CDK4/6 inhibitors in breast cancer: differences in toxicity profiles and impact on agent choice. A systematic review and meta-analysis.

Introduction: CDK4/6 inhibitor approval for hormone-responsive breast tumors has significantly changed therapeutic algorithms, with three drugs currently approved.Areas covered: Here, we analyze the toxicity profiles of palbociclib, ribociclib, and abemaciclib through a systematic review and meta-analysis. Palbociclib and ribociclib showed high rates of hematological toxicity, primarily neutropenia, and were associated with a low rate of severe infections. Abemaciclib was associated with a high rate of gastrointestinal toxicities, primarily diarrhea, of grade 1-2 in most cases. Ribociclib was associated with a high rate of hepatic, and respiratory toxicity and with QTc prolongation. The toxicity rate of ribociclib was higher in metastatic patients than non-metastatic patients, with approximately 33% more grade 3-4 toxicities and 21% more grade 3-4 neutropenic events. A 5% higher risk of diarrhea was observed in postmenopausal patients. Pre-treated patients did not show a higher toxicity rate for palbociclib/ribociclib than previously untreated patients, while a 26% higher risk of any grade neutropenia and 6% higher risk of grade 3-4 diarrhea were observed with abemaciclib.Expert opinion: Considering the similar efficacies and indications of palbociclib, ribociclib, and abemaciclib, the evaluation of their toxicity profiles may facilitate treatment choice.

Four lines of anaplastic lymphoma kinase inhibitors and brain radiotherapy in a long-surviving non-small-cell lung cancer anaplastic lymphoma kinase-positive patient with leptomeningeal carcinomatosis.

Lung cancer is the most common tumor and the leading cause of cancer-related death worldwide. Approximately 6.7% of non-small-cell lung cancers (NSCLCs) show anaplastic lymphoma kinase (ALK) rearrangement and could benefit from ALK-targeted treatment. Various anti-ALK drugs have been developed during the past years, but it is actually controversial which sequence and which ALK inhibitor is recommended for a single patient. Leptomeningeal carcinomatosis (LC) is associated with a poor prognosis, with an overall survival of 2-4 months for treated patients. The data about LC management derive mainly from retrospective studies, being an exclusion criterion for most trials. Intrathecal chemotherapy and whole-brain radiotherapy (WBRT), associated with a systemic treatment, are the most commonly used approach. Here we present a case of NSCLC harboring an ALK translocation treated with four lines of ALK inhibitors and receiving WBRT for LC, showing an overall survival of ∼5 years from the diagnosis of metastatic disease. This case report focuses mainly on several controversial clinical aspects, that is, the sequence of treatment in ALK-positive NSCLC, the ALK inhibitors' efficacy on brain disease and beyond progression, the management of LC, and the role of WBRT despite the risk of cognitive impairment.

A nomogram to predict 5-fluorouracil toxicity: when pharmacogenomics meets the patient.

Fluoropyrimidines combined with other agents are commonly used for gastrointestinal cancer treatment. Considering that severe toxicities occur in 30% of patients, we aimed to structure a nomogram to predict toxicity, based on metabolic parameter and patients' characteristics. We retrospectively enrolled patients affected by gastrointestinal tract cancers. Pretreatment 5-fluorouracil (5-FU) degradation rate and DPYD, TSER, MTHFR A1298T, and C677T gene polymorphisms were characterized. Data on toxicities were collected according to CTCAE v3.0. Multivariate logistic regression analysis was used to structure a nomogram. 642 patients were enrolled (384 men; 258 female; median age: 67 years, range: 27-87): 449 (69.9%) patients were affected by colorectal cancer; 118 (18.4%) by gastroesophageal cancer; 66 (10.3%) by pancreatic cancer; and nine (1.4%) by other cancers. Grade 3-4 toxicities were observed in 118 (18.4%) patients and were most frequently observed in patients with altered 5-FU degradation rate (43.5 and 26.7% of the patients in the poor metabolizer and in the ultrarapid metabolizer group respectively, vs. 17% in the normal metabolizer group) and in DPYD heterozygous mutated patients (83.3% of the patients). Age, DPYD status, the number of drugs administered, and 5-FU degradation rate value were associated to severe toxicities. On the basis of these findings, we structured a nomogram to assess a score to predict the risk of developing severe toxicity. Compared with the available pharmacogenetic tests, this approach can be applied to the whole population, predicting the risk for severe toxicity, with an easy, low-cost, and not invasive technique.

5-Fluorouracil degradation rate could predict toxicity in stages II-III colorectal cancer patients undergoing adjuvant FOLFOX.

5-Fluorouracil is commonly used for gastrointestinal cancer treatment in an adjuvant setting; however, the toxicity can lead to a reduction, delay, or discontinuation of treatment. We retrospectively investigated the association between the 5-fluorouracil degradation rate (5-FUDR) and genetic polymorphisms of TSER, DPYD, and MHTFR with toxicity in colorectal cancer patients treated with adjuvant FOLFOX. Pretreatment 5-FUDR and MTHFR A1298T or C677T, TSER, and DPYD gene polymorphisms were characterized in stages II-III colorectal cancer patients. Patients were classified into three metabolic classes according to the 5-FUDR value. Association with toxicities was evaluated retrospectively using logistic regression analysis. Overall, 126 patients were selected (35 women, 91 men). Seven patients were poor metabolizers, 116 patients were normal metabolizers and three patients were ultra-rapid metabolizers. The median 5-FUDR was 1.53 ng/ml/10 cells/min (range: 0.42-2.57 ng/ml/10 cells/min). Severe, rate-limiting toxicities (grades 3-4) were encountered in 22.2% of patients. No associations between MTHFR or TSER polymorphisms and toxicity were detected, whereas 5-FUDR showed a statistically significant association with toxicity (P=0.0047). The DPYD heterozygous mutation was detected in only one patient, who showed grade 4 hematological toxicity and a lower 5-FUDR value. The 5-FUDR value seems not to be affected by MTHFR and TSER polymorphisms. Compared with the available pharmacogenomics tests, the pretreatment evaluation of 5-FUDR increases the proportion of identified colorectal patients at high risk for severe toxicity. Thus, it appears to be a suitable pretreatment toxicity biomarker in a subgroup of patients in whom dose-intensity maintenance is the key factor.

The TYMS-TSER polymorphism is associated with toxicity of low-dose capecitabine in patients with advanced gastrointestinal cancer.

Low doses of drugs delivered at close, regular intervals are increasingly being used to manage patients with different neoplasms. Despite the good tolerability, treatment-related adverse events still occur following metronomic protocols. The aim of this study was to retrospectively investigate whether polymorphisms of different genes involved in fluoropyrimidine metabolism and 5-fluorouracil (5-FU) degradation rate were associated with the outcome of a low-dose capecitabine schedule. Genotyping of DPYD IVS14+1 G>A, MTHFR C677T, and A1298C single-nucleotide polymorphisms was performed by pyrosequencing technology. A PCR technique was used for genotyping TYMS-TSER. Using peripheral blood mononuclear cells, we also evaluated the 5-FU degradation rate, which determines the net result of all the enzymatic transformation of 5-FU, in terms of the amount of drug consumed by the cells in a time unit. The association of these variables with clinical outcome was evaluated using multivariate logistic regression analysis. Eighty-four patients with metastatic gastrointestinal cancer, who had been treated with a low-dose fluoropyrimidine schedule, as a rescue therapy were included in the study. The TSER 2R/2R genotype was significantly associated with both hematologic (odds ratio=7.90, P=0.002) and gastrointestinal toxicity (odds ratio=3.24, P=0.009). Because DPYD IVS14 G>A single-nucleotide polymorphism was not observed in the cohort, it was excluded from the statistical analysis. No significant association was detected between clinical outcome and both MTHFR polymorphisms and the 5-FU degradation rate. In the advanced setting of cancer care, high attention should be paid toward avoiding toxicity and worsening of quality of life. Although metronomic chemotherapy is generally well tolerated, treatment toxicity nonetheless does occur. Our data suggest a possible role of the TSER 2R/2R polymorphism as a predictive marker of toxicity in patients treated with low-dose capecitabine.

A metronomic schedule as salvage chemotherapy for upper gastrointestinal tract cancer.

In recent years, metronomic chemotherapy, consisting of continuous administration of low doses of cytotoxic agents, has being used as rescue therapy for different tumours. The aim of this study was to retrospectively assess the efficacy and safety of low-dose metronomic, oral capecitabine in pretreated or frail patients with recurrent upper gastrointestinal tract cancer. Patients with pretreated upper gastrointestinal tract cancer or who were not candidates for standard chemotherapy because of toxicity concerns received capecitabine at 1500 mg per day continuously until disease progression or occurrence of toxicity. Forty-seven patients (25 oesophagogastric cancer, 22 pancreatobiliary cancer; 25 men, 22 women; median age 69 years, range 42-90) were included in the study. Forty-five percent of the patients had received at least two previous lines of treatment and the median number of previous treatments was 1 (range 0-5). Twelve (31.6%) patients achieved clinical benefit (one partial response, 11 stable disease), whereas nine (23.7%) patients were progression free for at least 6 months. In an exploratory analysis, there was a significant relationship between performance status and clinical benefit (hazard ratio=8.25; P=0.01). The median overall survival was 5 months. A good performance status was associated with a longer survival (hazard ratio=0.26; P<0.01). No severe toxicity or treatment-related death was reported. Metronomic capecitabine showed good safety and moderate activity in frail or pretreated patients with advanced, upper gastrointestinal tract cancer.