Sacubitril/valsartan for cardioprotection in breast cancer (MAINSTREAM): design and rationale of the randomized trial

AIMS

In recent years, survival in patients with breast cancer has increased. Despite the improvement in outcomes of those patients, the risk of treatment-related cardiotoxicity remains high, and its presence has been associated with a higher risk of treatment termination and thus lower therapeutic efficacy. Prior trials demonstrated that a preventive initiation of heart failure drugs, including the renin-angiotensin-aldosterone inhibitors, might reduce the risk of treatment-related cardiotoxicity. However, to date, no study investigated the efficacy of sacubitril/valsartan, a novel antineurohormonal drug shown to be superior to the previous therapies, in the prevention of cardiotoxicity in patients with early-stage breast cancer, which is the aim of the trial.

METHODS AND RESULTS

MAINSTREAM is a randomized, placebo-controlled, double-blind, multicentre, clinical trial. After the run-in period, a total of 480 patients with early breast cancer undergoing treatment with anthracyclines and/or anti-human epidermal growth factor receptor 2 drugs will be randomized to the highest tolerated dose of sacubitril/valsartan, being preferably 97/103 mg twice daily or placebo in 1:1 ratio. The patients will be monitored, including routine transthoracic echocardiography (TTE) and laboratory biomarker monitoring, for 24 months. The primary endpoint of the trial will be the occurrence of a decrease in left ventricular ejection fraction by ≥5% in TTE within 24 months. The key secondary endpoints will be the composite endpoint of death from any cause or hospitalization for heart failure, as well as other imaging, laboratory, and clinical outcomes, including the occurrence of the cancer therapy-related cardiac dysfunction resulting in the necessity to initiate treatment. The first patients are expected to be recruited in the coming months, and the estimated completion of the study and publication of the results are expected in December 2027, pending recruitment.

CONCLUSIONS

The MAINSTREAM trial will determine the efficacy and safety of treatment with sacubitril/valsartan as a prevention of cardiotoxicity in patients with early breast cancer (ClinicalTrials.gov number: NCT05465031).

Thalidomide affects the skeletal system of young rats

Thalidomide has indications for the treatment of several immune-related, neoplastic, and inflammatory diseases, in both adults and children. Despite numerous therapeutic indications for the application of thalidomide, the influence of that drug upon skeletal system has not been recognized. The aim of the present study was to investigate the effects of thalidomide on the osseous tissue in young rats. The experiments were carried out on 5-week-old male Wistar rats. The animals were administered thalidomide in the doses of 15, 30 or 60 mg/kg p.o. over the period of 1, 3 or 6 weeks. The body mass gain, bone mass in the tibia, femur and L-4 vertebra, histomorphometric parameters of the femur (width of trabeculae, width of epiphyseal cartilage, the transverse cross-sectional area of the bone marrow cavity and the cortical bone) and the tibia (width of osteoid, diaphysis transverse growth, the transverse cross-sectional area of the bone marrow cavity and the cortical bone) were studied. The investigations carried out provide, for the first time, information concerning the influence of thalidomide upon bone remodeling processes in young rats. The effects of thalidomide on the skeletal system of young rats depended on the dose and upon application time. After administration of doses 15, 30 and 60 mg/kg p.o. for 1 and 3 weeks, no influence of thalidomide was noted upon the examined macrometric parameters and histomorphometric parameters of femur, tibia and L-4 vertebra in young rats. Significant disturbances of bone remodeling in young rats have been observed after 6 weeks of thalidomide application, while the progression of those changes increased with the increase of the dose administered. After administering the dose of 15 mg/kg p.o. for the period of 6 weeks, no significant changes were found, as regards the macrometric and histomorphometric parameters of bones. Thalidomide, applied 6 weeks in the dose of 30 mg/kg p.o., and in particular in the dose of 60 mg/kg p.o., turned out to disturb bone remodeling processes. In animals administered thalidomide in the dose of 60 mg/kg p.o., reduction mass of tibia, femur, and L-4 vertebra has been observed. In compact bone, thalidomide reduced the diaphysis transverse growth of tibia, reduced the width of osteoid, as well as reduced the transverse cross-sectional area of cortical bone, increased the transverse cross-sectional area of marrow cavity, and increased the transverse cross-sectional area of the marrow cavity/transverse cross-sectional area of the diaphysis ratio of tibia and femur. In cancellous bone, thalidomide reduced the width of bone trabeculae, and increased the width of epiphyseal cartilage. On the basis of the results obtained, one can conclude that thalidomide applied for 6 weeks in the dose of 60 mg/kg p.o. inhibited the bone formation processes and increased the bone resorption in young rats.

Effect of concurrent administration of alendronate sodium and retinol on development of changes in histomorphometric parameters of bones induced by ovariectomy in rats

Retinol is a commonly used vitamin, especially by elderly people. Alendronate sodium, an aminobisphosphonate, is a potent antiresorptive drug used in the treatment of osteoporosis in postmenopausal women. Frequently, alendronate sodium and retinol are used concurrently. There are no reports on the interaction between alendronate sodium and retinol. The aim of the present study was to investigate the effect of concurrent administration of alendronate sodium and retinol on bone remodeling in ovariectomized rats. The histomorphometric parameters of long bones were studied. The experiments were carried out on 3-month-old Wistar rats, divided into 7 groups: I (C) - sham operated control rats, II (OVX) - ovariectomized control rats, III (OVX + ALN) - ovariectomized rats + alendronate sodium (3 mg/kg po), IV (OVX + R-1) - ovariectomized rats + retinol (700 IU/kg po), V (OVX + R-2) - ovariectomized rats + retinol (3500 IU/kg po), VI (OVX + ALN + R-1) - ovariectomized rats + alendronate sodium (3 mg/kg po) + retinol (700 IU/kg po), VII (OVX + ALN + R-2) - ovariectomized rats + alendronate sodium (3 mg/kg po) + retinol (3500 IU/kg po). The drugs were administered to the rats daily by oral gavage (alendronate sodium in the morning, retinol in the afternoon) for 28 days. Body mass gain, bone mass, mineral content in the tibia, femur and L-4 vertebra, histomorphometric parameters of the right tibia (width of osteoid, periosteal and endosteal transverse growth, area of the transverse cross section of the bone marrow cavity and the cortical bone) and the right femur (width of epiphyseal and metaphyseal trabeculae, width of epiphyseal cartilage) were studied. Bilateral ovariectomy induced osteopenic skeletal changes in mature female rats. Alendronate sodium administered at a dose of 3 mg/kg po daily inhibited the development of changes induced by ovariectomy in the skeletal system of rats. Retinol, especially administered at the dose of 3500 IU/kg daily, intensified the changes in the osseous system caused by estrogen deficiency in rats. Retinol administered concurrently with alendronate sodium attenuated the antiresorptive effect of alendronate sodium on the skeletal system in ovariectomized rats.