乳腺癌（BC）是一种严重的疾病，被认为是全世界重要的健康问题。根据 Rosstat 的数据，2020 年俄罗斯联邦女性中该疾病的患病率为 64,951 例（占所有类型癌症的 21.7%）。  激素依赖性雌激素受体阳性（HR）、人表皮生长因子受体2型阴性（HER2-）转移性乳腺癌（mBC）占所有病例的70%。  约 40% 的 ER/HER2- mBC 患者存在 PIK3CA 基因突变，导致磷脂酰肌醇 3-激酶 (PI3K) 的 α 亚型 (p110α) 过度激活。联合或不联合细胞周期蛋白依赖性激酶 4 和 6 (CDK4/6) 抑制剂的激素治疗被认为是 ER /HER2- mBC 患者的标准治疗方法。然而，对该疗法的获得性耐药仍然是一个问题。治疗乳腺癌的创新方法是使用旨在直接抑制 PI3K 通路的靶向治疗药物与激素治疗相结合。 Alpelisib 是一种 PI3Kα 特异性抑制剂。高血糖是 alpelisib 治疗最常见的副作用。目前，对于接受 alpelisib 治疗的患者预防和纠正高血糖已达成共识，建议在开始治疗之前，为了诊断碳水化合物代谢紊乱并评估发生高血糖的风险，应确定所有患者的：糖化血红蛋白 (HbA1c)、空腹血糖血浆 (FPG)、体重指数 (BMI)。还要评估诸如是否存在 2 型糖尿病 (DM 2) 家族史、患者病史中是否存在妊娠期糖尿病或是否出生过体重超过 4 公斤的儿童等危险因素。 最近，新的药物组合已被积极用于治疗碳水化合物代谢紊乱，例如吡格列酮二甲双胍。本文讨论了PI3K抑制剂的作用机制、新的治疗组合及其不良反应，并介绍了治疗经验。

Breast cancer (BC) is a serious disease and is considered an important health problem worldwide. The prevalence of the disease in women according to Rosstat was 64,951 cases in the Russian Federation in 2020 (21.7% among all types of cancer).  Hormone-dependent estrogen receptor-positive (HR+), human epidermal growth factor receptor type 2 negative (HER2-) metastatic breast cancer (mBC) accounts for 70% of all cases.  About 40% of patients with ER+/HER2- mBC have mutations in the PIK3CA gene, leading to hyperactivation of the alpha isoform (p110α) of phosphatidylinositol 3-kinase (PI3K). Hormonal therapy with or without cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor is considered the standard treatment for patients with ER+/HER2- mBC. However, acquired resistance to this therapy remains a problem. Innovative methods for the treatment of breast cancer are the use of targeted therapeutic agents aimed at direct inhibition of the PI3K pathway in combination with hormone therapy. Alpelisib is a PI3Kα-specific inhibitor. Hyperglycemia is the most common side effect of alpelisib treatment. Currently, there is a consensus on the prevention and correction of hyperglycemia in patients receiving therapy with alpelisib, which recommends that before starting therapy, in  order to diagnose carbohydrate metabolism disorders and assess the risk of developing hyperglycemia, determine in all patients: the level of glycated hemoglobin (HbA1c), glucose fasting plasma (FPG), body mass index (BMI). And also to evaluate such risk factors as the presence of a family history of type 2 diabetes mellitus (DM 2), the presence of gestational diabetes in the patient's history, or the fact of the birth of children weighing more than 4 kilograms.Recently, new combinations of drugs have been actively used to treat disorders of carbohydrate metabolism, such as pioglitazone + metformin. This paper discusses the mechanism of action of PI3K inhibitors, new therapeutic combinations and their undesirable effects, and presents therapeutic experience.