Abbisko presents the research results of 5 programs at the 2023 AACR Annual Meeting

SHANGHAI, April 17, 2023 /PRNewswire/ -- Abbisko (Stock Code: 2256.HK) announced the results of five latest preclinical studies at the 2023 American Association for Cancer Research (AACR) annual meeting.

These include its self-developed CSF-1R inhibitor Pimicotinib (ABSK021), which has been recognized as a breakthrough therapy in China and the United States, and ABSK112, a next-generation of EGFR Exon20 inhibitor that may become the best-in-class to overcome resistance mutations, and a next-generation of the latest preclinical and translational research progress of the FGFR4 inhibitor ABSK012 and FGFR inhibitor ABSK121 that overcome drug-resistant mutations, and the next-generation KRAS inhibitor ABSK071.

Abbisko presented the following posters at the AACR Annual Meeting:

Title: A potent and selective small molecule inhibitor of CSF-1R ABSK021 demonstrates strong efficacy in preclinical models of osteosarcoma
Abstract Number: LB329
Research Background：
Osteosarcoma is the most common primary malignant bone tumor in children and young adults. Surgery combined with multimodal chemotherapy remains as the standard treatment for osteosarcoma patients. However, patients with osteosarcoma metastasis have a five-year survival rate of less than 30%, and their long-term outcomes have not improved over the last 30 years, representing a high unmet medical need. CSF-1/CSF-1R signaling is crucial for the survival, function, proliferation and differentiation of myeloid lineage cells, including osteoclasts and monocytes/macrophages. Targeting CSF-1R either on tumor cells or tumor-associated macrophages has been reported to limit osteosarcoma progression in preclinical models. ABSK021, an oral, highly potent and selective small molecule inhibitor of CSF-1R, showed significant anti-tumor activity and favorable safety profile in patients with advanced tenosynovial giant cell tumor in phase 1b trial. We demonstrated the treatment potential of ABSK021 for osteosarcoma patients through a series of preclinical in vitro and in vivo experiments, as well as human osteosarcoma profiling.
Result：
ABSK021 has strong inhibition of CSF-1R activity and corresponding anti-tumor activity in preclinical osteosarcoma models. High prevalence of CSF-1R expression was also found in osteosarcoma patients, suggesting great potential of utilizing ABSK021 as a novel therapy to treat osteosarcoma patients in clinic.

Title: ABSK112, a potential best-in-class EGFR exon 20 mutant Inhibitor with excellent selectivity and brain penetration
Abstract Number: LB327
Research Background：
EGFR Exon20 mutations are clinically validated oncogenic alterations including a wide spectrum of mutations occurring in lung cancer and various other cancer types. Although several EGFR Exon20 inhibitors have reached clinical stage or received approval, there still leave large room for improvement in safety and efficacy, likely due to their limited selectivity against wild-type EGFR or other kinases, suboptimal mutation coverage, and lack brain penetrating ability. Herein, we have discovered a novel and next-generation EGFR Exon20 mutation inhibitor, ABSK112. It showed high selectivity over wild-type EGFR and other kinases, as well as a more comprehensive coverage over majority of EGFR Exon20 mutations in comparison with other EGFR Exon20 inhibitors.
Result：
ABSK112 is a leading next-generation EGFR Exon20ins inhibitor with improved selectivity over wild-type EGFR and strong brain penetrating ability. It shows superior in vivo efficacy in various EGFR Exon20ins xenograft models, and broader spectrum of mutation coverage than clinical stage competitors.

Title: Discovery & characterization of a next-generation FGFR4 inhibitor overcoming resistant mutations
Abstract Number: LB328
Research Background：
Aberrant activation of FGF19-FGFR4 signaling pathway plays an essential role in the tumorigenesis of Hepatocellular carcinoma (HCC) and FGFR4 inhibitors have shown preliminary efficacy in recent clinical trials for patients with FGF19 overexpression. However, the observed responses only lasted a few months before tumors relapse. Acquired FGFR4 resistant mutations were found in ~30% of FGFR4 inhibitor responsive patients. Similar FGFR4 mutations haven also been found de novo in about 7-10% of Rhabdomyosarcoma (RMS) and ER-treated invasive lobular carcinoma patients. First generation FGFR4 inhibitors have minimal activity against these de novo or acquired resistant mutations. Therefore, next-generation of FGFR4 inhibitors are needed to overcome these resistant FGFR4 mutations to provide better treatment options for patients. Using advanced computation-aided structural analysis and medicinal chemistry design, we have discovered a next-generation small molecule FGFR4 inhibitor, ABSK012, and demonstrated its strong activities against de novo and acquired resistant FGFR4 mutations while retaining inhibition for wild-type FGFR4. 
Result：
ABSK012, presented here by Abbisko Therapeutics, is a highly potent, selective, and next-generation small molecule FGFR4 inhibitor overcoming FGFR4 mutations resistant to first-generation inhibitors. Its superior preclinical profile supports its fast-track development into clinic.

Title: Discovery and characterization of a next-generation FGFR inhibitor overcoming FGFR resistant mutations
Abstract Number: LB317
Research Background：
FGFRs play important roles in cancer development and inhibition of FGFR could disrupt tumor cell proliferation and growth. Four selective FGFR inhibitors have been approved (erdafitinib, pemigatinib, infigratinib, and futibatinib) and several others are in clinical development. Unfortunately upon treatment with these first-generation FGFR inhibitors, acquired resistance often develops and is frequently associated with the emergence of secondary FGFR2/3 kinase domain mutations. Therefore, selectively targeting FGFR2/3 as well as their resistant mutations may render a second-generation treatment approach for the refractory/relapsed patients. Using advanced computation-aided structural analysis and medicinal chemistry design, we have discovered a novel, next-generation, and highly selective FGFR inhibitor, ABSK121. This novel inhibitor demonstrated robust anti-tumor activity in FGFR-dependent tumor models with strong activities against not only de novo but also acquired resistant mutations.
Result：
ABSK121, presented here by Abbisko Therapeutics, is a highly potent, selective, and next-generation small molecule FGFR inhibitor with great potency against resistant FGFR mutations. Its superior profile supports fast-track preclinical and clinical development.

Title: A next-generation KRASG12C inhibitor ABSK071 demonstrated broad synergy with other therapeutic agents in KRASG12C mutated cancer models 
Abstract Number: LB316
Research Background：
KRAS is frequently mutated in human cancers, including pancreatic (~90%), colorectal (~35%), and lung cancer (~25%). The KRASG12C mutation (single amino acid substitution of cysteine for glycine at position 12) accounts for ~14% of lung cancer, ~4% of colorectal cancer, and ~2% of pancreatic cancer. Currently, two covalent KRASG12C inhibitors, namely sotorasib (AMG-510) and adagrasib (MRTX-849), have been approved as monotherapy to treat locally advanced or metastatic NSCLC with KRASG12C mutation through accelerated approval process.
Despite the beneficial effects of KRASG12C inhibitors in clinic for certain patients, the limited antitumor efficacy in most patients and potential drug resistance are major concerns. A next-generation inhibitor with better inhibitory activity may improve anti-tumor efficacy. Combination with other therapeutic agents may also improve the single-agent activity of KRASG12C inhibitors. These approaches could both overcome the limitations of sotorasib and adagrasib and provide additional benefits to patients.
Result：
ABSK071 is a next-generation KRASG12C inhibitor with greater activity and anti-tumor efficacy in vitro and in vivo. It also demonstrated broad synergistic effects with a large set of targeted agents and immuno-oncology agents, indicating its strong potential in combinatory therapy in treating a wider range of KRASG12C-dependent cancers.