Aromatase inhibitors: A comprehensive review in mechanisms of action, side effects and treatment in postmenopausal early breast cancer patients

Computational model to explore the endocrine response to trastuzumab action in HER-2/neu positive breast cancer

Breast cancer is a very frequent type of cancer and much attention is paid to therapy with considerable efforts both in the pharmacological and clinical fields.The present work aims to create a non-linear dynamic model of action of the drug Trastuzumab against HER-2 + breast cancer, mainly considering its action of ADCP (antibody-dependent phagocytosis) killing of cancer cells. The model, while also considering the other therapeutic effects induced by Trastuzumab, shows how the action of this monoclonal antibody in the induction of ADCP through the action of macrophages, is strictly connected to the formation of a multi-complex "Trastuzumab -HER-2 - macrophage" that shows a prolonged action over time, responsible for the increase in the Overall Survivor (OS) parameter reported in various. The model shows the correlation between the various therapeutic effects and the killing action of cancer cells through the variation of the dynamic fluctuation of the representative "c" parameter.

Aromatase Inhibitors in Postmenopausal Women with Hormone Receptor-Positive Breast Cancer: Profiles of Psychological Symptoms and Quality of Life in Different Patient Clusters

BACKGROUND

Aromatase inhibitors (AIs) as adjuvant therapy after breast cancer (BC) surgery have demonstrated to reduce the risk of disease recurrence, to lower the risk of contralateral BC, and to improve survival when compared to tamoxifen in patients with limited-stage hormone receptor-positive (HR+) BC. However, AIs are associated with adverse events that can have a significant impact on patient quality of life (QoL).

AIM

This study aimed to identify profiles of psychological symptoms and QoL in HR+ BC patients undergoing AI therapy.

METHOD

Data were collected with questionnaires administered at three time points: AI initiation (t0); 3 months after AI initiation (t1); and 6 months after AI initiation (t2). The FACT-G, FACT-B, and FACT-ES questionnaires were used to assess QoL; psychological symptoms were assessed using the SCL-90-R.

RESULTS

43 women were enrolled in the study (t0), and 37 completed the t1 evaluation and 29 the t2 evaluation. We found (1) a progressive decrease over time in FACT-G and FACT-ES scores, in particular in the Physical, Emotional, and Endocrine subscales, and an increase in the SOM (somatization) subscale of the SCL-90-R; (2) the presence of 4 clusters related to different psychological symptoms and QoL evolution over time; (3) that patients belonging to the cluster characterized by worsening symptoms and QoL during time differed from the others in the Emotional subscale of the FACT-B and in the GSI (Global Score), OCD (obsessive-compulsive), DEP (depression), ANX (anxiety), and SLP (sleep disorders) dimensions of the SCL-90-R and had significantly higher BMI levels; and (4) that 3 items from the SCL-90-R and 2 items from FACT Emotional Well-Being subscale were predictive of the "worst" cluster.

CONCLUSIONS

Although larger studies are needed to confirm these results, our data open up new ways of investigation into the effects of AIs on QoL in HR+ BC patients.

Palbociclib in combination with simvastatin induce severe rhabdomyolysis: a case report

Background

Palbociclib is a selective well-tolerated antineoplastic drug used in the treatment of advanced HER2-negative, estrogen-receptor positive breast cancer that has shown significant improvement in progression-free survival. We present a patient that developed severe rhabdomyolysis with tetra-affection and loss of gait after initiating the first cycle of Palbociclib concomitantly with Simvastatin 40 mg treatment.

Case presentation

A 71-year-old woman with metastatic breast cancer developed tetraparesis and near fatal rhabdomyolysis after initiation of first cycle Palbociclib. For 10 years prior to this treatment, the patient had been treated with Simvastatin without myalgia or other neuromuscular complaints prior to the first cycle of Palbociclib. The patient was admitted at the neurology department, where Palbociclib and Simvastatin were discontinued. The patient was aggressively hydrated and treated with intravenous immunoglobulin therapy with slowly remission and finally regaining independent gait function. Evaluation showed a negative myositis antibody work-up. Muscle magnetic resonance imaging showed edema in multiple foci, but skeletal muscle biopsy did not show necrosis. Post discharge genetic analysis showed single heterozygosity for nucleotide polymorphism rs4149056.

Conclusion

We present a patient who developed severe rhabdomyolysis induced by a combination of Palbociclib and Simvastatin treatment. Rhabdomyolysis was most likely induced by toxic plasma concentrations of Simvastatin due to Palbociclibs inhibition of the CYP3A4 enzyme in combination with a decreased hepatic uptake of Simvastatin due to single nucleotide polymorphism rs4149056. The study underscores that combining Simvastatin and Palbociclib should be done cautiously and genetic testing of the rs4149056 SNP is warranted. If present, Simvastatin should be discontinued or replaced with a lesser myopathic statin in regard to patients risk of cardiovascular events.

Efficacy and safety of fulvestrant in postmenopausal patients with hormone receptor-positive advanced breast cancer: a systematic literature review and meta-analysis

PURPOSE

This meta-analysis was conducted to compare the efficacy and safety of fulvestrant with aromatase inhibitors in postmenopausal women with hormone receptor-positive (estrogen and/or progesterone receptor positive) advanced breast cancer.

METHODS

Electronic databases were searched for randomized controlled trials comparing the efficacy and safety of fulvestrant with three aromatase inhibitors (anastrozole/letrozole/exemestane) published through August 31, 2017. Time to progression/progression-free survival was the primary outcome, while overall survival and safety were the secondary outcomes. Time to progression/progression-free survival was evaluated in subgroups determined on age, hormone receptor status, visceral metastasis, and measurable disease. Hazard ratios with 95% confidence intervals were analyzed by STATA 12.0.

RESULTS

Total of seven randomized controlled trials, with 3168 patients were included for analysis. In the overall population, fulvestrant and aromatase inhibitors had similar time to progression/progression-free survival (Hazard ratio 0.93; 95% confidence interval 0.86-1.01, P = 0.102); however, time to progression/progression-free survival for fulvestrant 500 mg was significantly longer compared with aromatase inhibitors (hazard ratio 0.75; 95% confidence interval 0.62-0.91, P = 0.003). Subgroup analysis revealed significant prolongation of time to progression/progression-free survival with fulvestrant compared with aromatase inhibitors in the patients of estrogen and progesterone receptor-positive (hazard ratio 0.86; 95% confidence interval, 0.75-0.98, P = 0.022) and patients aged ≥ 65 years (hazard ratio 0.81; 95% confidence interval 0.68-0.96, P = 0.014). Overall survival was similar in both groups (hazard ratio 0.89; 95% confidence interval 0.70, 1.13, P = 0.334).

CONCLUSION

In postmenopausal women with estrogen and/or progesterone receptor-positive advanced breast cancer, fulvestrant 500 mg showed better efficacy than aromatase inhibitor, which was not seen with fulvestrant 250 mg. Compared to aromatase inhibitors, fulvestrant prolonged time to progression/progression-free survival in the subgroups including estrogen and progesterone receptor-positive patients and those aged ≥ 65 years.

Chemotherapeutic agents for the treatment of metastatic breast cancer: An update

Breast cancer is the second greatest cause of death among women worldwide; it comprises a group of heterogeneous diseases that evolves due to uncontrolled cellular growth and differentiation and the loss of normal programmed cell death. There are different molecular sub-types of breast cancer; therefore, various options are selected for treatment of different forms of metastatic breast cancer. However, the use of chemotherapeutic drugs is usually accompanied by deleterious side effects and the development of drug resistance when applied for a longer period. This review offers a classification of these chemotherapeutic agents according to their modes of action and therefore improves the understanding of molecular targets that are affected during treatment. Overall, it will allow the clinician to identify more specific targets to increase the effectiveness of a drug and to reduce general toxicity, resistance and other side effects.