No abstract available

P1/2, N=127, Recruiting, BeiGene | Phase classification: P1 --> P1/2

P1/2, N=466, Recruiting, BeiGene | N=291 --> 466

Treatment of chronic lymphocytic leukemia with NX-2127 achieves >80% degradation of BTK in patients and demonstrates proof-of-concept therapeutic benefit. These data reveal an oncogenic scaffold function of mutant BTK that confers resistance across clinically approved BTK inhibitors but is overcome by BTK degradation in patients.

NX-2127 is orally bioavailable, exhibits in vivo degradation across species, and demonstrates efficacy in preclinical oncology models. NX-2127 has advanced into first-in-human clinical trials and achieves deep and sustained degradation of BTK following daily oral dosing at 100 mg.

P1, N=128, Recruiting, AbbVie | N=188 --> 128

P1, N=226, Recruiting, Nurix Therapeutics, Inc. | N=130 --> 226

P1, N=160, Active, not recruiting, Nurix Therapeutics, Inc. | Recruiting --> Active, not recruiting

This first-in-human study of NX-2127 is actively enrolling and dose-expansion cohorts in DLBCL and MCL have been initiated at the 300 mg daily dose. Findings include dose-dependent PK accompanied by degradation of BTK and Ikaros. Encouraging and persistent responses were observed in heavily pretreated patients with relapsed/refractory CLL and NHL with a manageable safety profile.

Preliminary data from this ongoing, first-in-human study of the novel BTK degrader BGB-16673 demonstrate a tolerable safety profile and clinical responses in heavily pretreated pts with B-cell malignancies, including those with BTKi-resistant disease. Substantial reductions in BTK protein levels in peripheral blood and tumor tissue were also observed, demonstrating proof-of-concept of a strong, on-target effect.

Current findings in this heavily pre-treated population of patients with CLL and NHL are encouraging and indicate that NX-5948 is safe and well tolerated and has clinical activity, supporting continuation of its development in CLL and NHL. NX-5948 also exhibits dose-proportional PK, resulting in rapid, robust and sustained BTK degradation. Additional data with higher dose levels and longer treatment duration will be presented at the meeting.

ABBV-101 is currently in phase 1 clinical trial for a variety of B-cell malignancies. ClinicalTrials.gov identifier: NCT05753501

P1, N=130, Recruiting, Nurix Therapeutics, Inc. | Trial completion date: May 2024 --> Jan 2027 | Trial primary completion date: Jan 2024 --> Dec 2025

P1/2, N=291, Recruiting, BeiGene | Phase classification: P1 --> P1/2

P1, N=160, Recruiting, Nurix Therapeutics, Inc. | Trial completion date: Nov 2023 --> Dec 2025 | Trial primary completion date: Oct 2023 --> Dec 2024

In addition to direct anti-neoplastic effects, BTK inhibitors ibrutinib and acalabrutinib were found to favorably modulate T-cell function in pre-clinical and clinical studies of CLL...In vitro polarization assays indicated that treatment with 1 μM NX-2127, but not NX-5948, resulted in a dramatic and significant upregulation of both IFN-γ and IL-2 under TH1-polarizing conditions, to a degree which significantly exceeded the effect of either ibrutinib or lenalidomide... CRBN-recruiting BTK degraders NX-2127 andNX-5948 induce degradation of BTK in primary CLL cells and do not interfere with T-cell activation and survival in vitro. More importantly, CRBN-immunomodulatory activity was required to upregulate CD38 (an IFN response gene), promote T-cell differentiation towards a TH1 phenotype, downregulate Treg differentiation, and facilitate immunological synapse formation, suggesting NX-2127 has the potential to reverse the immunosuppressive environment of CLL. Overall, our findings provide a strong rationale for continued investigation of these BTK degraders in CLL and lymphoid malignancies.

The C481S and C481R mutations eliminated the anti-proliferative effects of covalent inhibitors ibrutinib, acalabrutinib, and zanubrutinib, whereas the V416L, T474I, and L528W mutations had variable effects on the covalent inhibitors. By contrast, the non-covalent inhibitors pirtobrutinib, vecabrutinib, and fenebruitnib maintained activity against C481S but displayed partially reduced potency against the C481R mutation and dramatically reduced potency against the V416L, T474I, and L528W mutations...These degrader molecules may also have utility in earlier lines of therapy due to their ability to suppress scaffold-mediated BTK signaling. Phase 1a/b trials of NX-5948 and NX-2127 in patients with relapsed or refractory B-cell malignancies are ongoing (NX-5948: NCT05131022; NX-2127: NCT04830137).

Approximately 110 patients (30 in phase 1a, 80 in phase 1b) may be enrolled and treated until confirmed progression or unacceptable toxicity. Enrollment in the phase 1a portion of this study is underway in the UK and the US, and is anticipated to begin in the Netherlands in 2023.

P1, N=188, Recruiting, AbbVie | N=128 --> 188

P1, N=128, Recruiting, AbbVie | Not yet recruiting --> Recruiting

Enrollment in the phase 1a portion of this study is underway in the U.K. and is anticipated to begin in the United States and the Netherlands in 2023.

Preliminary findings suggest that NX-5948 exhibits dose-proportional PK and supports daily dosing, resulting in rapid, robust and sustained BTK degradation. Additional indications, including CLL, and additional dosing levels are currently being explored.

Inhibition of BTK by covalent BTK inhibitors (BTKi), such as ibrutinib, acalabrutinib, and zanubrutinib, have revolutionized the management of CLL and other B cell malignancies. BGB-16673 is a potent inhibitor against tumors expressing wildtype and clinical-relevant BTK mutations. In addition, it is superior to ibrutinib and LOXO-305 equivalent for more durable anti-tumor activities and less metastasis. Absolute lymphocyte count, Tumor model, Lymphoma, Mouse model

Combination therapy with ibrutinib, lenalidomide and rituximab demonstrated clinical activity in recurrent DLBCL [Goy et al. In this first-in-human, first-in-class study of a BTK degrader, NX-2127 was well tolerated and showed promising activity in a patient with non-GCB DLBCL. These data support further clinical development of NX-2127 in B cell lymphoid malignancies including DLBCL.

In summary, HZ-Q1070 is a potent and highly selective BTK degrader against both BTK-WT and multiple BTK inhibitors-resistant mutations. In vivo, HZ-Q1070 exhibits excellent pharmacokinetic properties, BTK degradation activity and robust tumor growth inhibition in TMD8 and Mino mouse xenograft tumor model. These findings support further clinical development of HZ-Q1070 for the treatment of B cell malignancies.

In pre-clinical safety studies, NX-2127 demonstrates an acceptable safety profile. NX-2127 is currently in phase 1 clinical trials (NCT04830137) for hematological malignancies.

Exploratory analyses will evaluate the relationship between HSK29116 anti-tumor activity and BTK gene mutations, as well as BTK protein degradation effects of HSK29116 . Descriptive statistics will be used to summarize all data.

P1, N=128, Not yet recruiting, AbbVie

P1, N=116, Recruiting, BeiGene | N=76 --> 116

Preclinical data support the activity of NX-2127 in tumor models harboring either wild-type BTK or BTK-mutants conferring clinical resistance to approved and investigational inhibitors. NX-2127 is currently being evaluated in an ongoing Phase 1 trial for patients with relapsed or refractory B-cell malignancies (ClinicalTrials.gov NCT04830137).

In in vitro testing against treatment-naïve CLL samples, NRX-0492 was as effective as ibrutinib at inhibiting BCR mediated signaling, transcriptional programs, and chemokine secretion. Oral bioavailability, >90% degradation of BTK at sub-nanomolar concentrations and sustained pharmacodynamic effects after drug clearance make this class of targeted protein degraders uniquely suitable for clinical translation, in particular as a strategy to overcome BTK inhibitor resistance. Clinical studies testing this approach have been initiated (NCT04830137, NCT05131022).

All have previously received a BTKi and 76.5% had also received venetoclax. Double- and emerging triple-refractory CLL (patients who progressed on cBTKi, ncBTKi, and a BCL2 inhibitor) represents a major unmet medical need with no approved therapeutic options and poor survival. These patients may thus benefit from the interruption of BTK kinase-independent scaffolding signaling. In this first-in-human, first-in-class study of a BTK degrader, clinical responses and benefit were observed in heavily pretreated (median 6 prior therapies) patients with CLL who have poor prognostic factors, including those with BTK mutations resistant to cBTKi and ncBTKi, BCL2 mutations and those who were previously treated with both BTKi and BCL2 inhibitors.

Covalent BTK inhibitors (BTKis), including ibrutinib and acalabrutinib, irreversibly bind to cysteine 481 in the kinase domain of BTK, inhibit growth, and induce loss of viability of MCL cells...In the present studies, we determined that in vitro exposure of human MCL cells, including MCL cell lines: REC1, Mino and JeKo-1, as well as patient-derived (PD) MCL cells, to NX-2127 (10 to 250 nM) for 2 to 24 hours markedly depleted BTK levels via proteasomal degradation, since co-treatment with the proteasome inhibitor carfilzomib restored BTK levels. NX-2127 but not NX-5948 treatment also degraded and depleted IKZF1 and IKZF3 levels...Co-treatment with NX-2127 (10 to 100 nM) and low nM levels of venetoclax or ABBV-744 was synergistically lethal against MCL cells (Delta synergy score above 1.0 by ZIP method). Collectively, these findings demonstrate that treatment with NX-2127 degrades and attenuates BTK and IKZF1/3 levels, as well as inhibits the downstream pro-growth and pro-survival signaling, resulting in loss of viability of MCL cells, including those resistant to covalent BTKi treatment. These findings also show promising anti-MCL activity of NX-2127-based combination with BCL2 or BET inhibitor which merits further in vivo validation.

In the subcutaneous transplanted tumor model of OCI-ly10 mice, the tumor growth was completely inhibited by 3mg/kg of HZ-Q1060 administered orally every day for 14 days, which was equivalent to that of ibrutinib 10mg/kg... In summary, HZ-Q1060 is a potent and selective degrader of BTK with good ADME properties and in vivo efficacy, which makes it suitable for further evaluation in clinical development.

By performing parallel genome-wide CRISPR-Cas9 screening in DLBCL cells with wild-type or kinase-inactive BTK, we discovered that DLBCL cells with kinase-inactive BTK displayed increased dependence on Toll-like receptor 9 (TLR9) for their growth and/or survival. Our study demonstrates that the kinase activity of BTK is not essential for oncogenic BCR signaling and suggests that BTK's non-catalytic function is sufficient to sustain the survival of diffuse large B-cell lymphoma.

The subsequent key areas hold promise: Alternative Inhibitors of BTK Here, non-covalent BTK inhibitors, such as pirtobrutinib (LOXO- 305) and nemtabrutinib (ARQ-531), have shown effi cacy in CLL resistant to covalent BTK inhibitors...AZD5991 is a highly selective BH3-mimetic that demonstrates high potency in MCL1-dependent cell lines.9 Our group has shown that selective targeting Mcl-1 induced metabolic dysfunction and abrogated survival of lymphoid cells in vitro and in vivo.10 Other BH3- mimetics targeting Mcl-1 include AMG-176 and S63845.11,12 However, Mcl-1 targeting agents may be associated with toxicities, including against the hematopoietic stem and progenitor cells, potentially leading to cytopenias in the clinic.13 The therapeutic window for these agents needs to be defi ned. BH3-mimetics which target Bcl-xL, such as navitoclax, are not being developed in CLL due to concerns of thrombocytopenia.14 However, AZD4320, an alternative Bcl-2/xL inhibitor, is being studied in lymphoid malignancies as an intravenous formulation, with hope to mitigate its effect on platelets.15 Therapeutic Antibodies Targeting surface receptors and inducing both direct and immunemediated apoptosis has been a success story in CLL with use of anti-CD20 agents...Lanalumab (VAY-736), a humanized defucosylated engineered antibody directed against BAFF-R, antagonized pro-survival effects of BAFF in CLL cells.16 In a phase 1 study in combination with ibrutinib in 32 patients with CLL, CR was achieved in 38% of patients, and 42% demonstrated undetectable minimal residual disease (uMRD) in the blood/bone marrow, a promising result not expected with ibrutinib alone.17 Alternative targets for therapeutic antibodies include ROR1 (cirmtuzumab) and CD19 (tafasitamab)...A recent report of a phase 1/2 study of lisocabtagene maraleucel, an autologous CD19-directed CAR T-cell therapy (TRANSCEND CLL 004), confi rmed effi cacy in patients with relapsed/refractory CLL.18 In this study, patients had a median of 4 prior therapies, including ibrutinib and venetoclax...In a Phase 1/2 trial, HLA-mismatched CD19-targeting CAR NK cells induced CRs in patients with CLL after a single infusion and without CRS or neurotoxicity attributable to the cellular product.19 Finally, bi-specifi c antibodies have demonstrated impressive effi cacy in non-Hodgkin lymphoma and are also an off-the-shelf product which boasts high tolerability. Development of bi-specifi c antibodies in CLL is still in early stages, however epcoritamab (a subcutaneously administered CD3xCD20 Duobody) demonstrated responses in an ongoing Phase 1 study.20 In sum, targeted therapy replaced chemo-immunotherapy in treatment of CLL, and emerging small molecule and cell therapy approaches auger an expansion of the therapeutic armamentarium for CLL in the next decade.

The oral administration of C13 effectively reduced BTK protein levels and suppressed tumor growth. This study led to the discovery of a new orally bioavailable BTK-PROTAC for the treatment of lymphoma, and we hope that the strategy will find wide utility.

Although BTK is considered as a key activator of PLCγ2, BTKi (ibrutinib and acalabrutinib) failed to fully inhibit calcium responses in CLL samples with strong BCR signalling capacity. Moreover, in CLL samples, inhibition of RAC, which can mediate BTK-independent activation of PLCγ2, cooperated with ibrutinib to suppress calcium responses. BTK-independent calcium signalling may limit the effectiveness of BTKi to suppress BCR signalling responses and our results suggest inhibition of SYK or dual inhibition of BTK and RAC as alternative strategies to strengthen pathway blockade.

Immunomodulatory drugs (IMiDs, e.g., lenalidomide) are approved as monotherapy for follicular lymphoma (FL), MZL, and MCL, in combination with other therapies for diffuse large B-cell lymphoma (DLBCL) and have shown synergy with BTK-targeted therapy...NX-2127 was shown to degrade both wild-type (WT) and C481-mutated (ibrutinib-resistant) BTK protein in vitro...The primary endpoint are dose-limiting toxicities and maximum tolerated dose (Phase 1a), objective response (Phase 1b), and safety (Phase 1a and Phase 1b) of NX-1607...Conclusion Accrual is ongoing. Clinical trial information: NCT04830137.