SNDX Syndax Pharmaceuticals Inc

– Rapid responses and symptom improvement observed in inflammatory and fibrotic manifestations of chronic GVHD in heavily pretreated patients –

WALTHAM, Mass., Nov. 5, 2024 /PRNewswire/ -- Syndax Pharmaceuticals (Nasdaq:SNDX), today announced that multiple abstracts evaluating Niktimvo™ (axatilimab-csfr), an anti-CSF-1R antibody for the treatment of chronic graft-versus-host disease (GVHD), have been accepted for presentation at the 66^th American Society of Hematology (ASH) Annual Meeting being held in San Diego, California, December 7-10, 2024. The presentations will highlight a secondary analysis of overall and organ-specific responses and findings from an exposure-response analysis in patients with chronic GVHD from the pivotal Phase 2 AGAVE-201 trial of Niktimvo, as well as preclinical data further characterizing the Niktimvo mechanism of action.

Copies of the abstracts are now available on the ASH website.

"Further analyses of data from the pivotal AGAVE-201 trial continue to reinforce our confidence in Niktimvo's ability to meaningfully advance the chronic GVHD treatment paradigm," said Neil Gallagher, M.D., Ph.D., President, Head of Research and Development at Syndax. "In collaboration with our partner Incyte, we look forward to providing clinicians and patients with a new approach to treating chronic GVHD and continuing to advance our clinical development programs investigating the potential use of Niktimvo earlier in the treatment of chronic GVHD as well as in other inflammatory and fibrotic diseases including idiopathic pulmonary fibrosis."

The Company will host an in-person investor event, along with a live webcast, to discuss the latest data supporting the Company's pipeline on Monday, December 9, 2024 at 7:00 a.m. PT/ 10:00 a.m. ET during the ASH Annual Meeting. The live webcast will be available on the Investor section of the Company's website at www.syndax.com, where a replay of the event will also be available for a limited time.

Overview of Presentations

AGAVE-201 Secondary Analysis

Incyte and Syndax previously announced positive topline data from the pivotal AGAVE-201 trial of Niktimvo in adult and pediatric patients with refractory chronic GVHD who received at least two prior lines of systemic therapy. The trial met the primary endpoint across all dose cohorts. Among patients who received Niktimvo at the approved dose of 0.3 mg/kg every two weeks (N=79), the overall response rate (ORR) was 75% within the first six months of treatment. Of the patients who had a response, an estimated 60% of patients maintained a response at 12 months (measured from first response until new systemic therapy or death, based on the Kaplan Meier estimate). Results from the pivotal AGAVE-201 trial were recently published in the New England Journal of Medicine.

The abstract published today highlights new data from the secondary analysis of patients in the 0.3 mg/kg dose cohort which show that more than half of responders had an overall clinical response by day 56 of treatment and more than half of those with at least a seven-point improvement in their modified Lee Symptom Scale (mLSS) score had improvement by day 56 of treatment. In the 0.3 mg/kg dose cohort, the median time to organ-specific responses ranged from 1.2 to 3.7 months across organs. Lower gastrointestinal (GI), upper GI, esophagus, liver, and joints/fascia were typically the fastest organs to respond, whereas lung, mouth, eye, and skin responses were slower due to the highly fibrotic nature of these organ manifestations. Previously reported results from the AGAVE-201 trial showed that Niktimvo was generally well tolerated.

Details for the oral presentation are as follows:

Abstract Number: 98
Title: Dynamics of Overall and Organ-Specific Responses to Axatilimab in Chronic Graft-Versus-Host Disease: Analysis From the AGAVE-201 Study
Presenter: Hannah Choe, M.D.
Session Name: 722. Allogeneic Transplantation: Acute and Chronic GVHD and Immune Reconstitution: Predicting and Treating Acute and Chronic GVHD
Session Date: Saturday, December 7, 2024  
Session Time: 9:30 AM - 11:00 AM  
Presentation Time: 9:45 AM

Pooled Exposure-Response Analysis

The abstract published today describes the exposure-efficacy and exposure-safety relationships in patients with chronic GVHD treated with distinct doses of axatilimab in the pivotal Phase 2 AGAVE-201 trial and the prior Phase 1/2 trial. For the exposure-efficacy analysis (n=239), ORR and mLSS responses were associated with axatilimab exposure, with lower axatilimab exposure increasing the odds of response. For the exposure-safety analysis (n=278), all safety endpoints except infections of unspecified etiology were associated with axatilimab exposure, with higher axatilimab exposure increasing the odds of treatment-emergent adverse events. These results provide rationale for the 0.3 mg/kg every two weeks regimen, which is the FDA approved dose of axatilimab (Niktimvo).  

Details for the poster presentation are as follows:

Abstract Number: 2140
Title: Exposure-Response Relationships for Axatilimab, a Humanized Monoclonal Antibody Targeting CSF-1R, in Patients With Chronic Graft-Versus-Host Disease
Presenter: Yan-ou Yang, Ph.D.
Session Name:  722. Allogeneic Transplantation: Acute and Chronic GVHD and Immune Reconstitution: Poster I
Session Date:  Saturday, December 7, 2024
Presentation Time: 5:30 PM - 7:30 PM

Preclinical Mechanism of Action Data

Preclinical data detailing the anti-inflammatory and anti-fibrotic mechanism through which axatilimab is thought to impact the disease process in chronic GVHD will be presented.

Details for the poster presentation are as follows:

Abstract Number: 1147
Title: Axatilimab Abrogates Inflammatory Cytokines and Chemokines and Interrupts the Differentiation of Monocytes to Macrophages, a Pathogenic Driver of Inflammation and Fibrosis in cGVHD
Presenter: Anamika Bajpai, Ph.D.
Session Name: 201. Granulocytes, Monocytes, and Macrophages: Poster I
Session Date:  Saturday, December 7, 2024
Presentation Time: 5:30 PM - 7:30 PM

About AGAVE-201

The global AGAVE-201 dose-ranging trial evaluated the efficacy, safety, and tolerability of axatilimab in 241 adult and pediatric patients with recurrent or refractory active chronic GVHD whose disease had progressed after two or more prior therapies. Patients were randomized to one of three treatment groups that investigated a distinct dose of axatilimab administered at 0.3 mg/kg every two weeks, 1.0 mg/kg every two weeks or 3.0 mg/kg every four weeks. The trial's primary endpoint was the proportion of patients in each dose group who achieved an objective response as defined by 2014 NIH Consensus Criteria for chronic GVHD by cycle 7 day 1. Secondary endpoints included duration of response, percent reduction in daily steroid dose, organ specific response rates and validated quality-of-life assessments using the Modified Lee Symptom Scale.

For more information about AGAVE-201, visit https://www.clinicaltrials.gov/study/NCT04710576.

About Niktimvo™ (axatilimab-csfr)

Niktimvo (axatilimab-csfr) is a first-in-class anti-CSF-1R antibody approved for use in the U.S. for the treatment of chronic graft-versus-host disease (GVHD) after failure of at least two prior lines of systemic therapy in adult and pediatric patients weighing at least 40 kg (88.2 lbs).

In the U.S., Niktimvo will be co-commercialized by Syndax and Incyte. Incyte has exclusive commercialization rights for Niktimvo outside of the U.S.  

In 2016, Syndax licensed exclusive worldwide rights to develop and commercialize axatilimab from UCB. In September 2021, Syndax and Incyte entered into an exclusive worldwide co-development and co-commercialization license agreement for axatilimab in chronic GVHD and any future indications.

Axatilimab is being studied in frontline combination trials in chronic GVHD – a Phase 2 combination trial with ruxolitinib (NCT06388564) is underway and a Phase 3 combination trial with steroids is in preparation. Axatilimab is also being studied in an ongoing Phase 2 trial in patients with idiopathic pulmonary fibrosis (NCT06132256).

Niktimvo is a trademark of Incyte.
All other trademarks are the property of their respective owners.

IMPORTANT SAFETY INFORMATION

WARNINGS AND PRECAUTIONS
Infusion-Related Reactions
Niktimvo™ (axatilimab-csfr) can cause infusion-related reactions. Infusion-related reactions, including hypersensitivity reactions, occurred in 18% of patients who received Niktimvo in the clinical trial (AGAVE-201), with Grade 3 or 4 reactions in 1.3%.

Premedicate with an antihistamine and an antipyretic for patients who have previously experienced an infusion-related reaction to Niktimvo. Monitor patients for signs and symptoms of infusion-related reactions, including fever, chills, rash, flushing, dyspnea, and hypertension. Interrupt or slow the rate of infusion or permanently discontinue Niktimvo based on severity of the reaction.

Embryo-Fetal Toxicity
Based on its mechanism of action, Niktimvo may cause fetal harm when administered to a pregnant woman. Advise pregnant women of the potential risk to the fetus. Advise females of reproductive potential to use effective contraception during treatment with Niktimvo and for 30 days after the last dose.

ADVERSE REACTIONS
Serious adverse reactions occurred in 44% of patients who received Niktimvo (N=79). Serious adverse reactions in >2 patients included infection (pathogen unspecified) (14%), viral infection (14%) and respiratory failure (5.1%). Permanent discontinuation of Niktimvo due to an adverse reaction occurred in 10% of patients and dose reduction due to adverse reaction occurred in 8% of patients. Dose interruptions due to an adverse reaction occurred in 44% of patients. The adverse reactions leading to dose interruption in >2 patients were viral infection, infection (pathogen unspecified), bacterial infection, musculoskeletal pain, and pyrexia.

The most common (≥15%) adverse reactions, including laboratory abnormalities, were increased aspartate aminotransferase (AST), infection (pathogen unspecified), increased alanine aminotransferase (ALT), decreased phosphate, decreased hemoglobin, viral infection, increased gamma glutamyl transferase (GGT), musculoskeletal pain, increased lipase, fatigue, increased amylase, increased calcium, increased creatine phosphokinase (CPK), increased alkaline phosphatase (ALP), nausea, headache, diarrhea, cough, bacterial infection, pyrexia, and dyspnea.

Clinically relevant adverse reactions in <10% of patients who received Niktimvo included:

• Eye disorders: periorbital edema
• Skin and subcutaneous skin disorders: pruritus
• Vascular disorders: hypertension

Immunogenicity: Anti-Drug Antibody–Associated Adverse Reactions
Across treatment arms in patients with cGVHD who received Niktimvo in clinical trials, among the patients who developed anti-drug antibodies (ADAs), hypersensitivity reactions occurred in 26% (13/50) of patients with neutralizing antibodies (NAb) and in 4% (2/45) of those without NAb.

USE IN SPECIFIC POPULATIONS
Lactation
Because of the potential for serious adverse reactions in a breastfed child, advise women not to breastfeed during treatment and for 30 days after the last dose of Niktimvo.

Females and Males of Reproductive Potential
Pregnancy Testing
Verify pregnancy status in females of reproductive potential prior to initiating Niktimvo.

Contraception
Females
Advise females of reproductive potential to use effective contraception during treatment with Niktimvo and for 30 days after the last dose of Niktimvo.

DOSAGE AND ADMINISTRATION
Dosage Modifications for Adverse Reactions
Monitor aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine phosphokinase (CPK), amylase, and lipase prior to the start of Niktimvo therapy, every 2 weeks for the first month, and every 1 to 2 months thereafter until abnormalities are resolved. See Table 1 in the Prescribing Information for more recommendations.

Please see the full Prescribing Information for Niktimvo.

About Syndax
Syndax Pharmaceuticals is a commercial-stage biopharmaceutical company developing an innovative pipeline of cancer therapies. Highlights of the Company's pipeline include revumenib, a selective menin inhibitor, and Niktimvo™ (axatilimab-csfr), an FDA-approved monoclonal antibody that blocks the colony stimulating factor 1 (CSF-1) receptor. Fueled by our commitment to reimagining cancer care, Syndax is working to unlock the full potential of its pipeline and is conducting several clinical trials across the continuum of treatment. For more information, please visit www.syndax.com/ or follow the Company on X (formerly Twitter) and LinkedIn.

Syndax Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as "may," "will," "expect," "plan," "anticipate," "estimate," "intend," "believe" and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Syndax's expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements about the progress, timing, clinical development and scope of clinical trials, the reporting of clinical data for Syndax's product candidates, the acceptance of Syndax and its partners' products in the marketplace, sales, marketing, manufacturing and distribution requirements, and the potential use of our product candidates to treat various cancer indications and fibrotic diseases. Many factors may cause differences between current expectations and actual results, including: unexpected safety or efficacy data observed during preclinical or clinical trials; clinical trial site activation or enrollment rates that are lower than expected; changes in expected or existing competition; changes in the regulatory environment; failure of Syndax's collaborators to support or advance collaborations or product candidates; and unexpected litigation or other disputes. Other factors that may cause Syndax's actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Syndax's filings with the U.S. Securities and Exchange Commission, including the "Risk Factors" sections contained therein. Except as required by law, Syndax assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.

Syndax Contact:
Sharon Klahre
sklahre@syndax.com
Tel 781.684.9827

SNDX-G

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