Efficacy of epidermal growth factor receptor tyrosine kinase inhibitors for brain metastasis in non-small cell lung cancer patients harboring either exon 19 or 21 mutation

Targeted therapies in brain metastases

OPINION STATEMENT

Brain metastases are a major clinical problem in patients with advanced breast cancer, lung cancer, melanoma, and renal cell carcinoma. Initial treatment for patients with brain metastases typically includes radiotherapy, either whole brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), or both. Surgical resection is generally reserved for good prognosis patients with limited/controlled extracranial metastases and a single brain lesion. Once patients progress through upfront treatment, the treatment approach is quite variable and there is no clearly defined standard-of-care. Over the past decade, the role of systemic therapies and in particular, targeted therapies has been increasingly explored in patients with brain metastases from solid tumors. For example, lapatinib has been studied as monotherapy, and in combination with capecitabine, in patients with HER2-positive breast cancer, and activity has been observed in both the upfront and refractory settings. In patients with nonsmall cell lung cancer (NSCLC), central nervous system (CNS) activity has been reported with gefinitib and erlotinib. Finally, in melanoma, the B-raf inhibitors vemurafenib and dabrafenib, and the immunomodulator, ipilumimab, have reported CNS activity. Moving forward, the challenge will be to understand how to optimize the activity of targeted agents in the CNS and how to best incorporate them into the current treatment paradigms in order to improve outcomes for this patient population.

Breaking and entering into the CNS: clues from solid tumor and nonmalignant models with relevance to hematopoietic malignancies

Various malignancies invade the CNS sanctuary site, accounting for the vast majority of CNS neoplastic foci and contributing to significant morbidity as well as mortality. The blood-brain barrier (BBB) exhibits considerable impermeability to chemotherapeutic agents, severely limiting therapeutic options available for patients developing metastatic CNS involvement, accounting for poor outcomes. The mechanisms by which malignant cells breach the highly exclusive BBB and subsequently survive in this unique anatomical site remain poorly understood, with most of the current knowledge stemming from nonmalignant and solid malignancy models. While solid and hematologic malignancies may face different challenges once within the CNS (e.g., solid tumor parenchymal metastasis compared to masses/nodules/leptomeningeal disease in hematologic malignancies), commonality exists in the process of migrating across the BBB from the circulation. Specifically considering this last point, this review aims to survey the current mechanistic knowledge regarding malignant migration across the BBB, necessarily emphasizing the better studied solid tumor and nonmalignant models with the intention of highlighting both the current knowledge gap and additional work required to effectively consider how hematopoietic malignancies breach the CNS.

Chemotherapy and EGFR tyrosine kinase inhibitors for treatment of brain metastases from non-small-cell lung cancer: survival analysis in 210 patients

BACKGROUND

Chemotherapy and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors are controversial in the treatment of patients with brain metastases from non-small-cell lung cancer (NSCLC).

METHODS

We retrospectively studied the effects of solely localized treatment or localized treatment in combination with chemotherapy and/or EGFR tyrosine kinase inhibitors on outcomes in 210 NSCLC patients with brain metastases. The effects of treatment modality, Karnofsky performance status, age, primary tumor histology, number of brain metastases, and other factors on survival time were analyzed, and the robustness of two prognostic indices, ie, recursive partitioning analysis and graded prognostic assessment, was evaluated.

RESULTS

The median survival time in patients with systemic medication and localized treatments was higher than in those with localized treatments alone (11 versus 3 months, P=0.000). Within the systemic medication group, median survival time was significantly longer for EGFR tyrosine kinase inhibitors than for other types of chemotherapy (12 versus 9 months, P=0.002). In the EGFR tyrosine kinase inhibitor group, median survival time for patients with EGFR gene mutation was 20 months versus 8 months for those with the wild-type EGFR gene. The median survival time with pemetrexed was significantly higher than with other chemotherapies (13 versus 7 months, P=0.006). In multivariate analysis, the prognosis was significantly correlated with treatment modality (P=0.000), Karnofsky performance status (P=0.000), number of brain metastases (P=0.001), and histologic tumor type (P=0.007). In the graded prognostic assessment model, survival curves for the subgroups showed clear separations.

CONCLUSION

NSCLC patients with brain metastasis benefited from pemetrexed and/or tyrosine kinase inhibitors along with localized treatments, and the graded prognostic assessment index is a robust model for prognostic evaluation.

The concentration of erlotinib in the cerebrospinal fluid of patients with brain metastasis from non-small-cell lung cancer

It has been demonstrated that erlotinib is effective in treating patients with brain metastasis from non-small-cell lung cancer. However, the number of studies determining the erlotinib concentration in these patients is limited. The purpose of this study was to measure the concentration of erlotinib in the cerebrospinal fluid of patients with brain metastasis from non-small-cell lung carcinoma. Six patients were treated with the standard recommended daily dose of erlotinib (150 mg) for 4 weeks. All the patients had previously received chemotherapy, but no brain radiotherapy. At the end of the treatment period, blood plasma and cerebrospinal fluid samples were collected and the erlotinib concentration was determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The average erlotinib concentration in the blood plasma and the cerebrospinal fluid was 717.7±459.7 and 23.7±13.4 ng/ml, respectively. The blood-brain barrier permeation rate of erlotinib was found to be 4.4±3.2%. In patients with partial response (PR), stable disease (SD) and progressive disease (PD), the average concentrations of erlotinib in the cerebrospinal fluid were 35.5±19.0, 19.1±8.7 and 16.4±5.9 ng/ml, respectively. In addition, the efficacy rate of erlotinib for metastatic brain lesions was 33.3%, increasing to 50% in patients with EGFR mutations. However, erlotinib appeared to be ineffective in cases with wild-type EGFR. In conclusion, a relatively high concentration of erlotinib was detected in the cerebrospinal fluid of patients with brain metastases from non-small-cell lung cancer. Thus, erlotinib may be considered as a treatment option for this patient population.

Pruritus in patients treated with targeted cancer therapies: systematic review and meta-analysis

BACKGROUND

Pruritus has been anecdotally described in association with targeted cancer therapies. The risk of pruritus has not been systematically ascertained.

OBJECTIVE

A systematic review and meta-analysis of the literature was conducted for axitinib, cetuximab, dasatinib, erlotinib, everolimus, gefitinib, imatinib, ipilimumab, lapatinib, nilotinib, panitumumab, pazopanib, rituximab, sorafenib, temsirolimus, tositumomab, vandetanib, and vemurafenib.

METHODS

Databases from PubMed, Web of Science (January 1998 through July 2012), and American Society of Clinical Oncology abstracts (2004 through 2012) were searched. Incidence and relative risk of pruritus were calculated using random- or fixed-effects model.

RESULTS

The incidences of all-grade and high-grade pruritus were 17.4% (95% confidence interval 16.0%-19.0%) and 1.4% (95% confidence interval 1.2%-1.6%), respectively. There was an increased risk of all-grade pruritus (relative risk 2.90 [95% confidence interval 1.76-4.77, P < .001]) and variation among different drugs (P < .001).

LIMITATIONS

The reporting of pruritus may vary, resulting from concomitant medications, comorbidities, and underlying malignancies. We found a higher incidence of pruritus in patients with solid tumors, concordant with those targeted therapies with the highest pruritus incidences.

CONCLUSION

There is a significant risk of developing pruritus in patients receiving targeted therapies. To prevent suboptimal dosing and decreased quality of life, patients should be counseled and treated against this untoward symptom.

[Advances in diagnosis and treatment of brain metastases from the primary lung cancer]

肺癌脑转移的发生率为23%-65%，是脑转移性肿瘤中最常见的类型，且预后较差。目前肺癌脑转移的诊治和分子机理已成为众多研究的热点之一。本文就肺癌脑转移的临床特征、诊断和治疗方面的进展以及最新脑转移的机制学研究做了系统的综述。

Treating Patients With EGFR-Sensitizing Mutations: First Line or Second Line—Is There a Difference?

First-line epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) is a standard treatment for patients with activating EGFR mutations. Six randomized studies have demonstrated consistent improvement in tumor response rate and progression-free survival over platinum-based combination chemotherapy. The only reason to consider EGFR TKI as second-line therapy is that none of the six comparative studies has shown improvement in overall survival, which can be explained by the high proportion of patients from the chemotherapy arm crossing over to the EGFR TKI arm on progression. It is true that patients with EGFR mutations may benefit from second-line EGFR TKI therapy, but we cannot conclude that the benefit is either equal to or inferior to first-line EGFR TKI therapy. To date, there are no direct comparative data between first- and second-line EGFR TKI in patients with activating EGFR mutations. Tumor response rates to second-line EGFR TKI have been inconsistent, which could potentially be explained by the impact of first-line chemotherapy on the abundance of tumor cells with activating EGFR mutations. However, numerous arguments, including assurance on drug exposure, improvement in quality of life, better tolerance by patients with poor performance status, and deferral of whole-brain radiation therapy for patients with brain metastasis, support the general application of first-line EGFR TKI.