Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ 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: 001-40925 Xilio Therapeutics, Inc. Indicate by check mark whether the registrant (1) has filed all reports requir ...

Unleashing the Potential of Immuno-Oncology Therapies March 2, 2023 1 © 2023 Xilio Therapeutics, Inc. Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding plans, timing and expectations related to: the initiation of patient enrollment in a Phase 2 clinical trial for XTX202 and reporting data from the Phase 1/2 clinical trial for XTX202; repor ...

Immuno-Oncology Therapies Development - The company is developing tumor-activated immuno-oncology therapies aimed at improving cancer treatment outcomes while minimizing systemic side effects [30]. - The company’s goal is to transform cancer treatment by developing highly potent, tumor-selective therapies that provide effective and durable options for patients [41]. - The company aims to explore combination therapies using XTX202 and XTX301 to increase the potential for curative regimens in oncology [40]. - The company intends to explore XTX202 in additional solid tumor indications, including non-small cell lung cancer (NSCLC) and head and neck squamous cell cancer [119]. - The company has a clinical-stage cytokine pipeline that includes tumor-activated product candidates XTX202 (IL-2) and XTX301 (IL-12) [186]. XTX202 Clinical Trials and Data - XTX202, an engineered IL-2 therapy, is currently in a Phase 1 clinical trial with a recommended Phase 2 dose expected to be established; no signs of vascular leak syndrome have been observed to date [31]. - The company plans to report preliminary anti-tumor activity, safety, pharmacokinetic, and pharmacodynamic data from the Phase 1/2 trial of XTX202 in Q3 2023, involving approximately 15-20 patients [44]. - Preliminary data from the Phase 1 trial of XTX202 shows increased numbers of tumor-infiltrating lymphocytes and CD8+ effector T cells, indicating tumor-selective activation [62]. - The ongoing Phase 1 clinical trial for XTX202 has treated 16 patients at dose levels ranging from 0.27 mg/kg to 1.4 mg/kg, with no signs of vascular leak syndrome observed [108]. - The company plans to initiate a Phase 2 trial for XTX202 in patients with unresectable or metastatic melanoma and metastatic renal cell carcinoma (RCC) in April 2023 [105]. XTX301 Clinical Trials and Data - XTX301, an engineered IL-12 therapy, has received FDA clearance for clinical evaluation, with preliminary safety data anticipated by Q4 2023 [32]. - XTX301, a tumor-activated IL-12 product candidate, has received FDA clearance for evaluation in patients with advanced solid tumors, with a starting dose of 5.0 µg/kg [122]. - Preliminary safety data from the Phase 1 clinical trial is expected to be reported in Q4 2023, focusing on monotherapy dose-escalation [140]. - XTX301 demonstrated potent anti-tumor activity in preclinical studies without inducing significant systemic toxicity, indicating effective masking design [129]. - XTX301 was tolerated in non-human primates (NHPs) at doses up to 2 mg/kg once weekly, with a circulating half-life of approximately 4 days [132]. XTX101 Clinical Trials and Data - XTX101, an anti-CTLA-4 monoclonal antibody, is in a Phase 1 trial, with a recommended Phase 2 dose of 150 mg every six weeks established; preliminary data is expected in Q2 2023 [33][35]. - XTX101 aims to achieve a three-fold increase in therapeutic index, potentially transforming treatment outcomes for patients [145]. - XTX101 demonstrated 67% overall activation in a study of 82 tumor biopsies across various solid tumors [29]. - The combination of XTX101 with an anti-PD-1/PD-L1 antibody resulted in robust tumor growth inhibition of 82%, with minimal toxicity observed [159]. - As of March 1, 2023, 24 patients have been treated with XTX101 in a Phase 1 trial, with enrollment in monotherapy dose-expansion ongoing [162]. GPS Platform and Technology - The GPS platform is designed to create tumor-activated molecules that minimize systemic toxicity, enhancing the therapeutic index of immuno-oncology therapies [39]. - The GPS platform has shown preclinical validation for developing tumor-activated cytokines and antibodies, with promising early clinical evidence [62]. - The proprietary GPS platform aims to develop additional product candidates for tumor-selective activation and improved therapeutic index [165]. - The company aims to develop novel immuno-oncology (I-O) therapies using its GPS platform, focusing on overcoming the limitations of cytokines, such as short half-life and significant toxicity [48]. - XTX202 was engineered to be activated preferentially within the tumor microenvironment, enhancing its therapeutic index [78]. Financial and Regulatory Considerations - The company has paid AskGene an upfront payment of $6.0 million and is obligated to pay up to $13.0 million upon achieving specified regulatory milestones for licensed IL-2 products [202]. - The company must secure FDA approval for new drug or biological products, which involves multiple regulatory steps and compliance with good clinical practices [218][224]. - The company is obligated to pay up to $10.3 million for the first three licensed products or services achieving specified milestones [208]. - The company must pay tiered royalties in the low single digits on aggregate annual net sales of licensed products on a country-by-country basis until the expiration of the last-to-expire patent [208]. - The company has entered into a cross-license agreement with AskGene, granting exclusive licenses for AskGene patent rights related to non-antigen binding IL-2 products in oncology [201]. Patent and Intellectual Property - The company has 16 patent application families related to its business, with statutory expiration dates ranging between 2037 and 2043 [180]. - The company owns, co-owns, or exclusively in-licenses three patent families related to masked anti-CTLA-4 antibody constructs, including XTX101, with statutory expiration dates ranging between 2037 and 2042 [187]. - The company owns two patent families relating to masked IL-2 cytokines, including XTX202, with six pending U.S. applications and one issued U.S. patent [188]. - The company has a statutory expiration date for its IL-12 patent family in 2041, without considering any possible patent term adjustments or extensions [188]. - The company intends to apply for patent term extensions on issued patents covering product candidates once they receive FDA approval [197].

Unleashing the Potential of Immuno-Oncology Therapies November 9, 2022 Placeholder area for citations and references 1 © 2022 Xilio Therapeutics, Inc. Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding plans, timing and expectations related to the initiation of patient enrollment in a monotherapy expansion cohort for the Phase 1 clinical tr ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ 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: 001-40925 Xilio Therapeutics, Inc. (Exact name of registrant as specified in its charter) Delaware 85-1623397 ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ 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: 001-40925 Xilio Therapeutics, Inc. (Exact name of registrant as specified in its charter) Delaware 85-1623397 (Sta ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ 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: 001-40925 Xilio Therapeutics, Inc. (Exact name of registrant as specified in its charter) Delaware 85-1623397 (St ...

| --- | --- | --- | --- | --- | --- | --- | |-------|----------------------------------------------------------------------------------------|-------|-------|-------|-------|-------| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | XILIO THERAPEUTICS (NASDAQ: XLO) | | | | | | | | HARNESSING THE IMMUNE SYSTEM TO IMPROVE THE LIVES OF PEOPLE WITH CANCER MARCH 1, 2022 | | | | | | © 2022 Xilio Therapeutics, Inc. Forward-looking st ...

Part I [Business](index=6&type=section&id=Item%201.%20Business) Xilio Therapeutics is a clinical-stage biotechnology company developing tumor-selective immuno-oncology therapies using its proprietary Geographically Precise Solutions (GPS) platform [Overview and Pipeline](index=6&type=section&id=Overview%20and%20Pipeline) Xilio Therapeutics is a clinical-stage biotechnology company utilizing its Geographically Precise Solutions (GPS) platform to develop tumor-selective immuno-oncology (I-O) therapies - The company's core technology is its Geographically Precise Solutions (GPS) platform, designed to engineer molecules that are activated by proteases preferentially active in the tumor microenvironment (TME), aiming to localize therapeutic effects and minimize systemic toxicity[23](index=23&type=chunk)[30](index=30&type=chunk)[44](index=44&type=chunk) Product Pipeline and Anticipated Milestones (as of Feb 2022) | Tumor-Selective Programs | Mechanism of Action | Discovery | IND-Enabling | Phase 1 | Phase 2 | Anticipated Upcoming Milestones | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | **XTX101** | Anti-CTLA-4 | ✓ | ✓ | **Ongoing** | **Ongoing** | Preliminary Phase 1 monotherapy data mid-2022 | | **XTX202** | IL-2 | ✓ | ✓ | **Ongoing** | **Ongoing** | Preliminary Phase 1 data 2H 2022 | | **XTX301** | IL-12 | ✓ | **Ongoing** | | | IND submission 2H 2022 | | **XTX401** | IL-15 | ✓ | **Ongoing** | | | IND-enabling studies | - Key strategic elements include advancing XTX202 and XTX101 through clinical development, progressing preclinical candidates XTX301 and XTX401, expanding the portfolio using the GPS platform, and building a fully-integrated I-O company while exploring strategic collaborations[32](index=32&type=chunk)[35](index=35&type=chunk) [XTX101 Program (Anti-CTLA-4)](index=14&type=section&id=XTX101%20Program%20%28Anti-CTLA-4%29) XTX101 is a tumor-selective anti-CTLA-4 monoclonal antibody designed to improve the therapeutic index over existing therapies like ipilimumab - A Phase 1/2 clinical trial for XTX101 in patients with advanced solid tumors was initiated in September 2021. Preliminary monotherapy data is expected in mid-2022, and combination therapy (with pembrolizumab) data is expected in the second half of 2022[62](index=62&type=chunk)[86](index=86&type=chunk) - In a preclinical mouse model, XTX101 at a **0.3 mg/kg dose** achieved a similar anti-tumor response and complete response (CR) rate as an ipilimumab analog at a **3.0 mg/kg dose**, suggesting a **10-fold increase in potency**[75](index=75&type=chunk) - Preclinical data indicated tumor-selective activity, with XTX101 increasing CD8+ T cells and decreasing Tregs within the tumor without a corresponding increase in CD4+ T cells in the blood, unlike the ipilimumab analog which showed systemic activity[79](index=79&type=chunk)[80](index=80&type=chunk) [Cytokine Programs](index=21&type=section&id=Cytokine%20Programs) The company's cytokine programs aim to develop tumor-selective versions of potent cytokines to overcome their historical toxicity limitations - **XTX202 (IL-2):** A Phase 1/2 trial was initiated in January 2022 for patients with solid tumors, with preliminary data expected in the second half of 2022. The program targets RCC and melanoma[95](index=95&type=chunk)[139](index=139&type=chunk) - **XTX202 Preclinical Results:** In mouse models, XTX202 demonstrated comparable tumor growth inhibition to aldesleukin and a non-masked IL-2 at their maximum tolerated doses, but without the associated systemic toxicities like vascular leak syndrome (VLS), splenomegaly, or body weight loss[121](index=121&type=chunk)[122](index=122&type=chunk)[127](index=127&type=chunk) - **XTX301 (IL-12):** The company plans to submit an IND to the FDA in the second half of 2022. Preclinical studies showed the molecule was well-tolerated in NHPs at doses at least **50-fold higher** than a non-masked IL-12 control[150](index=150&type=chunk)[157](index=157&type=chunk)[169](index=169&type=chunk) - **XTX401 (IL-15):** Currently in preclinical IND-enabling studies. Preclinical data showed tumor-selective activation of NK and NKT cells in the tumor without systemic expansion in the blood[170](index=170&type=chunk)[178](index=178&type=chunk)[179](index=179&type=chunk) [Competition, IP, and Manufacturing](index=37&type=section&id=Competition%2C%20IP%2C%20and%20Manufacturing) Xilio faces substantial competition from major pharmaceutical and biotech companies developing various immuno-therapies, including specific competitors in the anti-CTLA-4, IL-2, IL-12, and IL-15 spaces - The company faces competition from established and developing therapies, including Yervoy (ipilimumab) for anti-CTLA-4 and Proleukin (aldesleukin) for IL-2, as well as numerous companies with programs in development for CTLA-4, IL-2, IL-12, and IL-15[189](index=189&type=chunk)[191](index=191&type=chunk)[192](index=192&type=chunk) - As of February 15, 2022, the company's patent portfolio consists of **11 owned, co-owned, or exclusively licensed patent application families**. Patents issuing from these applications are expected to expire between **2037 and 2042**[195](index=195&type=chunk)[197](index=197&type=chunk) - Material license agreements include a cross-license with AskGene for IL-2 and IL-15 technology, an exclusive license from City of Hope for the anti-CTLA-4 program, and an exclusive license from WuXi Biologics for anti-CTLA-4 mAb technology[217](index=217&type=chunk)[224](index=224&type=chunk)[227](index=227&type=chunk) - The company relies on third-party contract manufacturers for all clinical and potential commercial supply of its product candidates and does not own or operate its own manufacturing facilities[231](index=231&type=chunk) [Government Regulation](index=44&type=section&id=Government%20Regulation) The company's operations are subject to extensive regulation by the FDA in the United States and comparable authorities abroad, covering research, development, testing, manufacturing, and marketing - The company must navigate a multi-step regulatory process with the FDA, including preclinical testing, filing an Investigational New Drug (IND) application, and conducting Phase 1, 2, and 3 clinical trials before submitting a Biologics License Application (BLA) for marketing approval[235](index=235&type=chunk)[237](index=237&type=chunk)[244](index=244&type=chunk) - The company's biologic products may be eligible for **12 years of regulatory exclusivity** in the U.S. under the BPCIA, which would prevent the FDA from approving a biosimilar version during that period[288](index=288&type=chunk)[290](index=290&type=chunk) - Operations are subject to various healthcare laws, including the federal Anti-Kickback Statute, False Claims Act, HIPAA, and the Physician Payments Sunshine Act, which regulate interactions with healthcare providers and third-party payors[301](index=301&type=chunk)[576](index=576&type=chunk) - The company is subject to complex data privacy regulations globally, such as the GDPR in Europe and the CCPA/CPRA in California, which govern the collection, use, and transfer of personal data, including health information from clinical trials[315](index=315&type=chunk)[313](index=313&type=chunk) [Risk Factors](index=59&type=section&id=Item%201A.%20Risk%20Factors) This section details numerous risks that could materially affect the company's business, financial condition, and results of operations - **Financial Risks:** The company has a history of significant operating losses (**$75.8 million in 2021**) and expects to incur more. It will require substantial additional funding to complete development, and failure to raise capital could force delays or elimination of programs[328](index=328&type=chunk)[333](index=333&type=chunk) - **Development and Clinical Risks:** The business is highly dependent on the success of its early-stage product candidates (XTX101, XTX202). The GPS platform is unproven in humans, and preclinical results may not translate to clinical trials. Trials may be delayed or halted due to enrollment difficulties, safety issues, or unfavorable results[347](index=347&type=chunk)[358](index=358&type=chunk)[360](index=360&type=chunk) - **Third-Party Reliance:** The company relies on third-party Contract Manufacturing Organizations (CMOs) for all manufacturing, which is complex and subject to regulatory oversight and potential disruptions. It also relies on Contract Research Organizations (CROs) to conduct clinical trials[397](index=397&type=chunk)[416](index=416&type=chunk) - **Commercial and IP Risks:** The company faces substantial competition from well-resourced companies. Its ability to successfully commercialize products depends on obtaining and maintaining broad patent protection, which is uncertain. It also relies on in-license agreements that impose obligations and could be terminated[432](index=432&type=chunk)[461](index=461&type=chunk)[470](index=470&type=chunk) [Unresolved Staff Comments](index=125&type=section&id=Item%201B.%20Unresolved%20Staff%20Comments) The company reports that it has no unresolved staff comments from the Securities and Exchange Commission - None[665](index=665&type=chunk) [Properties](index=126&type=section&id=Item%202.%20Properties) The company leases approximately 28,000 square feet of office and laboratory space for its headquarters in Waltham, Massachusetts - The company leases approximately **28,000 square feet** of office and laboratory space in Waltham, Massachusetts, under a lease that expires in **March 2030**[667](index=667&type=chunk) [Legal Proceedings](index=126&type=section&id=Item%203.%20Legal%20Proceedings) The company is not currently a party to any material legal proceedings - The company is not currently a party to any material legal proceedings[668](index=668&type=chunk) [Mine Safety Disclosures](index=126&type=section&id=Item%204.%20Mine%20Safety%20Disclosures) This item is not applicable to the company - Not applicable[669](index=669&type=chunk) Part II [Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities](index=126&type=section&id=Item%205.%20Market%20for%20Registrant%27s%20Common%20Equity%2C%20Related%20Stockholder%20Matters%20and%20Issuer%20Purchases%20of%20Equity%20Securities) The company's common stock began trading on the Nasdaq Global Select Market under the symbol "XLO" on October 22, 2021 - The company's common stock began trading on the Nasdaq Global Select Market under the symbol "**XLO**" on **October 22, 2021**[671](index=671&type=chunk) - The company closed its IPO on October 26, 2021, raising aggregate net proceeds of **$116.4 million** after deducting underwriting discounts, commissions, and offering expenses[680](index=680&type=chunk)[682](index=682&type=chunk) - The company has never paid cash dividends and does not anticipate paying any in the foreseeable future, intending to retain future earnings for reinvestment[673](index=673&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=128&type=section&id=Item%207.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) For the year ended December 31, 2021, Xilio reported a net loss of $75.8 million, driven by increased operating expenses, and ended the year with $198.1 million in cash [Results of Operations](index=134&type=section&id=Results%20of%20Operations) For the fiscal year 2021, the company's net loss increased to $75.8 million from $55.2 million in 2020 Comparison of Results of Operations (in thousands) | | Year Ended December 31, | | Change | | :--- | :--- | :--- | :--- | | | **2021** | **2020** | **($)** | | **Research and development** | $51,188 | $43,910 | $7,278 | | **General and administrative** | $23,856 | $10,653 | $13,203 | | **Total operating expenses** | $75,044 | $54,563 | $20,481 | | **Loss from operations** | $(75,044) | $(54,563) | $(20,481) | | **Net loss** | **$(75,800)** | **$(55,219)** | **$(20,581)** | Research and Development Expenses Breakdown (in thousands) | | Year Ended December 31, | | Change | | :--- | :--- | :--- | :--- | | | **2021** | **2020** | **($)** | | XTX202 | $14,143 | $14,866 | $(723) | | XTX101 | $5,941 | $11,554 | $(5,613) | | Other early programs & indirect R&D | $15,292 | $9,483 | $5,809 | | Personnel-related | $15,812 | $8,007 | $7,805 | | **Total R&D expenses** | **$51,188** | **$43,910** | **$7,278** | - The increase in G&A expenses was primarily driven by a **$7.5 million** increase in personnel-related costs and a **$4.1 million** increase in professional and consulting fees related to transitioning to and operating as a public company[723](index=723&type=chunk)[727](index=727&type=chunk) [Liquidity and Capital Resources](index=135&type=section&id=Liquidity%20and%20Capital%20Resources) As of December 31, 2021, the company had $198.1 million in cash and cash equivalents, which is expected to fund operations into 2024 - The company had cash and cash equivalents of **$198.1 million** as of December 31, 2021, which is expected to fund operations and capital expenditures into **2024**[725](index=725&type=chunk)[738](index=738&type=chunk) Summary of Cash Flows (in thousands) | | Year Ended December 31, | | :--- | :--- | :--- | | | **2021** | **2020** | | **Net cash used in operating activities** | $(80,751) | $(36,091) | | **Net cash used in investing activities** | $(1,100) | $(2,188) | | **Net cash provided by financing activities** | $260,668 | $10,029 | | **Net increase (decrease) in cash** | $178,817 | $(28,250) | - Net cash from financing activities in 2021 was **$260.7 million**, primarily from the IPO and issuances of Series B and C convertible preferred stock[733](index=733&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=143&type=section&id=Item%207A.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) As a smaller reporting company, Xilio Therapeutics is not required to provide the information for this item - The company is a smaller reporting company and is not required to provide this information[776](index=776&type=chunk) [Financial Statements and Supplementary Data](index=143&type=section&id=Item%208.%20Financial%20Statements%20and%20Supplementary%20Data) This section indicates that the company's audited consolidated financial statements and supplementary data are appended to the Annual Report on Form 10-K - The financial statements required by this item are appended to the Annual Report on Form 10-K[777](index=777&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[778](index=778&type=chunk) [Controls and Procedures](index=144&type=section&id=Item%209A.%20Controls%20and%20Procedures) Management, including the CEO and CFO, evaluated the company's disclosure controls and procedures and concluded they were effective as of December 31, 2021 - Management concluded that as of **December 31, 2021**, the company's disclosure controls and procedures were effective[781](index=781&type=chunk) - A management report on internal control over financial reporting is not included due to the transition period for newly public companies[782](index=782&type=chunk) Part III [Directors, Executive Officers, Corporate Governance, Compensation, Security Ownership, and Accountant Fees](index=144&type=section&id=Item%2010%2C%2011%2C%2012%2C%2013%2C%20and%2014) The information required for Items 10 through 14 will be included in the company's definitive proxy statement for its 2022 Annual Meeting of Stockholders - Information for Items 10, 11, 12, 13, and 14 is incorporated by reference from the company's definitive proxy statement for its 2022 Annual Meeting of Stockholders[787](index=787&type=chunk)[791](index=791&type=chunk)[792](index=792&type=chunk) Part IV [Exhibits and Financial Statement Schedules](index=145&type=section&id=Item%2015.%20Exhibits%20and%20Financial%20Statement%20Schedules) This section provides an index of the consolidated financial statements and a list of all exhibits filed as part of the Annual Report on Form 10-K - This item contains the index to the consolidated financial statements and the exhibit index for the Form 10-K filing[796](index=796&type=chunk)[801](index=801&type=chunk) [Form 10-K Summary](index=147&type=section&id=Item%2016.%20Form%2010-K%20Summary) The company indicates that there is no Form 10-K summary - None[805](index=805&type=chunk) Financial Statements [Consolidated Financial Statements](index=151&type=section&id=Consolidated%20Financial%20Statements) The consolidated financial statements present Xilio Therapeutics' financial position as of December 31, 2021, showing $218.1 million in total assets and a $75.8 million net loss for the year Consolidated Balance Sheet Data (in thousands) | | Dec 31, 2021 | Dec 31, 2020 | | :--- | :--- | :--- | | **Assets** | | | | Cash and cash equivalents | $198,053 | $19,238 | | Total current assets | $202,517 | $20,590 | | **Total assets** | **$218,060** | **$36,317** | | **Liabilities and Equity** | | | | Total current liabilities | $12,778 | $22,155 | | Total liabilities | $32,631 | $41,602 | | Total stockholders' equity (deficit) | $185,429 | $(83,287) | | **Total liabilities and equity** | **$218,060** | **$36,317** | Consolidated Statement of Operations Data (in thousands) | | Year Ended Dec 31, 2021 | Year Ended Dec 31, 2020 | | :--- | :--- | :--- | | Research and development | $51,188 | $43,910 | | General and administrative | $23,856 | $10,653 | | **Total operating expenses** | **$75,044** | **$54,563** | | **Loss from operations** | **$(75,044)** | **$(54,563)** | | **Net loss** | **$(75,800)** | **$(55,219)** | [Notes to Consolidated Financial Statements](index=155&type=section&id=Notes%20to%20Consolidated%20Financial%20Statements) The notes detail accounting policies, liquidity, intellectual property licenses, and commitments, including $198.1 million cash and significant NOL carryforwards - The company's October 2021 IPO generated net proceeds of **$116.4 million**. Management believes its cash and cash equivalents of **$198.1 million** as of Dec 31, 2021, are sufficient to fund operations for at least the next twelve months[842](index=842&type=chunk)[844](index=844&type=chunk) - The company has significant license agreements, including a **$6.0 million** upfront payment to AskGene in 2020 for IL-2 patent rights, and potential future milestone payments of up to **$13.0 million per product**[901](index=901&type=chunk)[905](index=905&type=chunk) - As of December 31, 2021, the company had federal and state net operating loss (NOL) carryforwards of approximately **$149.5 million** and **$141.0 million**, respectively. A full valuation allowance has been recorded against the net deferred tax assets[980](index=980&type=chunk)[981](index=981&type=chunk)

Part I Financial Information [Financial Statements](index=6&type=section&id=Item%201.%20Financial%20Statements) This section presents Xilio Therapeutics, Inc.'s unaudited condensed consolidated financial statements, reflecting its pre-revenue status and significant operating losses driven by research and development [Condensed Consolidated Balance Sheets](index=6&type=section&id=Condensed%20Consolidated%20Balance%20Sheets) As of September 30, 2021, total assets increased to $120.7 million, driven by cash from financing, while total liabilities decreased and stockholders' deficit widened to $136.5 million due to net loss Condensed Consolidated Balance Sheet Highlights (in thousands) | Account | Sep 30, 2021 | Dec 31, 2020 | | :--- | :--- | :--- | | **Assets** | | | | Cash and cash equivalents | $99,767 | $19,238 | | Total current assets | $105,572 | $20,590 | | Total assets | $120,725 | $36,317 | | **Liabilities & Stockholders' Deficit** | | | | Total current liabilities | $12,871 | $22,155 | | Total liabilities | $34,292 | $41,602 | | Total stockholders' deficit | ($136,455) | ($83,287) | | Total liabilities, convertible preferred stock and stockholders' deficit | $120,725 | $36,317 | [Condensed Consolidated Statements of Operations and Comprehensive Loss](index=7&type=section&id=Condensed%20Consolidated%20Statements%20of%20Operations%20and%20Comprehensive%20Loss) For the nine months ended September 30, 2021, net loss increased to $56.1 million, driven by higher operating expenses, with R&D at $39.8 million and G&A at $15.7 million Statement of Operations Highlights (in thousands) | Account | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | | :--- | :--- | :--- | | Research and development | $39,836 | $26,243 | | General and administrative | $15,652 | $7,725 | | **Total operating expenses** | **$55,488** | **$33,968** | | Loss from operations | ($55,488) | ($33,968) | | **Net loss** | **($56,099)** | **($34,447)** | | Net loss per share, basic and diluted | ($76.18) | ($72.02) | [Condensed Consolidated Statements of Cash Flows](index=10&type=section&id=Condensed%20Consolidated%20Statements%20of%20Cash%20Flows) For the nine months ended September 30, 2021, net cash used in operations was $63.6 million, offset by $144.8 million from financing, resulting in cash, cash equivalents, and restricted cash of $101.3 million Cash Flow Highlights (in thousands) | Activity | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | | :--- | :--- | :--- | | Net cash used in operating activities | ($63,589) | ($23,386) | | Net cash used in investing activities | ($722) | ($2,080) | | Net cash provided by financing activities | $144,842 | $9,904 | | **Increase (decrease) in cash, cash equivalents & restricted cash** | **$80,531** | **($15,562)** | [Notes to Condensed Consolidated Financial Statements](index=11&type=section&id=Notes%20to%20Condensed%20Consolidated%20Financial%20Statements) The notes detail the company's biotechnology business, including its October 2021 IPO raising $116.3 million, expected cash runway into 2024, and significant accounting policies and financing activities - The company completed its IPO on October 26, 2021, receiving net proceeds of approximately **$116.3 million**[48](index=48&type=chunk)[50](index=50&type=chunk). All outstanding preferred stock was converted into **18,398,248 shares** of common stock[109](index=109&type=chunk) - Management expects that cash and cash equivalents as of September 30, 2021, combined with the net proceeds from the IPO, will be sufficient to fund operating requirements and capital expenditures into **2024**[51](index=51&type=chunk)[121](index=121&type=chunk) - In September 2021, the company amended its loan agreement with PacWest, borrowing **$10.0 million** under a new term loan to repay the prior balance. The amendment extended the interest-only payment period through December 31, 2022, and increased a one-time fee payable upon IPO to **$0.8 million**[77](index=77&type=chunk) - During the first nine months of 2021, the company raised approximately **$144.9 million** in net proceeds from the issuance of Series B and Series C convertible preferred stock[86](index=86&type=chunk)[88](index=88&type=chunk)[165](index=165&type=chunk) [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 discusses the company's financial condition, results of operations, and business strategy, highlighting increased operating expenses, liquidity from the recent IPO, and future funding requirements for its immuno-oncology pipeline [Overview](index=24&type=section&id=Overview) Xilio, a biotechnology company, develops tumor-selective immuno-oncology therapies with lead candidates XTX101 and XTX202, and recently completed an IPO raising $116.3 million to fund its pipeline - The company's most advanced product candidates are **XTX101** (an anti-CTLA-4 monoclonal antibody) and **XTX202** (an interleukin 2 therapy)[115](index=115&type=chunk) - An IND for XTX101 was cleared in June 2021, and a Phase 1/2 clinical trial was initiated in September 2021. An IND for XTX202 was cleared in October 2021, with a Phase 1/2 trial anticipated in **Q1 2022**[115](index=115&type=chunk) - The company completed its IPO on October 26, 2021, raising aggregate net proceeds of approximately **$116.3 million**[116](index=116&type=chunk) - Existing cash and cash equivalents, together with IPO proceeds, are expected to fund operations and capital expenditures into **2024**[121](index=121&type=chunk) [Results of Operations](index=30&type=section&id=Results%20of%20Operations) For the nine months ended September 30, 2021, total operating expenses increased by $21.5 million to $55.5 million, driven by higher R&D costs for XTX202 and increased G&A expenses Comparison of Operating Expenses (in thousands) | Expense Category | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | Change | | :--- | :--- | :--- | :--- | | Research and development | $39,836 | $26,243 | $13,593 | | General and administrative | $15,652 | $7,725 | $7,927 | | **Total operating expenses** | **$55,488** | **$33,968** | **$21,520** | Research and Development Expenses by Program (in thousands) | Program | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | Change | | :--- | :--- | :--- | :--- | | XTX202 | $13,524 | $4,091 | $9,433 | | XTX101 | $5,340 | $9,769 | ($4,429) | | Other/Indirect R&D | $9,966 | $6,816 | $3,150 | | Personnel-related | $11,006 | $5,567 | $5,439 | | **Total R&D Expenses** | **$39,836** | **$26,243** | **$13,593** | - The increase in R&D expense was primarily due to a **$9.4 million** increase for the XTX202 program, driven by manufacturing and preclinical activities, and a **$5.4 million** increase in personnel costs[158](index=158&type=chunk) - The increase in G&A expense was primarily due to a **$3.7 million** increase in personnel-related costs and a **$3.5 million** increase in professional fees related to ongoing business activities[155](index=155&type=chunk) [Liquidity and Capital Resources](index=32&type=section&id=Liquidity%20and%20Capital%20Resources) As of September 30, 2021, the company had $99.8 million in cash, with operations funded by $144.8 million from financing and $63.6 million used in operations, expecting funds to last into 2024 - As of September 30, 2021, the company had cash and cash equivalents of **$99.8 million**[159](index=159&type=chunk) - Net cash provided by financing activities for the nine months ended Sep 30, 2021 was **$144.8 million**, primarily from the issuance of Series B and Series C convertible preferred stock[165](index=165&type=chunk) - Net cash used in operating activities for the nine months ended Sep 30, 2021 was **$63.6 million**, primarily due to a net loss of **$56.1 million**[162](index=162&type=chunk) - The company believes its existing cash and cash equivalents, together with the net proceeds from its IPO, will fund operating expenses and capital expenditure requirements into **2024**[171](index=171&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=37&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) As a smaller reporting company, Xilio is not required to provide quantitative and qualitative disclosures about market risk - As a smaller reporting company, Xilio is not required to provide quantitative and qualitative disclosures about market risk[190](index=190&type=chunk) [Controls and Procedures](index=37&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded that the company's disclosure controls and procedures were effective as of September 30, 2021, with no material changes in internal control over financial reporting during the quarter - Management concluded that as of September 30, 2021, the company's disclosure controls and procedures were effective at the reasonable assurance level[192](index=192&type=chunk) - No changes in internal control over financial reporting occurred during the quarter that materially affected, or are reasonably likely to materially affect, internal controls[193](index=193&type=chunk) Part II Other Information [Risk Factors](index=38&type=section&id=Item%201A.%20Risk%20Factors) This section outlines key risks, including significant operating losses, dependence on early-stage product candidates, development uncertainties, manufacturing complexities, reliance on third parties, lack of commercialization experience, intense competition, intellectual property challenges, and regulatory complexities [Risks Related to Financial Position and Capital Requirements](index=38&type=section&id=Risks%20Related%20To%20Our%20Limited%20Operating%20History%2C%20Financial%20Position%20and%20Capital%20Requirements) The company faces risks from significant operating losses, no revenue generation, and the need for substantial additional funding to advance its pipeline, given its limited operating history and unproven technology - The company has incurred significant operating losses since inception, with a net loss of **$56.1 million** for the nine months ended September 30, 2021, and an accumulated deficit of **$141.2 million**[197](index=197&type=chunk) - Substantial additional funding is needed to complete development and commercialization. Existing cash, including IPO proceeds, is not sufficient to complete development of any current product candidate[204](index=204&type=chunk)[206](index=206&type=chunk) - The company's approach using its GPS platform is unproven, and it has not yet demonstrated the ability to successfully complete clinical trials, obtain regulatory approvals, or commercialize a product[213](index=213&type=chunk) [Risks Related to Discovery and Development](index=42&type=section&id=Risks%20Related%20to%20the%20Discovery%20and%20Development%20of%20Our%20Product%20Candidates) The business is highly dependent on early-stage product candidates XTX101 and XTX202, facing high risks of clinical failure, potential delays, and severe side effects, with preclinical results not predictive of human outcomes - The business is highly dependent on the success of its current product candidates, which are in early stages of development and face a high risk of failure[219](index=219&type=chunk) - Preclinical development is uncertain, and positive results in preclinical studies (e.g., for XTX101 and XTX202) may not be replicated in human clinical trials[228](index=228&type=chunk)[230](index=230&type=chunk) - Clinical trials may be substantially delayed or suspended due to numerous factors, including patient enrollment difficulties, manufacturing issues, or unfavorable results[232](index=232&type=chunk) - Product candidates may cause undesirable or severe side effects, which could delay or prevent regulatory approval or limit their commercial profile[247](index=247&type=chunk) [Risks Related to Commercialization](index=58&type=section&id=Risks%20Related%20to%20Commercialization) The company lacks commercialization experience and faces intense competition, with market potential and successful reimbursement uncertain, and no guarantee of market acceptance even if products are approved - The company has no commercialization experience and currently lacks a sales force, marketing, or distribution capabilities[304](index=304&type=chunk) - The company faces substantial competition from established therapies and other companies developing immunotherapies, including those with similar mechanisms like anti-CTLA-4 (e.g., Yervoy) and IL-2 therapies[305](index=305&type=chunk)[307](index=307&type=chunk)[310](index=310&type=chunk) - Successful commercialization depends on obtaining favorable insurance coverage and reimbursement, which is increasingly difficult due to pricing pressures and challenges from third-party payors[326](index=326&type=chunk) [Risks Related to Intellectual Property](index=63&type=section&id=Risks%20Related%20to%20Our%20Intellectual%20Property) The company's success relies on obtaining and maintaining patent protection, but faces risks of insufficient patent scope, loss of in-licensed IP, costly infringement lawsuits, and inability to protect trade secrets - The company's success depends on obtaining and maintaining patent protection, but the patent process is uncertain and may not provide a meaningful competitive advantage[336](index=336&type=chunk)[337](index=337&type=chunk) - The company relies on in-license agreements for key patent rights (e.g., from AskGene for IL-2/IL-15 programs, City of Hope for anti-CTLA-4) and faces risks of losing these rights if it fails to comply with diligence or payment obligations[346](index=346&type=chunk)[348](index=348&type=chunk) - The company may be subject to third-party claims of intellectual property infringement, which could lead to costly litigation, substantial damages, or being blocked from commercializing its products[375](index=375&type=chunk) - The company may not be able to protect the confidentiality of its trade secrets, which could allow competitors to duplicate its technological achievements[372](index=372&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=101&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) This section details unregistered equity transactions, including stock option grants and exercises, and the October 2021 IPO which raised $116.3 million in net proceeds, none of which were used as of September 30, 2021 - During **Q3 2021**, the company granted stock options to purchase **408,777 shares** of common stock and issued **2,585 shares** upon option exercises[531](index=531&type=chunk) - Upon closing its IPO on October 26, 2021, all outstanding preferred stock converted into **18,398,248 shares** of common stock[533](index=533&type=chunk) - The company received aggregate net proceeds of approximately **$116.3 million** from its IPO. As of September 30, 2021, none of these proceeds had been used[536](index=536&type=chunk) [Exhibits](index=102&type=section&id=Item%206.%20Exhibits) This section provides an index of exhibits filed with the Quarterly Report on Form 10-Q, including corporate documents, stock incentive plans, key agreements, and officer certifications - Lists key corporate documents and agreements filed as exhibits, including the **2021 Stock Incentive Plan**, **Loan and Security Agreement with Pacific Western Bank**, and officer certifications[538](index=538&type=chunk)