8-K

 

 

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

 

 

FORM 8-K

 

 

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 4, 2021

 

 

SURFACE ONCOLOGY, INC.

(Exact name of Registrant as Specified in Its Charter)

 

 

 

Delaware   001-38459   46-5543980

(State or Other Jurisdiction

of Incorporation)

 

(Commission

File Number)

 

(IRS Employer

Identification No.)

 

50 Hampshire Street, 8th Floor Cambridge, MA     02139
(Address of principal executive offices)     (zip code)

Registrant’s telephone number, including area code: (617) 714-4096

 

 

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instructions A.2. below):

 

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

 

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

 

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

 

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

 

Title of each class

 

Trading

Symbol(s)

 

Name of exchange

on which registered

Common stock, $0.0001   SURF   The Nasdaq Global Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company  ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☒

 

 

 


Item 8.01

Other Events.

On June 4, 2021, Surface Oncology, Inc. (the “Company”) announced new data from the ongoing Phase 1 studies of SRF388 and SRF617. Preliminary SRF388 results indicate promising single-agent activity in a heavily pre-treated population, including a confirmed partial response demonstrating 66% tumor shrinkage and symptomatic improvement in a patient with squamous cell non-small-cell lung carcinoma (“NSCLC”), whose disease was resistant to three prior regimens including chemotherapy and PD-1 blockade. In addition, early data from SRF617’s combination cohorts point to its potential as a combination therapy, including an unconfirmed partial response with an approximate 50% tumor shrinkage in a patient with pancreatic cancer receiving second-line treatment with SRF617 in combination with gemcitabine/albumin-bound paclitaxel (Abraxane®). A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Also on June 4, 2021, the Company will hold a webcast to review data from its ongoing SRF388 and SRF617 Phase 1 clinical studies. The slide presentation to be presented during the webcast is furnished as Exhibit 99.2 to this Current Report on Form 8-K.

The information in Exhibits 99.1 and 99.2 attached hereto is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933 or the Exchange Act, except as expressly set forth by specific reference in such filing.

 

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits

 

Exhibit

Number

  

Description

99.1    Press release issued by Surface Oncology, Inc. on June 4, 2021
99.2    Presentation of Surface Oncology, Inc. dated June 4, 2021


SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

 

    Surface Oncology, Inc.
Date: June 4, 2021     By:  

/s/ Jessica Fees

      Jessica Fees
      Chief Financial Officer
EX-99.1

Exhibit 99.1

 

LOGO

SRF388, a First-in-Class IL-27 Antibody, Demonstrates Monotherapy Activity in Data Presented at American Society of Clinical Oncology Annual Meeting

Preliminary Data for SRF617 Show Good Tolerability and Promise in Combination Approaches

Company to Hold Webcast to Review Data from Ongoing SRF388 and SRF617 Phase 1 Clinical Studies on Friday, June 4th at 8:00 a.m. ET

CAMBRIDGE, Mass., June 4, 2021 (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 data from the ongoing Phase 1 studies of SRF388 and SRF617. Data from the SRF388 study are to be presented in a scientific poster at the American Society of Clinical Oncology (ASCO) 2021 Annual Meeting, being held virtually June 4-8, 2021. In conjunction, Surface will host a webcast on Friday, June 4, 2021, at 8:00 a.m. ET to provide updates on both SRF388 and SRF617.

“Generating evidence of monotherapy activity is a highly sought after, yet elusive, goal in immuno-oncology and we are excited to report that one of our molecules, SRF388, has produced a partial response in a heavily pretreated patient with lung cancer,” said Rob Ross, M.D., chief executive officer. “These findings validate our scientific rationale and represent an important step forward in our pursuit of transformative treatments to help patients with cancer. We are also pleased to report that SRF617 continues to demonstrate good tolerability with evidence of biological activity. Moving forward, we are opening monotherapy and combination cohorts for both molecules across a range of tumor types, informed by the data we have generated to date.”

“SRF388 is an antibody against IL-27, an immunosuppressive cytokine that plays a key role in controlling immunotolerance to cancer. These data from the ongoing SRF388 Phase 1 clinical study reinforce the potential benefit of IL-27 blockade as a promising anticancer strategy, particularly given the monotherapy partial response in a patient with PD-1-refractory lung cancer,” said Amita Patnaik, M.D., co-director of clinical research at the START Center for Cancer Care in San Antonio, Texas, and lead author of the SRF388 results summary presented at ASCO.

SRF388 Highlights:

Preliminary SRF388 results indicate promising single-agent activity in a heavily pretreated population, including a confirmed partial response demonstrating 66% tumor shrinkage and symptomatic improvement in a patient with squamous cell non-small-cell lung carcinoma (NSCLC), whose disease was resistant to three prior regimens including chemotherapy and PD-1 blockade.


   

In addition, there was evidence of disease stabilization, with 6 of 18 (33%) of evaluable patients experiencing disease stabilization at eight weeks and five (28%) persisting beyond 16 weeks.

 

   

SRF388 was well tolerated at all doses tested, with no dose-limiting toxicity observed to date, and with only low-grade treatment-related adverse events.

 

   

The recommended Phase 2 dose of 10 mg/kg was confirmed based on observed efficacy, tolerability, optimal pSTAT1 inhibition and pharmacokinetics.

SRF617 Highlights:

Early data from combination cohorts point to SRF617’s potential as a combination therapy, including an unconfirmed partial response with an approximately 50% tumor shrinkage in a patient with pancreatic cancer receiving second-line treatment with SRF617 in combination with gemcitabine/albumin-bound paclitaxel (Abraxane®).

 

   

In addition, with SRF617 monotherapy, 7 of 19 evaluable patients (37%) achieved disease stabilization at eight weeks, with 4 (21%) persisting beyond 16 weeks.

 

   

SRF617 was well tolerated at all tested doses as a monotherapy and has a tolerability profile that is conducive to combination strategies.

“Results from both ongoing clinical trials support further evaluation of SRF388 and SRF617 as monotherapies and in combination with standard and investigational regimens in both immune checkpoint naïve and experienced patients,” said Alison O’Neill, M.D., chief medical officer. “We’re pleased to see a profile allowing patients in both studies to escalate to higher doses with good tolerability.”

Presentation at American Society of Clinical Oncology:

Presentation Type: e-poster (Abstract: 2551)

Title: Results of a phase 1 study of SRF388, a first-in-human, first-in-class, high-affinity anti-IL-27 antibody in advanced solid tumors

Session: Developmental Therapeutics - Immunotherapy

Lead Authors: Amita Patnaik, M.D. and Daniel Morgensztern, M.D.

The ASCO e-poster website will be launched on Friday, June 4, 2021, and will remain available for viewing through Tuesday, July 6, 2021. The full poster can be found on Surface Oncology’s website following the presentation.

Webcast Information:

The webcast, scheduled for June 4, 2021, at 8:00 a.m. ET, can be accessed online, and by telephone by dialing (866) 394-2883 (US/Canada) or (314) 888-4236 (international) five minutes prior to the start time and referring to conference ID 4567647. A recording of the webcast will be posted on the Surface website and available on-demand for one year.

About the SRF388-101 Clinical Trial:

The trial is a Phase 1, open-label, multicenter, first-in-human dose-escalation trial of SRF388, a monoclonal antibody targeting IL-27, conducted in patients with advanced solid tumors refractory to standard therapy. The first portion of the study will establish the preliminary safety, tolerability,


pharmacokinetics (PK) and pharmacodynamics (PD) of SRF388 as a monotherapy and identify a dose suitable for expansion studies. In the second portion of the study, indication-specific expansion cohorts will evaluate the safety, preliminary efficacy, tolerability, PK and PD of SRF388 monotherapy and SRF388 in combination with pembrolizumab in patients with advanced or metastatic kidney and liver cancer.

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 immuno-suppressive 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 hepatocellular carcinoma from the FDA.

About the SRF617-101 Clinical Trial:

The trial is a Phase 1, open-label, multicenter, first-in-human dose-escalation trial of SRF617, a monoclonal antibody that binds and inhibits CD39 activity, in patients with advanced solid tumors. The monotherapy dose escalation portion of the study will evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of SRF617 as a monotherapy in patients with advanced solid tumors. The monotherapy tumor biopsy expansion portion of the study will further evaluate the safety and intratumoral PD of SRF617 as a monotherapy. The combination therapy dose escalation portion of the study will evaluate the safety, tolerability, PK and preliminary efficacy of SRF617 in combination with gemcitabine + albumin-bound paclitaxel (Abraxane®), or SRF617 in combination with pembrolizumab, in patients with locally advanced or metastatic solid tumors.

About SRF617:

SRF617 is a fully human antibody designed to inhibit the enzymatic activity of CD39 in the tumor microenvironment, allowing for a dual mechanism of action to promote anti-tumor immunity via reduction of immunosuppressive adenosine in addition to increasing levels of immunostimulatory ATP. A substantial body of research supports a role for CD39 in allowing cancer to evade immune responses. For example, pancreatic cancer stromal cells within the tumor micro-environment express high levels of CD39 which may inhibit anti-cancer immune responses. In preclinical studies, SRF617 has exhibited strong affinity for and inhibition of CD39, the ability to reduce adenosine and increase ATP levels and anti-tumor activity both as a single agent and in combination with multiple therapeutic agents. SRF617 has been granted Orphan Drug designation for the treatment of advanced pancreatic cancer by 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 depleting tumor regulatory T cells 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 (SRF813; preclinical). Surface’s novel 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 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 and SRF617, 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 our 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, 2020, which is 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.

Contacts:

Investors

Matt Lane

matt@gilmartinir.com

617-901-7698

Media

Chris Railey

chris@tenbridgecommunications.com

617-834-0936

EX-99.2

Slide 1

Initial Phase 1 Clinical Data for SRF388 & SRF617 WEBCAST JUNE 4, 2021 Exhibit 99.2


Slide 2

This presentation includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. All statements contained in this presentation other than statements of historical facts, including statements regarding future results of operations and financial position of Surface Oncology, Inc. (“we,” “us” or “our”) our business strategy and plans, the preclinical and clinical development of our product candidates and our objectives for future operations, are forward-looking statements. The words “anticipate,” “believe,” “continue,” “estimate,” “expect,” “intend,” “may,” “will” and similar expressions are intended to identify forward-looking statements. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our financial condition, results of operations, business strategy, clinical development, short-term and long-term business operations and objectives and financial needs. These forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward looking statements. These risks and uncertainties include the timing, progress, and results of preclinical studies and clinical trials for SRF617, SRF388 and SRF813, and our other product candidates, the timing and likelihood of regulatory approvals and those risks identified and discussed in the section titled “Risk Factors,” set forth in our Annual Report on Form 10-K and in our other SEC filings. Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, levels of activity, performance, achievements or events and circumstances reflected in the forward-looking statements will occur. We are under no duty to update any of these forward-looking statements after the date of this presentation to conform these statements to actual results or revised expectations, except as required by law. You should, therefore, not rely on these forward-looking statements as representing our views as of any date subsequent to the date of this presentation. Moreover, except as required by law, neither we nor any other person assumes responsibility for the accuracy and completeness of the forward-looking statements contained in this presentation. By attending or receiving this presentation you acknowledge that you will be solely responsible for your own assessment of the market and our market position and that you will conduct your own analysis and be solely responsible for forming your own view of the potential future performance of our business. Legal Disclaimer


Slide 3

Today’s Highlights Wholly-owned, first-in-class SRF388 (IL-27) demonstrates monotherapy activity and good tolerability – expansions opening Wholly-owned SRF617 (CD39) demonstrates good tolerability, activity in combination – combination expansions enrolling New clinical collaboration with Roche for SRF388 in first-line hepatocellular carcinoma in combination with atezolizumab and bevacizumab


Slide 4

SRF388 Targeting IL-27 to Enhance Inflammation in the Tumor Microenvironment


Slide 5

Novel anti-IL-27 antibody that blocks the interaction of IL-27 with its receptor, thereby promoting immune activation in the tumor microenvironment   Preclinical models have demonstrated that SRF388 inhibits:  IL-27-induced STAT1 phosphorylation in murine and human primary T cells and cell lines IL-27-mediated immunoregulatory receptor expression in primary murine and human immune cells Tumor growth in mouse models of renal cell carcinoma (RCC) lung metastases and hepatocellular carcinoma (HCC) Recent single-cell RNA sequencing data suggests a role for IL-27 in the progression of non-small-cell lung cancer (NSCLC) (Maynard et al Cell 2020*) SRF388: First-in-class IL-27 Antibody with Compelling I-O Rationale IL-27 blockade represents a promising anti-cancer strategy IL-27RA (WSX-1) gp130 EBI3 p28 IL-27 Ligand IL-27 Receptor Jak2 Jak1 STAT3 STAT1 Inhibitory Receptors on Immune Cells Inflammatory Cytokines SRF388 *Note that in this paper IL-27 is part of the gene signature of the macrophage population associated with progressive disease


Slide 6

SRF388-101: Phase 1, First-in-Human Study Design * 3 RCC backfill slots were enrolled RCC = Renal Cell Carcinoma ccRCC = clear cell Renal Cell Carcinoma HCC = Hepatocellular Carcinoma Patnaik et al ASCO 2021, Abstract 2551, NCT04374877; database snapshot date: April 16, 2021 All dosing q4 weeks


Slide 7

SRF388-101: Baseline Patient Characteristics Heavily treated patient population refractory to multiple prior therapeutics All Patients (N=21) Median age, years (range) 66 (46, 83) Sex, n (%) Male Female 7 (33%) 14 (67%) ECOG PS at baseline, n (%) 0 1 6 (29%) 15 (71%) Median time since initial diagnosis, months (range) 46 (6, 234) Number of prior systemic therapies, n (%) 1 2 3 ≥4 3 (14%) 4 (19%) 2 (10%) 12 (57%) Prior aPD-1/aPD-L1 , n (%) Yes No 17 (81%) 4 (19%) Patnaik et al ASCO 2021, Abstract 2551, NCT04374877; database snapshot date: April 16, 2021


Slide 8

SRF388-101 Results: Safety and Tolerability No DLTs observed; only low-grade related adverse events noted  Adverse Event Summary n=21 Treatment-emergent adverse event (TEAE), n (%) Treatment-related AE, n (%) 15 (71%) 4 (19%) Grade ≥3 TEAE, n (%) Grade ≥3 treatment-related AE, n (%) 6 (29%) 0 (0%) Serious Adverse Event (TESAE), n (%) Treatment-related SAE, n (%) 4 (19%) 0 (0%) TEAE leading to discontinuation, n (%) 0 (0%) TEAEs Occurring in ≥10% of Patients by Preferred Term, n (%) Grade 1 Grade 2 Grade 3 All Grades Fatigue 1 (5%) 2 (10%) 1 (5%) 4 (20%) Anemia 1 (5%) 1 (5%) 0 2 (10%) Hypoalbuminemia 2 (10%) 0 0 2 (10%) Hyponatremia 0 2 (10%) 0 2 (10%) * TEAE is defined as an adverse event that emerges or worsens in the period from the first dose of SRF388 to 30 days after the last dose. Patnaik et al ASCO 2021, Abstract 2551, NCT04374877; database snapshot date: April 16, 2021 Reported Treatment-Related AEs were low grade: Fatigue (n=2) Nausea (n=1) Excess salivation (n=1) Cough (n=1) Hyperthyroidism (n=1)


Slide 9

SRF388-101 Results: Time on Study 7 patients remaining on study; 5 able to escalate to higher dose groups Median time on study: 8 weeks (range 1-49) Disease assessment performed at week 8 and then every 12 weeks thereafter Response observed at 8 weeks Patnaik et al ASCO 2021, Abstract 2551, NCT04374877; database snapshot date: April 16, 2021 Confirmed Partial Response (cPR) Unconfirmed Partial Response Prior α-PD-(L)1 therapy Progressive Disease Patient Continuing DL1 (0.003 mg/kg) DL2 (0.03 mg/kg) DL3 (0.1 mg/kg) DL4 (0.3 mg/kg) DL5 (1.0 mg/kg) DL6 (3.0 mg/kg) DL7 (10.0 mg/kg)


Slide 10

SRF388-101: Monotherapy Activity PR observed in patient with NSCLC; 28% with stable disease beyond 16 weeks †1 patient had SD by RECISTv1.1, but experienced overall clinical progression Best Overall Response, n (%) Response Evaluable (n=18) Complete response 0 Partial response 1 (6%) Stable disease 7 (39%)† Progressive disease 10 (55%) Patnaik et al ASCO 2021, Abstract 2551, NCT04374877; database snapshot date: April 16, 2021


Slide 11

SRF388-101: Evidence of Monotherapy Activity in NSCLC Confirmed partial response with 66% tumor shrinkage Baseline Week 8 Week 12 Target Lesion 1 Target Lesion 2 Resolved 64-year-old man with squamous cell NSCLC whose disease was resistant to three prior regimens, including chemotherapy and PD-1 blockade Partial response with 66% decrease in target lesions after three cycles and significant improvement in dyspnea Patnaik et al ASCO 2021, Abstract 2551, NCT04374877; database snapshot date: April 16, 2021


Slide 12

Linear PK with Complete Inhibition of Downstream Signaling  10 mg/kg q4 weeks chosen as RP2D 10 mg/kg (n=5) 3 mg/kg (n=6) 1 mg/kg (n=3) 0.3 mg/kg (n=3) 0.1 mg/kg (n=1) 0.03 mg/kg (n=1) Estimated median t1/2 is 12 days Evidence of accumulation and steady state reached by Cycle 3 No evidence of anti-drug antibody development to date Complete pSTAT1 inhibition maintained through trough at DL4 (0.3 mg/kg) and above Patnaik et al ASCO 2021, Abstract 2551, NCT04374877; database snapshot date: April 16, 2021


Slide 13

SRF388-101 Study Conclusions Support further evaluation as monotherapy and combination therapy SRF388 is well tolerated at all doses tested to date  Preliminary results show promising single-agent activity even in heavily pre-treated patients: Confirmed PR in a patient with squamous cell NSCLC whose disease was resistant to three prior regimens, including chemotherapy and PD-1 blockade 6 of 18 evaluable patients (33%) experienced disease stabilization at eight weeks, with five (28%) persisting beyond 16 weeks PK are linear and dose-proportional with maximal target inhibition of IL-27 mediated pSTAT1 throughout the dosing interval Recommended Phase 2 dose of 10mg/kg q4 weeks confirmed  These data support further evaluation of SRF388  Initial focus in HCC, RCC and NSCLC Patnaik et al ASCO 2021, Abstract 2551, NCT04374877; database snapshot date: April 16, 2021


Slide 14

SRF617 Targeting CD39 for Dual Immune System Activation


Slide 15

Significance of CD39 in Immuno-oncology Key enzyme modulating innate and adaptive immune responses Extracellular adenosine suppresses tumor immunity Extracellular ATP stimulates innate immunity Decreased Decreased Increased CD39 inhibition decreases AMP/adenosine and increases ATP in the TME


Slide 16

SRF617-101: Phase 1, First-in-Human Study Design  * Includes biopsy backfill slots **Clinical collaboration with Merck NCT04336098; database snapshot date April 9, 2021. Dosing is q2 weeks


Slide 17

SRF617-101: Baseline Patient Characteristics, Monotherapy Heavily treated patient population refractory to multiple prior therapeutics  All Patients (N-27) Median age, years (range) 65 (20, 80) Sex, n (%) Male Female 10 (37%) 17 (63%) ECOG PS at baseline, n (%) 0 1 11 (41%) 16 (59%) Median time since initial diagnosis, months (range) 38 (7, 351) Number of prior systemic therapies, n (%) 0 1 2 3 ≥4 2 (7%) 3 (11%) 4 (15%) 4 (15%) 14 (52%) Prior aPD-1/aPD-L1 , n (%) Yes No 8 (30%) 19 (70%) NCT04336098; database snapshot date April 9, 2021.


Slide 18

*TEAE defined as an adverse event that emerges or worsens in the period from the first dose of SRF617 to 30 days after the last dose. Adverse Event Summary n=27 Treatment-emergent adverse event* (TEAE), n (%) Treatment-related AE, n (%) 23 (85%) 14 (52%) Grade ≥3 TEAE, n (%) Grade ≥3 treatment-related AE, n (%) 7 (26%) 0 (0%) Serious Treatment- Emergent Adverse Event (TESAE), n (%) Treatment-related SAE, n (%) 6 (22%) 0 (0%) TEAE leading to discontinuation, n (%) 0 (0%) TEAEs Occurring in ≥10% of Patients by Preferred Term, n (%) Grade 1 Grade 2 Grade 3 All Grades Fatigue 6 (22%) 4 (15%) 0 (0%) 10 (37%) Constipation 3 (11%) 2 (7%) 0 (0%) 5 (18%) Nausea 3 (11%) 1 (4%) 1 (4%) 5 (18%) Vomiting 2 (7%) 0 (0%) 1 (4%) 3 (11%) Anemia 0 (0%) 0 (0%) 3 (11%) 3 (11%) Dehydration 1 (4%) 2 (7%) 0 (0%) 3 (11%) Headache 2 (7%) 1 (4%) 0 (0%) 3 (11%) Pruritus 2 (7%) 1 (4%) 0 (0%) 3 (11%) SRF617-101 Results: Monotherapy Safety and Tolerability No DLTs observed through 1400 mg dose level  NCT04336098; database snapshot date April 9, 2021.


Slide 19

Progressive Disease Prior α-PD-(L)1 therapy Patient Continuing DL1 (20 mg) DL2 (70 mg) DL3 (200 mg) DL4 (700 mg) DL5 (1400 mg) NCT04336098; database snapshot date April 9, 2021. Median time on study: 8 weeks (range 1-43 weeks) Disease assessment performed at week 8 and then every 8 weeks thereafter SRF617-101 Results: Monotherapy Time on Study (N=27) 37% with stable disease beyond 8 weeks


Slide 20

SRF617-101: Early Data from Combination Cohorts SRF617 + Gem/Abraxane Cohort * Five patients dosed with SRF617 (200 mg) + full-dose gemcitabine/Abraxane; four with follow-up beyond one cycle Adverse events as expected, with reported bone marrow suppression and diarrhea One unconfirmed Partial Response reported at first response evaluation (week 8) in a patient with pancreatic cancer previously progressed on FOLFIRINOX chemotherapy; confirmation scan pending SRF617 + Pembrolizumab Cohort * Three patients dosed with SRF617 (700 mg) + pembrolizumab (200mg); all within first cycle of follow-up No early safety signals *Preliminary data as of 5/19/21


Slide 21

SRF617-101: Evidence of Combination Activity Partial response in patient with pancreatic cancer 60-year-old man with pancreatic cancer with liver metastases receiving 200 mg SRF617 + gemcitabine/Abraxane Progressive disease on prior FOLFIRINOX treatment Unconfirmed PR with ~ 50% tumor shrinkage after two cycles of therapy


Slide 22

SRF617 monotherapy is well tolerated at all tested doses to date in patients with advanced solid tumors and has a positive profile for intended combinations Early results support further evaluation: Monotherapy: 7 of 19 evaluable patients (37%) had disease stabilization at eight weeks with four (21%) persisting beyond 16 weeks, including one patient with NSCLC whose disease previously progressed on chemotherapy and PD-1 blockade Combination therapy: One PR (unconfirmed) in a patient with pancreatic cancer whose disease progressed on prior chemotherapy PK are linear and dose-proportional Maximal CD39 target occupancy throughout the dosing interval at doses of 200 mg and above Preliminary results support further evaluation of SRF617 in combination with standard and investigational regimens: Pancreatic cancer: with gemcitabine and Abraxane chemotherapy  Gastric cancer: with pembrolizumab Prostate cancer: with etrumadenant and zimberelimab in a separate study to be initiated this year SRF617-101: Preliminary Results Support further evaluation as monotherapy and combination therapy


Slide 23

Clinical Collaboration Agreement with Roche  Strong non-clinical and translational data for SRF388 in immuno-oncology-naive hepatocellular carcinoma (HCC) Current standard of care in first-line, immuno-oncology-naive HCC is the combination of atezolizumab (Roche’s anti-PD-L1 Tecentriq®) with bevacizumab (Roche’s Avastin®) Surface and Roche have agreed to a clinical collaboration for a Surface-run Phase 2 study to evaluate the combination of Roche’s atezolizumab and bevacizumab with SRF388 in patients with treatment-naïve HCC. Roche will provide both combination agents.


Slide 24

Reviewing Today’s Highlights Wholly-owned, first-in-class SRF388 (IL-27) demonstrates monotherapy activity, good tolerability, expansions opening Wholly-owned SRF617 (CD39) demonstrates good tolerability, activity in combination – combination expansions enrolling New clinical collaboration with Roche for SRF388 in first-line hepatocellular carcinoma in combination with atezolizumab and bevacizumab We intend to provide clinical updates on SRF617 and SRF388 at medical meetings in late 2021 and early 2022, respectively


Slide 25

Thank You