Financial Position - As of September 30, 2024, cash, cash equivalents, and short-term investments totaled $45.3 million, sufficient to fund operations into Q2 2026[4]. - Turnstone's total liabilities as of September 30, 2024, were $14.8 million, with total stockholders' deficit at $43.6 million[9]. Research and Development - Research and development (R&D) expenses for Q3 2024 were $14.4 million, slightly up from $14.2 million in Q3 2023, primarily due to increased costs related to TIDAL-01 clinical trials[4]. - The STARLING Phase 1 trial of TIDAL-01 reported a 25% overall response rate (ORR) and a 50% disease control rate (DCR) in heavily pre-treated patients with microsatellite stable colorectal cancer[2]. - A complete response was achieved in one patient from the STARLING trial, who has been progression-free for over one year, highlighting the potential of the Selected TIL therapy[2]. - The company plans to share its next clinical update in the first half of 2025, indicating ongoing commitment to advancing its TIL therapy[1]. Operational Changes - General and administrative (G&A) expenses decreased to $3.9 million in Q3 2024 from $4.8 million in Q3 2023, attributed to reductions in personnel and professional service costs[4]. - The company executed a 60% workforce reduction to prioritize the development of the TIDAL-01 program and extend its cash runway[3]. - Turnstone's corporate restructuring aims to sharpen focus on the TIDAL-01 program, enhancing its financial position and achieving clinical milestones[2]. Financial Performance - The net loss for Q3 2024 was $17.0 million, compared to a net loss of $17.3 million in Q3 2023[4].

Core Insights - Turnstone Biologics Corp. has released initial data from its Phase 1 STARLING trial of TIDAL-01 in metastatic microsatellite-stable colorectal cancer (MSS mCRC), leading to a decline in stock price [1] Clinical Data Summary - The initial data from the trial indicates a 25% overall response rate (ORR) and a 50% disease control rate (DCR) among four evaluable MSS mCRC patients [2] - One patient achieved a deep and durable ongoing complete response (CR), with 50% of patients showing sustained clinical benefit [2] - Notable progression-free survival was over one year for the patient with ongoing complete response and six months for a patient with stable disease [2] - The TIDAL-01 process successfully generated high-titer, polyclonal, and multi-epitope tumor neoantigen-reactive T cells that expanded in the patient and correlated with increased CD8 T cell tumor infiltration [2] - The therapy was generally well-tolerated, with safety events consistent with known adverse events associated with the lymphodepletion regimen, IL-2, and pembrolizumab administration [2] Strategic Focus - The clinical development strategy for TIDAL-01 is now concentrated on three high unmet medical need indications: colorectal cancer, head and neck cancer, and uveal melanoma [3] - The trial is currently enrolling patients for these indications, while cutaneous melanoma and breast cancer have been deprioritized [3] Financial Position - As of June 30, 2024, the company reported cash, cash equivalents, and short-term investments totaling $62.4 million, which are expected to fund operations into the third quarter of 2025 [4] - Following the release of the trial data, Turnstone Biologics stock has decreased by 57.53%, trading at 93 cents [4]

Financial Performance - The net loss for the six months ended June 30, 2024, was $40.933 million, compared to a net loss of $21.431 million for the same period in 2023, indicating a significant increase in losses[10]. - The accumulated deficit as of June 30, 2024, was $217.691 million, up from $176.758 million at the end of 2023, reflecting ongoing financial challenges[8]. - Total stockholders' equity decreased to $59.736 million as of June 30, 2024, from $98.667 million at the end of 2023, a decline of approximately 39.4%[8]. - The company experienced a comprehensive loss of $41.040 million for the six months ended June 30, 2024, compared to a comprehensive loss of $21.251 million for the same period in 2023[10]. - The company reported a net loss per share attributable to common stockholders of $0.92 for the three months ended June 30, 2024, compared to a loss of $7.56 per share for the same period in 2023[10]. - The net loss for the six months ended June 30, 2024, was $40.933 million, compared to a net loss of $21.431 million for the same period in 2023, representing an increase of approximately 91%[10]. - The accumulated deficit increased to $217.691 million as of June 30, 2024, from $176.758 million at the end of 2023, marking an increase of approximately 23%[8]. Operating Expenses - Total operating expenses for the six months ended June 30, 2024, were $42.748 million, compared to $41.552 million for the same period in 2023, representing an increase of 2.9%[10]. - Research and development expenses for the three months ended June 30, 2024, were $17.730 million, compared to $17.193 million for the same period in 2023, showing a year-over-year increase of 3.1%[10]. - Total operating expenses for the three months ended June 30, 2024, were $22.1 million, compared to $21.9 million for the same period in 2023, an increase of $205,000[154]. - General and administrative expenses for the six months ended June 30, 2024, were $9.2 million, an increase of $0.5 million, or 6.2%, compared to $8.7 million for the same period in 2023[163]. - Research and development expenses increased significantly from $5,675,000 on December 31, 2023, to $9,187,000 on June 30, 2024, representing an increase of approximately 62.5%[57]. Cash and Funding - Cash, cash equivalents, and restricted cash at the end of the period were $17.5 million, down from $21.6 million at the beginning of the period[18]. - The company anticipates future financing needs to support ongoing research and development efforts, although specific amounts and timelines were not disclosed[4]. - The company entered into a Loan and Security Agreement for a revolving credit facility of up to $20 million, with a requirement to secure at least $40 million in new funding by March 31, 2025[25]. - The company is dependent on its ability to raise additional funding to continue as a going concern, facing substantial doubt about its ability to do so within the next 12 months[24]. - The company expects to require substantial additional funding to support ongoing operations and product development, particularly for clinical trials and commercialization efforts[172]. Clinical Trials and Research - The company is currently conducting three ongoing Phase 1 clinical trials for its TIL therapies, targeting colorectal cancer, head and neck cancer, and uveal melanoma[19]. - The company is advancing three ongoing Phase 1 clinical trials for TIDAL-01, targeting colorectal cancer, head and neck cancer, and uveal melanoma[119]. - TIDAL-01 has shown a 25% overall response rate (ORR) and a 50% disease control rate (DCR) in a multi-site trial for advanced colorectal cancer, significantly outperforming the current standard of care which has an ORR of 1-6%[123]. - The company plans to substantially increase research and development expenses in the foreseeable future to advance product candidates and improve manufacturing processes[157]. - TIDAL-02 is in preclinical development and aims to enhance TIL quality and function, addressing distinct solid tumor indications compared to TIDAL-01[124]. Collaboration and Agreements - The Company agreed to pay Moffitt a total of at least $17.5 million over five years for research and development services, starting from June 1, 2023[79]. - The Company is entitled to receive up to $200 million in aggregate upon achieving certain clinical and regulatory milestones for the first Takeda Licensed Product[62]. - The Company recognized a $19.4 million charge to research and development expense related to the asset acquisition of Myst during the year ended December 31, 2020[89]. - The Company ceased all work under the Takeda Agreement as of March 31, 2023, following the termination notice[65]. - Collaboration revenue was $0.0 million for the six months ended June 30, 2024, compared to $19.3 million for the same period in 2023, a decrease of $19.3 million[161]. Stock and Equity - The company executed a 1-for-7.9872 reverse stock split on July 14, 2023, adjusting all share and per share amounts retroactively[20]. - The Company’s authorized capital stock is now 500 million shares, consisting of 490 million shares of common stock and 10 million shares of undesignated preferred stock[22]. - The Company had 23,128,454 shares of common stock outstanding as of June 30, 2024, compared to 23,099,335 shares at the end of 2023[8]. - The fair value of stock options granted was estimated using the Black-Scholes model, with a risk-free interest rate of 4.30% for the six months ended June 30, 2024[102]. - The Company adopted the 2023 Equity Incentive Plan, reserving 1,889,435 new shares for future issuance[100]. Financial Position - The total liabilities and stockholders' equity as of June 30, 2024, was $76.877 million, down from $112.815 million at the end of 2023, indicating a reduction in overall financial position[8]. - The Company’s total financial assets were valued at $52.238 million, including $7.125 million in money market funds and $44.997 million in U.S. government securities[48]. - The Company’s total financial liabilities included $1.024 million in contingent consideration as of June 30, 2024[48]. - The Company has not generated any revenue from product sales and has financed its operations primarily through equity offerings and collaboration revenue[25]. - The company has incurred significant operating losses and expects to continue doing so for the foreseeable future, heavily relying on successful product development for profitability[170].

Core Insights - Turnstone Biologics announced positive initial data from the Phase 1 trial of TIDAL-01 in metastatic colorectal cancer, including a complete response in one of the four patients [1][2] - The company expects its cash position to fund operations into the third quarter of 2025, with cash, cash equivalents, and short-term investments totaling $62.4 million as of June 30, 2024 [5][11] Clinical Developments - The STARLING Phase 1 trial of TIDAL-01 reported a 25% overall response rate (ORR) and a 50% disease control rate (DCR) in microsatellite stable metastatic colorectal cancer patients, where current standard care has an ORR of only 1-6% [3] - One patient achieved a complete response and has been progression-free for over one year, while another patient had stable disease, highlighting the potential of TIDAL-01 in a heavily pre-treated patient population [3] - The company is focusing its clinical development strategy on high unmet medical need indications, including colorectal cancer, head and neck cancer, and uveal melanoma, while deprioritizing cutaneous melanoma and breast cancer [3] Financial Performance - Research and development (R&D) expenses for Q2 2024 were $17.7 million, up from $17.2 million in Q2 2023, primarily due to increased manufacturing costs related to TIDAL-01 clinical trials [6] - General and administrative (G&A) expenses decreased to $4.3 million in Q2 2024 from $4.7 million in Q2 2023, attributed to reduced personnel costs [6] - The net loss for Q2 2024 was $21.3 million, slightly improved from a net loss of $21.5 million in the same period of 2023 [7] Leadership Changes - In July 2024, Ines Verdon was promoted to Senior Vice President of Clinical Development, and David Stojdl's role was expanded to oversee all research and translational science activities [4]

Core Insights - Turnstone Biologics reported positive initial data from its Phase 1 STARLING trial of TIDAL-01 in metastatic microsatellite stable colorectal cancer (MSS mCRC) with an overall response rate (ORR) of 25% and a disease control rate (DCR) of 50% [1][2][3] - The trial demonstrated a complete response in a heavily pre-treated patient with progression-free survival extending beyond one year, indicating the potential for TIDAL-01 to transform treatment paradigms for solid tumors [1][3] - TIDAL-01 showed favorable tolerability and a manufacturing success rate of 80%, with all manufactured products exceeding the target dose of at least 1 billion total T cells [2][3] Clinical Trial Details - The Phase 1 STARLING trial is a multi-site, first-in-human, non-randomized, open-label study evaluating the safety, tolerability, and clinical activity of TIDAL-01 in patients with colorectal cancer, head and neck squamous cell carcinoma, and uveal melanoma [2][4] - As of July 15, 2024, 50% of patients in the trial exhibited sustained clinical benefit, with notable progression-free survival of over one year for the complete response patient and six months for a patient with stable disease [2][3] Product and Technology Overview - TIDAL-01 utilizes an unbiased identification and functional screening process to isolate and expand tumor-reactive TILs, aiming for a higher proportion of functional T cells compared to traditional bulk TIL therapies [4][6] - The manufacturing process for TIDAL-01 has shown consistency and success, with an 80% success rate for generating sufficient starting material for patients [2][3] Market Context - Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer-related deaths in the United States, with an estimated 153,000 new cases and 53,000 deaths in 2024 [5] - Approximately 85% of CRC patients are classified as microsatellite stable (MSS), which are generally less responsive to existing immunotherapies, highlighting the unmet need for effective treatment options in this patient population [5][6]

Financial Performance - Net loss for Q1 2024 was $19,629,000, compared to a net income of $68,000 in Q1 2023, indicating a significant shift in financial performance[16]. - The company reported a comprehensive loss of $19,746,000 for Q1 2024, compared to a comprehensive income of $189,000 in Q1 2023[16]. - The net loss per share attributable to common stockholders for Q1 2024 was $(0.85), compared to $0.00 in Q1 2023[16]. - For the three months ended March 31, 2024, the company reported a net loss of $19.6 million compared to a net income of $0.1 million for the same period in 2023[29]. - The company incurred a net loss of $19.6 million for the three months ended March 31, 2024, with an accumulated deficit of $196.4 million[157]. - The company reported a decrease in net operating assets and liabilities of $1.4 million in Q1 2024, which partially offset the net loss[209]. Revenue and Expenses - Collaboration revenue for Q1 2024 was $0, down from $19,306,000 in Q1 2023, representing a 100% decrease[16]. - Total operating expenses increased to $20,691,000 in Q1 2024, compared to $19,700,000 in Q1 2023, an increase of about 5.0%[16]. - Total research and development expenses were $15.8 million for the three months ended March 31, 2024, an increase of $0.1 million, or 0.6%, compared to $15.7 million in 2023[194]. - General and administrative expenses rose to $4.9 million for the three months ended March 31, 2024, an increase of $0.9 million, or 22.5%, compared to $4.0 million in 2023[195]. - Manufacturing expenses increased by $2.4 million, contributing to the rise in research and development costs, while clinical and regulatory costs decreased by $0.9 million[194]. Assets and Cash Flow - Total assets decreased from $112,815,000 as of December 31, 2023, to $94,390,000 as of March 31, 2024, a decline of approximately 16.3%[14]. - Cash and cash equivalents decreased from $17,798,000 as of December 31, 2023, to $14,433,000 as of March 31, 2024, a reduction of approximately 18.5%[14]. - As of March 31, 2024, the company had cash, cash equivalents, and restricted cash totaling $14.5 million, down from $33.6 million at the end of Q1 2023[29]. - As of March 31, 2024, the company had cash, cash equivalents, and short-term investments totaling $77.8 million, down from $94.8 million as of December 31, 2023[205]. - Cash used in operating activities for Q1 2024 was $17.5 million, compared to $17.2 million in Q1 2023, primarily due to a net loss of $19.6 million[209][210]. Equity and Financing - Total stockholders' equity fell from $98,667,000 as of December 31, 2023, to $80,011,000 as of March 31, 2024, a decrease of about 19.0%[14]. - The weighted-average shares of common stock outstanding increased to 23,011,795 in Q1 2024 from 2,786,017 in Q1 2023, a significant increase of approximately 726.0%[16]. - The company completed its initial public offering on July 25, 2023, raising net proceeds of $68.7 million from the sale of 6,666,667 shares at $12.00 per share[27]. - The company intends to fund future operations through equity and/or debt financings, as well as potential asset sales and collaborations[33]. - The company is required to receive at least $40.0 million in new funding by March 31, 2025, as part of the loan agreement[147]. Clinical Trials and Development - The company is currently conducting three ongoing Phase 1 clinical trials for its TIL therapies, targeting various solid tumors[25]. - The company is currently conducting three Phase 1 clinical trials for TIDAL-01, targeting breast cancer, colorectal cancer, head and neck cancer, and uveal melanoma[155]. - TIDAL-01, the lead Selected TIL product candidate, is designed to deliver at least 1 billion cells with over 70% functional tumor-reactive T cells, with a clinical program update expected in mid-2024[154][155]. - The company has established a standardized manufacturing process for large-scale production of Selected TILs, with plans to enhance TIL quality and function in future programs[161][155]. Collaborations and Agreements - The company has entered into a collaboration agreement with Moffitt, committing to pay at least $17.5 million over five years for research and development services related to TIL products[173]. - The company recognized collaboration revenue related to the Takeda Agreement of $19.3 million for the three months ended March 31, 2023, and $0.0 million for the same period in 2024[90]. - Takeda is obligated to pay the company up to $200,000,000 upon achieving certain clinical and regulatory milestones for the first Takeda Licensed Product[77]. - The company has a contractual right to receive $58.6 million under expense sharing through the completion of the Phase IIa clinical trial, which was included in the transaction price at inception[87]. Market and Economic Conditions - The company is actively monitoring macroeconomic and geopolitical trends that could impact its business but has not yet experienced material disruptions[162][163]. - The company considers the decline in market value of its investments primarily attributable to economic and market conditions rather than credit-related factors[68].

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 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: 001-41747 Turnstone Biologics Corp. (Exact name of Registrant as specified in its Charter) (State or other jurisdiction of incorporation ...

Exhibit 99.1 Turnstone Biologics Corp. Reports Fourth Quarter and Full Year 2023 Financial Results and Provides Recent Business Highlights Lead program, TIDAL-01, advancing in Phase 1 trials with initial clinical data expected in mid-2024 Promising preclinical data highlighting Turnstone's novel Selected TIL programs for solid tumors presented at SITC 2023 Further strengthened Scientific Advisory Board with appointment of internationally recognized cancer immunotherapy expert, Dr. Jef rey S. Weber SAN DIEGO ...

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, 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: 001-41747 Turnstone Biologics Corp. (Exact name of registrant as specified in its charter) Delaware 83-2909368 (State or othe ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ☐ 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: 001-41747 Turnstone Biologics Corp. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For th ...