Beside moderate persistent arthralgia and myalgia, no side effects were documented. expression was 90%. After three months of initial treatment, the tumor-associated ulcerations disappeared, and no measurable pulmonary disease was detectable on CT scan. Treatment was well tolerated, and after dosage reduction due to neutropenia, no further side effects have been documented. At present, complete clinical response remains after 15 months of ongoing treatment. Conclusion This case report files an exceptional tumor response of a fast growing, locally advanced, pulmonary metastatic HR+/HER2C de novo breast cancer treated by ribociclib/letrozole combination therapy. Treatment success was long lasting with few side effects. The patient was very satisfied with the treatment and had no specific restrictions in her daily life. strong class=”kwd-title” Keywords: Complete clinical response, Locally advanced metastatic de novo breast cancer, Front-line treatment, Ribociclib, Letrozole Established Facts Endocrine therapy is recommended Rabbit Polyclonal to PRIM1 for advanced hormone receptor-positive breast cancer. CDK 4/6 inhibitors significantly improve disease-free survival in human epidermal growth factor receptor 2-unfavorable, hormone receptor-positive advanced breast cancer. Novel Insights Complete clinical remission in a patient with locally advanced hormone receptor-positive, human epidermal growth factor receptor 2-unfavorable de novo breast cancer treated with ribociclib + letrozole. Long-lasting remission of locally advanced and pulmonary metastatic breast cancer treated with ribociclib/letrozole within the RIBANNA trial. Introduction A total of 3C25% of all newly diagnosed patients Rabeprazole present with de novo hormone receptor-positive (HR+) advanced breast cancer . Current guidelines recommend to use first-line endocrine therapy, with or without a cyclin-dependent kinase (CDK) 4/6 inhibitor, in patients with de novo or relapsed HR+ advanced breast cancer . Three different CDK 4/6 inhibitors are currently available: palbociclib, ribociclib, and abemaciclib . Ribociclib is an orally bioavailable CDK 4/6 inhibitor that has been approved for use in combination with aromatase inhibitor letrozole for the treatment of HR+/human epidermal growth factor receptor 2-unfavorable (HER2?) advanced breast cancer Rabeprazole . This approval is based on findings from the MONALEESA-2 study, a double-blind, placebo-controlled, randomized phase 3 trial (“type”:”clinical-trial”,”attrs”:”text”:”NCT01958021″,”term_id”:”NCT01958021″NCT01958021). First-line therapy with ribociclib + letrozole significantly improved progression-free survival compared with placebo + letrozole in patients with HR+/HER2? advanced breast cancer . Within the MONALEESA-2 study, only two patients with de novo advanced breast cancer receiving ribociclib + letrozole had complete clinical response (CCR) . RIBANNA is an ongoing non-interventional study running in Germany since October 2017 . 3,020 pre-/postmenopausal patients are expected to be finally enrolled receiving ribociclib + aromatase inhibitors (AI), endocrine monotherapy, or chemotherapy as first-line treatment for HR+/HER2C advanced breast cancer. The aim of this study is usually to assess the safety and efficacy of different treatment options. Here, we report about a patient treated within the RIBANNA study with locally extended ulcerated breast cancer and multiple pulmonary metastases. She had had no prior systemic therapy and was treated with ribociclib + AI. After four cycles of treatment, CCR was achieved. Case Report A 60-year-old Caucasian female was referred to our institution with an Rabeprazole enlarged and ulcerated lump in her left breast. She had had no prior history of breast cancer. Except moderate hypertension, no preexisting conditions were reported. Clinical examination revealed an enormous ulcerated tumor in her left breast with widespread erythema and intense local edema (Fig. ?(Fig.1a).1a). Pathological lymph node involvement was palpable in the left axilla. Her right breast and regional lymph nodes showed no tumor involvement. Full body CT scan documented locally advanced breast disease Rabeprazole with axillary lymph node involvement and both-sided pulmonary metastases (Fig. ?(Fig.2a).2a). No other secondary deposits were observed. Scintigraphy showed no bone metastasis at that time. Tru-cut biopsies of the left breast detected a ductal invasive carcinoma, G2, highly progesterone and estrogen receptor positive, HER2C. Ki67 was strongly expressed in more than 90% of the tumor cells. Our local tumor board recommended treatment with CDK 4/6 inhibitor ribociclib and letrozole. Open in a separate window Fig. 1 Locally advanced breast cancer before (a) and after 4 (b) and 8 (c) cycles into the treatment. Open in.