lisaftoclax (APG-2575)

P3, N=344, Recruiting, Ascentage Pharma Group Inc. | Not yet recruiting --> Recruiting

P3, N=344, Not yet recruiting, Ascentage Pharma Group Inc.

P1, N=35, Recruiting, Ascentage Pharma Group Inc. | Trial completion date: Jan 2023 --> Jun 2026 | Trial primary completion date: Dec 2022 --> Mar 2025

P3, N=400, Recruiting, Ascentage Pharma Group Inc. | Not yet recruiting --> Recruiting

P2, N=75, Recruiting, Ascentage Pharma Group Inc. | Trial completion date: Jan 2024 --> Dec 2024 | Trial primary completion date: Oct 2023 --> Sep 2024

P1, N=74, Active, not recruiting, Ascentage Pharma Group Inc. | Trial completion date: Dec 2024 --> Dec 2025 | Trial primary completion date: Dec 2023 --> Dec 2024

P1/2, N=40, Not yet recruiting, Ascentage Pharma Group Inc.

Multiplex immunohistochemistry confirmed that patients with better immunotherapeutic efficacy had higher CD86, p-NF-κB p65 and NLRP3 levels, accompanied by lower CD206 expression on macrophages. Collectively, these data provide evidence that further study on APG-2575 in combination with immunotherapy for tumor treatment is required.

P1/2, N=65, Recruiting, Ascentage Pharma Group Inc. | Trial completion date: Oct 2023 --> Oct 2024 | Trial primary completion date: Jul 2023 --> Jul 2024

P2, N=36, Recruiting, Ascentage Pharma Group Inc. | Phase classification: P2a --> P2 | Trial completion date: May 2024 --> May 2025 | Trial primary completion date: May 2023 --> May 2024

P1, N=90, Recruiting, Ascentage Pharma Group Inc. | Trial completion date: Feb 2023 --> Feb 2025 | Trial primary completion date: Sep 2022 --> Sep 2024

P3, N=400, Not yet recruiting, Ascentage Pharma Group Inc.

P1, N=123, Recruiting, Ascentage Pharma Group Inc. | Trial completion date: Dec 2024 --> Dec 2025

P1/2, N=108, Recruiting, Ascentage Pharma Group Inc. | Trial primary completion date: Sep 2023 --> Sep 2024

P1/2, N=24, Recruiting, Ascentage Pharma Group Inc. | Trial completion date: Oct 2023 --> Oct 2024 | Trial primary completion date: Jul 2023 --> Jul 2024

Lisaftoclax was well tolerated, with no evidence of tumor lysis syndrome. Dose-limiting toxicity was not reached at the highest dose level. Lisaftoclax has a unique pharmacokinetic profile compatible with a potentially more convenient daily (vs. weekly) dose ramp-up schedule and induced rapid clinical responses in patients with CLL/SLL, warranting continued clinical investigation.

Among 52 patients with hematological malignancies the maximum tolerated dose (MTD) was not reached and no clinical TLS was observed.20 In this study of 22 evaluable patients with RR CLL there was an overall response rate (ORR) of 63.6% (14/22).20 A larger study of 114 patients with RR CLL evaluated lisaftoclax in combination with either the Bruton's tyrosine kinase inhibitor (BTKi) acalabrutinib or the anti CD20 monoclonal antibody rituximab (NCT04215809)...In CLL an overall response rate (ORR) to BGB-1147 of 100% as monotherapy was observed among 8 patients with RR disease.25 In 12 patients with RR MM, the ORR to BGB-1147 in combination with dexamethasone varied from 0–68% depending on the dose cohort.26 In combination with azacytidine in AML the ORR to BGB-11417 was 74% among those with treatment naïve (TN) disease (n=20/27) and 65% (n=13/20) in the cohort with RR disease.27 BGB-11417 monotherapy in 23 patients with RR NHL demonstrated responses in 2 patients with diffuse large B cell lymphoma (DLBCL) and one patient with marginal zone lymphoma (MZL).28 In 11 patients with RR MCL treated with BGB-11417 in combination with zanubrutinib there was a 55% (6/11) ORR.28 S55746 is a potent BAX/BAK dependent BCL2 inhibitor administered orally.18,29 Developed by Servier, it has been tested in phase I studies in CLL, NHL and AML. In a study of S55746 among 37 patients with RR NHL, no dose limiting toxicities (DLT) or TLS was observed after a medium duration of treatment of 42 days.30 FCN-338 is another orally available selective BCL2 inhibitor developed by Fochon currently undergoing phase I testing in RR CLL.18,31 Clinical outcomes with this drug are yet to be publicly reported...More recently navitoclax has been tested in RR myelofibrosis (MF) in combination with ruxolinitib with evidence of clinical response to the combination.35 AZD0466 by Astrazeneca is a nanomedicine potent dual BCL2/ BCLxL inhibitor that mediates BAX/BAK induced apoptosis36,37 and is administered intravenously...Among 9 patients reported undergoing testing for RR hematological malignancy the DLT had not yet been reached.38 Pelcitoclax or APG1252 by Ascentage is a more recent BAX/BAK dependent dual BCL2 and BCLxL inhibitor18,39,40 currently in phase I trials in RR NHL (NCT05186012)...There are multiple emerging BCL2 inhibitors currently undergoing clinical trial testing in hematological malignancies, and it remains too early to appreciate the differential efficacy and toxicity profiles that these agents may carry compared with venetoclax. It is hoped that the results seen with venetoclax can be improved upon across a raft of disease groups over the coming years.

Our results demonstrate that olverembatinib and BCL-2 inhibitor lisaftoclax have additive antitumor effects in imatinib-resistant GIST. This novel dual approach may have the potential for treating patients with GISTs whose disease has progressed after treatment with TKIs.

P1, N=22, Recruiting, Institute of Hematology & Blood Diseases Hospital | Not yet recruiting --> Recruiting

Seventeen (12%) pts had progressed on BTKi (n = 15) and/or after venetoclax (n = 3) therapy. Conclusions The RP2D of lisaftoclax was 600 mg daily. Initiated with a daily dose ramp-up, lisaftoclax alone or combined with acalabrutinib or rituximab had a manageable safety profile and was active in pts with treatment-naïve or R/R CLL/SLL.

Lisaftoclax in combination with alrizomadlin overcomes venetoclax resistance mediated by various mechanisms, including BCL-2 mutations. In addition, we posit further, putative molecular mechanisms. Our data rationalize clinical development of this treatment combination in patients with diseases that are insensitive or resistant to venetoclax.

These findings demonstrate that lisaftoclax is a novel, orally bioavailable BH3 mimetic BCL-2-selective inhibitor with considerable potential for the treatment of certain hematologic malignancies.

P1/2, N=65, Recruiting, Ascentage Pharma Group Inc. | Trial primary completion date: Jul 2022 --> Jul 2023

P1, N=22, Not yet recruiting, Institute of Hematology & Blood Diseases Hospital

Our results provide an effective AML treatment strategy through combination of APG-2575 and HHT, which is worthy of further clinical research.

Although indicated for the management of certain hematological malignances (HMs), BCL-2 inhibitor (BCL-2i) venetoclax requires a slow dose ramp-up to reduce the risk of tumor lysis syndrome (TLS) and is associated with severe neutropenia. Lisaftoclax may offer a more convenient treatment alternative, with a daily ramp-up schedule that may be more pt friendly. ClinicalTrials.gov: NCT03913949.

Investigational agent lisaftoclax (APG-2575) is a novel, potent, selective BCL-2 inhibitor, while palbociclib inhibits cyclin-dependent kinases (CDK) 4 and 6. The primary objective for phase II is to determine clinical benefit response, and secondary efficacy endpoints include overall response rate, duration of response, time to response, and progression-free survival. Lisaftoclax is being administered orally once daily in a 28-day cycle at the assigned dose.

As a result, APG-2575-mediated macrophages transition could improve tumor immunosuppression, thus skewing the cytokines profiles into immunostimulatory one in the TME and further enhancing antitumor T cell immunity. These results provided a novel promising strategy for NSCLC treatment and warranted future clinical evaluation of combination therapy of APG-2575 and ICIs.Key words: BCL-2, APG-2575, ICIs, macrophages, non-small cell lung cancer.

The BCL-2 inhibitor venetoclax has shown impressive efficacy in patients with chronic lymphocytic leukemia, but its clinical benefits are limited by acquired BCL-2 gene mutations that confer drug resistance. Further, lisaftoclax plus alrizomadlin more effectively blocked cell cycle entry into the G2/M phase, resulting in accumulation of sub-G1 apoptotic cells. In summary, our study demonstrates, for the first time, that co-targeting BCL-2 and MDM2-p53 apoptosis pathways overcame resistance to BCL-2 inhibitors conferred by acquired BCL-2 gene mutations, potentially offering a viable strategy to overcome drug resistance and thus providing a rationale for clinical investigation.

Studies of the BCL-2i venetoclax have demonstrated activity in certain HMs but show that venetoclax requires a slow dose ramp-up over several weeks to reduce the risk of tumor lysis syndrome (TLS), which may warrant frequent or intensive laboratory monitoring. The BCL-2i lisaftoclax offers a treatment alternative for pts with R/R HMs, with a daily ramp-up schedule that may be more pt friendly with a favorable preliminary safety profile. Internal study identifier APG-2575-CN-001; ClinicalTrials.gov identifier: NCT03913949.

We next treated NSG mice harboring PDX cells derived from an AML patient who relapsed on the VEN/decitabine therapy with APG2575 (50 mg/kg, p.o., daily), APG1387 (10 mg/kg, i.v., once/wk), APG115 (50 mg/kg, p.o., daily at wk 1 and 5), or combinations. Only in the triple combination group, cIAP1, cIAP2, and XIAP as well as MDM2 were largely diminished and p21 was marked decreased. In conclusion, our study demonstrates that co-targeting intrinsic and extrinsic apoptosis maximizes cell death induction in AML cells with acquired resistance to VEN or with TP53 deletion/mutations by antagonizing Bcl-2, eliminating cIAPs and XIAP, as well as MDM2 and p21, a finding that needs to be validated clinically.

FLT3 inhibition by HQP1351 downregulates MCL-1 and synergizes with BCL-2 inhibitor APG-2575 to potentiate cellular apoptosis in FLT3-ITD mutant AML. Our findings provide a scientific rationale for further clinical investigation of HQP1351 combined with APG-2575 in patients with FLT3-ITD mutant AML.

No abstract available

However, 10–50% of newly diagnosed patients with AML may not respond to venetoclax and HMA or LDAC, and 3–15% patients may not respond to venetoclax with intensive or non-intensive chemotherapy.1–6 In addition, up to 40% of responding patients may relapse with low rates of response of 20% to salvage therapy and poor overall survival of 2 months after relapse.7 Clinical and biological factors associated with primary and acquired resistance to venetoclax include secondary AML, monocytic differentiation, complex cytogenetics, mutations in TP53, BAX, dependence on other anti- apoptotic proteins, altered metabolism of nicotinamide, fatty acids, and oxidative phosphortylation.3,8–14 Several novel inhibitors of BCL-2 are currently being tested in clinic, including BGB 11417, APG-2575, LP-108 and others...There is strong pre-clinical rationale for targeting MCL-1 alone as well as in conjunction with BCL-2 inhibition in AML.15 Recently several selective and highly potent MCL-1 inhibitors have entered pre-clinical and clinical development including S63845, AZD5991, AMG397, and others. Questions remain regarding the therapeutic window of these inhibitors given the important physiologic role of MCL-1 in vital organs and early reports of cardiac adverse events from the AMG176 phase 1 trial.15,16 Multiple pre-clinical studies have expectedly shown synergism between BCL- 2 and MCL-1 inhibition making it a promising path for clinical development of these agents.17,18 Multifactorial challenges in design of specific MCL-1 inhibitors also led to interest in compounds which downregulate MCL-1 expression. Cyclin dependent kinase (CDK) inhibitors including alvocidib, dinaciclib, voruciclib are in various stages of evaluation. Although addition of alvocidib to intensive chemotherapy improved response rates but failed to improve event-free or overall survival.19 Novel CDK inhibitors are currently in early phase trials including AZD4573, CYC065, TG02-101, and others. Inhibition of Nedd8 activating enzyme has complex repercussions for the intrinsic apoptotic pathway with eventual increase in Noxa leading to MCL-1 neutralization.20 Pevonedistat has shown promising early results in AML and myelodysplastic syndrome and is being investigated multiple clinical trials for solid tumors as well. BCL-xL Inhibition Another anti-apoptotic protein BCL-xL had been long recognized as a potential therapeutic target in AML, in particular AML from preceding MPN and AML recurrent post venetoclax failure, but toxicity of earlier inhibitors precluded clinical development.21–23 Recently, AZD0466, a dual BCL-2/xL inhibitor with a favorable therapeutic index and robust activity has been developed and is undergoing pre-clinical development and planned for phase iin hematological malignancies.24 Targeting the Extrinsic Apoptosis Pathway Inhibitor of apoptosis protein (IAP) inhibition: X-linked IAP (XIAP), cellular IAP (cIAP) and survivin have been of long- standing interest in AML. Prior clinical trials with XIAP inhibitor AEG35156, cIAP targeting agent birinapant, and survivin targeting agent LY2181308 have not succeeded in clinc.16,25 ASTX660 is a dual antagonist of XIAP and cIAP which is currently being investigated in phase 1/2 trials in solid tumors and in combination with HMA in relapsed or refractory AML.26,27 TRAIL Agonism Agonists of the TNF-related apoptosis-inducing ligand (TRAIL) receptors have been tested in AML with low response rates.28,29 Previous agents have had limited success in part due to suboptimal clustering of TRAIL receptors.30 Novel antibodies against TRAILR1 and TRAILR2 including an IgM molecule IGM-8444, a tetravalent compound INBRX-109, and HLX56 are currently in phase 1 trials and preclinical data suggests potential synergy with venetoclax.31 FLIP Inhibition FLICE-like inhibitor protein (FLIP or CFLAR) is a key regulator of the death-inducing signaling complex (DISC) involved in the extrinsic apoptotic pathway...This can be augmented by inhibiting p53 degradation via MDM2, which is often upregulated in AML.34 Idasanutlin in combination with venetoclax showed anti- Figure 1 leukemic activity in the dose finding stage in R/R AML.35 Several other inhibitors of MDM2 and dual MDM2/X inhibitors are currently in various stages of pre-clinical and clinical development including HDM-201, KRT-232, BI-9078282, and others.34 Conclusions Opportunities to target the apoptosis machinery in AML has considerably evolved in the last decade. While venetoclax heralded a paradigm shift for patients, we are now faced with challenges in patients who relapse or remain refractory. We have novel clinical stage compounds to methodologically target different facets of the apoptotic pathway and optimize novel combinations with the goal to improve the cure rates in AML patients.

P1/2, N=65, Recruiting, Ascentage Pharma Group Inc. | Not yet recruiting --> Recruiting

P1/2, N=65, Not yet recruiting, Ascentage Pharma Group Inc.

We investigated mechanisms of action (MOAs) for synergistic effects of this combination.In MCF-7 cells sensitive to treatment with tamoxifen/fulvestrant, the CDK4/6i palbociclib inhibited expression of both ER and phospho-Rb (pRb) proteins, resulting in cell cycle arrest and senescence as demonstrated by cell cycle analysis and beta-galactosidase staining, respectively. Similar to palbociclib, APG-2575 also causes cell cycle arrest, and both agents collaboratively induce apoptosis in the combination setting. Our data reveal a viable MOA for synergistic effects, strengthening the scientific rationale for clinical development of the combination of the BCL-2 selective inhibitor APG-2575 and CDK4/6i palbociclib-based therapy in patients with ER+/HER2− breast cancer.

BCL-2 inhibition combined with a hypomethylating agent or low-dose cytosine arabinoside (Ara-C) is also effective in previously untreated elderly patients who are not candidates for standard induction therapy. HHT suppresses MCL-1 protein, preventing or abolishing formation of MCL-1:BIM, MCL-1:PUMA, and MCL-1:BAK complexes, and hence allowing prodeath proteins to fully engage in tumor cell apoptosis induction. Our results provide scientific rationale for clinical development of APG-2575 plus HHT in patients with AML/MDS.

Notably, HQP1351 substantially decreased cellular MCL-1 expression when combined with APG-2575, further enhancing apoptosis.Taken together, our data suggest that FLT3 inhibition by HQP1351 downregulates MCL-1 and synergizes with BCL-2 inhibitor APG-2575 to potentiate cellular apoptosis in FLT3-mutant AML. The results provide scientific rationale for clinical development of HQP1351 combined with APG-2575 in patients with FLT3-ITD-mutant AML.

Our data demonstrate that APG-2575 can synergizes with ICIs in vitro and in vivo, which was involved in switching TAMs from M2 to M1 polarization and further improving tumor immunosuppression, finally enhancing T cell anti-tumor activity. These results warranted future clinical evaluation of combination therapy of APG-2575 and ICIs.Key words: BCL-2, APG-2575, ICIs, macrophages, non-small cell lung cancer

Primary cells were treated with APG-2575 or ABT-199 (venetoclax) for 18-24 hours, and the loss of CD138 surface marker was used to quantify cell death. Conclusions In both cell lines and primary samples derived from MM patients, APG-2575 demonstrates cell death inducing activity as a single agent, and enhanced/synergistic effects when it combines with lenalidomide in RRMM resistant to lenalidomide and bortezomib. The combination decreases IKZF1, IKZF3 and MCL-1 proteins, and upregulates pro-death protein BAK, thus providing a strong rationale to combine BCL-2 inhibitor and lenalidomide to treat high-risk patient populations carrying 1q21 amplification.

In ER+ breast cancer, anti-estrogen therapies with tamoxifen, or CDK4/6 plus aromatase inhibitors remain the standard endocrine therapy, whereas the combination of CDK4/6-targeted therapy plus fulvestrant (an ER degrader) follows when the disease progresses on the hormonal therapy. The mechanisms underlying the synergistic effect of the combinations are currently under investigation and will be included in our presentation. Taken together, we demonstrated that combining APG-2575 with tamoxifen or palbociclib therapies substantially enhances antitumor activity and overcomes tamoxifen resistance in the preclinical models of ER+ breast cancer, suggesting a novel strategy for the clinical development of BCL-2 inhibitors in ER+ breast cancers.