Randomized phase II study of the Bruton tyrosine kinase inhibitor acalabrutinib, alone or with pembrolizumab in patients with advanced pancreatic cancer.
ABSTRACT: BACKGROUND:The immunosuppressive desmoplastic stroma of pancreatic cancer represents a major hurdle to developing an effective immune response. Preclinical studies in pancreatic cancer have demonstrated promising anti-tumor activity with Bruton tyrosine kinase (BTK) inhibition combined with programmed cell death receptor-1 (PD-1) blockade. METHODS:This was a phase II, multicenter, open-label, randomized (1:1) clinical trial evaluating the BTK inhibitor acalabrutinib, alone (monotherapy) or in combination with the anti-PD-1 antibody pembrolizumab (combination therapy). Eligible patients were adults with histologically confirmed metastatic or locally advanced unresectable pancreatic ductal adenocarcinoma with an Eastern Cooperative Oncology Group Performance Status (ECOG PS) ?1?who had received at least one prior systemic therapy. Oral acalabrutinib 100?mg twice daily was administered with or without intravenous pembrolizumab 200?mg on day 1 of each 3-week cycle. Peripheral blood was analyzed for changes in immune markers, and tumors from exceptional responders were molecularly analyzed. RESULTS:A total of 77 patients were enrolled (37 monotherapy; 40 combination therapy) with a median age of 64 years; 77% had an ECOG PS of 1. The median number of prior therapies was 3 (range 1-6). Grade 3-4 treatment-related adverse events were seen in 14.3% of patients in the monotherapy arm and 15.8% of those in the combination therapy arm. The overall response rate and disease control rate were 0% and 14.3% with monotherapy and 7.9% and 21.1% with combination therapy, respectively. Median progression-free survival was 1.4 months in both arms. Peripheral blood flow analysis demonstrated consistent reductions in granulocytic (CD15+) myeloid-derived suppressor cells (MDSCs) over time. Two exceptional responders were found to be microsatellite stable with low tumor mutation burden, low neoantigen load and no defects in the homologous DNA repair pathway. CONCLUSIONS:The combination of acalabrutinib and pembrolizumab was well tolerated, but limited clinical activity was seen with either acalabrutinib monotherapy or combination therapy. Peripheral reductions in MDSCs were seen. Efforts to understand and target the pancreatic tumor microenvironment should continue. TRIAL REGISTRATION NUMBER:NCT02362048.
Project description:BACKGROUND:Inhibition of the programmed cell death protein 1 (PD-1) pathway has demonstrated clinical benefit in metastatic urothelial cancer (mUC); however, response rates of 15% to 26% highlight the need for more effective therapies. Bruton tyrosine kinase (BTK) inhibition may suppress myeloid-derived suppressor cells (MDSCs) and improve T-cell activation. METHODS:The Randomized Phase 2 Trial of Acalabrutinib and Pembrolizumab Immunotherapy Dual Checkpoint Inhibition in Platinum-Resistant Metastatic Urothelial Carcinoma (RAPID CHECK; also known as ACE-ST-005) was a randomized phase 2 trial evaluating the PD-1 inhibitor pembrolizumab with or without the BTK inhibitor acalabrutinib for patients with platinum-refractory mUC. The primary objectives were safety and objective response rates (ORRs) according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Secondary endpoints included progression-free survival (PFS) and overall survival (OS). Immune profiling was performed to analyze circulating monocytic MDSCs and T cells. RESULTS:Seventy-five patients were treated with pembrolizumab (n = 35) or pembrolizumab plus acalabrutinib (n = 40). The ORR was 26% with pembrolizumab (9% with a complete response [CR]) and 20% with pembrolizumab plus acalabrutinib (10% with a CR). The grade 3/4 adverse events (AEs) that occurred in ?15% of the patients were anemia (20%) with pembrolizumab and fatigue (23%), increased alanine aminotransferase (23%), urinary tract infections (18%), and anemia (18%) with pembrolizumab plus acalabrutinib. One patient treated with pembrolizumab plus acalabrutinib had high MDSCs at the baseline, which significantly decreased at week 7. Overall, MDSCs were not correlated with a clinical response, but some subsets of CD8+ T cells did increase during the combination treatment. CONCLUSIONS:Both treatments were generally well tolerated, although serious AE rates were higher with the combination. Acalabrutinib plus pembrolizumab did not improve the ORR, PFS, or OS in comparison with pembrolizumab alone in mUC. Baseline and on-treatment peripheral monocytic MDSCs were not different in the treatment cohorts. Proliferating CD8+ T-cell subsets increased during treatment, particularly in the combination cohort. Ongoing studies are correlating these peripheral immunome findings with tissue-based immune cell infiltration.
Project description:Recently, the treatment landscape for chronic lymphocytic leukemia (CLL) has changed dramatically due to the development of drugs targeting proteins in the B cell antigen receptor (BCR) pathway. Acalabrutinib, a second-generation Bruton's tyrosine kinase (BTK) inhibitor, was recently FDA approved for treatment of treatment naïve and relapsed refractory CLL. Acalabrutinib was designed as a more selective BTK inhibitor as compared to ibrutinib in an attempt to mitigate some of the treatment limiting toxicities seen with ibrutinib such as atrial fibrillation and bleeding. In preclinical studies, acalabrutinib was demonstrated to have efficacy in CLL in both patient blood samples and murine models. A multinational phase 1/2 study demonstrated the efficacy and safety of acalabrutinib monotherapy in treatment naïve, relapsed refractory and ibrutinib-intolerant CLL patients. Subsequent phase 3 studies, ASCEND and ELEVATE-TN, compared acalabrutinib monotherapy or combination acalabrutinib and obinutuzumab to standard of care treatments and demonstrated acalabrutinib's improved efficacy and tolerability. Currently, a phase 3 study is ongoing to compare acalabrutinib to ibrutinib monotherapy (NCT02477696). In the setting of recent FDA approval, real-world evidence will help to elucidate the optimal use of acalabrutinib in the treatment of CLL.
Project description:Bruton's tyrosine kinase (BTK) is a critical terminal enzyme in the B-cell antigen receptor (BCR) pathway. BTK activation has been implicated in the pathogenesis of certain B-cell malignancies. Targeting this pathway has emerged as a novel target in B-cell malignancies, of which ibrutinib is the first-in-class agent. A few other BTK inhibitors (BTKi) are also under development (e.g., acalabrutinib). While the predominant action of BTKi is the blockade of B-cell receptor pathway within malignant B-cells, increasing the knowledge of off-target effects as well as a potential role for B-cells in proliferation of solid malignancies is expanding the indication of BTKi into non-hematological malignancies. In addition to the expansion of the role of BTKi monotherapy, combination therapy strategies utilizing ibrutinib with established regimens and combination with modern immunotherapy compounds are being explored.
Project description:BACKGROUND:Transformation of chronic lymphocytic leukaemia (CLL) to diffuse large B-cell lymphoma (DLCBL) type Richter's syndrome (RS) carries a dismal prognosis. Standard-of-care chemoimmunotherapy for de novo RS is inadequate with median survival of less than one year. Patients are frequently elderly or have co-morbidities limiting dose-intense chemotherapy. Treatment of relapsed/refractory (R/R) RS and RS emerging after CLL-directed therapy represent urgent unmet clinical needs. Agents targeting Bruton's tyrosine kinase (BTK) deliver improved outcomes for patients with high-risk CLL and expand effective treatments to frailer patients. Acalabrutinib is an oral, second-generation BTK inhibitor with a favourable toxicity profile and demonstrated activity in CLL and B-cell lymphomas. Combination of acalabrutinib with standard-of-care CHOP-R chemoimmunotherapy offers a sound rationale to test in a prospective trial for de novo RS. METHODS:The prospective multicentre STELLAR study is designed in two elements, consisting of a randomised study to evaluate the safety and activity of CHOP-R chemoimmunotherapy in combination with acalabrutinib in newly diagnosed RS and single-arm studies of novel agents for other RS patient cohorts. Eligible patients with newly diagnosed DLBCL-type RS are randomised between six cycles of CHOP-R therapy and six cycles CHOP-R plus acalabrutinib, followed by acalabrutinib maintenance. The primary endpoint of the randomised component is progression free survival (PFS). Cohort 1 enrols RS patients with progressive disease following chemoimmunotherapy for acalabrutinib monotherapy. Patients with RS diagnosed while on ibrutinib may enrol in Cohort 2, a single-arm study of CHOP-R plus acalabrutinib. The primary endpoint for the single-arm studies is overall response rate (ORR). Secondary endpoints for all cohorts are overall survival (OS), quality of life and proportion of patients proceeding to stem cell transplantation. The study will be accompanied by exploratory analysis of the mutational landscape of RS and the relationship between dynamic changes in sequential circulating tumour DNA samples and clinical outcomes. DISCUSSION:The STELLAR randomised trial evaluates the role of CHOP-R plus acalabrutinib in newly diagnosed RS patients. The single-arm platform studies enable the incorporation of promising novel therapies into the protocol. The STELLAR study has potential to identify novel biomarkers of treatment response in this high-risk malignancy. TRIAL REGISTRATION:EudraCT: 2017-004401-40 , registered on the 31-Oct-2017. IRSCTN: https://www.isrctn.com/ISRCTN52839057 , registered on the 04-Mar-2019. ClinicalTrials.gov : NCT03899337 , registered on 02-April-2019.
Project description:BACKGROUND:Irreversible inhibition of Bruton's tyrosine kinase (BTK) by ibrutinib represents an important therapeutic advance for the treatment of chronic lymphocytic leukemia (CLL). However, ibrutinib also irreversibly inhibits alternative kinase targets, which potentially compromises its therapeutic index. Acalabrutinib (ACP-196) is a more selective, irreversible BTK inhibitor that is specifically designed to improve on the safety and efficacy of first-generation BTK inhibitors. METHODS:In this uncontrolled, phase 1-2, multicenter study, we administered oral acalabrutinib to 61 patients who had relapsed CLL to assess the safety, efficacy, pharmacokinetics, and pharmacodynamics of acalabrutinib. Patients were treated with acalabrutinib at a dose of 100 to 400 mg once daily in the dose-escalation (phase 1) portion of the study and 100 mg twice daily in the expansion (phase 2) portion. RESULTS:The median age of the patients was 62 years, and patients had received a median of three previous therapies for CLL; 31% had chromosome 17p13.1 deletion, and 75% had unmutated immunoglobulin heavy-chain variable genes. No dose-limiting toxic effects occurred during the dose-escalation portion of the study. The most common adverse events observed were headache (in 43% of the patients), diarrhea (in 39%), and increased weight (in 26%). Most adverse events were of grade 1 or 2. At a median follow-up of 14.3 months, the overall response rate was 95%, including 85% with a partial response and 10% with a partial response with lymphocytosis; the remaining 5% of patients had stable disease. Among patients with chromosome 17p13.1 deletion, the overall response rate was 100%. No cases of Richter's transformation (CLL that has evolved into large-cell lymphoma) and only one case of CLL progression have occurred. CONCLUSIONS:In this study, the selective BTK inhibitor acalabrutinib had promising safety and efficacy profiles in patients with relapsed CLL, including those with chromosome 17p13.1 deletion. (Funded by the Acerta Pharma and others; ClinicalTrials.gov number, NCT02029443.).
Project description:The Bruton tyrosine kinase (Btk) inhibitor ibrutinib induces platelet dysfunction and causes increased risk of bleeding. Off-target inhibition of Tec is believed to contribute to platelet dysfunction and other side effects of ibrutinib. The second-generation Btk inhibitor acalabrutinib was developed with improved specificity for Btk over Tec. We investigated platelet function in patients with non-Hodgkin lymphoma (NHL) receiving ibrutinib or acalabrutinib by aggregometry and by measuring thrombus formation on collagen under arterial shear. Both patient groups had similarly dysfunctional aggregation responses to collagen and collagen-related peptide, and comparison with mechanistic experiments in which platelets from healthy donors were treated with the Btk inhibitors suggested that both drugs inhibit platelet Btk and Tec at physiological concentrations. Only ibrutinib caused dysfunctional thrombus formation, whereas size and morphology of thrombi following acalabrutinib treatment were of normal size and morphology. We found that ibrutinib but not acalabrutinib inhibited Src family kinases, which have a critical role in platelet adhesion to collagen that is likely to underpin unstable thrombus formation observed in ibrutinib patients. We found that platelet function was enhanced by increasing levels of von Willebrand factor (VWF) and factor VIII (FVIII) ex vivo by addition of intermediate purity FVIII (Haemate P) to blood from patients, resulting in consistently larger thrombi. We conclude that acalabrutinib avoids major platelet dysfunction associated with ibrutinib therapy, and platelet function may be enhanced in patients with B-cell NHL by increasing plasma VWF and FVIII.
Project description:Mantle cell lymphoma (MCL) is an incurable intermediate-grade lymphoma representing 5-6% of non-Hodgkin's lymphomas diagnosed in the United States. The introduction of inhibitors of Bruton's tyrosine kinase (BTK) into targeted therapy for MCL has significantly improved outcomes in patients with relapsed/refractory (R/R) disease. Since the initial approval of the first-generation inhibitor, ibrutinib, several second-generation inhibitors have been explored. Acalabrutinib, a second-generation BTK inhibitor, has demonstrated impressive efficacy in clinical trials along with a safety profile that thus far appears improved compared to ibrutinib. The results of a Phase II trial in patients with R/R MCL led to the approval of acalabrutinib in this patient population while fueling further exploration of acalabrutinib in several ongoing clinical trials.
Project description:Background: Over 13,000 new cases of non-Hodgkin's lymphoma (NHL) are diagnosed in the UK, with approximately 4,900 attributable deaths each year. Diffuse Large B-cell Lymphoma (DLBCL) is the most common NHL comprising one third of adult NHL cases. R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) is accepted as the international standard first-line regimen, but improvement in first line treatment is needed. Dysregulated B-cell receptor (BCR) signalling has been identified as a feature of DLBCL. Inhibition of Bruton's tyrosine kinase (Btk), downstream of the BCR has proven efficacious in other B-cell malignancies and in combination with R-CHOP. The second generation Btk inhibitor, acalabrutinib, may have improved target potency and specificity, and therefore better efficacy and tolerability. Methods: ACCEPT is an open-label non-randomised Phase Ib/II trial testing the addition of acalabrutinib to conventional R-CHOP therapy. ACCEPT incorporates an initial 6+6 modified Phase I design of up to 24 participants followed by 15 participant single arm Phase II expansion cohort in treatment naive patients with histologically confirmed DLBCL expressing CD20. Participants are recruited from UK secondary care sites. Phase I will establish the recommended Phase II dose (RP2D, primary endpoint) of acalabrutinib in combination with R-CHOP. Phase II will gain additional information on safety and efficacy on the RP2D. The primary endpoints of Phase II are overall response rate and toxicity profile. Secondary endpoints include duration of response (progression-free survival and overall survival OS) in relation to cell of origin. Analyses are not powered for formal statistical comparisons; descriptive statistics will describe rates of toxicity, efficacy and translational endpoints. Discussion: ACCEPT will provide evidence for whether acalabrutinib in combination with R-CHOP is safe and biologically effective prior to future Phase II/III trials in patients with previously untreated CD20 positive DLBCL. Trial registration: EudraCT Number: 2015-003213-18 (issued 16 July 2015); ISRCTN 13626902 (registered 07 March 2017).