey L. Ives, Ph.D. |  |  |  |  | X |  |  |  |  |  | X |  |  |  |  |  | X |  |  | 
| Martin Vogelbaum |  |  |  |  | X |  |  |  |  |  | X* |  |  |  |  |  | X* |  |  | 
| Susan Shiff, Ph.D. |  |  |  |  |  |  |  |  |  |  | X |  |  |  |  |  | X |  |  | 
| Lisa von Moltke, M.D. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | X |  |  | 
| Helen M. Boudreau(2) |  |  |  |  | X* |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Total meetings during 2023 |  |  |  |  | 4 |  |  |  |  |  | 1 |  |  |  |  |  | 1 |  |  | 
| 
                Name 
               |  |  | 
                Age 
               |  |  | 
                Position(s) 
               |  | 
| Christopher Posner |  |  | 
                54 
               |  |  | President, Chief Executive Officer and Director |  | 
| Ryan Maynard |  |  | 
                54 
               |  |  | Chief Financial Officer |  | 
| Scott M. Terrillion |  |  | 
                61 
               |  |  | General Counsel, Secretary and Chief Compliance Officer |  | 
| 
                Name 
               |  |  | 
                Age 
               |  |  | 
                Position 
               |  | 
| Martin Vogelbaum |  |  | 
                60 
               |  |  | Director |  | 
| Jeffrey L. Ives, Ph.D. |  |  | 
                73 
               |  |  | Director |  | 
| Susan Shiff, Ph.D. |  |  | 
                63 
               |  |  | Director |  | 
| Lisa von Moltke, M.D. |  |  | 
                65 
               |  |  | Director |  | 
| Helen M. Boudreau |  |  | 
                58 
               |  |  | Director |  | 
| 
                Director 
               |  |  | 
                Fees Earned or 
                 Paid in Cash(3) ($) |  |  | 
                Stock
                 Awards(4)(5) ($) |  |  | 
                Option
                 Awards(4)(5) ($) |  |  | 
                Total
                 ($) |  | ||||||||||||
| Harrison M. Bains, Jr.(1) |  |  |  |  | 60,772 |  |  |  |  |  | 99,999 |  |  |  |  |  | 99,993 |  |  |  |  |  | 260,764 |  |  | 
| Martin Vogelbaum |  |  |  |  | 120,000 |  |  |  |  |  | 199,997 |  |  |  |  |  | 199,989 |  |  |  |  |  | 519,986 |  |  | 
| Jeffrey L. Ives, Ph.D. |  |  |  |  | 72,500 |  |  |  |  |  | 99,999 |  |  |  |  |  | 99,993 |  |  |  |  |  | 272,492 |  |  | 
| Susan Shiff, Ph.D. |  |  |  |  | 62,500 |  |  |  |  |  | 99,999 |  |  |  |  |  | 99,993 |  |  |  |  |  | 262,492 |  |  | 
| Lisa von Moltke, M.D. |  |  |  |  | 55,000 |  |  |  |  |  | 99,999 |  |  |  |  |  | 99,993 |  |  |  |  |  | 254,992 |  |  | 
| Helen M. Boudreau(2) |  |  |  |  | 26,043 |  |  |  |  |  | — |  |  |  |  |  | 349,964 |  |  |  |  |  | 376,007 |  |  | 
| 
                Director 
               |  |  | 
                RSUs 
               |  |  | 
                Number of Shares
                 Underlying Options |  | ||||||
| Martin Vogelbaum |  |  |  |  | 135,152 |  |  |  |  |  | 257,616 |  |  | 
| Jeffrey L. Ives, Ph.D. |  |  |  |  | 64,638 |  |  |  |  |  | 100,596 |  |  | 
| Susan Shiff, Ph.D. |  |  |  |  | 51,438 |  |  |  |  |  | 110,757 |  |  | 
| Lisa von Moltke, M.D. |  |  |  |  | 32,362 |  |  |  |  |  | 90,802 |  |  | 
| Helen M. Boudreau |  |  |  |  | — |  |  |  |  |  | 155,747 |  |  | 
|  |  |  | 
                Member 
                 Annual Service Retainer |  |  | 
                Chairperson / Lead Independent 
                 Director and Committee Chair Annual Service Retainer |  | ||||||
| Board of Directors |  |  |  | $ | 50,000 |  |  |  |  | $ | 35,000 |  |  | 
| Audit Committee |  |  |  |  | 10,000 |  |  |  |  |  | 20,000 |  |  | 
| Compensation Committee |  |  |  |  | 7,500 |  |  |  |  |  | 15,000 |  |  | 
| Nominating and Corporate Governance Committee |  |  |  |  | 5,000 |  |  |  |  |  | 10,000 |  |  | 
|  | 
                What we do:
               |  |  | 
                What we do not do:
               |  | 
|  | 
                ✓
                 
                
                Performance metrics tied to company performance. The performance metrics for our annual executive bonus plan are tied to company performance, aligning the interests of our executives with those of our stockholders.
                
                ✓
                 
                
                Multi-year vesting requirements. The equity awards we grant to our executive officers generally vest over multi-year periods, consistent with current market practice and our retention objectives.
                
                ✓
                 
                
                Double-trigger termination rights. Our agreements with our executive officers require both a change-in-control and a termination of employment for full severance benefits to be triggered.
                
                ✓
                 
                
                Independent compensation committee. Our compensation committee is comprised solely of independent members of our Board.
                
                ✓
                 
                
                Independent compensation consultant. Our compensation committee uses an independent compensation consultant that provides no other material services to the company. 
                |  |  | 
                ✘
                 
                
                No tax gross-ups. None of our compensation agreements and arrangements provide for tax “gross-ups.”
                
                ✘
                 
                
                No special perquisites. Except as otherwise discussed below, we generally do not provide our executives with perquisites or other personal benefits that differ materially from those available to employees generally.
                
                ✘
                 
                
                No retirement plans other than 401(k). We do not provide any pension or other retirement benefits to our executive officers, except that we offer all employees the right to participate in a company-sponsored 401(k) plan under which we contribute 3% of their salary up to the annual Internal Revenue Code limit.
                
                ✘
                 
                
                No special health or welfare benefits. We do not provide our executives with any special health or welfare benefits. Our executive officers participate in the same broad-based company-sponsored health and welfare benefits programs to our other full-time, salaried employees.
                
                ✘
                 
                
                Hedging, short selling and pledging prohibited. Our insider trading policy prohibits our executive officers and directors from hedging, short selling or pledging our securities.
                |  | 
| 
                Name and Principal Position 
               |  |  | 
                Year 
               |  |  | 
                Salary 
               |  |  | 
                Bonus 
               |  |  | 
                Stock
                 Awards(1) |  |  | 
                Option
                 Awards(2) |  |  | 
                Non-Equity 
                 Incentive Plan Compensation(3) |  |  | 
                All Other 
                 Compensation(4) |  |  | 
                Total 
               |  | ||||||||||||||||||||||||
| 
                Christopher Posner
                 President and Chief Executive Officer |  |  |  |  | 2023 |  |  |  |  | $ | 728,000 |  |  |  |  |  | — |  |  |  |  | $ | 0 |  |  |  |  | $ | 1,769,000 |  |  |  |  | $ | 414,960 |  |  |  |  | $ | 10,509 |  |  |  |  | $ | 2,922,469 |  |  | 
|  |  |  | 2022 |  |  |  |  |  | 700,000 |  |  |  |  | $ | 200,000 |  |  |  |  |  | 407,940 |  |  |  |  |  | 898,280 |  |  |  |  |  | 294,000 |  |  |  |  |  | 9,759 |  |  |  |  |  | 2,509,979 |  |  | ||
| 
                Ryan Maynard
                 Chief Financial Officer |  |  |  |  | 2023 |  |  |  |  | $ | 478,400 |  |  |  |  |  | — |  |  |  |  | $ | 0 |  |  |  |  | $ | 573,156 |  |  |  |  | $ | 181,792 |  |  |  |  | $ | 10,509 |  |  |  |  | $ | 1,243,857 |  |  | 
|  |  |  | 2022 |  |  |  |  |  | 140,600 |  |  |  |  | $ | 8,312 |  |  |  |  |  | — |  |  |  |  |  | 1,701,405 |  |  |  |  |  | 38,788 |  |  |  |  |  | 197 |  |  |  |  |  | 1,889,302 |  |  | ||
| 
                Joana Goncalves, M.D.
                 former Chief Medical Officer |  |  |  |  | 2023 |  |  |  |  | $ | 500,240 |  |  |  |  |  | — |  |  |  |  | $ | 0 |  |  |  |  | $ | 573,156 |  |  |  |  | $ | 190,091 |  |  |  |  | $ | 10,509 |  |  |  |  | $ | 1,273,996 |  |  | 
|  |  |  | 2022 |  |  |  |  |  | 481,000 |  |  |  |  | $ | 121,860 |  |  |  |  |  | 209,200 |  |  |  |  |  | 593,904 |  |  |  |  |  | 134,680 |  |  |  |  |  | 9,711 |  |  |  |  |  | 1,550,355 |  |  | ||
| 
                Named Executive Officer 
               |  |  | 
                Target Bonus % 
               |  | |||
| Christopher Posner |  |  |  |  | 60 |  |  | 
| Ryan Maynard |  |  |  |  | 40 |  |  | 
| Joana Goncalves, M.D. |  |  |  |  | 40 |  |  | 
| 
                Executive 
               |  |  | 
                Stock Option Grant
                 (# shares) |  | |||
| Chris Posner |  |  |  |  | 250,000 |  |  | 
| Ryan Maynard |  |  |  |  | 81,000 |  |  | 
| Joana Goncalves, M.D. |  |  |  |  | 81,000 |  |  | 
|  |  |  | 
                Performance-based RSUs
                 (# shares) |  | |||||||||
| 
                Executive 
               |  |  | 
                Target 
               |  |  | 
                Stretch 
               |  | ||||||
| Chris Posner |  |  |  |  | 125,000(1) |  |  |  |  |  | 56,000(2) |  |  | 
| Ryan Maynard |  |  |  |  | 27,000(1) |  |  |  |  |  | 13,000(2) |  |  | 
| Joana Goncalves, M.D. |  |  |  |  | 27,000(1) |  |  |  |  |  | 13,000(2) |  |  | 
|  |  |  | 
                Option Awards 
               |  |  | 
                Stock Awards 
               |  | ||||||||||||||||||||||||||||||||||||||||||||||||
| 
                Name 
               |  |  | 
                Grant Date 
               |  |  | 
                Number of 
                 Securities Underlying Unexercised Option (#) Exercisable |  |  | 
                Number of 
                 Securities Underlying Unexercised Options (#) Unexercisable |  |  | 
                Option 
                 Exercise Price ($) |  |  | 
                Option 
                 Expiration Date |  |  | 
                Number of 
                 Shares or Units of Stock That Have Not Vested (#)(1) |  |  | 
                Market Value 
                 of Shares of Units of Stock That Have Not Vested ($)(2) |  |  | 
                Equity
                 Incentive Plan Awards: Number of Unearned Shares, Units or Other Rights That Have Not Vested (#)(3) |  |  | 
                Equity
                 Incentive Plan Awards: Market or Payout Value of Unearned Shares, Units or Other Rights That Have Not Vested ($)(2) |  | |||||||||||||||||||||||||||
| 
                Christopher Posner
                 President and Chief Executive Officer |  |  |  |  | 8/2/2018 |  |  |  |  |  | 35,000 |  |  |  |  |  | — |  |  |  |  |  | 17.94 |  |  |  |  |  | 08/02/2028 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  | 
|  |  |  | 6/4/2019 |  |  |  |  |  | 9,000 |  |  |  |  |  | — |  |  |  |  |  | 20.47 |  |  |  |  |  | 06/04/2029 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  | ||
|  |  |  | 6/4/2020 |  |  |  |  |  | 10,800 |  |  |  |  |  | — |  |  |  |  |  | 15.62 |  |  |  |  |  | 06/04/2030 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  | ||
|  |  |  | 6/3/2021 |  |  |  |  |  | 10,800 |  |  |  |  |  | — |  |  |  |  |  | 13.06 |  |  |  |  |  | 06/03/2031 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  | ||
|  |  |  | 10/29/2021 |  |  |  |  |  | 283,000 |  |  |  |  |  | 283,000(4) |  |  |  |  |  | 16.83 |  |  |  |  |  | 10/29/2031 |  |  |  |  |  | 71,000(5) |  |  |  |  |  | 52,753 |  |  |  |  |  | — |  |  |  |  |  | — |  |  | ||
|  |  |  | 2/25/2022 |  |  |  |  |  | 55,458 |  |  |  |  |  | 65,542(6) |  |  |  |  |  | 10.46 |  |  |  |  |  | 2/25/2032 |  |  |  |  |  | 26,000(7) |  |  |  |  |  | 19,318 |  |  |  |  |  | — |  |  |  |  |  | — |  |  | ||
|  |  |  | 3/1/2023 |  |  |  |  |  | 46,875 |  |  |  |  |  | 203,125(6) |  |  |  |  |  | 10.06 |  |  |  |  |  | 3/1/2033 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | 181,000 |  |  |  |  |  | 134,483 |  |  | ||
| 
                Ryan Maynard
                 Chief Financial Officer |  |  |  |  | 9/12/2022 |  |  |  |  |  | 70,132 |  |  |  |  |  | 154,688(8) |  |  |  |  |  | 10.75 |  |  |  |  |  | 9/12/2032 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  | 
|  |  |  | 3/1/2023 |  |  |  |  |  | 15,187 |  |  |  |  |  | 65,813(6) |  |  |  |  |  | 10.06 |  |  |  |  |  | 3/1/2033 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | 40,000 |  |  |  |  |  | 29,720 |  |  | ||
| 
                Joana Goncalves, M.D.
                 former Chief Medical Officer |  |  |  |  | 10/22/2018 |  |  |  |  |  | 250,000 |  |  |  |  |  | — |  |  |  |  |  | 19.27 |  |  |  |  |  | 10/22/2028 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  | 
|  |  |  | 2/24/2020 |  |  |  |  |  | 30,666 |  |  |  |  |  | 1,334(6) |  |  |  |  |  | 16.36 |  |  |  |  |  | 02/24/2030 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | — |  |  | ||
|  |  |  | 3/30/2021 |  |  |  |  |  | 22,000 |  |  |  |  |  | 10,000(6) |  |  |  |  |  | 20.59 |  |  |  |  |  | 03/30/2031 |  |  |  |  |  | 5,334(7) |  |  |  |  |  | 3,963 |  |  |  |  |  | — |  |  |  |  |  | — |  |  | ||
|  |  |  | 2/25/2022 |  |  |  |  |  | 36,666 |  |  |  |  |  | 43,334(6) |  |  |  |  |  | 10.46 |  |  |  |  |  | 2/25/2032 |  |  |  |  |  | 13,334(7) |  |  |  |  |  | 9,907 |  |  |  |  |  | — |  |  |  |  |  | — |  |  | ||
|  |  |  | 3/1/2023 |  |  |  |  |  | 15,187 |  |  |  |  |  | 65,813(6) |  |  |  |  |  | 10.06 |  |  |  |  |  | 3/1/2033 |  |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | 40,000 |  |  |  |  |  | 29,720 |  |  | ||
| 
                Year 
               |  |  | 
                Summary
                 Compensation Table Total for Christopher Posner(1) ($) |  |  | 
                Summary
                 Compensation Table Total for Derek Chalmers(1) ($) |  |  | 
                Compensation
                 Actually Paid to Christopher Posner(1)(2)(3) ($) |  |  | 
                Compensation
                 Actually Paid to Derek Chalmers(1)(2)(3) ($) |  |  | 
                Average
                 Summary Compensation Table Total for Non-PEO NEOs(1) ($) |  |  | 
                Average
                 Compensation Actually Paid to Non-PEO NEOs(1)(2)(3) ($) |  |  | 
                Value of
                 Initial Fixed $100 Investment based on TSR ($)(4) |  |  | 
                Net Income
                 ($ Millions) |  | ||||||||||||||||||||||||
| 2023 |  |  |  |  | 4,743,329 |  |  |  |  |  | — |  |  |  |  |  | (2,735,603) |  |  |  |  |  | — |  |  |  |  |  | 1,661,327 |  |  |  |  |  | (817,170) |  |  |  |  |  | 4.91 |  |  |  |  |  | (11.85) |  |  | 
| 2022 |  |  |  |  | 2,509,979 |  |  |  |  |  | — |  |  |  |  |  | 1,365,402 |  |  |  |  |  | — |  |  |  |  |  | 1,719,829 |  |  |  |  |  | 1,953,544 |  |  |  |  |  | 70.98 |  |  |  |  |  | (85.5) |  |  | 
| 2021 |  |  |  |  | 9,901,376 |  |  |  |  |  | 10,196,785 |  |  |  |  |  | 6,770,961 |  |  |  |  |  | 3,949,591 |  |  |  |  |  | 1,467,504 |  |  |  |  |  | 1,099,179 |  |  |  |  |  | 80.50 |  |  |  |  |  | (88.4) |  |  | 
|  |  | 
                2021 
               |  |  |  | 
                2022 – 2023 
               |  |  | 
|  |  | 
                Frédérique Menzaghi, Ph.D. 
               |  |  |  | 
                Joana Goncalves, M.D. 
               |  |  | 
|  |  | 
                Joana Goncalves, M.D. 
               |  |  |  | 
                Ryan Maynard 
               |  |  | 
|  |  | 
                Scott Terrillion 
               |  |  |  |  |  |  | 
|  |  | 
                Thomas Reilly 
               |  |  |  |  |  |  | 
| 
                Year 
               |  |  | 
                Summary 
                 Compensation Table Total for PEO 1 ($) |  |  | 
                Exclusion of 
                 Stock Awards and Option Awards for PEO 1 ($) |  |  | 
                Inclusion of 
                 Equity Values for PEO 1 ($) |  |  | 
                Compensation 
                 Actually Paid to PEO 1 ($) |  | ||||||||||||
| 2023 |  |  |  |  | 4,743,329 |  |  |  |  |  | (3,589,860) |  |  |  |  |  | (3,889,072) |  |  |  |  |  | (2,735,603) |  |  | 
| 
                Year 
               |  |  | 
                Average 
                 Summary Compensation Table Total for Non-PEO NEOs ($) |  |  | 
                Average 
                 Exclusion of Stock Awards and Option Awards for Non-PEO NEOs ($) |  |  | 
                Average 
                 Inclusion of Equity Values for Non-PEO NEOs ($) |  |  | 
                Average 
                 Compensation Actually Paid to Non-PEO NEOs ($) |  | ||||||||||||
| 2023 |  |  |  |  | 1,661,327 |  |  |  |  |  | (975,556) |  |  |  |  |  | (1,502,941) |  |  |  |  |  | (817,170) |  |  | 
| 
                Year 
               |  |  | 
                Year-End 
                 Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for PEO 1 ($) |  |  | 
                Change in 
                 Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for PEO 1 ($) |  |  | 
                Vesting-Date 
                 Fair Value of Equity Awards Granted During Year that Vested During Year for PEO 1 ($) |  |  | 
                Change in 
                 Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for PEO 1 ($) |  |  | 
                Fair Value at 
                 Last Day of Prior Year of Equity Awards Forfeited During Year for PEO 1 ($) |  |  | 
                Total –  
                 Inclusion of Equity Values for PEO 1 ($) |  | ||||||||||||||||||
| 2023 |  |  |  |  | 157,175 |  |  |  |  |  | (3,218,622) |  |  |  |  |  | 74,225 |  |  |  |  |  | (901,850) |  |  |  |  |  | — |  |  |  |  |  | (3,889,072) |  |  | 
| 
                Year 
               |  |  | 
                Average 
                 Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for Non-PEO NEOs ($) |  |  | 
                Average 
                 Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for Non-PEO NEOs ($) |  |  | 
                Average 
                 Vesting-Date Fair Value of Equity Awards Granted During Year that Vested During Year for Non-PEO NEOs ($) |  |  | 
                Average 
                 Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for Non-PEO NEOs ($) |  |  | 
                Average Fair 
                 Value at Last Day of Prior Year of Equity Awards Forfeited During Year for Non-PEO NEOs ($) |  |  | 
                Total – 
                 Average Inclusion of Equity Values for Non-PEO NEOs ($) |  | ||||||||||||||||||
| 2023 |  |  |  |  | 40,895 |  |  |  |  |  | (1,076,410) |  |  |  |  |  | 24,047 |  |  |  |  |  | (491,473) |  |  |  |  |  | — |  |  |  |  |  | (1,502,941) |  |  | 
![[MISSING IMAGE: bc_companytsr-4c.jpg]](bc_companytsr-4c.jpg) 
        ![[MISSING IMAGE: bc_netincome-4c.jpg]](bc_netincome-4c.jpg) 
        | 
                Plan Category 
               |  |  | 
                Number of 
                 securities to be issued upon exercise of outstanding options, warrants and rights (a) |  |  | 
                Weighted-
                 average exercise price of outstanding options, warrants and rights (b)(2) |  |  | 
                Number of 
                 securities remaining available for future issuance under equity compensation plans (excluding shares of common stock reflected in column (a))(c)(4) |  | |||||||||
| Equity compensation plans approved by security holders(1) |  |  |  |  | 8,463,971(3) |  |  |  |  |  | 12.12 |  |  |  |  |  | 1,252,843 |  |  | 
| 
                Equity compensation plans not approved by security 
                 holders |  |  |  |  | — |  |  |  |  |  | — |  |  |  |  |  | 300,000(5) |  |  | 
| Total |  |  |  |  | 8,463,971 |  |  |  |  |  | 12.12 |  |  |  |  |  | 1,552,843 |  |  | 
|  |  |  | 
                Year ended December 31, 
               |  | |||||||||
|  |  |  | 
                2023 
               |  |  | 
                2022 
               |  | ||||||
|  |  |  | 
                (in thousands) 
               |  | |||||||||
| Audit Fees(1) |  |  |  | $ | 1,039 |  |  |  |  | $ | 870 |  |  | 
| Total |  |  |  | $ | 1,039 |  |  |  |  | $ | 870 |  |  | 
| 
                Name of beneficial owner 
               |  |  | 
                Number of Shares
                 Beneficially Owned |  |  | 
                Percentage of Shares
                 Beneficially Owned |  | ||||||
| 5% stockholders: |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Vifor (International) Ltd(1) |  |  |  |  | 7,396,770 |  |  |  |  |  | 13.5% |  |  | 
| Blackrock, Inc.(2) |  |  |  |  | 3,554,258 |  |  |  |  |  | 6.5% |  |  | 
| Directors and named executive officers: |  |  |  |  |  |  |  |  |  |  |  |  |  | 
| Christopher Posner(3) |  |  |  |  | 674,599 |  |  |  |  |  | 1.2% |  |  | 
| Ryan Maynard(4) |  |  |  |  | 125,387 |  |  |  |  |  | * |  |  | 
| Joana Goncalves, M.D.(5) |  |  |  |  | 419,055 |  |  |  |  |  | * |  |  | 
| Martin Vogelbaum(6) |  |  |  |  | 192,681 |  |  |  |  |  | * |  |  | 
| Helen M. Boudreau(7) |  |  |  |  | 38,936 |  |  |  |  |  | * |  |  | 
| Jeffrey L. Ives, Ph.D.(8) |  |  |  |  | 116,072 |  |  |  |  |  | * |  |  | 
| Susan Shiff, Ph.D.(9) |  |  |  |  | 81,272 |  |  |  |  |  | * |  |  | 
| Lisa von Moltke, M.D.(10) |  |  |  |  | 65,796 |  |  |  |  |  | * |  |  | 
| All current executive officers and directors as a group (8 persons)(11) |  |  |  |  | 1,739,035 |  |  |  |  |  | 3.1% |  |  | 
| 
                Status 
               |  |  | 
                Number of
                 Shares of Common Stock Authorized |  |  | 
                Number of
                 Shares of Common Stock Issued and Outstanding |  |  | 
                Number of
                 Shares of Common Stock Reserved for Future Issuance |  |  | 
                Number of
                 Shares of Common Stock Authorized but Unissued and Unreserved |  | ||||||||||||
| Pre-Reverse Stock Split |  |  |  |  | 200,000,000 |  |  |  |  |  | 54,667,079 |  |  |  |  |  | 11,464,860 |  |  |  |  |  | 133,868,061 |  |  | 
| Post-Reverse Stock Split 1:4 |  |  |  |  | 50,000,000 |  |  |  |  |  | 13,666,769 |  |  |  |  |  | 2,866,215 |  |  |  |  |  | 33,467,016 |  |  | 
| Post-Reverse Stock Split 1:5 |  |  |  |  | 40,000,000 |  |  |  |  |  | 10,933,415 |  |  |  |  |  | 2,292,972 |  |  |  |  |  | 26,773,613 |  |  | 
| Post-Reverse Stock Split 1:6 |  |  |  |  | 33,333,333 |  |  |  |  |  | 9,111,179 |  |  |  |  |  | 1,910,810 |  |  |  |  |  | 22,311,344 |  |  | 
| Post-Reverse Stock Split 1:7 |  |  |  |  | 28,571,429 |  |  |  |  |  | 7,809,582 |  |  |  |  |  | 1,637,837 |  |  |  |  |  | 19,124,010 |  |  | 
| Post-Reverse Stock Split 1:8 |  |  |  |  | 25,000,000 |  |  |  |  |  | 6,833,384 |  |  |  |  |  | 1,433,107 |  |  |  |  |  | 16,733,509 |  |  | 
| Post-Reverse Stock Split 1:9 |  |  |  |  | 22,222,222 |  |  |  |  |  | 6,074,119 |  |  |  |  |  | 1,273,873 |  |  |  |  |  | 14,874,230 |  |  | 
| Post-Reverse Stock Split 1:10 |  |  |  |  | 20,000,000 |  |  |  |  |  | 5,466,707 |  |  |  |  |  | 1,146,486 |  |  |  |  |  | 13,386,807 |  |  | 
| Post-Reverse Stock Split 1:11 |  |  |  |  | 18,181,818 |  |  |  |  |  | 4,969,734 |  |  |  |  |  | 1,042,260 |  |  |  |  |  | 12,169,824 |  |  | 
| Post-Reverse Stock Split 1:12 |  |  |  |  | 16,666,667 |  |  |  |  |  | 4,555,589 |  |  |  |  |  | 955,405 |  |  |  |  |  | 11,155,673 |  |  | 
| 
                Status 
               |  |  | 
                Number of
                 Shares of Common Stock Authorized |  |  | 
                Number of
                 Shares of Common Stock Issued and Outstanding |  |  | 
                Number of
                 Shares of Common Stock Reserved for Future Issuance |  |  | 
                Number of
                 Shares of Common Stock Authorized but Unissued and Unreserved |  | ||||||||||||
| Pre-Reverse Stock Split |  |  |  |  | 100,000,000 |  |  |  |  |  | 54,667,079 |  |  |  |  |  | 11,464,860 |  |  |  |  |  | 33,868,061 |  |  | 
| Post-Reverse Stock Split 1:4 |  |  |  |  | 25,000,000 |  |  |  |  |  | 13,666,769 |  |  |  |  |  | 2,866,215 |  |  |  |  |  | 8,467,016 |  |  | 
| Post-Reverse Stock Split 1:5 |  |  |  |  | 20,000,000 |  |  |  |  |  | 10,933,415 |  |  |  |  |  | 2,292,972 |  |  |  |  |  | 6,773,613 |  |  | 
| Post-Reverse Stock Split 1:6 |  |  |  |  | 16,666,667 |  |  |  |  |  | 9,111,179 |  |  |  |  |  | 1,910,810 |  |  |  |  |  | 5,644,678 |  |  | 
| Post-Reverse Stock Split 1:7 |  |  |  |  | 14,285,714 |  |  |  |  |  | 7,809,582 |  |  |  |  |  | 1,637,837 |  |  |  |  |  | 4,838,295 |  |  | 
| Post-Reverse Stock Split 1:8 |  |  |  |  | 12,500,000 |  |  |  |  |  | 6,833,384 |  |  |  |  |  | 1,433,107 |  |  |  |  |  | 4,233,509 |  |  | 
| Post-Reverse Stock Split 1:9 |  |  |  |  | 11,111,111 |  |  |  |  |  | 6,074,119 |  |  |  |  |  | 1,273,873 |  |  |  |  |  | 3,763,119 |  |  | 
| Post-Reverse Stock Split 1:10 |  |  |  |  | 10,000,000 |  |  |  |  |  | 5,466,707 |  |  |  |  |  | 1,146,486 |  |  |  |  |  | 3,386,807 |  |  | 
| Post-Reverse Stock Split 1:11 |  |  |  |  | 9,090,909 |  |  |  |  |  | 4,969,734 |  |  |  |  |  | 1,042,260 |  |  |  |  |  | 3,078,915 |  |  | 
| Post-Reverse Stock Split 1:12 |  |  |  |  | 8,333,333 |  |  |  |  |  | 4,555,589 |  |  |  |  |  | 955,405 |  |  |  |  |  | 2,822,339 |  |  | 
| By: |  | 
| By: |  | 
![[MISSING IMAGE: px_24caratheraproxy1pg01-bw.jpg]](px_24caratheraproxy1pg01-bw.jpg) 
        ![[MISSING IMAGE: px_24caratheraproxy1pg02-bw.jpg]](px_24caratheraproxy1pg02-bw.jpg)