Mechanisms of resistance to cyclin-dependent kinase 4/6 inhibitors.

Cyclin-dependent kinase (CDK) 4/6 inhibitors have emerged in the treatment of metastatic hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer. However, most patients will eventually present disease progression, highlighting the inevitable resistance of cancer cells to CDK4/6 inhibition. Several studies have suggested that resistance mechanisms involve aberrations of the molecules that regulate the cell cycle, and the re-wiring of the cell to escape CDK4/6 dependence and turn to alternative pathways. Loss of retinoblastoma function, overexpression of CDK 6, upregulation of cyclin E, overexpression of CDK 7, and dysregulation of several signaling pathways, notably the PI3/AKT/mTOR pathway, have been implicated in the development of resistance to CDK4/6 inhibitors. Overlap with endocrine resistance mechanisms might be possible. Combinational therapeutic strategies should be explored in order to prevent resistance and optimize the management of patients after progression under CDK 4/6 inhibition.

Observational Study of Clinical Practice in Patients with Pancreatic Adenocarcinoma in Greece.

BACKGROUND: During the last decade, significant improvement was made in systemic therapy of pancreatic adenocarcinoma (PAC). The impact of this progress in everyday clinical practice has not been fully described yet. The aim of the study was to investigate the pattern followed by Greek Medical Oncologists regarding the treatment of patients with PAC. METHODS: This observational, noninterventional multicenter study recorded clinical data from the files of 200 active patients (alive and under treatment or follow-up) for a two-year period (November 2015 until November 2017) from 20 oncology centers around Greece. RESULTS: In total, 51 (25.5%) patients underwent radical surgical resection of PAC, and 40 (78.4%) of them received adjuvant and 1 (2.0%) neoadjuvant chemotherapy. The median time to recurrence was 7.9 months, and median overall survival (OS), 20.2 months. First-line chemotherapy was administered to 193 (96.5%) patients. The majority of patients were treated with the combination of nab-paclitaxel-gemcitabine (NPG), 5-fluorouracil, leucovorin, irinotecan, oxaliplatin (FOLFIRINOX), or gemcitabine monotherapy. Of them, 39.5% responded to the treatment. Median OS and PFS were 14.1 months and 7.0 months, respectively. Second-line treatment was administered to 112 patients. The majority received NPG, FOLFIRINOX/capecitabine, oxaliplatin, irinotecan (CAPOXIRI), or 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX)/capecitabine, oxaliplatin (CAPOX). Median OS with second-line treatment was 8.6 months, and median PFS, 5.5 months. The most common chemotherapy sequences were NPG as first-line followed by FOLFIRINOX/CAPOXIRI as second-line, NPG followed by FOLFOX/CAPOX, NPG followed by other regimens, and FOLFIRINOX/CAPOXIRI followed by NPG. CONCLUSION: This study described the significant improvement in prognosis of PAC patients receiving palliative chemotherapy and the relatively high rate of receipt of second-line chemotherapy, according to real-world data. However, due to the nonrandomized nature of the study, any comparison between different chemotherapy regimens should be regarded with caution.

Cerebral metastasis from osteosarcoma: "Bone" in the brain.

Although brain metastases from bone and soft tissue sarcoma are uncommon, advances in sarcoma treatment have led to an increasing incidence of them. We present a 23-year-old male with a history of metastatic femoral osteosarcoma, who presented with headache and unsteady gait and was diagnosed with a cerebellar metastasis. CT scan revealed a mass in the left cerebellar parenchyma with large intralesional central calcification and perilesional edema. Corticosteroid treatment led to neurological symptoms resolution, with a rapid tapering. The patient had also lung metastases and we opted to administer systemic treatment with the tyrosine kinase inhibitor cabozantinib. Given the relative radioresistance of osteosarcomas, the patient did not receive radiation therapy.

Nivolumab in patients with rare head and neck carcinomas: A single center's experience.

Immunotherapy (IO) with anti-PD1 inhibitors is available for the treatment of recurrent/metastatic squamous cell carcinomas of the head and neck (SCCHD) since 2016. Both nivolumab and pembrolizumab were tested in phase 3 randomized trials in adults progressing on or after platinum-based therapy and were found to confer an overall survival benefit compared to investigator's choice. However, very limited data exist concerning IO use in rare subtypes of head and neck carcinoma, like salivary gland carcinoma. We retrospectively collected clinical data of all patients diagnosed with rare subtypes of head and neck carcinoma, who were treated with immune checkpoint inhibitors in our department during the last 5 years. We analyzed safety and efficacy of these therapies. We identified six patients who received nivolumab for recurrent or metastatic head and neck carcinomas, between 31 and 57 years old. All patients had received at least one line of platinum-chemotherapy, as well as radiation therapy. Treatment was administered every 2 weeks, at a dose of 3 mg per kilogram of body weight. Number of nivolumab cycles varied between 2 and 18. Progression-free survival varied from 1 to 12 months and overall survival from 4 to 24 months. Tolerance was very good, except for one case of diabetes and hypothyroidism requiring medication. There is currently insufficient evidence regarding the optimal treatment of the rare non-squamous cell carcinoma of the head and neck. Our case series supports a role for immunotherapy in these patients. However, larger collaborative studies are needed to evaluate this treatment.

Subcutaneous Trastuzumab Combined with Pertuzumab and Docetaxel as First-line Treatment of Advanced HER2-positive Breast Cancer.

BACKGROUND/AIM: Subcutaneous (s.c.) trastuzumab was introduced in the (neo)adjuvant setting, based on the non-inferiority results and patient preference. In the advanced setting, preliminary safety data have only been reported. We conducted an observational study of s.c. trastuzumab in combination with i.v. pertuzumab and docetaxel in the first-line setting of human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer. PATIENTS AND METHODS: In this single-institution study, patients received 600 mg s.c. trastuzumab in combination with 840 mg pertuzumab for the first cycle and 420 mg for the following cycles, and 75-100 mg/m2 docetaxel, followed by maintenance with s.c. trastuzumab and pertuzumab until disease progression or unacceptable toxicity. Endpoints were efficacy and safety. RESULTS: Forty patients were enrolled. The median number of cycles with docetaxel was six, while the median number of maintenance cycles was 21. With a median follow-up of 37 months, median progression-free survival and overall survival were 24 and 35 months. CONCLUSION: Subcutaneous trastuzumab in combination with pertuzumab and docetaxel is well tolerated and effective in HER2-positive advanced breast cancer.

Biweekly Gemcitabine/Nab-Paclitaxel as First-line Treatment for Advanced Pancreatic Cancer.

BACKGROUND/AIM: During recent years, a survival advantage was reported for first-line treatment of advanced pancreatic cancer with two new regimens, FOLFIRINOX and gemcitabine/nab-paclitaxel, over gemcitabine monotherapy. Gemcitabine/nab-paclitaxel administration on days 1, 8 and 15 of a 4-week cycle is associated with some practical disadvantages. We adopted a biweekly regimen with the same dose density. PATIENTS AND METHODS: Patients with Eastern Cooperative Oncology Group performance status 0-2 diagnosed with advanced histologically or cytologically confirmed pancreatic cancer and no prior treatment were included in the study. Study combination included 1.5 g/m2 gemcitabine and 175 mg/m2 nab-paclitaxel given every 2 weeks. Survival analysis was performed using the Kaplan-Meier method. RESULTS: Forty-six patients were treated with this regimen. Adverse events were similar to those of the original regimen. Median progression-free and overall survival were 5 and 10 months, respectively. CONCLUSION: Biweekly gemcitabine/nab-paclitaxel seems to have a similar safety and efficacy profile as the original regimen.