– SRF388 demonstrated clinical activity in multiple solid tumor types with

three confirmed partial responses across NSCLC, RCC and HCC –

– Data support continued evaluation of SRF388 in NSCLC, RCC, and first line HCC –

– Surface plans to initiate new expansion study of SRF388 in combination with pembrolizumab in relapsed/refractory NSCLC –

CAMBRIDGE, Mass., May 26, 2022 (GLOBE NEWSWIRE) -- Surface Oncology (NASDAQ:SURF), a clinical-stage immuno-oncology company developing next-generation immunotherapies that target the tumor microenvironment, today announced the presentation of new clinical data on SRF388, a potential first-in-class IL-27 antibody. Data from the Phase 1/1b clinical trial of SRF388 as a monotherapy and in combination with pembrolizumab, Merck's anti-PD-1 therapy, will be presented in an oral abstract session at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting.  

"In the ongoing SRF388 Phase 1 trial, we observed three confirmed partial responses across three different indications with multiple other patients experiencing durable clinical benefit in the form of disease stabilization," said Alison O'Neill, M.D., chief medical officer at Surface Oncology. "While still early, these findings are compelling and support our view that SRF388 holds exciting potential in the treatment of a variety of tumor types, particularly in combination with other immuno-oncology therapies."

"SRF388 is a potential first-in-class cytokine antagonist with a unique mechanism of anti-tumor activity that is showing encouraging early efficacy with a favorable safety and tolerability profile even in heavily pre-treated patients," added Aung Naing, M.D., professor of Investigational Cancer Therapeutics at The University of Texas MD Anderson Cancer Center. "The biology of the pathway, strong preclinical data, and tolerability of SRF388 support the potential for IL-27 blockade to complement PD-1 inhibition and other standard-of-care therapies across a range of cancers."

SRF388 Data Highlights:

• Confirmed partial responses (PR) were observed in two patients who received SRF388 monotherapy treatment: one in non-small-cell lung cancer (NSCLC) (previously reported) and one in clear cell renal cell carcinoma (RCC). In addition, a PR was observed in a patient who was treated with SRF388 in combination with pembrolizumab for hepatocellular carcinoma (HCC). The patient with HCC was refractory to two prior VEGFR TKIs, while the patients with NSCLC and RCC had both progressed on prior anti-PD-(L)1 therapy.
• SRF388 was well tolerated at all doses investigated (up to 20 mg/kg), with no dose-limiting toxicity or high-grade safety signals observed.
• Encouraging pharmacodynamic data demonstrated that, after SRF388 administration, circulating IFNg increased —an on-target mechanism of action indicating increased immune activation.
• Based on these efficacy data, the criteria for opening Stage 2 of the RCC monotherapy cohort was met. SRF388 is also being evaluated in NSCLC as a monotherapy and in combination with pembrolizumab, as well as in triplet therapy with atezolizumab and bevacizumab in first-line HCC.

SRF388 Clinical Program Updates:

• Surface will initiate a new Simon two-stage expansion study of SRF388 in combination with pembrolizumab in up to 40 patients with relapsed/refractory NSCLC.
• Data from multiple SRF388 cohorts, including in NSCLC and first-line HCC, are anticipated in the first half of 2023.

ASCO Presentation Details:

• Title: First-in-human study of SRF388, a first-in-class IL-27 targeting antibody, as monotherapy and in combination with pembrolizumab in patients with advanced solid tumors
• Abstract: 2501
• Session Type/Title: Oral abstract session / Developmental Therapeutics – Immunotherapy
• Session Date and Time: Saturday, June 4, 2022, 1:15 p.m. – 4:15 p.m. CDT

Slides from the ASCO presentation will be posted on the Surface Oncology website following the conclusion of the session.

About SRF388

SRF388 is a fully human anti-IL-27 antibody designed to inhibit the activity of this immunosuppressive cytokine. Surface Oncology has identified particular tumor types, including liver, kidney and lung cancer, where IL-27 appears to play an important role in the immunosuppressive tumor microenvironment and may contribute to resistance to treatment with checkpoint inhibitors. SRF388 targets the rate-limiting p28 subunit of IL-27, and preclinical studies have shown that treatment with SRF388 blocks the immunosuppressive biologic effects of IL-27, resulting in immune cell activation in combination with other cancer therapies including anti-PD-1 therapy, as well as potent anti-tumor effects as a monotherapy. Furthermore, Surface Oncology has identified a potential biomarker associated with IL-27 that may be useful in helping to identify patients most likely to respond to SRF388. In November 2020, Surface announced that SRF388 was granted Orphan Drug designation and Fast Track designation for the treatment of refractory hepatocellular carcinoma from the FDA.

About Surface Oncology

Surface Oncology is an immuno-oncology company developing next-generation antibody therapies focused on the tumor microenvironment. Its pipeline includes two wholly-owned clinical-stage programs targeting CD39 (SRF617) and IL-27 (SRF388), as well as a preclinical program focused on selectively depleting regulatory T cells in the tumor microenvironment via targeting CCR8 (SRF114). In addition, Surface has two partnerships with major pharmaceutical companies: a collaboration with Novartis targeting CD73 (NZV930; Phase 1) and a collaboration with GlaxoSmithKline targeting PVRIG (GSK4381562, formerly SRF813; Phase 1). Surface's novel, investigational cancer immunotherapies are designed to achieve a clinically meaningful and sustained anti-tumor response and may be used alone or in combination with other therapies. For more information, please visit www.surfaceoncology.com.

Cautionary Note Regarding Forward-Looking Statements:

Certain statements set forth in this press release constitute "forward-looking" statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements can be identified by terms such as "believes," "expects," "plans," "potential," "would" or similar expressions, and the negative of those terms. These forward-looking statements are based on Surface Oncology's management's current beliefs and assumptions about future events and on information currently available to management.

Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause Surface Oncology's actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. These risks include, but are not limited to, risks and uncertainties related to Surface Oncology's ability to successfully develop SRF388, SRF617, SRF114 and its other product candidates through current and future milestones or regulatory filings on the anticipated timeline, if at all, the therapeutic potential of Surface Oncology's product candidates, the risk that results from preclinical studies or early clinical trials may not be representative of larger clinical trials, the risk that Surface Oncology's product candidates, including SRF388, SRF617 and SRF114, will not be successfully developed or commercialized, the risks related to Surface Oncology's dependence on third-parties in connection with its manufacturing, clinical trials and preclinical studies, and the potential impact of COVID-19 on Surface Oncology's clinical and preclinical development timelines and results of operations. Additional risks and uncertainties that could affect Surface Oncology's future results are included in the section titled "Risk Factors" in our Annual Report on Form 10-K for the year ending December 31, 2021, available on the Securities and Exchange Commission's website at www.sec.gov and Surface Oncology's website at www.surfaceoncology.com. Additional information on potential risks will be made available in other filings that Surface Oncology makes from time to time with the Securities and Exchange Commission. In addition, any forward-looking statements contained in this press release are based on assumptions that Surface Oncology believes to be reasonable as of this date. Except as required by law, Surface Oncology assumes no obligation to update these forward-looking statements, or to update the reasons if actual results differ materially from those anticipated in the forward-looking statements.

Contact

Scott Young

(617) 865-3250

syoung@surfaceoncology.com