Abstract P1-08-17: Successful Treatment of Early Triple-Negative Breast Cancer with Chemotherapy and Immune Checkpoint Inhibitor in the Setting of Sickle Cell Disease: a Case Report

Abstract Triple-negative breast cancer (TNBC) accounts for 10-15% of all breast cancers and is known for its aggressive clinical behavior and limited treatment options compared to other breast cancer subtypes1. In recent years, immunotherapy, particularly PD-1/PD-L1 checkpoint inhibitors, has shown promise in treating TNBC when combined with chemotherapy2. The keynote 522 trial3 demonstrated a significant improvement in pathological complete response with the addition of pembrolizumab to multiagent chemotherapy. Although improved responses have been observed, administering this regimen may pose challenges in patients with significant comorbidities. In rare cases, such as in patients with sickle cell disease, the benefit of standard-of-care treatment must be carefully weighed with the increased risk for severe side effects and complications resulting from cancer therapy. We report a case of TNBC diagnosed in a patient with sickle cell disease. This case underscores the feasibility of the Keynote 522 regimen in such individuals and emphasizes the importance of coordinated care between breast oncology and benign hematology teams. Our patient of interest is a 46-year-old African-American woman with a longstanding history of sickle cell disease (SCD) on hydroxyurea, diagnosed with a self-palpated T2N0M0 breast cancer that was ER 0%, PR 0%, Ki-67 40%, and HER2-Neu negative (TNBC). The patient’s other comorbidities include hypertension, diabetes mellitus, and deep vein thrombosis treated with long-term anticoagulation. Given the benefits of chemotherapy and pembrolizumab (the keynote 522 regimen) in TNBC, this protocol was offered to this patient with curative intent. A literature review highlighted the paucity of data on the treatment of breast cancer with immunotherapy and chemotherapy in the setting of sickle cell anemia. Our patient was started on neoadjuvant chemotherapy with paclitaxel and carboplatin for the first cycle, with pembrolizumab added to the regimen from cycle 2 onwards. The patient ceased use of hydroxyurea and was switched to chronic simple blood transfusions of 2 units PRBCs every 4 weeks, with a goal Hgb S of <45% and total Hgb of 7.0 g/dL. The care team also elected to forego the use of G-CSF and limited use of dexamethasone during treatment due to the potential increased risk for sickle cell crisis with these agents. Additionally, an extra 500 mL normal saline was administered with each chemotherapy infusion. With these measures, our patient has successfully completed 3 cycles of therapy without significant adverse events. She is exhibiting an excellent clinical response to therapy with near resolution of the palpable area of disease on physical exam. Following the completion of 4 cycles of carboplatin, paclitaxel, and pembrolizumab therapy, we plan to obtain a mid-treatment breast MRI to further assess treatment response and proceed to anthracycline-based therapy with pembrolizumab. This patient’s reasonable tolerance to therapy coupled with the robust clinical response provides an optimistic view regarding treatment options for breast cancer in patients with sickle cell disease. While close observation and meticulous care coordination are necessary in patients with hemoglobinopathies undergoing cancer treatment, this case demonstrates a significant benefit from treatment with only expected treatment toxicities observed at this time. References: [1] Won KA, Spruck C. Triple-negative breast cancer therapy: Current and future perspectives (Review). Int J Oncol. 2020;57(6):1245-1261. doi:10.3892/ijo.2020.5135 [2] Cortes J, Rugo HS, Cescon DW, et al. Pembrolizumab plus Chemotherapy in Advanced Triple-Negative Breast Cancer. N Engl J Med. 2022;387(3):217-226. doi:10.1056/NEJMoa2202809 [3] Schmid P, Cortes J, Pusztai L, et al.: Pembrolizumab for early triple-negative breast cancer. N Engl J Med. 2020, 382:810-21. 10.1056/NEJMoa1910549 Citation Format: Stevany Saxon-Filipe, Luise Froessl, Samira Syed. Successful Treatment of Early Triple-Negative Breast Cancer with Chemotherapy and Immune Checkpoint Inhibitor in the Setting of Sickle Cell Disease: a Case Report [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P1-08-17.