bims-cyhorp Biomed News
on Cyclin-dependent kinases in hormone receptor positive breast cancer
Issue of 2022–10–30
five papers selected by
Piotr Okupski,



  1. Bull Cancer. 2022 Oct 25. pii: S0007-4551(22)00357-5. [Epub ahead of print]
      HR+ breast cancers are defined by the prominence of signaling pathways dependent on the estrogen receptor. Endocrine therapy is the standard treatment for these advanced diseases. Resistance to these treatments, called hormone resistance, appears invariably with biological mechanisms that have led to the development of therapeutic opportunities. An exhaustive literature review was carried out concerning the biology of the hormone resistance pathways, the therapeutic options before the era of CDK4/6 inhibitors, the rise of CDK4/6 inhibitors and the therapeutic prospects in a situation of hormone resistance. Various biological abnormalities have been identified in the mechanisms of hormone resistance such as changes in the estrogen receptor, mutations in the ESR1 gene, aberrant activation of the PI3K pathway or cell cycle deregulations. Historical strategies for circumventing this hormone resistance have been based on hormonal manipulation, on the development of new endocrine therapy such as fulvestrant (selective estrogen receptor inhibitor, SERD), on combinations of treatments such as everolimus, a mTOR inhibitor. This strategy combining endocrine therapy and targeted therapy has led to the development of combinations with CDK4/6 inhibitors which have now become a standard treatment in the hormone resistance phase. The future of this therapeutic era remains to be written with new combinations of hormone therapy and targeted therapy such as PI3K inhibitors or even with the positioning of new SERDs in clinical development.
    Keywords:  Breast cancer; Cancer du sein; ESR1 mutation; Hormone resistance, CDK4/6 inhibitor; Hormonorésistance; Iinhibiteur de CDK4/6; Mutation ESR1; SERD
    DOI:  https://doi.org/10.1016/j.bulcan.2022.09.007
  2. J Manag Care Spec Pharm. 2022 Nov;28(11): 1282-1291
      BACKGROUND: Breast cancer is the most prevalent type of cancer in women in the United States. Ribociclib plus fulvestrant combination therapy gained US Food and Drug Administration approval to treat postmenopausal women with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced or metastatic breast cancer in 2018. OBJECTIVE: To determine the cost-effectiveness of ribociclib plus fulvestrant vs placebo plus fulvestrant therapy in the target population from a US payer perspective. METHODS: A partitioned survival analysis model composed of 3 health states (progression free, progressed disease, and death) was constructed to evaluate the cost-effectiveness of ribociclib plus fulvestrant vs placebo plus fulvestrant. The progression-free survival and the overall survival data points were extracted from published Kaplan-Meier curves in the MONALEESA-3 study and fitted to parametric curves. The safety and efficacy of the treatment was referenced from the MONALEESA-3 trial. Costs were obtained from standard sources including the Red Book for medication costs, Medicare Clinical Laboratory/Physician Fee Schedule for clinical utilization, and the literature for costs of managing adverse events, subsequent therapy, and end-of-life care. Utility and disutility values were obtained from literature to calculate quality-adjusted life-years (QALYs). One-way and probabilistic sensitivity analyses were conducted to test the model robustness. Several scenario analyses were also investigated. RESULTS: In the base case, the ribociclib plus fulvestrant arm was associated with $522,844 and 3.25 QALYs compared with $50,395 and 2.14 QALYs in the placebo plus fulvestrant arm, leading to an incremental cost-effectiveness ratio of $425,951/QALY. The cost of ribociclib had the biggest impact on the model and constituted 84% of the total cost for the ribociclib plus fulvestrant arm. The probabilistic sensitivity analysis projected that the ribociclib plus fulvestrant treatment would have a net benefit over the placebo plus fulvestrant therapy at a willingness-to-pay (WTP) threshold of $405,600/QALY. CONCLUSIONS: At a WTP threshold of $150,000/QALY, the addition of ribociclib to fulvestrant is not considered to be cost-effective in postmenopausal women with HR+/HER2- advanced or metastatic breast cancer. The findings send a strong price signal to the manufacturer and can be used to facilitate payers with price negotiation in making coverage decisions.
    DOI:  https://doi.org/10.18553/jmcp.2022.28.11.1282
  3. Breast. 2022 Oct 15. pii: S0960-9776(22)00170-9. [Epub ahead of print]66 157-161
       BACKGROUND: Gastric pH changes by proton-pump-inhibitors (PPIs) were found to affect progression-free survival (PFS) in metastatic breast cancer (mBC) patients treated with palbociclib. The current study was aimed at investigating whether the same effect could occur in patients treated with ribociclib.
    PATIENTS AND METHODS: Patients with hormone-positive/HER-2-negative mBC candidates for first-line treatment with ribociclib were enrolled in this retrospective-cohort study. Patients were classified as "no concomitant PPIs" or "concomitant PPIs"; PPI administration covered the entire or not less than 2/3 of treatment with ribociclib. All clinical interventions were made according to clinical practice.
    RESULTS: A total of 128 patients were consecutively enrolled in the study; 78 belonged to the "no concomitant PPIs" group and 50 to the "concomitant PPIs" group. One hundred and six patients were endocrine-sensitive and received ribociclib and letrozole, while 22 were endocrine-resistant and were treated with ribociclib and fulvestrant. The most prescribed PPI was lansoprazole. According to PFS, patients taking PPIs had a PFS almost superimposable to those assuming ribociclib and endocrine therapy alone (35.3 vs. 49.2 months, p = 0.594). No difference in PFS was observed in estrogen-sensitive or estrogen-resistant mBC in the presence or absence of concomitant PPI treatment (p = 0.852). No correlation with adverse events was found including grade>2 hematological toxicities.
    CONCLUSIONS: The present study supports the hypothesis that the concomitant use of PPIs does not compromise the efficacy of ribociclib in a real-life setting.
    Keywords:  Breast cancer; Drug-drug interactions; PFS; Proton pump inhibitors; Ribociclib
    DOI:  https://doi.org/10.1016/j.breast.2022.10.005
  4. Cancers (Basel). 2022 Oct 11. pii: 4981. [Epub ahead of print]14(20):
       BACKGROUND: Approximately 45-50% of breast cancers (BCs) have a HER2 immunohistochemical score of 1+ or 2+ with negative in situ hybridization, defining the "HER2-low BC" subtype. No anti-HER2 agents are currently approved for this subgroup in Europe, where treatment is still determined by HR expression status. In this study, we investigated the prognostic significance of HER2-low status in HR+/HER2- metastatic BC (MBC) patients treated with endocrine therapy (ET) plus palbociclib as first line.
    METHODS: We conducted a retrospective study including 252 consecutive HR+/HER2- MBC patients who received first-line ET plus palbociclib at six Italian Oncology Units between March 2016 and June 2021. The chi-square test was used to assess differences in the distribution of clinical and pathological variables between the HER-0 and HER2-low subgroups. Survival outcomes, progression-free survival (PFS) and overall survival (OS), were calculated by the Kaplan-Meier method, and the log-rank test was performed to estimate the differences between the curves.
    RESULTS: A total of 165 patients were included in the analysis: 94 (57%) and 71 (43%) patients had HER2-0 and HER2-low disease, respectively. The median age at treatment start was 64 years. No correlation between patients and tumor characteristics and HER2 status was found. Median PFS (mPFS) for the entire study cohort was 20 months (95% CI,18-25 months), while median OS (mOS) was not reached at the time of analysis. No statistically significant differences, in terms of PFS (p = 0.20) and OS (p = 0.1), were observed between HER2-low and HER2-0 subgroups.
    CONCLUSIONS: In our analysis, HR+ MBC patients with low HER2 expression who received first-line treatment with ET plus Palbociclib reported no statistically different survival outcomes compared to HER2-0 patients. Further prospective studies are needed to confirm the clinical role of HER2 expression level.
    Keywords:  HER2-low; breast cancer; cyclin-dependent kinase inhibitor 4 and 6; palbociclib
    DOI:  https://doi.org/10.3390/cancers14204981
  5. Cancers (Basel). 2022 Oct 12. pii: 4996. [Epub ahead of print]14(20):
      A phase I study evaluated the safety, tolerability, and maximum-tolerated dose (MTD)/recommended phase II dose (RP2D) of FCN-437c, a novel, orally available cyclin-dependent kinase inhibitor (CDK4/6i), in participants with advanced/metastatic solid tumors (aSTs). FCN-437c was escalated from 50 mg (once daily [QD] on days 1-21 of 28-day cycles) to the MTD/RP2D. In the dose-expansion phase, patients with CDK4/6i-treated breast cancer, or KRAS-mutant (KRASmut) non-small-cell lung cancer (NSCLC) received the MTD. Twenty-two patients were enrolled. The most common tumors in the dose-escalation phase (n = 15) were breast, colorectal, and lung (each n = 4 [27.3%]). The dose-expansion phase included five (71.4%) patients with breast cancer and two (28.6%) with KRASmut NSCLC. Twenty (90.9%) participants experienced FCN-437c-related adverse events. Dose-limiting toxicities occurred in two (33.3%) participants (200-mg dose, dose-escalation phase): grade 3 neutropenia and grade 4 neutrophil count decreased. Due to toxicities reported at 150 mg QD, the MTD was de-escalated to 100 mg QD. One (4.5%) participant (KRASmut NSCLC, 100-mg dose) achieved a partial response lasting 724+ days, and five (22.7%) had stable disease lasting 56+ days. In conclusion, FCN-437c was well tolerated with encouraging signs of antitumor activity and disease control. Further exploration of FCN-437c in aSTs is warranted.
    Keywords:  CDK4/6 inhibitor; FCN-437c; advanced solid tumors; phase I
    DOI:  https://doi.org/10.3390/cancers14204996