vecabrutinib (SNS-062)

The therapies received in the first line after BTKi and BCL2i were allogeneic HSCT (4 patients), duvelisib (3 patients), oral CDK9i (2 patients), and 1 patient each with CAR-T, anti-CD20 bispecific antibody, alemtuzumab, vecabrutinib, zanubrutinib; and for patients with RT: venetoclax plus rituximab with anthracycline chemotherapy (2 patients), PI3Ki/PD-1 (1 patient), duvelisib (1 patient) (Figure 1). Patients with CLL/SLL who were failed by BTKi and BCL2i treatment have poor prognosis. Overall response rates to treatment immediately after BTKi and BCL2i treatment are low among doubly refractory patients. More effective treatments are needed to address the unmet therapeutic needs of CLL/SLL patients who are refractory to both BTKi and BCL2i.

Despite an initial good clinical response to BTK inhibitor ibrutinib, anti-CD20 antibody rituxan, alkylating agent bendamustine, and hematopoietic stem-cell transplant, the lymphoma relapsed, accompanied by morphologic and molecular evidence of disease progression. Finally, the relapsed lymphoma cells showed in vitro resistance to standard BTK inhibitors but sensitivity to vecabrutinib, active against mutated BTK, and to PIM1 inhibitor. In summary, we provide in-depth molecular characterization of a case representing leukemic form of DLBCL and discuss mechanisms that may have contributed to lymphoma progression and development of drug resistance.

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).

Background: There remains an unmet need for patients with aggressive disease refractory to both Bruton Tyrosine Kinase inhibitors (BTKi) and Venetoclax...Two patients received acalabrutinib and obinutuzumab, one patient had a sustained partial response while the other died due to POD. One patient was started on vecabrutinib and died due to POD. A total of 17 double refractory CLL patients were identified between 2016 and 2021. The median age was 66 years (range 47–80 years), and 10 (58.8%) patients were female. At the time of double refractory status, 15 (88.2%) patients had unmutated IgHV disease, 11 (64.7%) had 17p deletion, while 9 (52.9%) had complex karyotype identified on the CLL fluorescence in situ hybridization (FISH) test.

73 patients had only one BTKi (ibrutinib (IBR), 64; acalabrutinib (ACA), 9). 12 pts had multiple BTKis, 8 with two drugs with IBR first followed by ACA (Nf3, 37.5%), vecabrutinib (Nf1, 12.5%), and PIR (Nf4, 50.0%); and 4 with three or more drugs... Our retrospective report summarizes mutations detected during BTKi treatment and shows that BTK L528W can occur during both covalent and non-covalent BTK inhibitor therapy. Four of six patients who progressed on PIR had T474 mutations. In addition, our results may suggest that activating mutations in RAS/RAF/MAPK pathway are related to BTKi resistance.

New antiCD20 antibody (obinutuzumab) is of advantage in patients with WM with rituximab intolerance as well as bendamustin and new proteasome inhibitors (ixazomib and carfilzomib) or new BTK inhibitors with lower cardiotoxicity. Many of the abovementioned drugs do not have official registration for WM and can be administrated with the consent of the health care provider only. Thus, this work brings evidence of their efficacy.

Here,we generated and comprehensively characterized BTK and PLCG2 mutations conferring resistance to ibrutinib and five different non-covalent BTKi namely pirtobrutinib (LOXO-305), vecabrutinib (SNS-062), nemtabrutinib (ARQ-531), fenebrutinib (GDC-0853), and RN-486. We also found that cells harboring these novel BTK mutations showed differential sensitivity to the covalent vs. non-covalent BTKi. We further demonstrate the potential of venetoclax as follow up treatment upon resistance to non-covalent BTKi.

It has also been studied in combination with idelalisib or entospletinib in CLL and other B-cell lymphomas though without clear benefi t for the combinations over monotherapy16,17. Tirabrutinib is approved in Japan for WM, lymphoplasmacytic lymphoma (LPL), and RRPCNSL, and in South Korea for RR-PCNSL18. TG-1701 is a selective covalent BTKi that has been studied as a monotherapy and in combination with ublituximab and umbralisib with preliminary results suggesting both effi cacy and manageable safety19. Orelabrutinib, another selective covalent BTKi, has been studied as a monotherapy in CLL in addition to other B-cell malignancies, also with favorable safety and effi cacy20,21 and it is approved in China for rel/ref CLL and MCL22. Finally, DTRMWXHS-12 is a covalent BTKi that uniquely is being studied in combination with everolimus and pomalidomide (triplet referred to as DTRM-555), given that this combination was determined to lead to synthetic lethality in both in vivo and in vitro screening studies, with safety and activity seen in early studies23,24...This resistance mechanism appears shared among available irreversible BTK inhibitors including ibrutinib, acalabrutinib and zanubrutinib26...Three such inhibitors have completed phase 1 studies in CLL: vecabrutinib, nemtabrutinib, and pirtobrutinib with another currently in phase 1, luxeptinib...Subsequently, pirtobrutinib is being further studied as both a monotherapy and in combination with venetoclax-rituximab in phase 3 trials in both the frontline and relapsed/refractory settings in CLL in addition to MCL...These non-C481 BTK mutations conferred resistance across multiple non-covalent BTKi’s (in addition to pirtobrutinib, vecabrutinib, nemtabrutinib and fenebrutinib were tested) in addition to variable levels of resistance to covalent BTKi’s36...This is being accomplished by improved tolerability, allowing for patients to stay on drug for longer, and potentially improved effi cacy, including activity despite acquisition of C481 resistance mutations, in the case of the non-covalent inhibitors. The non-covalent inhibitors would help fi ll a major area of unmet need for CLL patients progressing on covalent BTK inhibitors who are not candidates for or progress following venetoclax therapy.

The Bruton’s tyrosine kinase BTK inhibitor, ibrutinib, has been shown to favorably modulate CART functions. 1J-L in the serum of patients enrolled in phase 1 clinical trial NCT03037645 testing vecabrutinib in B cell malignancies at baseline and four weeks after treatment. Mechanistically, total RNA sequencing of activated CART19 incubated with vecabrutinib highlighted a significant enhanced expression of multiple genes involved in the PI3K/AKT proliferation and Th1 pathways cytotoxicity Fig.1M, N. Conclusion We demonstrate that vecabrutinib is a potent and a novel strategy to favorably modulate CART19 functions by increasing their efficacy and decreasing toxicity.

These agents (pirtobrutinib, ARQ-531, SNS-062) reversibly bind BTK and overcome acquired resistance to covalent BTKis (cBTKi). In this first study to report outcomes of CLL and RT pts who have discontinued a ncBTKi, several important themes have emerged. For venetoclax naive CLL pts, venetoclax appears to be a promising strategy following ncBTKi discontinuation supporting the ability to stay within the BTKi class prior to switching to venetoclax. Cellular therapies including CAR T-cell therapy and allo SCT had a high ORR and warrant further investigation (80% of pts had prior cBTKi, ncBTKi and venetoclax and 100% had prior cBTKi and ncBTKi).