bims-cyhorp 2021-12-19 papers

Issue of 2021–12–19
seven papers selected by
Piotr Okupski,

Gan To Kagaku Ryoho. 2021 Dec;48(12): 1475-1483

[Development of CDK4 & 6 Inhibitor Abemaciclib in Breast Cancer].

Norikazu Masuda, Shigehira Saji, Tsutomu Kawaguchi, Yucherng Chen, Shinji Ohno.

Abemaciclib is a selective cyclin-dependent kinase(CDK)4 & 6 inhibitor, which induces G1 cell cycle arrest and tumour growth inhibition. Abemaciclib has been developed for use in hormone receptor positive(HR+)breast cancer, dosed daily in combination with endocrine therapy. In a phase Ⅲ clinical trial, MONARCH 2, for women with HR+ and human epidermal growth factor receptor 2 negative(HER2-)advanced breast cancer who progressed after endocrine therapy, abemaciclib in combination with fulvestrant significantly improved not only progression-free survival and objective response rate but also overall survival, and demonstrated a tolerable safety profile. Another phase Ⅲ clinical trial, MONARCH 3, for women with HR+ and HER2- advanced breast cancer, abemaciclib in combination with nonsteroidal aromatase inhibitor as an initial therapy also significantly improved progression-free survival and objective response rate. This review presents the rationale for the use of CDK4 & 6 inhibitors in the treatment of breast cancer, background on the development of abemaciclib, clinical data focusing on phase Ⅲ studies of abemaciclib, and information on ongoing clinical studies of abemaciclib.

Eur Rev Med Pharmacol Sci. 2021 Dec;pii: 27418. [Epub ahead of print]25(23): 7252-7267

Overall survival and progression-free survival with cyclin-dependent kinase 4/6 inhibitors plus endocrine therapy in breast cancer: an updated meta-analysis of randomized controlled trials.

Q Tian, H Gao, Y Zhou, J Yang.

OBJECTIVE: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in combination with endocrine therapy (ET) have been recommended as standard therapeutic strategies for hormone receptor-positive (HR+), human epidermal growth factor receptor type 2-negative (Her2-) advanced breast cancer (ABC). While the benefits to progression-free survival (PFS) rates have been confirmed, whether the combination of CDK4/6i and ET leads to overall survival (OS) rate improvements remains controversial. This study aimed to assess the long-term efficacy and safety of CDK4/6i in HR+, Her2- ABC patients and identify a population suitable for treatment with CDK4/6i by subgroup analysis.
MATERIALS AND METHODS: Electronic literature databases (MEDLINE, EMBASE and the Cochrane Library) were searched for relevant randomized controlled trials (rcts) published from Jan 2014 to Jan 2020. In addition, abstracts and presentations from all major conference proceedings were reviewed. All rcts that compared the efficacy and safety of CDK4/6i plus ET with ET alone in HR+, Her2- ABC patients were selected. The pooled analyses of hazard ratios (hrs) for PFS and OS, and risk ratios (rrs) for the objective response rate (ORR) and adverse events (aes) were obtained with the random-effects model.
RESULTS: A total of 6 rcts and 3421 HR+, Her2- ABC patients were enrolled for OS outcome analysis, while all 8 trials and 4580 patients were included for PFS outcome analysis. The pooled hrs for the OS and PFS were 0.76 (95% CI: 0.67-0.84) and 0.55 (95% CI: 0.50-0.59), respectively, and were consistent in the subgroup analysis. Moreover, CDK4/6i meaningfully improved the ORR in both the intention-to-treat population (RR=1.47; 95% CI: 1.29-1.67) and patients with measurable disease (RR=1.47; 95% CI: 1.30-1.67); however, CDK4/6i increased the incidence of grade 3/4 aes (RR=2.69; 95% CI: 2.43-2.97).
CONCLUSIONS: The combination of CDK4/6i and ET was superior to ET alone in terms of OS and PFS regardless of the drugs administered, the treatment line, age distribution, race, PR status, menopausal status, metastasis site and endocrine resistance status.

DOI: https://doi.org/10.26355/eurrev_202112_27418

Asia Pac J Clin Oncol. 2021 Dec 14.

Palbociclib plus letrozole as treatment for postmenopausal women with hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer for whom letrozole therapy is deemed appropriate: An expanded access study in Australia and India.

Sherene Loi, Christos S Karapetis, Nicole McCarthy, Catherine Oakman, Andrew Redfern, Michelle White, Mustafa Khasraw, Dinesh Chandra Doval, Vinod Gore, Mahmood Alam, Justin Binko, Dongrui Ray Lu, Sindy Kim, Frances Boyle.

AIM: Palbociclib was approved in the United States in 2015 to treat estrogen receptor-positive/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). This study evaluated outcomes and safety in patients treated with palbociclib in Australia and India with hormone receptor-positive (HR+)/HER2- ABC before palbociclib became commercially available.
METHODS: Postmenopausal women (≥18 years) with HR+/HER2- ABC who were appropriate candidates for letrozole therapy received palbociclib 125 mg once daily for 21 days followed by 7 days off, and letrozole 2.5 mg once daily (continuous). Safety, tumor response, and patient-reported outcomes (Australian cohort) were evaluated.
RESULTS: In total, 252 patients received palbociclib plus letrozole (Australia, n = 152; India, n = 100). More patients in the Australian versus Indian cohort had received prior chemotherapy (advanced/metastatic setting: 45.9% vs. 32.0%), endocrine therapy (advanced/metastatic setting: 63.2% vs. 54.3%), and advanced/metastatic therapies (61.8% vs. 31.0%). The most frequently reported all-grade palbociclib-related treatment-emergent adverse events were neutropenia (66.7%), fatigue (35.3%), and stomatitis (26.6%); grade 3/4 neutropenia was reported as palbociclib-related in 62.7% of patients. Febrile neutropenia was reported in six patients (2.4%). Eight patients (3.2%) discontinued because of an adverse event. The objective response rate was 19.4% (95% CI, 14.7%-24.9%) overall and 2.3% in Australian patients with ≥2 lines of prior therapy for metastatic disease. Patient-reported quality of life scores were maintained throughout the study.
CONCLUSIONS: In an expanded access setting in Australia and India, palbociclib plus letrozole was well tolerated in patients with HR+/HER2- ABC, with a safety profile consistent with previous reports.

Keywords: Australia; HR+/HER2-; India; advanced breast cancer; letrozole; palbociclib

DOI: https://doi.org/10.1111/ajco.13653

Cancer Discov. 2021 Dec 14.

Novel SERD Has PFS Edge against Breast Cancer.

In the phase III EMERALD trial, the investigational oral selective estrogen receptor degrader elacestrant offered a modest but statistically significant improvement in progression-free survival in patients with ER-positive/HER2-negative breast cancer previously treated with endocrine therapy and a CDK4/6 inhibitor.

DOI: https://doi.org/10.1158/2159-8290.CD-NB2021-0406

Bioorg Chem. 2021 Dec 08. pii: S0045-2068(21)00925-1. [Epub ahead of print]119 105547

Synthesis and identification of a novel skeleton of N-(pyridin-3-yl) proline as a selective CDK4/6 inhibitor with anti-breast cancer activities.

Jing-Wei Liang, Wan-Qiu Li, Qing-Yang Nian, Si-Hua Xie, Lulu Yang, Fan-Hao Meng.

CDK4/6 were attractive chemotherapeutic targets for the treatment of malignant tumors, CDK4/6 selective inhibitors have made outstanding contributions in the treatment of breast cancer. However, these inhibitors share a single skeleton of N-(pyridin-2-yl) pyrimidin-2-amine which cannot overcome the side effects in clinical application. In our previous study, an N'- acetylpyrrolidine-1-carbohydrazide was hit as the initial fragment by analyzing the active site characteristics of CDK6. Two series of N-(pyridin-3-yl) proline were obtained by fragment growth method. The QSAR study was carried out according to the in vitro activities data against CDK4/6, and two compounds 7c and 7p with potent inhibitory activities were found to interact with CDK4 in different binding conformation. They showed potential inhibition of cell proliferation against the breast cancer cell, and 7c exhibited promised anti-breast cancer effect in vivo.

Keywords: Fragment-based drug design; Proline derivatives; QSAR; Selective CDK4/6 inhibitor

DOI: https://doi.org/10.1016/j.bioorg.2021.105547

Eur J Cancer. 2021 Dec 10. pii: S0959-8049(21)01221-1. [Epub ahead of print]161 26-37

Randomized phase II study of fulvestrant plus palbociclib or placebo in endocrine-sensitive, hormone receptor-positive/HER2-advanced breast cancer: GEICAM/2014-12 (FLIPPER).

BACKGROUND: The potential benefit of adding palbociclib to fulvestrant as first-line treatment in hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative endocrine-sensitive advanced breast cancer (ABC) patients remains uncharacterized.
PATIENTS AND METHODS: In this randomized (1:1), double-blind, phase II study, postmenopausal women with HR-positive, HER2-negative ABC with de novo metastatic disease or those who relapsed after >12 months of adjuvant endocrine therapy received palbociclib/fulvestrant or placebo/fulvestrant. Stratification was based on recurrent versus de novo metastatic disease and visceral involvement. The primary objective was one-year progression-free survival (PFS-1y) rate. The sample size was 190 patients. The two-sided alpha of 0.2, 80% of power to detect a difference between the arms, assuming PFS rates of 0.695 and 0.545 for palbociclib/fulvestrant and placebo/fulvestrant, respectively.
RESULTS: In total, 189 patients were randomized to palbociclib/fulvestrant ([n = 94] or placebo/fulvestrant [n = 95]). 45.5% and 60.3% of patients had de novo metastatic disease and visceral involvement, respectively. PFS-1y rates were 83.5% and 71.9% in the palbociclib/fulvestrant and placebo/fulvestrant arms, (HR 0.55, 80% CI 0.36-0.83, P = 0.064). The median PFS were 31.8 and 22.0 months for the palbociclib/fulvestrant and placebo/fulvestrant arms (aHR 0.48, 80% CI 0.37-0.64, P = 0.001). The most frequent grade 3-4 adverse events were neutropenia (68.1% vs. 0%), leucopenia (26.6% vs. 0%), anemia (3.2% vs. 0%), and lymphopenia (14.9% vs. 2.1%) for the palbociclib/fulvestrant and placebo/fulvestrant, respectively. The most frequent non-hematologic grade 3-4 adverse event was fatigue (4.3% vs. 0%).
CONCLUSIONS: Palbociclib/fulvestrant demonstrated better PFS-1y rates and median PFS than placebo/fulvestrant in HR-positive/HER2-negative endocrine-sensitive ABC patients.

Keywords: Breast cancer; CDK 4/6; Endocrine-sensitive; First-line; Fulvestrant; Metastatic; Palbociclib

DOI: https://doi.org/10.1016/j.ejca.2021.11.010

Cell Cycle. 2021 Dec 16. 1-21

Monoclonal antibodies to activated CDK4: use to investigate normal and cancerous cell cycle regulation and involvement of phosphorylations of p21 and p27.

Katia Coulonval, Vincent Vercruysse, Sabine Paternot, Jaime M Pita, Robert Corman, Eric Raspé, Pierre P Roger.

Cyclin-dependent kinase 4 (CDK4) is a master integrator that couples mitogenic/oncogenic signaling with the cell division cycle. It is deregulated in most cancers and inhibitors of CDK4 have become standard of care drugs for metastatic estrogen-receptor positive breast cancers and are being evaluated in a variety of other cancers. We previously characterized the T-loop phosphorylation at T172 of CDK4 as the highly regulated step that determines the activity of cyclin D-CDK4 complexes. Moreover we demonstrated that the highly variable detection of T172-phosphorylated CDK4 signals the presence or absence of the active CDK4 targeted by the CDK4/6 inhibitory drugs, which predicts the tumor cell sensitivity to these drugs including palbociclib. To date, the phosphorylation of CDK4 has been very poorly studied because only few biochemical techniques and reagents are available for it. In addition, the available ones including 2D-IEF separation of CDK4 modified forms are considered too tedious. The present report describes the generation, selection and characterization of the first monoclonal antibodies that specifically recognize the active CDK4 phosphorylated on its T172 residue. One key to this success was the immunization with a long phosphopeptide corresponding to the complete activation segment of CDK4. These monoclonal antibodies specifically recognize T172-phosphorylated CDK4 in a variety of assays, including western blotting, immunoprecipitation and, as a capture antibody, a sensitive ELISA from cell lysates. The specific immunoprecipitation of T172-phosphorylated CDK4 allowed to clarify the involvement of phosphorylations of co-immunoprecipitated p21 and p27, showing a privileged interaction of T172-phosphorylated CDK4 with S130-phosphorylated p21 and S10-phosphorylated p27. Abbreviations: 2D: two-dimensional; CAK: CDK-activating kinase; CDK: cyclin-dependent kinase; HAT: Hypoxanthine-Aminopterin-Thymidine; FBS: fetal bovine serum; IP: immunoprecipitation; ID: immunodetection; mAb: monoclonal antibody; PAGE: polyacrylamide gel electrophoresis; PBS: phosphate buffer saline; pRb: retinoblastoma susceptibility protein; SDS: sodium dodecyl sulfate; DTT: dithiotreitol; TET: tetracyclin repressor; Avi: Avi tag; TEV: tobacco etch virus cleavage site; EGFP: enhanced green fluorescent protein; BirA: bifunctional protein biotin ligase BirA; IRES: internal ribosome entry site; HIS: poly-HIS purification tag; DELFIA: dissociation-enhanced lanthanide fluorescent immunoassay; 3-MBPP1: 1-(1,1-dimethylethyl)-3[(3-methylphenyl) methyl]-1H-pyrazolo[3,4-d] pyrimidin-4-amine; BSA: bovine serum albumin; ECL: Enhanced chemiluminescence.

Keywords: CDK4; ELISA; Phosphospecific monoclonal antibodies; S10-phosphorylation; S130-phosphorylation; T172-phosphorylation; p21; p27

DOI: https://doi.org/10.1080/15384101.2021.1984663