Part I. Financial Information [Item 1. Financial Statements (Unaudited)](index=4&type=section&id=Item%201.%20Financial%20Statements%20%28Unaudited%29) Unaudited consolidated financial statements, including balance sheets, operations, equity, cash flows, and notes, reflect a strategic restructuring for ITIL-306 [Condensed Consolidated Balance Sheets](index=4&type=section&id=Condensed%20Consolidated%20Balance%20Sheets) | Metric | Sep 30, 2023 (in thousands) | Dec 31, 2022 (in thousands) | | :--- | :--- | :--- | | Total Assets | $340,272 | $482,128 | | Total Liabilities | $106,248 | $118,523 | | Total Stockholders' Equity | $234,024 | $363,605 | | Cash and Cash Equivalents | $9,133 | $43,716 | | Marketable Securities | $174,315 | $217,204 | [Condensed Consolidated Statements of Operations and Comprehensive Loss](index=5&type=section&id=Condensed%20Consolidated%20Statements%20of%20Operations%20and%20Comprehensive%20Loss) | Metric | 3 Months Ended Sep 30, 2023 (in thousands) | 3 Months Ended Sep 30, 2022 (in thousands) | 9 Months Ended Sep 30, 2023 (in thousands) | 9 Months Ended Sep 30, 2022 (in thousands) | | :--- | :--- | :--- | :--- | :--- | | Research and development | $8,492 | $39,660 | $37,621 | $120,334 | | General and administrative | $11,941 | $16,989 | $36,681 | $49,325 | | Restructuring and impairment charges | $46,283 | — | $71,847 | — | | Total operating expenses | $66,716 | $56,649 | $146,149 | $169,659 | | Loss from operations | $(66,716) | $(56,649) | $(146,149) | $(169,659) | | Net loss | $(67,432) | $(56,224) | $(143,162) | $(169,333) | | Net loss per share, basic and diluted | $(0.52) | $(0.43) | $(1.10) | $(1.31) | [Condensed Consolidated Statements of Stockholders' Equity](index=6&type=section&id=Condensed%20Consolidated%20Statements%20of%20Stockholders%27%20Equity) | Metric | Balance - Dec 31, 2022 (in thousands) | Balance - Sep 30, 2023 (in thousands) | | :--- | :--- | :--- | | Additional Paid-in Capital | $788,992 | $802,605 | | Accumulated Deficit | $(424,894) | $(568,056) | | Total Stockholders' Equity | $363,605 | $234,024 | - **Stock-based compensation** for the nine months ended September 30, 2023, was **$13,613 thousand**[16](index=16&type=chunk) [Condensed Consolidated Statements of Cash Flows](index=8&type=section&id=Condensed%20Consolidated%20Statements%20of%20Cash%20Flows) | Cash Flow Activity (9 Months Ended Sep 30) | 2023 (in thousands) | 2022 (in thousands) | | :--- | :--- | :--- | | Net cash used in operating activities | $(68,648) | $(143,188) | | Net cash provided by investing activities | $27,178 | $81,739 | | Net cash provided by financing activities | $8,082 | $65,684 | | Net (decrease) increase in cash, cash equivalents, and restricted cash | $(33,388) | $4,235 | | Cash, cash equivalents and restricted cash—end of period | $10,146 | $41,618 | [Notes to Condensed Consolidated Financial Statements](index=10&type=section&id=Notes%20to%20Condensed%20Consolidated%20Financial%20Statements) - Instil Bio, Inc. is a clinical-stage biopharmaceutical company focused on developing an innovative cell therapy pipeline of autologous tumor infiltrating lymphocyte (TIL) therapies for the treatment of patients with cancer, with principal operations commencing in Q1 2019[26](index=26&type=chunk) - A restructuring plan was approved in December 2022 and expanded in January 2023, discontinuing the ITIL-168 program and prioritizing ITIL-306, transitioning clinical manufacturing and trial operations to the United Kingdom[27](index=27&type=chunk)[28](index=28&type=chunk)[75](index=75&type=chunk) - The company operates in a single operating segment[32](index=32&type=chunk) | Asset Category (in thousands) | Sep 30, 2023 | Dec 31, 2022 | | :--- | :--- | :--- | | Land | $31,243 | $31,243 | | Laboratory equipment | $7,936 | $19,050 | | Buildings | $23,198 | $32,778 | | Office and computer equipment | $818 | $4,969 | | Leasehold improvements | $1,365 | $4,340 | | Manufacturing equipment | $1,933 | $8,803 | | Vehicles | — | $64 | | Construction work-in-progress | $79,235 | $104,117 | | Total property, plant and equipment, net | $139,435 | $196,880 | - **Impairment charges** of **$41.5 million** for buildings and construction work-in-progress, and **$4.6 million** for assets held for sale, were recognized in Q3 2023 due to restructuring and strategic prioritization[47](index=47&type=chunk)[48](index=48&type=chunk) | Accrued Liability (in thousands) | Sep 30, 2023 | Dec 31, 2022 | | :--- | :--- | :--- | | Accrued construction costs | $60 | $12,359 | | Accrued compensation and benefits | $3,294 | $3,273 | | Accrued operational expenses | $1,387 | $2,203 | | Accrued restructuring costs | $3,188 | $5,434 | | Accrued research, development and clinical trial expenses | $1,773 | $3,827 | | Operating lease liabilities, current | $1,796 | $2,381 | | Other current liabilities | $324 | $592 | | Total accrued expenses and other current liabilities | $11,822 | $30,069 | - The outstanding principal amount under the construction loan was **$82.8 million** as of September 30, 2023, with the building substantially complete[62](index=62&type=chunk) - **Total restructuring and impairment charges** for the nine months ended September 30, 2023, amounted to **$71.8 million**, primarily from asset impairments and employee termination benefits[76](index=76&type=chunk) [Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations](index=24&type=section&id=Item%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) This section provides management's perspective on the company's financial condition and results of operations, highlighting significant operating losses, strategic reprioritization of clinical programs to focus on ITIL-306, and the impact of restructuring charges - The company is a clinical-stage biopharmaceutical company focused on developing autologous TIL therapies for cancer, utilizing its CoStAR platform for genetically engineered TILs[83](index=83&type=chunk) - **Net loss** was **$67.4 million** for the three months and **$143.2 million** for the nine months ended September 30, 2023, with an **accumulated deficit** of **$568.1 million**[90](index=90&type=chunk) - **Cash, cash equivalents, restricted cash, and marketable securities** totaled **$184.5 million** as of September 30, 2023, which is believed to be sufficient to fund operating expenses and capital expenditure requirements beyond 2026[90](index=90&type=chunk)[125](index=125&type=chunk)[128](index=128&type=chunk) - **Research and development expenses** decreased by **$31.2 million** (QoQ) and **$82.7 million** (YoY) due to reduced headcount and discontinuation of the ITIL-168 program, but are anticipated to increase as the ITIL-306-202 clinical trial progresses[106](index=106&type=chunk)[114](index=114&type=chunk)[116](index=116&type=chunk)[117](index=117&type=chunk) - **Restructuring and impairment charges** totaled **$46.3 million** for the three months and **$71.8 million** for the nine months ended September 30, 2023, primarily due to the impairment of commercial and clinical buildings, assets held for sale, and right-of-use assets, as well as severance payments[109](index=109&type=chunk)[111](index=111&type=chunk)[119](index=119&type=chunk)[

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission file number 001-40215 Instil Bio, Inc. (Exact name of registrant as specified in its charter) Delaware 83-2072195 (I.R.S. Employer Identif ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission file number 001-40215 Instil Bio, Inc. (Exact name of registrant as specified in its charter) Delaware 83-2072195 (State or other jurisdi ...

Part I [Business](index=5&type=section&id=Item%201.%20Business) Instil Bio is a clinical-stage biopharmaceutical company focused on developing autologous tumor-infiltrating lymphocyte (TIL) therapies, with a strategic shift in late 2022 to prioritize its CoStAR platform and consolidate operations to the UK - The company is a clinical-stage biopharmaceutical firm focused on developing autologous tumor-infiltrating lymphocyte (TIL) therapies for cancer[12](index=12&type=chunk) - A key strategic shift in December 2022 discontinued the ITIL-168 program to reallocate resources towards the ITIL-306 CoStAR platform and next-generation TIL technologies[25](index=25&type=chunk) - The lead product candidate, **ITIL-306**, is a genetically engineered CoStAR-TIL therapy targeting folate receptor alpha (FRα) expressed on numerous solid tumors[23](index=23&type=chunk) - A Phase 1 dose escalation trial for **ITIL-306** was initiated in the U.S. in October 2022 for NSCLC, ovarian, and renal cancers, with a similar trial planned for the UK in 2023[12](index=12&type=chunk)[23](index=23&type=chunk) - As part of a restructuring plan, the company reduced its US workforce by approximately **60%** in Q1 2023 and consolidated operations to the United Kingdom[131](index=131&type=chunk)[132](index=132&type=chunk) [Risk Factors](index=34&type=section&id=Item%201A.%20Risk%20Factors) The company faces significant risks including substantial financial losses, high development uncertainties for novel clinical-stage products, complex manufacturing challenges, and potential Nasdaq delisting - The company reported significant net losses of **$223.2 million** in 2022 and **$156.8 million** in 2021, with an accumulated deficit of **$424.9 million** as of December 31, 2022[142](index=142&type=chunk) - All product candidates are in clinical or preclinical development, representing novel approaches with inherent uncertainties regarding development, market acceptance, and commercial potential[156](index=156&type=chunk)[158](index=158&type=chunk) - Manufacturing of cell therapies is complex and has faced challenges, leading to a pause in clinical trial enrollment in October 2022 to analyze processes after decreased success rates for ITIL-168[162](index=162&type=chunk)[166](index=166&type=chunk)[233](index=233&type=chunk) - The company faces significant competition from other firms developing TIL, CAR-T, and TCR-T cell therapies, including **Iovance Biotherapeutics**, **Adaptimmune Therapeutics**, and subsidiaries of **Bristol-Myers Squibb** and **Gilead**[257](index=257&type=chunk) - On January 24, 2023, Nasdaq notified the company of non-compliance with the minimum bid price requirement of **$1.00 per share**, posing a risk of delisting[378](index=378&type=chunk) [Unresolved Staff Comments](index=97&type=section&id=Item%201B.%20Unresolved%20Staff%20Comments) The company reports no unresolved staff comments from the Securities and Exchange Commission - There are no unresolved staff comments[418](index=418&type=chunk) [Properties](index=97&type=section&id=Item%202.%20Properties) The company operates manufacturing sites in Manchester, UK, and Tarzana, California, with headquarters in Dallas, Texas, and is evaluating monetization options for its Tarzana facility - The company owns a **128,097 sq. ft.** clinical and commercial manufacturing facility in Tarzana, California, and operates a **13,596 sq. ft.** manufacturing site in Manchester, United Kingdom[128](index=128&type=chunk)[419](index=419&type=chunk) - The company is currently evaluating various monetization options for the Tarzana manufacturing facility, including a potential sale or lease, and subleasing other facilities[130](index=130&type=chunk)[422](index=422&type=chunk) [Legal Proceedings](index=98&type=section&id=Item%203.%20Legal%20Proceedings) The company is not currently subject to any material legal proceedings - The company is not currently a party to any material legal proceedings[135](index=135&type=chunk)[423](index=423&type=chunk) [Mine Safety Disclosures](index=98&type=section&id=Item%204.%20Mine%20Safety%20Disclosures) This item is not applicable to the company - Not applicable[424](index=424&type=chunk) Part II [Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities](index=99&type=section&id=Item%205.%20Market%20for%20Registrant's%20Common%20Equity%2C%20Related%20Stockholder%20Matters%20and%20Issuer%20Purchases%20of%20Equity%20Securities) The company's common stock has been listed on Nasdaq under "TIL" since March 2021, with no history or plans for cash dividends, retaining earnings for growth - Common stock is listed on the Nasdaq Global Select Market under the symbol **"TIL"** since March 19, 2021[427](index=427&type=chunk) - The company has never declared or paid cash dividends and does not plan to in the foreseeable future[429](index=429&type=chunk) [Reserved](index=99&type=section&id=Item%206.%20Reserved) This item is reserved [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=100&type=section&id=Item%207.%20Management's%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) The company's net loss increased to **$223.2 million** in 2022 due to higher expenses and a **$23.2 million** restructuring charge, with **$260.9 million** in cash expected to fund operations beyond 2026 Results of Operations (in thousands) | | Year Ended December 31, | Change | | :--- | :--- | :--- | | | **2022** | **2021** | **$** | | Research and development | $141,056 | $107,251 | $33,805 | | General and administrative | $62,235 | $48,309 | $13,926 | | Restructuring and impairment charges | $23,167 | $— | $23,167 | | **Total operating expenses** | **$226,458** | **$155,560** | **$70,898** | | **Loss from operations** | **($226,458)** | **($155,560)** | **($70,898)** | | **Net loss** | **($223,177)** | **($156,794)** | **($66,383)** | - The increase in R&D expenses by **$33.8 million** in 2022 was due to higher headcount costs (**$14.0 million**), increased clinical development and manufacturing activities (**$8.2 million**), and higher facility and overhead expenses (**$11.6 million**)[459](index=459&type=chunk) - Restructuring and impairment charges of **$23.2 million** in 2022 resulted from strategic reprioritization, including a **$15.8 million** goodwill and IPR&D impairment charge, **$3.0 million** in severance costs, and **$2.4 million** in contract termination fees[462](index=462&type=chunk)[464](index=464&type=chunk) - As of December 31, 2022, the company had **$260.9 million** in cash, cash equivalents, and marketable securities, which management believes is sufficient to fund operations beyond 2026[467](index=467&type=chunk)[471](index=471&type=chunk) Cash Flow Summary (in thousands) | | Years Ended December 31, | | :--- | :--- | | | **2022** | **2021** | | Cash used in operating activities | $(180,164) | $(122,138) | | Cash provided by (used in) investing activities | $114,541 | $(474,396) | | Cash provided by financing activities | $71,886 | $393,164 | [Quantitative and Qualitative Disclosures About Market Risk](index=111&type=section&id=Item%207A.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company's primary market risk is interest rate fluctuations on its **$260.9 million** in cash and marketable securities, with a hypothetical 1% change not expected to materially impact financial statements - The company's main market risk is interest rate risk on its **$260.9 million** of cash, cash equivalents, and marketable securities[509](index=509&type=chunk) - A hypothetical **1%** change in interest rates is not expected to have a material impact on the company's financial statements, partly due to an interest rate swap[510](index=510&type=chunk) [Financial Statements and Supplementary Data](index=112&type=section&id=Item%208.%20Financial%20Statements%20and%20Supplementary%20Data) This section presents the company's audited consolidated financial statements for 2021 and 2022, reflecting significant operating losses, no revenue, and reliance on financing as a clinical-stage entity Consolidated Balance Sheet Highlights (in thousands) | | Dec 31, 2022 | Dec 31, 2021 | | :--- | :--- | :--- | | **Assets** | | | | Cash and cash equivalents | $43,716 | $37,590 | | Marketable securities | $217,204 | $416,509 | | Property, plant and equipment, net | $196,880 | $121,999 | | **Total Assets** | **$482,128** | **$609,983** | | **Liabilities & Equity** | | | | Loan payable | $72,350 | $— | | **Total Liabilities** | **$118,523** | **$54,784** | | **Total Stockholders' Equity** | **$363,605** | **$555,199** | Consolidated Statement of Operations Highlights (in thousands) | | Year Ended Dec 31, 2022 | Year Ended Dec 31, 2021 | | :--- | :--- | :--- | | Research and development | $141,056 | $107,251 | | General and administrative | $62,235 | $48,309 | | Restructuring and impairment charges | $23,167 | $— | | **Loss from operations** | **($226,458)** | **($155,560)** | | **Net loss** | **($223,177)** | **($156,794)** | | **Net loss per share** | **($1.72)** | **($1.48)** | - In December 2022, the company recognized a non-cash impairment charge of **$15.8 million** due to the discontinuation of the ITIL-168 program and stock price decline, comprising **$10.1 million** for IPR&D and **$5.7 million** for goodwill[498](index=498&type=chunk)[500](index=500&type=chunk)[590](index=590&type=chunk) - The company recorded total restructuring and impairment charges of **$23.2 million** in 2022, including asset impairments (**$17.7 million**), one-time employee termination benefits (**$3.0 million**), and contract terminations (**$2.4 million**)[645](index=645&type=chunk) [Changes in and Disagreements With Accountants on Accounting and Financial Disclosure](index=143&type=section&id=Item%209.%20Changes%20in%20and%20Disagreements%20With%20Accountants%20on%20Accounting%20and%20Financial%20Disclosure) The company reports no changes in or disagreements with its accountants on accounting and financial disclosure - None reported[651](index=651&type=chunk) [Controls and Procedures](index=143&type=section&id=Item%209A.%20Controls%20and%20Procedures) Management concluded that the company's disclosure controls and procedures and internal control over financial reporting were effective as of December 31, 2022, with no material changes reported - Management concluded that as of December 31, 2022, the company's disclosure controls and procedures were effective[651](index=651&type=chunk) - Management's assessment concluded that internal control over financial reporting was effective as of December 31, 2022[653](index=653&type=chunk) [Other Information](index=144&type=section&id=Item%209B.%20Other%20Information) The company reports no other information for this item - None reported[657](index=657&type=chunk) [Disclosure Regarding Foreign Jurisdictions that Prevent Inspections](index=144&type=section&id=Item%209C.%20Disclosure%20Regarding%20Foreign%20Jurisdictions%20that%20Prevent%20Inspections) This item is not applicable to the company - None reported[658](index=658&type=chunk) Part III [Directors, Executive Officers and Corporate Governance](index=145&type=section&id=Item%2010.%20Directors%2C%20Executive%20Officers%20and%20Corporate%20Governance) Information on directors, executive officers, and corporate governance is incorporated by reference from the company's 2023 definitive proxy statement - Information is incorporated by reference from the registrant's definitive proxy statement for the 2023 Annual Meeting of Stockholders[660](index=660&type=chunk) [Executive Compensation](index=145&type=section&id=Item%2011.%20Executive%20Compensation) Information regarding executive and director compensation is incorporated by reference from the company's 2023 definitive proxy statement - Information is incorporated by reference from the 2023 Proxy Statement[662](index=662&type=chunk) [Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters](index=145&type=section&id=Item%2012.%20Security%20Ownership%20of%20Certain%20Beneficial%20Owners%20and%20Management%20and%20Related%20Stockholder%20Matters) Information on security ownership by beneficial owners and management, and equity compensation plans, is incorporated by reference from the company's 2023 definitive proxy statement - Information is incorporated by reference from the 2023 Proxy Statement[663](index=663&type=chunk) [Certain Relationships and Related Transactions, and Director Independence](index=145&type=section&id=Item%2013.%20Certain%20Relationships%20and%20Related%20Transactions%2C%20and%20Director%20Independence) Information regarding related party transactions and director independence is incorporated by reference from the company's 2023 definitive proxy statement - Information is incorporated by reference from the 2023 Proxy Statement[664](index=664&type=chunk) [Principal Accountant Fees and Services](index=145&type=section&id=Item%2014.%20Principal%20Accounting%20Fees%20and%20Services) Information regarding fees paid to and services provided by the principal accountant is incorporated by reference from the company's 2023 definitive proxy statement - Information is incorporated by reference from the 2023 Proxy Statement[665](index=665&type=chunk) Part IV [Exhibits, Financial Statement Schedules](index=146&type=section&id=Item%2015.%20Exhibits%2C%20Financial%20Statement%20Schedules) This section lists financial statements from Item 8, notes the omission of schedules, and provides an index of exhibits filed or incorporated by reference - This section contains the index of exhibits filed with the Form 10-K[671](index=671&type=chunk) [Form 10-K Summary](index=148&type=section&id=Item%2016.%20Form%2010-K%20Summary) The company did not provide a summary for this item - None provided[678](index=678&type=chunk)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission file number 001-40215 Instil Bio, Inc. (Exact name of registrant as specified in its charter) Delaware 83-2072195 (State or other jur ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission file number 001-40215 Instil Bio, Inc. (Exact name of registrant as specified in its charter) Delaware 83-2072195 (State or other jurisdic ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission file number 001-40215 Instil Bio, Inc. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporati ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission file number 001-40215 Instil Bio, Inc. (Exact name of registrant as specified in its charter) Delaware 83-2072195 (State or other jurisdiction ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission file number 001-40215 Instil Bio, Inc. (Exact name of registrant as specified in its charter) Delaware 83-2072195 (State or other jur ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission file number 001-40215 Instil Bio, Inc. (Exact name of registrant as specified in its charter) Delaware 83-2072195 (State or other jurisdic ...