Efficacy of nab-paclitaxel plus trastuzumab in a long-surviving heavily pretreated HER2-positive breast cancer patient with brain metastases.

Brain metastases (BMs) represent a major issue in clinical practice and are associated with a significant worsening of patient's quality of life and, often, a dismal prognosis. Breast cancer (BC) is the second most common solid malignancy that metastasizes to the central nervous system. Incidence of BM varies according to the tumor subtype, with higher rates in patients with epidermal growth factor receptor 2 (HER2) overexpression and in triple negative breast cancers. The incidence of BM in HER2-positive BC patients has increased as a consequence of the success of trastuzumab-based therapy. BM represents an emerging unmet medical need and no specific treatment options exist because, until recently, nearly all randomized clinical trials in metastatic breast cancer (MBC) excluded such patients. Therefore, novel approaches in this setting are eagerly awaited. Herein, we report a lengthy progression-free survival with the combination trastuzumab/nanoparticle albumin-bound (nab)-paclitaxel in a heavily pretreated HER2-positive BC patient with BM. The long-term disease stabilization reported in the present case (>13 months) is of note for several reasons. First, the nab-paclitaxel plus trastuzumab combination, despite several previous lines of treatment, some of which were associated with known activity on BM, was the first systemic therapy not associated with central nervous system recurrence, avoiding recourse to additional locoregional treatments. Moreover, this combination was associated with long extracranial stabilization with minimal toxicity. The remarkably lengthy progression-free survival reported in our case with the nab-paclitaxel plus trastuzumab combination further confirms the efficacy and the favorable toxicity profile of this promising schedule that showed intriguing results in two phase II studies in first-line MBC and suggests a possible activity on BM. In conclusion, weekly nab-paclitaxel plus trastuzumab may represent a valuable option in the treatment of HER2-positive MBC with BM after radiotherapy and is effective and associated with a good toxicity profile, even in heavily pretreated patients.