Syndax to Highlight Late-Stage Programs and Unveil New Pipeline Assets at R&D Event

Syndax Unveils New Pipeline Assets and R&D Strategy

Syndax Pharmaceuticals announced its R&D strategy, unveiling two new pipeline assets: SNDX-4321, a mutant-selective allosteric EGFR inhibitor for NSCLC, and SNDX-62122, a next-generation menin inhibitor for myelofibrosis (MF). The company plans to submit IND applications for both by late 2026 or 2027 and initiate Phase 1 trials in 2027. Additionally, Syndax provided updates on its late-stage programs, including expected topline Phase 2 data for axatilimab in IPF in Q4 2026 and the initiation of a Phase 1/2 trial for revumenib in MF in Q4 2026, with initial clinical data anticipated in H2 2027.

• SNDX-4321: A Novel Allosteric EGFR Inhibitor: Syndax is developing SNDX-4321, a mutant-selective, allosteric EGFR inhibitor, for NSCLC patients with significant unmet needs, including those with L858R mutations, CNS metastases, atypical activating mutations, or acquired resistance. Unlike ATP-site directed inhibitors, SNDX-4321 binds to an adjacent pocket accessible only with specific EGFR mutations. An IND submission is expected by late 2026, with a Phase 1 trial initiating in 2027.
• SNDX-62122: Next-Generation Menin Inhibitor for MF: SNDX-62122 is the first candidate from Syndax's internally developed library of next-generation menin inhibitors, selected for development in myelofibrosis (MF). Its development is informed by compelling preclinical data for revumenib, which identified menin as a novel dependency in proliferative megakaryocytes, key drivers of MF. Syndax anticipates submitting an IND and initiating a Phase 1 trial for SNDX-62122 in MF in 2027.
• Late-Stage Program Updates: Syndax provided updates on its existing late-stage assets. The Phase 2 trial of axatilimab in idiopathic pulmonary fibrosis (IPF) is on track to deliver topline data in the fourth quarter of 2026. Furthermore, a Phase 1/2 proof-of-principal trial of revumenib in myelofibrosis is expected to commence in the fourth quarter of 2026, with initial clinical data anticipated in the second half of 2027, aiming to de-risk SNDX-62122's development.

Addressing Persistent Unmet Needs in EGFRm NSCLC

Despite significant therapeutic advances in NSCLC, substantial unmet needs persist across multiple patient populations — from those with acquired resistance to targeted therapies to underserved molecular subtypes and undertreated older adults. The field continues to grapple with the heterogeneity of resistance mechanisms, gaps in precision diagnostics, and systemic disparities in treatment access.

• Resistance to EGFR-targeted and other therapies: Resistance to third-generation EGFR TKIs, particularly osimertinib, remains a defining clinical challenge. Mechanisms include on-target mutations (e.g., C797S), MET amplification, histologic transformation, and tumor microenvironment (TME) alterations — compounded by tumor heterogeneity and tolerability issues. No clear standard of care based on personalized, actionable resistance mutations has yet been established, and treatment options following progression on first-line osimertinib remain limited.

• Rare and molecularly defined subtypes: MET fusions occur in approximately 0.5% of NSCLC patients, and the therapeutic landscape for MET-rearranged NSCLC remains significantly underexplored. Lung squamous cell carcinoma (LUSC) harboring ROS1, ALK, or EGFR alterations is exceptionally rare, and current targeted therapy protocols are largely extrapolated from lung adenocarcinoma data — highlighting the need for subtype-specific clinical evidence.

• STK11-mutant NSCLC: STK11-mutant tumors, particularly with KRAS or TP53 co-mutations (present in ~50% of STK11-mutant cases), demonstrate aggressive behavior, higher metastatic rates, increased necrosis, and poor response to PD-1/PD-L1 inhibitors. Patients treated with pembrolizumab in this context had a median overall survival of only 4.1 ± 2.8 months, underscoring the need for novel therapeutic strategies in this immunotherapy-resistant subgroup.

• Older adult and octogenarian populations: Among 254,611 patients with metastatic NSCLC aged ≥65 years, only 46.8% ever received systemic therapy — a proportion that improved only minimally between 2006 and 2021. Patients ≥80 years showed a 15.4% lower cumulative incidence of treatment at 180 days compared to those aged 65–69, despite a documented improvement in four-year overall survival from 6.3% (2010) to 13.1% (2020). Structural barriers including lack of oncology referral, absence of biomarker testing, comorbidity burden, and sociodemographic factors drive persistent treatment disparities.

• Trial-ineligible patients with low PD-L1 expression (1–49%): A multicenter study (2018–2023) of 395 trial-ineligible patients identified performance status (PS) ≥2 and squamous cell carcinoma histology as factors associated with worse survival prognosis. Median overall survival was 18.2 months with ICI-chemotherapy versus 14.9 months with chemotherapy alone (HR 0.75; 95% CI: 0.59–0.95), though clinical benefit of ICI-chemotherapy in this population appears limited in those with PS ≥2 or squamous histology.

• Patients not achieving pathological complete response (pCR): Stage IB–IIIB (N2) NSCLC patients who undergo neoadjuvant chemo-immunotherapy but fail to achieve pCR following surgical resection represent a distinct unmet population with unfavorable outcomes and no established post-surgical therapeutic standard.

• Brain metastases: Intracranial disease progression requiring stereotactic radiosurgery (SRS) or craniotomy remains a significant clinical challenge. Evidence gaps persist regarding the CNS activity of agents such as crizotinib in ALK-positive NSCLC with brain metastases, and the safety and efficacy of bevacizumab in patients with active brain metastases remains undefined.

• Need for precision diagnostics and re-biopsy strategies: Serial next-generation sequencing (NGS) has demonstrated critical value in guiding therapeutic management, particularly in identifying rare histologic transformations. The importance of re-biopsy during disease course — especially in patients with poor treatment response — is increasingly recognized as essential to enabling precision medicine approaches in NSCLC.

Syndax's Strategic Play: Novel Targets and Pipeline Expansion

Syndax Pharmaceuticals is charting a course that balances innovative early-stage research with the strategic expansion of its late-stage portfolio. This dual approach is critical in today's dynamic pharmaceutical environment, where both novel mechanisms and broader applications of existing therapies are key to growth.

The introduction of SNDX-4321, a mutant-selective allosteric EGFR inhibitor, signals an intent to tackle persistent challenges in non-small cell lung cancer (NSCLC). Despite the success of EGFR inhibitors, drug resistance, particularly from mutations like T790M, remains a significant hurdle. A highly selective agent could offer a crucial advantage, potentially improving outcomes and tolerability, especially for patients with poor performance status who often face higher toxicity and less durable responses with current treatments. However, the NSCLC market is fiercely competitive, demanding clear differentiation for any new entrant.

Perhaps the most intriguing development is SNDX-62122, a next-generation menin inhibitor for myelofibrosis (MF). Menin inhibitors have recently emerged as a transformative class of targeted therapies for specific acute leukemias, disrupting oncogenic transcriptional programs. Extending this mechanism to MF represents a bold scientific leap, potentially opening a novel therapeutic avenue in a disease with limited targeted options. This move leverages Syndax's expertise in menin inhibition, but the translation of this mechanism to a distinct hematologic malignancy will require rigorous validation of both efficacy and safety, particularly concerning known risks like differentiation syndrome and QT prolongation.

Updates on axatilimab in IPF and revumenib in MF highlight a strategy to maximize the value of assets with established or emerging clinical profiles. Axatilimab, already showing promise in steroid-refractory chronic graft-versus-host disease, could address another fibrotic disease with high unmet need in IPF. Similarly, revumenib, recently approved for acute leukemias, is being explored in MF, leveraging its validated mechanism. This approach can accelerate market access by building on existing clinical data, but each new indication requires careful evaluation of the benefit-risk profile in the specific patient population. The long lead times for these early-stage assets, with INDs planned for late 2026 or 2027, underscore the significant investment and inherent risks in bringing truly novel therapies to market.