{"transactions":[{"id":4629931,"issuer":{"id":5349,"kind":"organization","name":"Altimmune, Inc.","symbol":"ALT"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Restricted Stock Units","published_at":"2026-10-05T20:10:15.000Z","date":"2026-10-01","kind":"exercise","planned":false,"acquired":false,"shares":37500,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each Restricted Stock Unit (\"RSU\") represents a contingent right to receive one share of Common Stock, par value $0.0001, when vested."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The RSUs become vested over four (4) years with 25% of the shares vesting on October 1, 2026, with the remainder vesting in equal annual installments for the following three (3) years, subject to the reporting person's continued service through the applicable vesting date, and have no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"The RSUs become vested over four (4) years with 25% of the shares vesting on October 1, 2026, with the remainder vesting in equal annual installments for the following three (3) years, subject to the reporting person's continued service through the applicable vesting date, and have no expiration date."}],"balance_after":112500,"derivative":{"underlying":"Common Stock, par value $0.0001","underlying_shares":37500},"source":{"system":"sec-edgar","filing":"0001802615-26-000002","document":"form4-10052026_041009.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1802615/000180261526000002/form4-10052026_041009.xml","form_type":"4"}},{"id":4629930,"issuer":{"id":5349,"kind":"organization","name":"Altimmune, Inc.","symbol":"ALT"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Common Stock, par value $0.0001","published_at":"2026-10-05T20:10:15.000Z","date":"2026-10-01","kind":"tax_withholding","planned":false,"acquired":false,"shares":12679,"price":2.76,"value":34994.04,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F2","text":"Vesting transaction: Shares surrendered to the Issuer solely to cover taxes associated with vesting of RSUs."}],"balance_after":24821,"source":{"system":"sec-edgar","filing":"0001802615-26-000002","document":"form4-10052026_041009.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1802615/000180261526000002/form4-10052026_041009.xml","form_type":"4"}},{"id":4629929,"issuer":{"id":5349,"kind":"organization","name":"Altimmune, Inc.","symbol":"ALT"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Common Stock, par value $0.0001","published_at":"2026-10-05T20:10:15.000Z","date":"2026-10-01","kind":"exercise","planned":false,"acquired":true,"shares":37500,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Each Restricted Stock Unit (\"RSU\") represents a contingent right to receive one share of Common Stock, par value $0.0001, when vested."}],"balance_after":37500,"source":{"system":"sec-edgar","filing":"0001802615-26-000002","document":"form4-10052026_041009.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1802615/000180261526000002/form4-10052026_041009.xml","form_type":"4"}},{"id":1024363,"issuer":{"id":5349,"kind":"organization","name":"Altimmune, Inc.","symbol":"ALT"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Restricted Stock Units","published_at":"2025-10-03T20:23:25.000Z","date":"2025-10-01","kind":"grant","planned":false,"acquired":true,"shares":150000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each Restricted Stock Unit (\"RSU\") represents a contingent right to receive one share of Common Stock, par value $0.0001, when vested"},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The RSUs become vested over four (4) years with 25% of the shares vesting October 1, 2026, with the remainder vesting in equal annual installments for the following three (3) years, subject to the reporting person's continued service through the applicable vesting date, and have no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"The RSUs become vested over four (4) years with 25% of the shares vesting October 1, 2026, with the remainder vesting in equal annual installments for the following three (3) years, subject to the reporting person's continued service through the applicable vesting date, and have no expiration date."}],"balance_after":150000,"derivative":{"underlying":"Common Stock, par value $0.0001","underlying_shares":150000},"source":{"system":"sec-edgar","filing":"0001104659-25-096678","document":"tm2527887-2_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1326190/000110465925096678/tm2527887-2_4seq1.xml","form_type":"4"}},{"id":1024362,"issuer":{"id":5349,"kind":"organization","name":"Altimmune, Inc.","symbol":"ALT"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Stock Options (option to buy)","published_at":"2025-10-03T20:23:25.000Z","date":"2025-10-01","kind":"grant","planned":false,"acquired":true,"shares":450000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"The shares underlying the option become vested and exercisable over four (4) years with 25% of the shares vesting on October 1, 2026, with the remainder vesting in equal monthly installments for the following thirty-six (36) months, subject to the reporting person's continued service on each applicable vesting date."}],"balance_after":450000,"derivative":{"exercise_price":3.87,"expiration_date":"2035-10-01","underlying":"Common Stock, par value $0.0001","underlying_shares":450000},"source":{"system":"sec-edgar","filing":"0001104659-25-096678","document":"tm2527887-2_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1326190/000110465925096678/tm2527887-2_4seq1.xml","form_type":"4"}},{"id":1266830,"issuer":{"id":5638,"kind":"organization","name":"X4 Pharmaceuticals, Inc","symbol":"XFOR"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Common Stock","published_at":"2025-02-14T21:09:09.000Z","date":"2025-02-12","kind":"grant","planned":false,"acquired":true,"shares":850000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Grant of restricted stock units to the Reporting Person under the Issuer's Amended and Restated 2017 Equity Incentive Plan with each restricted stock unit representing the right to receive one share of common stock on the applicable vesting date. No amount was paid upon the grant of the restricted stock units. The restricted stock units vest in three equal annual installments on February 12, 2026, February 12, 2027 and February 12, 2028, subject to the Reporting Person continuing to provide service as an employee of the Issuer through such date."}],"balance_after":864207,"source":{"system":"sec-edgar","filing":"0001628280-25-005704","document":"wk-form4_1739567336.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1501697/000162828025005704/wk-form4_1739567336.xml","form_type":"4"}},{"id":1294300,"issuer":{"id":5638,"kind":"organization","name":"X4 Pharmaceuticals, Inc","symbol":"XFOR"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Common Stock","published_at":"2025-01-27T23:15:12.000Z","date":"2025-01-24","kind":"sale","planned":false,"acquired":false,"shares":11624,"price":0.4546,"value":5284.2704,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"These transactions were made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 28, 2024."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $0.4478 to $0.47, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":14207,"source":{"system":"sec-edgar","filing":"0001628280-25-002705","document":"wk-form4_1738019705.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1501697/000162828025002705/wk-form4_1738019705.xml","form_type":"4"}},{"id":1294299,"issuer":{"id":5638,"kind":"organization","name":"X4 Pharmaceuticals, Inc","symbol":"XFOR"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Common Stock","published_at":"2025-01-27T23:15:12.000Z","date":"2025-01-23","kind":"grant","planned":false,"acquired":true,"shares":25831,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents shares earned upon the vesting of performance-based restricted stock units. The Compensation Committee of the Board of Directors of the Issuer certified the achievement of a performance condition, which occurred upon the acceptance by the European Medicines Agency of the Issuer's Marketing Authorization Application for mavorixafor for the treatment of WHIM syndrome."}],"balance_after":25831,"source":{"system":"sec-edgar","filing":"0001628280-25-002705","document":"wk-form4_1738019705.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1501697/000162828025002705/wk-form4_1738019705.xml","form_type":"4"}},{"id":1611808,"issuer":{"id":5638,"kind":"organization","name":"X4 Pharmaceuticals, Inc","symbol":"XFOR"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Stock Appreciation Right","published_at":"2024-02-28T22:52:37.000Z","date":"2024-02-13","kind":"grant","planned":false,"acquired":true,"shares":180816,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"This Form 4 amendment is being filed to correct the number of stock appreciation rights awarded to the Reporting Person on February 13, 2024. The original Form 4 filed on February 16, 2024 inadvertently reported the number of stock appreciation rights awarded as 475,831 due to an administrative error."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The Stock Appreciation Right will vest and become exercisable in equal annual installments (rounding down to the nearest whole share, except for the last installment) on the first, second, and third anniversaries of February 13, 2024, subject to the Reporting Person remaining an employee of the Issuer through and including each applicable vesting date."}],"balance_after":180816,"derivative":{"exercise_price":0.921,"expiration_date":"2034-02-13","underlying":"Common Stock","underlying_shares":180816},"source":{"system":"sec-edgar","filing":"0001628280-24-007711","document":"wk-form4a_1709160742.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1501697/000162828024007711/wk-form4a_1709160742.xml","form_type":"4/A","original_submission_date":"2024-02-16"}},{"id":1637699,"issuer":{"id":5638,"kind":"organization","name":"X4 Pharmaceuticals, Inc","symbol":"XFOR"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Stock Appreciation Right","published_at":"2024-02-16T22:11:27.000Z","date":"2024-02-13","kind":"grant","planned":false,"acquired":true,"shares":475831,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"The Stock Appreciation Right will vest and become exercisable in equal annual installments (rounding down to the nearest whole share, except for the last installment) on the first, second, and third anniversaries of February 13, 2024, subject to the Reporting Person remaining an\nemployee of the Issuer through and including each applicable vesting date."}],"balance_after":475831,"derivative":{"exercise_price":0.921,"expiration_date":"2034-02-13","underlying":"Common Stock","underlying_shares":475831},"source":{"system":"sec-edgar","filing":"0001628280-24-005385","document":"wk-form4_1708121451.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1501697/000162828024005385/wk-form4_1708121451.xml","form_type":"4"}},{"id":1788823,"issuer":{"id":5638,"kind":"organization","name":"X4 Pharmaceuticals, Inc","symbol":"XFOR"},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Stock Option (right to buy)","published_at":"2023-09-05T20:15:36.000Z","date":"2023-08-31","kind":"grant","planned":false,"acquired":true,"shares":1250000,"price":1.28,"value":1600000.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"25% of the shares subject to the option shall vest on August 31, 2024, with the remainder vesting in equal installments of 2.0833% of the shares subject to the option each successive month thereafter for a period of 36 months, subject to the Reporting Person continuing to provide services through each such date."}],"balance_after":1250000,"derivative":{"exercise_price":1.28,"expiration_date":"2033-08-30","underlying":"Common Stock","underlying_shares":1250000},"source":{"system":"sec-edgar","filing":"0001628280-23-031389","document":"wk-form4_1693944923.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1501697/000162828023031389/wk-form4_1693944923.xml","form_type":"4"}},{"id":3133245,"issuer":{"id":7734,"kind":"organization","name":"Tempest Therapeutics, Inc."},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Stock Option (right to buy)","published_at":"2020-05-28T01:38:43.000Z","date":"2020-05-25","kind":"grant","acquired":true,"shares":80000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Fifty percent (50%) of the shares subject to this option shall vest on the earlier of: (i) December 31, 2020 or (ii) the Board's approval of the achievement of certain performance criteria, and one twelfth (1/12th) of the\nremaining shares subject to this option shall vest in equal monthly installments thereafter, subject to the Reporting Person continuing to provide service to the Issuer through each such date."}],"balance_after":80000,"derivative":{"exercise_price":2,"expiration_date":"2030-05-24","underlying":"Common Stock","underlying_shares":80000},"source":{"system":"sec-edgar","filing":"0001209191-20-032486","document":"doc4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1544227/000120919120032486/doc4.xml","form_type":"4"}},{"id":3279322,"issuer":{"id":7734,"kind":"organization","name":"Tempest Therapeutics, Inc."},"owners":[{"id":74547,"kind":"person","name":"Arbet-Engels Christophe","position":1,"cik":"0001802615","reported_name":"Arbet-Engels Christophe","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Medical Officer"}}],"security":"Employee Stock Option (right to buy)","published_at":"2020-02-11T22:02:44.000Z","date":"2020-02-10","kind":"grant","acquired":true,"shares":140000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Twenty-five percent (25%) of the shares subject to this option shall vest on February 10, 2021, and one thirty-sixth (1/36th) of the remaining shares subject to this option shall vest each month thereafter, subject to the recipient continuing to provide service through that date."}],"balance_after":140000,"derivative":{"exercise_price":6.9,"expiration_date":"2030-02-09","underlying":"Common Stock","underlying_shares":140000},"source":{"system":"sec-edgar","filing":"0001209191-20-008370","document":"doc4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1544227/000120919120008370/doc4.xml","form_type":"4"}}]}