Spring Bank Pharmaceuticals Reports First Quarter 2019 Financial and Operational Results and Provides Corporate Update

• ACHIEVE trial completed – inarigivir HBsAg reduction comparable to interferon but with significantly better tolerability profile
  
• Phase 2 co-administration study of inarigivir + nucleotide analogue fully enrolled – top-line results expected 2H'19
• Study results to be presented at Science of HBV Cure meeting in Singapore demonstrating immune activation of inarigivir 400mg without systemic cytokine toxicity
• CATALYST Phase 2b trials launched – designed to demonstrate functional cure in HBV
• On track to initiate Phase 1b trial of IV-administered STING agonist SB 11285 in mid-2019
• Nominated lead antisense HBV compound to advance into non-clinical development

HOPKINTON, Mass., April 29, 2019 (GLOBE NEWSWIRE) -- Spring Bank Pharmaceuticals, Inc. SBPH, a clinical-stage biopharmaceutical company developing novel therapeutics for the treatment of viral infections, inflammatory diseases and certain cancers, today announced its financial results for the first quarter ended March 31, 2019 and provided an update on recent corporate and clinical development highlights.

"In the first few months of 2019, we continued to make significant progress with our inarigivir clinical program, the development of our intravenously-administered Stimulator of Interferon Genes (STING) agonist SB 11285, and the lead novel antisense compound for HBV emerging from our R&D platform," said Martin Driscoll, president and chief executive officer of Spring Bank Pharmaceuticals. "We completed the ACHIEVE trial in the first quarter of 2019 with positive findings and important insights from this trial presented recently at the annual meeting of the European Association for the Study of the Liver (EASL). This trial demonstrated that orally-administered inarigivir can achieve HBsAg reduction in chronic hepatitis B virus (HBV) patients comparable to interferon but with a significantly better tolerability profile than interferon. The HBsAg responder rate of 26% in the ACHIEVE trial is the best reported response rate for a novel oral agent in HBV treatment to date and is superior to that reported in studies of interferon monotherapy, indicating the functional cure potential for inarigivir. Importantly, the ACHIEVE trial has identified for us the predictors of response to inarigivir, including HBV genotype, baseline HBsAg and IP-10 levels for both HBeAg positive and negative patients, providing us with important guidance for the selection and stratification of the target populations for our Phase 2b/3 programs."

Mr. Driscoll continued, "We also revealed at EASL new preliminary data for the 400mg dose of inarigivir from a study in healthy volunteers. This study demonstrated uniform innate immune-activation with the inarigivir 400mg dose, yet without the systemic cytokine toxicity commonly associated with the use of interferon. Full data from this study will be reported at the Science of HBV Cure meeting in Singapore in June 2019. The ACHIEVE trial results, notably the insights regarding the predictors of response, combined with the findings from the 400mg immune-activation data, have informed the global Phase 2b CATALYST trials that we have just launched. The CATALYST trials involve dosing naïve and nucleotide analogue ("NUC")-suppressed HBV patients using inarigivir 400mg for up to one year, and we have designed these trials to have the ability to demonstrate functional cure. The results from the ongoing study of 12 weeks of dosing of inarigivir in combination with a NUC due in the second half of this year and our CATALYST trials will inform the Phase 3 design for our inarigivir HBV program anticipated to launch in the second half of 2020."

Mr. Driscoll commented further, "I am also pleased to announce that our R&D team under Dr. Kris Iyer's leadership has nominated a novel, lead antisense compound for advancement into non-clinical studies in HBV. It is our plan to accelerate this program with the goal to potentially enter clinical trials in chronic HBV patients in late 2020 with a triple combination consisting of our lead antisense compound co-administered with inarigivir and a NUC." Mr. Driscoll added, "We are on track to progress our second development program, the novel intravenous STING agonist, SB 11285, into a first in human trial in the summer of this year. We have recently conducted positive interactions with regulatory authorities about our clinical development plans for the IV SB 11285 program and expect to submit an investigational new drug application (IND) for this program in the current quarter."

Recent Highlights and Business Developments

• Completed Phase 2 Chronic Hepatitis B ACHIEVE Trial and Announced Positive Results at EASL. During the first quarter of 2019, the company completed dosing patients with chronic HBV in the inarigivir Phase 2 dose escalation ACHIEVE trial. The company presented robust results from this trial at EASL. Across all four dosing cohorts (25mg, 50mg, 100mg and 200mg), 26% of patients had a clinically significant (i.e., 0.5log₁₀ or greater) reduction in HBsAg at week 12 or, following the switch to tenofovir disoproxil fumarate 300mg, at week 24. More importantly, the results of this responder population in the ACHIEVE trial provide the company with valuable insights into the treatment of chronic HBV, including that the HBsAg response to inarigivir was both viral and host dependent, confirming the immuno-modulatory mechanism of inarigivir. Key viral response predictors were viral burden defined by HBsAg levels at baseline and HBV genotype with a good response of up to 33% in genotype B patients and an excellent response of up to 80% in genotype A and D patients, which are the common US and European genotypes. Host baseline IP-10, a marker of immune activity, was also predictive in a similar fashion as reported for interferon. These insights will significantly aid the company in designing future pivotal trials for the treatment of chronic HBV. In addition, data from the ACHIEVE trial revealed that inarigivir 200mg continued to demonstrate a dose-dependent effect on HBV DNA and HBV RNA over the 12-week dosing period. Inarigivir 200mg monotherapy dosing exhibited a maximal decrease of 3.26log₁₀ in HBV DNA and a maximal decrease of 4.88log₁₀ in HBV RNA, with several patients having undetectable HBV RNA levels following treatment. The combination of HBV DNA, HBV RNA and HBsAg reduction is strongly suggestive of cccDNA targeting by inarigivir. Notably, inarigivir 200mg monotherapy showed a uniform antiviral response (HBV DNA) in HBeAg-positive patients who had not responded to the lower doses of inarigivir monotherapy in the earlier ACHIEVE cohorts, demonstrating the potential of inarigivir as a backbone therapy in its utility to treat diverse patient populations.

• Launched CATALYST Trials Examining Inarigivir 400mg. In April 2019, the company launched two Phase 2 global trials (CATALYST 1 and CATALYST 2) examining the administration of inarigivir 400mg as monotherapy and co-administered with a NUC in naïve and NUC-suppressed chronic HBV patients. The CATALYST trials include multiple patient cohorts with dosing periods to include 12 weeks, 24 weeks, and 48 weeks. The CATALYST 1 trial design allows for evaluation of the likelihood of functional cure in treatment-naïve patients and will guide study design for a pivotal trial, expected to commence in 2020, for inarigivir plus a NUC in this population. The CATALYST 2 trial will evaluate NUC-suppressed patients in both an add-on strategy (current NUC treatment + inarigivir 400mg) and a "STOP and SHOCK" strategy (stopping NUC treatment and adding inarigivir 400mg), which will enable Spring Bank to design Phase 3 programs for the large population of patients waiting for HBV cure.

• Phase 2 Co-Administration 12-Week Study of Inarigivir and a NUC Fully Enrolled. This Phase 2 study includes the co-administration of escalating doses of inarigivir and a NUC in naïve patients and inarigivir 100mg added to a NUC in an exploratory cohort of NUC-suppressed chronic HBV patients. The company anticipates that initial results from these cohorts of the study could be reported or presented at a major scientific conference in the second half of 2019.

• Announced Preliminary Results from Inarigivir 400mg Healthy Volunteer Study. The company also announced preliminary results from a healthy volunteer study showing that inarigivir 400mg rapidly and uniformly increased activation markers of innate immunity on circulating peripheral monocytes and dendritic cells which was sustained over a ten-day period of dosing without evidence of tolerance. This data, in combination with the immune activation and favorable tolerability profile seen at the 400mg dose in an earlier trial of inarigivir in HCV patients, has led Spring Bank to choose the 400mg dose of inarigivir for the CATALYST trials.

• Announced Initiation of Liver Biopsy Study. The company recently launched a single-center study to evaluate the intra-hepatic activation of the immune response with inarigivir 400mg and to correlate immunology findings with the effect on HBV intra-hepatic virology, in particular cccDNA. The company anticipates reporting initial results from this study in late 2019.

• On Track to File IND for Intravenous SB 11285 in Second Quarter of 2019. Based on recent productive interactions with regulatory authorities, the company remains on track to submit an IND for the intravenously-administered STING agonist, SB 11285, in the second quarter of 2019 and, if the IND is approved, the company will initiate a Phase 1b clinical trial in solid tumors quickly thereafter.
  
  
• Nominated a novel lead antisense compound for HBV developed with our internal nucleic acid technology capabilities for advancement into non-clinical studies. The company will seek to accelerate the new internal antisense development program with a goal to potentially position the lead compound for use in a clinical trial in late 2020 involving a triple combination for HBV consisting of the lead antisense compound co-administered with inarigivir and a NUC.

2019 First Quarter Financial Results

• Cash Position: Cash, cash equivalents and marketable securities were $57.5 million as of March 31, 2019, compared to cash, cash equivalents and marketable securities of $64.4 million as of December 31, 2018. Net cash used in operating activities for the three months ended March 31, 2019 was $6.8 million, compared to $6.2 million for the same period in 2018. Spring Bank expects that its existing cash, cash equivalents and marketable securities as of March 31, 2019 is sufficient to fund its operating expenses and capital expenditure requirements into the second quarter of 2021.

• Operating Expenses: Total operating expenses for the first quarter ended March 31, 2019 were $8.4 million, which consisted of $5.6 million of research and development (R&D) expenses and $2.8 million of general and administrative (G&A) expenses, compared to total operating expenses of $6.2 million, which consisted of $4.0 million of research and development (R&D) expenses and $2.2 million of general and administrative (G&A) expenses for the quarter ended March 31, 2018.

• Net loss: The company's net loss for the first quarter ended March 31, 2019 was $(5.2) million, or $(0.32) per basic and diluted share, compared to net loss for the first quarter ended March 31, 2018 of $(4.9) million, or $(0.37) per basic and diluted share.

About Spring Bank Pharmaceuticals
Spring Bank Pharmaceuticals, Inc. is a clinical-stage biopharmaceutical company engaged in the discovery and development of a novel class of therapeutics using its proprietary small molecule nucleotide platform. The company designs its compounds to selectively target and modulate the activity of specific proteins implicated in various disease states. The company's lead product candidate, inarigivir, is being developed for the treatment of chronic HBV. Inarigivir is designed to activate within infected cells retinoic acid-inducible gene 1 (RIG-I), which has been shown to inhibit HBV viral replication and induce the intracellular interferon signaling pathways for antiviral defense. The company is also developing its lead STING agonist product candidate, SB 11285, an immunotherapeutic agent for the treatment of selected cancers.

Forward-Looking Statements
Statements in this press release about Spring Bank's future expectations, plans and prospects, as well as any other statements regarding matters that are not historical facts, may constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. These statements include, but are not limited to, statements about the company having sufficient funds to enable it to fund its operating expenses and capital expenditure requirements into the second quarter of 2021; the company's clinical trial designs for CATALYST 1 and CATALYST 2; the timing for initiating and reporting results from multiple inarigivir clinical trials; and the timing of regulatory and clinical developments with respect to SB 11285.

Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including whether Spring Bank's product candidates will advance through the clinical trial process on a timely basis, or at all; whether Spring Bank's cash resources will be sufficient to fund its continuing operations for the periods and/or trials anticipated; whether the results of the company's trials will warrant submission for approval from the United States Food and Drug Administration or equivalent foreign regulatory agencies; whether Spring Bank's product candidates will receive approval from regulatory agencies on a timely basis or at all; whether, if product candidates obtain approval, they will be successfully distributed and marketed; and other factors discussed in the "Risk Factors" section of Spring Bank's Annual Report on Form 10-K for the year ended December 31, 2018, which was filed with the Securities and Exchange Commission (SEC) on March 11, 2019, Spring Bank's Quarterly Reports on Form 10-Q that have been filed with the SEC, and in other filings Spring Bank makes with the SEC from time to time.

In addition, the forward-looking statements included in this press release represent Spring Bank's views as of the date hereof. Spring Bank anticipates that subsequent events and developments could cause Spring Bank's views to change. However, while Spring Bank may elect to update these forward-looking statements at some point in the future, Spring Bank specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing Spring Bank's views as of any date subsequent to the date hereof.

Contacts
Spring Bank Pharmaceuticals, Inc.
Jonathan Freve
Chief Financial Officer
(508) 473-5993

LifeSci Advisors, LLC
Ashley R. Robinson
(617) 535-7742
Ashley@lifesciadvisors.com

Source: Spring Bank Pharmaceuticals, Inc.

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