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Salarius Pharmaceuticals CEO Issues Letter to Stockholders

HOUSTON, Sept. 13, 2022 (GLOBE NEWSWIRE) -- Salarius Pharmaceuticals, Inc. (NASDAQ: SLRX), a clinical-stage biopharmaceutical company developing medicines for patients fighting cancer and in need of new treatment options, today issued the following letter to stockholders from its President and Chief Executive Officer, David Arthur.

To My Fellow Salarius Stockholders,

This past year, and particularly the past few months, have been busy, productive and rewarding for Salarius, and through this letter I’d like to review the team’s accomplishments and provide insight into what should be an active autumn. As you’ll read, we are looking forward to many important milestones in both our protein inhibitor and protein degradation programs by year end.

I’ll begin with our reversible LSD1 protein inhibitor, seclidemstat, which is furthest along the clinical development pathway, and then I’ll share our excitement for our targeted protein degrader, SP-3164.


Enrollment in our Phase 1/2 clinical study in Ewing and other FET-rearranged sarcomas is progressing well. We recently announced the addition of several prestigious institutions to the study, bringing the total to 17 clinical trial sites with 25 separate locations. During July and August we added the Seattle Cancer Care Alliance, which is comprised of the Fred Hutchinson Cancer Research Center, Seattle Children's Hospital and the University of Washington Medical Center, along with Oregon Health & Sciences University, the Mayo Clinic in Rochester, Minnesota and the Mayo Clinic in Jacksonville, Florida. These are all well-known and highly regarded cancer research centers that join the cadre of existing sites that are active and enrolling patients in the sarcoma trial, and while we might add more sites in the future, the initiation of sites for this study is now largely complete.

We remain on track to report interim sarcoma data later this year, with additional data being available as patients continue to enroll and are treated with seclidemstat. As a reminder, Ewing and FET-rearranged sarcomas are rare cancers and patients face limited treatment options and poor prognoses. At the recent American Society of Clinical Oncology annual meeting (ASCO), results from the rEECur study (a randomized trial evaluating first- and second- Ewing relapse treatments) found that patients treated with topotecan plus cyclophosphamide demonstrated progression-free survival of only 3.5 months, and patients treated with high-dose ifosfamide demonstrated only 5.7 months of progression-free survival.1 We believe these Ewing patients need improved treatment options and that delaying disease progression or improving progression-free survival is a significant patient benefit.   

With the help of our investigators, we have enrolled a number of patients with first- and second- relapsed Ewing sarcoma, we are treating these patients with a combination of topotecan, cyclophosphamide and seclidemstat and we are tracking these patients’ time to progression, duration of treatment and other key measures of long-term benefit. We look forward to sharing interim data later this year. All of us at Salarius are motivated by the prospect of making a difference in the lives of patients battling these cancers with high unmet need.

The study of seclidemstat is also progressing at the MD Anderson Cancer Center in an investigator-initiated hematologic, or blood cancer, clinical trial. As a reminder, the cost of investigator-initiated clinical trials is heavily subsidized by the sponsoring institution, which markedly reduces the cost to generate proof-of-concept patient data. We also expect an interim clinical update from this trial before the end of the year.

We are excited to be collaborating with Volition, a multi-national epigenetics company, in the field of biomarker identification. This is a new relationship for Salarius and the profiling we’ll be conducting with their technology will support further development of seclidemstat. This research collaboration provides another tool to aid in the development of seclidemstat to treat patients in the clinic and beyond.

And finally, the abstract titled “Pre-clinical investigation of the LSD1 inhibitor, SP-2577 (seclidemstat) in a Small Cell Lung Cancer” was recently accepted for presentation at the American Association of Cancer Research (AACR) Special Conference on Cancer Epigenomics to be held in Washington, D.C. on October 6-8, 2022. We hope this is just one of several abstracts that will be presented in the near future.

In summary, we believe the development of seclidemstat is advancing nicely and as we’ve discussed throughout the year, the fourth quarter of 2022 should be an active quarter.


In January 2022 we acquired an intellectual property portfolio including the drug candidate SP-3164, which now forms the basis of our targeted protein degradation (TPD) development program.

TPD is the subject of heightened interest in the pharmaceutical community because of its potential to develop medicines that target cancer-promoting proteins that have historically been considered undruggable. In addition, we believe TPD is a validated area of cancer research with a class of early protein degraders, called molecular glues, showing considerable therapeutic and commercial success.

Underscoring the commercial success of this class, global sales of first-generation molecular glues exceeded $16 billion in 2021. We are currently planning to develop SP-3164, a next-generation molecular glue, to treat lymphomas, multiple myeloma and potentially solid tumors, and we believe the potential for SP-3164 is significant.

The value of SP-3164 lies in the fact it is the preferred half – or preferred enantiomer – of the widely studied drug avadomide, but is considered a new chemical entity (NCE) with the potential for increased efficacy and improved safety when compared to avadomide. In fact, as an NCE, SP-3164 has its own issued composition-of-matter patent that along with expected patent extensions, extends SP-3164 exclusivity into the second half of the next decade.

Since acquiring SP-3164 we have made great progress including completing the pre-Investigational New Drug (IND) meeting process with the U.S. Food and Drug Administration, which provided valuable input and clarity on preclinical, clinical and other regulatory matters for preparing and submitting an IND application. Planning and executing these IND-enabling studies and other development activities including pilot toxicology studies, Good Laboratory Practice (GLP) toxicology studies and Good Manufacturing Practice (GMP) scale-ups are underway.

Coupled with our IND-enabling studies and our work evaluating SP-3164 preclinical activity as both a single-agent therapy and a combination therapy in a variety of hematologic and solid tumors, along with our work comparing SP-3164 activity to existing anti-cancer treatments and treatments in development, we believe we remain on track for an IND submission in the first half of next year and the start of clinical studies soon thereafter. We are looking forward to providing an update on this ongoing preclinical research later this year at the 5th Annual Targeted Protein Degradation Summit to be held in Boston, Massachusetts on October 25-28, 2022.

Financial Position and Outlook

As of June 30, 2022, Salarius had cash, cash equivalents and restricted cash of $22.6 million, and while we expect SP-3164 R&D expenses to ramp up in 2022 and 2023, we believe planned operations are funded well into 2023. We continue to manage expenses tightly while looking for opportunities to advance development of both our protein inhibition and protein degrader programs.

In Summary

As I’ve discussed throughout the year, we are looking forward to these last months of 2022 with great anticipation. We expect interim data not only from our own Ewing and FET-rearranged sarcomas studies, but also from the investigator-initiated hematologic study at MD Anderson Cancer Center. We also anticipate some exciting preclinical data from our SP-3164 IND-enabling and other development studies and look forward to our work potentially being highlighted at several upcoming scientific conferences. We will certainly update our stockholders as milestones are achieved.

On behalf of the dedicated team at Salarius, as well as our board of directors, I want to thank our stockholders for their continued support, and our investigators and their patients for advancing potential innovative cancer treatments for others in need.


David Arthur
President and Chief Executive Officer

September 13, 2022

About Salarius Pharmaceuticals
Salarius Pharmaceuticals, Inc. is a clinical-stage biopharmaceutical company developing therapies for patients with cancer in need of new treatment options. Salarius’ product portfolio includes seclidemstat, the company’s lead candidate, which is being studied as a potential treatment for pediatric cancers, sarcomas and other cancers with limited treatment options, and SP-3164, an oral small molecule protein degrader. Seclidemstat is currently in a Phase 1/2 clinical trial for relapsed/refractory Ewing sarcoma and certain additional sarcomas that share a similar biology, also referred to as Ewing-related or FET-rearranged sarcomas. Seclidemstat has received fast track, orphan drug and rare pediatric disease designations for Ewing sarcoma from the U.S. Food and Drug Administration. Salarius is also exploring seclidemstat’s potential in several cancers with high unmet medical need, with an investigator-initiated Phase 1/2 clinical study in hematologic cancers underway at MD Anderson Cancer Center. Salarius has received financial support from the National Pediatric Cancer Foundation to advance the Ewing sarcoma clinical program and was a recipient of a Product Development Award from the Cancer Prevention and Research Institute of Texas (CPRIT). For more information, please visit salariuspharma.com or follow Salarius on Twitter and LinkedIn.

Forward-Looking Statements
This letter contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical facts, included in this letter are forward-looking statements. These forward-looking statements may be identified by terms such as “believe,” “developing,” “expect,” “may,” “progress,” “potential,” “could,” “look forward,” “might,” “should,” and similar terms or expressions or the negative thereof. Examples of such statements include, but are not limited to, statements relating to the following: the impact that the addition of new clinical sites will have on the development of Salarius’ product candidates; the timing of Salarius’ IND submissions to the U.S. Food and Drug Administration and subsequent timing for initiating clinical trials; interim data related to Salarius’ clinical trials, including the timing of when such data is available and made public; Salarius’ growth strategy; the value of seclidemstat as a treatment for Ewing sarcoma, Ewing-related sarcomas, and other cancers and its ability to improve the life of patients; expanding the scope of Salarius’ research and focus to high unmet need patient populations; milestones of Salarius’ current and future clinical trials, including the timing of data readouts. Salarius may not actually achieve the plans, carry out the intentions or meet the expectations or objectives disclosed in the forward-looking statements. You should not place undue reliance on these forward-looking statements. These statements are subject to risks and uncertainties which could cause actual results and performance to differ materially from those discussed in the forward-looking statements. These risks and uncertainties include, but are not limited to, the following: the sufficiency of Salarius’ capital resources; the ability of, and need for, Salarius to raise additional capital to meet Salarius’ business operational needs and to achieve its business objectives and strategy; future clinical trial results and impact of results on Salarius; that the results of studies and clinical trials may not be predictive of future clinical trial results; risks related to the drug development and the regulatory approval process; the competitive landscape and other industry-related risks; and other risks described in Salarius’ filings with the Securities and Exchange Commission, including its Annual Report on Form 10-K for the fiscal year ended December 31, 2021, as revised or supplemented by its Quarterly Reports on Form 10-Q and other documents filed with the SEC. The forward-looking statements contained in this letter speak only as of the date of this letter and are based on management’s assumptions and estimates as of such date. Salarius disclaims any intent or obligation to update these forward-looking statements to reflect events or circumstances that exist after the date on which they were made.


LHA Investor Relations
Kim Sutton Golodetz

1 rEECur - International Randomized Controlled Trial of Chemotherapy for the Treatment of Recurrent and Primary Refractory Ewing Sarcoma

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Source: Salarius Pharmaceuticals, Inc.