zipalertinib (CLN-081)

Biochemical, structural, and cellular studies of a diverse panel of EGFR inhibitors revealed that the more recently developed compounds BAY-568, TAS6417, and TAK-788 inhibit EGFR insASV and insSVD in a mutant-selective manner, with BAY-568 being the most potent and selective versus wild-type (WT) EGFR. Cocrystal structures with WT EGFR reveal the binding modes of each of these inhibitors and of poziotinib, a potent but not mutantselective inhibitor, and together they define interactions shared by the mutant-selective agents. Collectively, our results show that these exon20 insertion variants are not inherently inhibitor resistant, rather they differ in their drug sensitivity from WT EGFR. However, they are similar to each other, indicating that a single inhibitor should be effective for several of the diverse exon 20 insertion variants.

In conclusion, MD simulations can effectively predict patient outcomes by connecting computational results with clinical data and advancing our understanding of EGFR mutations and their therapeutic responses.

P1/2, N=284, Active, not recruiting, Cullinan Therapeutics Inc. | Recruiting --> Active, not recruiting

We also studied preclinical Ba/F3 models expressing EGFR -K745_E746insIPVAIK (Ba/F3-IPVAIK) and EGFR -delE746_A750 (Ba/F3-Del19) to investigate the sensitivity to 1st-generation (gen) (gefitinib and erlotinib), 2nd-gen (afatinib, dacomitinib, and poziotinib), 3rd-gen (osimertinib), and EGFR exon 20 insertion active TKIs (mobocertinib, sunvozertinib, and zipalertinib). The preclinical therapeutic window of Ba/F3-IPVAIK and Ba/F3-Del19 for all the 2nd generation TKIs were similarly favorable, whereas Ba/F3-IPVAIK had much unfavorable therapeutic windows to other EGFR-TKIs compared to Ba/F3-Del19. Conclusions : Our clinical and preclinical findings indicate 2nd-gen EGFR-TKIs are more effective than 1st and 3rd-gen EGFR-TKIs in patients with EGFR exon 19 insertions.

This review explores key therapeutic agents, such as Amivantamab, Mobocertinib, Poziotinib, Zipalertinib, and Sunvozertinib, which have shown promise in treating NSCLC with EGFR exon 20 insertions. Despite these advances, challenges in overcoming resistance mutations and improving central nervous system penetration remain. Future research should focus on optimizing first-line combination therapies and enhancing diagnostic strategies for comprehensive mutation profiling.

A strategically designed HTS campaign, multiple iterations of structure-based drug design (SBDD), and tactical linker replacement led to a potent and wild-type selective series of molecules and ultimately the discovery of 36. Compound 36 is a potent and selective inhibitor of EGFR Exon20 insertions and has demonstrated encouraging efficacy in NSCLC EGFR CRISPR-engineered H2073 xenografts that carry an SVD Exon20 insertion and reduced efficacy in a H2073 wild-type EGFR xenograft model compared to CLN-081 (5), indicating that 36 may have lower EGFR wild-type associated toxicity.

P3, N=272, Recruiting, Taiho Oncology, Inc. | Trial completion date: May 2026 --> Aug 2026 | Trial primary completion date: Jan 2026 --> Jul 2026

EGFR-C797S in cis to all EGFR mutations evaluated generated dependent cells that were resistant to the covalent EGFR tyrosine kinase inhibitors mobocertinib, zipalertinib, furmonertinib, sunvozertinib, poziotinib, and osimertinib. This report highlights that poziotinib and mobocertinib are susceptible to on-target resistance mediated by EGFR-T790M or -C797S in the background of the most prevalent EGFR exon 20 insertion mutations. Furmonertinib, sunvozertinib, and to a less extent zipalertinib can overcome EGFR-T790M compound mutants, whereas EGFR-C797S leads to covalent inhibitor cross-resistance-robust data that support the limitations of mobocertinib and should further spawn the development of next-generation covalent and reversible EGFR exon 20 insertion mutation active inhibitors with favorable therapeutic windows that are less vulnerable to on-target resistance.

Furthermore, we hypothesized that the expression patterns of feature genes in the LUAD model were related to the sensitivity to lung cancer therapeutic drugs TAS-6417 and Erlotinib. To sum up, our LUAD prognostic model possessed clinical applicability for prognosis and immunotherapy response prediction.

P2, N=160, Recruiting, Taiho Oncology, Inc. | Phase classification: P2b --> P2

No abstract available

Zipalertinib has encouraging preliminary antitumor activity in heavily pretreated patients with EGFR ex20ins-mutant NSCLC, with an acceptable safety profile, including low frequency of high-grade diarrhea and rash.

T790M or C797S, depending on the original X20ins mutations, conferred acquired resistance to mobocertinib. Sunvozertinib may be the treatment of choice for patients with tumors resistant to mobocertinib because of T790M.

P3, N=312, Recruiting, Taiho Oncology, Inc. | Trial completion date: Apr 2027 --> May 2026 | Trial primary completion date: Dec 2026 --> Jan 2026

The majority of EGFR exon 20 insertions occur within the loop following the regulatory C-helix and activate the kinase domain of EGFR without generating a therapeutic window to gefitinib, erlotinib, afatinib, dacomitinib or osimertinib...The clinical development of kinase inhibitors for ERBB2-mutated NSCLC has been thwarted by mucocutaneous/gastrointestinal toxicities that preclude a pathway for drug approval, as the case of poziotinib...Other therapies in clinical development include sunvozertinib and zipalertinib, among others. In addition, traditional cytotoxic chemotherapy has some activity in these tumors. The approvals of mobocertinib, amivantamab, and trastuzumab deruxtecan represent the first examples of precision oncology for EGFR exon 20 insertion-mutated and ERBB2-mutated NSCLCs.

P3, N=312, Recruiting, Taiho Oncology, Inc.

P2b, N=160, Recruiting, Taiho Oncology, Inc.

Results In vitro testing with different EGFRex20ins indicated a favorable IC50 for afatinib, CLN-081, and poziotinib in near-loop (A767-P772) versus far-loop (H773-R776) insertions, whereas mobocertinib had similar IC50 values in near- and far-loop insertions. Conclusions Preclinical and clinical data indicated that near- vs far-loop EGFRex20 insertions differentially impact sensitivity to individual TKIs. Thus, knowledge of insertion location may allow for more effectively tailored TKI therapy.

However, a novel EGFR-TKI, mobocertinib, was approved by the US FDA for NSCLC patients with EGFR exon20 insertion. We examined efficacy of mobocertinib and other EGFR-TKIs (erlotinib, afatinib, poziotinib, CLN-081, sunvozertinib , osimertinib, and brigatinib) using murine pro-B-cell line (Ba/F3) models harboring one of five most common EGFR exon 20 insertions (A763_Y764insFQEA, V769_D770insASV, D770_N771insSVD, H773_V774insNPH and H773_V774insH). These findings indicate that T790M or C797S, depending on the original activating mutations, will cause acquired resistance to mobocertinib in NSCLCs with EGFR exon 20 mutations. Further analyses suggest that sunvozertinib will be effective against acquired resistant cells with T790M mutation. However, except for A763_Y764insFQEA plus C797S mutation that is sensitive to erlotinib, other treatment strategy, such as cytotoxic chemotherapy, should be considered for patients who develop C797S secondary mutation.

Pimitespib, a selective heat shock protein 90 inhibitor, induced apoptosis in Ba/F3-C797S cells in vitro and inhibited growth of Ba/F3-C797S tumors in vivo. Ba/F3 cells with A763_Y764insFQEA-C797S remained sensitive to erlotinib. We conclude that the EGFR C797S mutation confers resistance to CLN-081. Our preclinical data suggest a potential small molecule to overcome CLN-081 resistance, which may benefit patients with lung cancer with EGFR exon 20 insertions.

P1/2, N=284, Recruiting, Cullinan Oncology, LLC | Trial completion date: Dec 2023 --> Dec 2024 | Trial primary completion date: Dec 2023 --> Dec 2024

We also examined growth inhibitory effect of poziotinib, afatinib, CLN-081, erlotinib, osimertinib, brigatinib and BI4020 using the same Ba/F3 models. These findings indicate that T790M or C797S, depending on the activating mutations, will cause acquired resistance to mobocertinib in NSCLCs with EGFR exon 20 mutations. We also found a novel secondary mutation (F856V) that may confer acquired resistance to mobocertinib.

P1/2, N=284, Recruiting, Cullinan Oncology, LLC | N=80 --> 284 | Trial completion date: Mar 2022 --> Dec 2023 | Trial primary completion date: Mar 2022 --> Dec 2023

Ba/F3 cells harboring EGFR exon 20 insertion and C797S mutations were resistant to mobocertinib, poziotinib, and TAS-6417. Conclusions EGFR C797S mutation and EGFR amplification were identified as resistance mechanisms to mobocertinib in EGFR exon 20 insertion-mutant NSCLC models. Combined treatment of brigatinib plus cetuximab or amivantamab may be an effective therapeutic strategy for EGFR exon 20 insertion/C797S-mutant NSCLC in preclinical models.

STX-721 demonstrates EGFR exon 20 mutant selectivity approaching the selectivity of Osimertinib in EGFR T790M mutants, warranting further exploration of this potential best-in-class exon 20 inhibitor in the clinic. Ba/F3: proliferation selectivity vs. EGFR WT Human cells: proliferation selectivity (vs.

Interventional studies reported outcomes for TKIs (mobocertinib, poziotinib, osimertinib, afatinib, CLN-081, DZD9008), a monoclonal antibody (amivantamab), and a heat shock protein 90 inhibitor (luminespib). Conventional treatments used in patients with EGFR exon 20 insertion mutation-positive NSCLC have limited efficacy, though chemotherapy appeared to be associated with better response and survival outcomes than non-exon 20 targeting EGFR-TKIs and IO agents. This supports the need to identify EGFR exon 20 insertion mutations as the availability of new targeted treatments may offer additional therapeutic options to these patients.

In pts with heavily-pretreated advanced EGFR ins20 NSCLC, CLN-081 has a manageable safety profile, with anti-tumor activity across the range of doses tested. Further, CLN-081 has demonstrated a favorable clinical profile at the dose of 100 mg BID, with an encouraging objective response rate, response durability, and no Gr 3 rash or diarrhea.

Interestingly, drug sensitivity analysis revealed that the low-risk group was more sensitive to Bendamustine and TAS-6417 than the high-risk group. This study firstly confirms that DR-lncRNAs play a vital role in the prognosis and immune cells infiltration in patients with PTC, as well as a predictor of the drugs' chemosensitivity. Based on our results, DR-lncRNAs can serve as a promising prognostic biomarkers and treatment targets.

NSCLC with EGFR exon 20 insertions is resistance to conventional epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as osimertinib. Our preclinical study identified several mechanisms of resistance to CLN-081 including acquired mutations and inflammatory responses. These results will provide new insights into development of a novel strategy to overcome or prevent resistance to CLN-081.

While several small molecules have been approved (mobocertinib) or are in clinical development (e.g. CLN-081, BDTX-189) none have demonstrated meaningful CNS activity and they can be associated with treatment-limiting adverse events, including wild-type (WT) EGFR-mediated toxicities. LNG-451 potently suppressed EGFR phosphorylation in tumor tissue (e.g. 99%, 3 h post 50 mg/kg dose) but had minimal-to modest suppression of phospho-EGFR in large intestine tissue (e.g. 4.2%, 3h post 50 mg/kg dose) and skin tissue (e.g 1.9%, 3h post 50 mg/kg dose). Taken together, LNG-451 is a wild-type EGFR-sparing, CNS-penetrant EGFR Ex20ins inhibitor that is expected to provide strong anti‑tumor efficacy for patients with advanced/metastatic solid cancers harboring oncogenic EGFR exon 20 insertions with reduced WT EGFR-driven toxicities.

While several small molecules have been approved (mobocertinib) or are in clinical development (e.g. CLN-081, BDTX-189) none have demonstrated meaningful CNS activity and they can be associated with treatment-limiting adverse events, including wild-type (WT) EGFR-mediated toxicities. An ex vivo imaging analysis of the brain and spinal cords from all animals at the end of the study showed a dose-dependent decrease in the bioluminescent signal in both brain and spinal cords from mice treated with LNG-451 relative to the vehicle control animals. Taken together, LNG-451 is a CNS-penetrant, wild-type EGFR-sparing, EGFR Ex20ins inhibitor that is expected to provide strong anti‑tumor efficacy for patients with advanced/metastatic solid cancers harboring oncogenic EGFR exon 20 insertions with reduced WT EGFR driven toxicities.

P1/2, N=80, Recruiting, Cullinan Pearl | Trial primary completion date: Sep 2021 --> Mar 2022

Two pts (5%) discontinued tx due to TRAEs of gr 2 hypersensitivity reaction (1) and gr 2 pneumonitis (1); the latter also experienced pneumonitis while receiving prior osimertinib . CLN-081 has an acceptable safety profile, including diarrhea in < 25% of pts treated to date . CLN-081 has demonstrated encouraging preliminary anti-tumor activity across the full dose range tested, in multiple distinct EGFR ins20 variants, and in heavily pre-treated pts that are either naïve or refractory to other EGFR ins20 inhibitors . Since the time of the data cut, a Ph 2a expansion has been initiated at 100 mg BID.

EGFR mutations, such as T790M and C797S, are the most common mechanism of EGFR-TKI resistance. Here, we discuss the mechanisms of EGFR-TKIs resistance induced by secondary EGFR mutations, highlight the development of targeted drugs to overcome EGFR mutation-mediated resistance, and predict the promising directions for development of novel candidates.

Our results suggest that organoid culture is feasible from small biopsy specimens and these organoids could be applied for personalized medicine.

The potential of natural compounds was compared to the positive controls such as erlotinib, TAS6417 and poziotinib. Moreover, the binding free energy of the natural drugs against EGFRs was also comparable to the positive controls. This computational study suggests that Wi-A and Wi-N have potential against multiple mutated EGFRs, warranting further in vitro and in vivo experiments.

Lung cancer and genetically engineered cell lines, as well as murine xenograft models were used to evaluate the efficacy of TAS6417 and other approved/in-development EGFR TKIs (erlotinib, afatinib, osimertinib, and poziotinib). Taken together, we demonstrate that TAS6417 is a potent EGFR TKI with a broad spectrum of activity and a wider therapeutic window than most approved/in-development generations of EGFR inhibitors. Implications: TAS6417/CLN-081 is a potent EGFR TKI with a wide therapeutic window and may be effective in lung cancer patients with clinically relevant EGFR mutations.

Both pts with PR (1 confirmed, 1 pending confirmation) previously received poziotinib and TAK-788. Funding: Cullinan Pearl, Inc. Clinical trial identification: NCT04036682.