Maintenance therapy for advanced non-small cell lung cancer: current status, controversies, and emerging consensus

The efficacy and toxicity of maintenance therapy with bevacizumab plus pemetrexed versus bevacizumab/pemetrexed alone for stage IIIB/IV nonsquamous non-small cell lung cancer: A meta-analysis of randomized controlled trials

WHAT IS KNOWN AND OBJECTIVE

Whether maintenance therapy with bevacizumab (Bev) + pemetrexed (Pem) can achieve greater clinical benefits than Bev or Pem alone for stage IIIB/IV nonsquamous non-small cell lung cancer (NSCLC) remains unclear. We assessed the antitumour effect and toxicity of maintenance Bev+Pem versus maintenance with single-agent Bev/Pem in this meta-analysis.

METHODS

Appropriate randomized controlled trials (RCTs) were screened using electronic databases (Google Scholar, PubMed, Embase, Scopus, ScienceDirect, Ovid MEDLINE, Cochrane and Web of Science). The endpoints were progression-free survival (PFS), overall survival (OS) and adverse events (AEs).

RESULTS AND DISCUSSION

We included six RCTs that contained 2,447 patients receiving induction therapy with platinum-based combination therapies. The maintenance therapy Bev+Pem group had prolonged PFS (HR = 0.74, 95% CI 0.69-0.80, p < 0.00001) and OS (HR = 0.91, 95% CI 0.83-0.99, p = 0.02) compared with the Bev/Pem group. Moreover, we further analysed the PFS rate (PFSR) and OS rate (OSR) and found that the Bev+Pem group exhibited improved PFSR-0.5y, PFSR-1y, PFSR-1.5y, PFSR-2y and OS-2y, with preferable trends in OS-1y, OS-3y and OS-4y compared with the Bev/Pem single-agent maintenance therapy. In addition, subgroup analyses indicated that the Bev+Pem group had greater PFS and OS among patients aged <65 years, patients with an Eastern Cooperative Oncology Group (ECOG) score of 0, and patients who never smoked. Regarding adverse events (AEs), the Bev+Pem group exhibited an increased occurrence of anaemia, fatigue, thrombocytopenia and anorexia.

WHAT IS NEW AND CONCLUSION

For stage IIIB/IV nonsquamous NSCLC patients, maintenance therapy with Bev+Pem offers an increased survival outcome (PFS, OS) compared with monotherapy. However, the increased incidence of AEs should not be neglected.

Optimal Maintenance Strategy for First-Line Oxaliplatin-Containing Therapy with or without Bevacizumab in Patients with Metastatic Colorectal Cancer: A Meta-Analysis

PURPOSE

Maintenance therapy after oxaliplatin withdrawal is useful in patients with metastatic colorectal cancer (mCRC). This study aimed to investigate the timing of discontinuation or reintroduction of oxaliplatin and the optimal maintenance therapy regimen for survival.

MATERIALS AND METHODS

PubMed and conference abstracts were searched to select phase II and III trials of first-line oxaliplatin-containing therapy with or without bevacizumab using maintenance therapy for mCRC. Correlations of median overall survival (OS) with induction therapy regimens, induction therapy duration, maintenance therapy regimens (fluoropyrimidine plus bevacizumab [FP+Bev], FP/Bev alone, and no treatment), and oxaliplatin reintroduction were investigated using correlation and weighted multivariate regression analyses.

RESULTS

Twenty-two treatment arms were analyzed, including 2,581 patients. The maintenance therapy regimen FP+Bev showed the strongest correlation with a prolonged OS (Spearman's partial correlation coefficient=0.42), and the other three variables correlated weakly with the OS. The maintenance therapy regimen significantly interacted with the induction chemotherapy duration (p=0.019). The predicted OS for FP+Bev crossed the lines of FP/Bev alone at 18 weeks of induction therapy, and of no treatment at 23 weeks. The corresponding OS at 12 and 27 weeks of induction therapies were 28.6 and 24.2 months for FP+Bev, 25.9 and 28.8 months for FP/Bev alone, and 20.5 and 27.5 months for no treatment.

CONCLUSION

The optimal maintenance therapy regimen for the OS is a continuous induction therapy as long as possible followed by FP/Bev alone and switching to FP+Bev within approximately 4 months if induction therapy is discontinued.

Chloroquine increases the anti-cancer activity of epirubicin in A549 lung cancer cells

The present study investigated whether the autophagy inhibitor chloroquine (CQ) can improve the sensitivity of the A549 lung cancer cell line to epirubicin (EPI). The Cell Counting Kit 8 (CCK8) assay was used to determine the EPI IC₅₀ in A549 cells treated for 72 h. A549 cells were treated with Western blot analysis was performed to detect the expression level of the autophagy-associated protein, microtubule associated protein 1 light chain 3 β (LC3B), and apoptosis-associated proteins such as cleaved caspase-9 and cleaved caspase-3. CCK8, colony formation, wound healing and Transwell assays were performed to analyze cell proliferation, migration and invasion capacity. Reverse transcription-quantitative PCR (RT-qPCR) was used to analyze the mRNA expression levels of LC3B and beclin-1, and the apoptosis rate was analyzed by flow cytometry. The IC₅₀ of EPI was 0.03 µg/ml. The CCK8 results demonstrated that the cell survival rate was lower in CQ + EPI-treated cells when compared with the individual treatment groups. The colony formation results revealed that the number of clones in the EPI + CQ-treated group was reduced compared with EPI or CQ treatment alone. The wound healing assay revealed that migration was reduced in the EPI + CQ-treated group compared with the other treatment groups, and the Transwell results indicated that the number of cells passing through the Matrigel and membrane was lowest in the CQ + EPI treatment group. The mRNA expression levels of LC3B and beclin-1 were increased in the CQ + EPI group by 51.5 and 61.2%, respectively, when compared with the control group. The results indicated that LC3B protein expression was enhanced by EPI in a concentration-dependent manner, and the protein levels of cleaved caspase-3 and cleaved caspase-9 were higher in the combination group than in the EPI alone group. The flow cytometry results demonstrated that the apoptosis rate was highest in the EPI + CQ group. In conclusion, the autophagy inhibitor CQ increased the sensitivity of A549 cells to EPI, and the underlying mechanism of action may be associated with the activation of apoptosis.

Single-agent maintenance therapy for advanced non-small cell lung cancer (NSCLC): a systematic review and Bayesian network meta-analysis of 26 randomized controlled trials

Background

The benefit of maintenance therapy has been confirmed in patients with non-progressing non-small cell lung cancer (NSCLC) after first-line therapy by many trials and meta-analyses. However, since few head-to-head trials between different regimens have been reported, clinicians still have little guidance on how to select the most efficacious single-agent regimen. Hence, we present a network meta-analysis to assess the comparative treatment efficacy of several single-agent maintenance therapy regimens for stage III/IV NSCLC.

Methods

A comprehensive literature search of public databases and conference proceedings was performed. Randomized clinical trials (RCTs) meeting the eligible criteria were integrated into a Bayesian network meta-analysis. The primary outcome was overall survival (OS) and the secondary outcome was progression free survival (PFS).

Results

A total of 26 trials covering 7,839 patients were identified, of which 24 trials were included in the OS analysis, while 23 trials were included in the PFS analysis. Switch-racotumomab-alum vaccine and switch-pemetrexed were identified as the most efficacious regimens based on OS (HR, 0.64; 95% CrI, 0.45–0.92) and PFS (HR, 0.54; 95% CrI, 0.26–1.04) separately. According to the rank order based on OS, switch-racotumomab-alum vaccine had the highest probability as the most effective regimen (52%), while switch-pemetrexed ranked first (34%) based on PFS.

Conclusions

Several single-agent maintenance therapy regimens can prolong OS and PFS for stage III/IV NSCLC. Switch-racotumomab-alum vaccine maintenance therapy may be the most optimal regimen, but should be confirmed by additional evidence.

Maintenance therapy with pemetrexed and bevacizumab versus pemetrexed monotherapy after induction therapy with carboplatin, pemetrexed, and bevacizumab in patients with advanced non-squamous non small cell lung cancer

OBJECTIVES

Single agent maintenance therapy is widely accepted for advanced non-squamous non small cell lung cancer (NSCLC). However, there is no consensus on the initial and maintenance phase regimens, and the clinical benefit of adding bevacizumab to cytotoxic drugs in the maintenance phase remains unclear.

METHODS

Chemotherapy-naïve patients with non-squamous NSCLC were randomly assigned to maintenance therapy with pemetrexed and bevacizumab or pemetrexed alone, after achieving disease control after four cycles of induction therapy with carboplatin (area under the curve = 6), pemetrexed (500 mg/m(2)), and bevacizumab (15 mg/kg). The primary end-point was 1-year progression-free survival (PFS) rate.

RESULTS

One hundred ten patients were enrolled in the study, with 55 patients assigned to the two groups. The mean 1-year PFS rate was 43.9% (95% confidence interval [CI]: 29.6-59.2%) in the combination maintenance group and 35.2% (95% CI: 22.1-51.0%) in the pemetrexed maintenance group, and the difference was not significant (p = 0.433). Median PFS measured from enrolment was 11.5 months (95% CI: 7.1-19.0) in the combination maintenance group and 7.3 months (95% CI: 5.7-14.1, hazard ratio: 0.73, 95% CI: 0.44-1.19, log-rank p = 0.198) in the pemetrexed maintenance group. Nasal haemorrhage, hypertension, and proteinuria were significantly more frequent in the combination maintenance group, but they were mild and tolerable.

CONCLUSION

Both maintenance therapy with pemetrexed alone and pemetrexed and bevacizumab in combination were feasible in patients with non-squamous NSCLC who have achieved disease control after induction therapy with carboplatin, pemetrexed, and bevacizumab. According to the selection design, differences in the superiority between these maintenance therapies were not demonstrated.

Chinese herbal medicine as maintenance therapy for improving the quality of life for advanced non-small cell lung cancer patients

OBJECTIVE

The purpose of the study was to assess the efficacy and safety of using Chinese herbal medicine (CHM) as maintenance therapy considering the survival of advanced non-small-cell lung cancer (NSCLC) patients after first-line conventional platinum-based chemotherapy.

DESIGN

An open-label, randomized, controlled trial.

SETTING

Four hospitals in China.

INTERVENTIONS AND MAIN OUTCOME MEASURES

A total of 106 patients were eligible and randomly divided into two groups from four hospitals in China. Both groups received the best supporting care (BSC). Additionally, patients in the trial group were given CHM every day until the disease became aggravated or the patients resigned. The study took both progression-free survival (PFS) and quality of life (QOL) as the primary outcomes to comprehensively evaluate the effect of the treatment. QOL was measured by the Functional Assessment of Cancer Therapy-Lung (FACT-L) 4.0 questionnaire. Side effects and safety were evaluated at the same time.

RESULTS

Of the 106 patients, 99 completed the study. After treatment and follow-up for PFS, there were no significant differences in the median PFS time and the 6-month PFS probability between the two groups. However, the 3-month PFS probability in the trial group was significantly higher than that in the control group (FAS, PPS: P<0.01). For QOL, there were significant differences between the two groups in the following: physical well-being, emotional well-being, functional well-being, lung cancer symptom domain and total score of the FACT-L4.0 (FAS, PPS: P<0.05). There was no significant difference in the social well-being domain. No serious adverse side effects to the treatment were observed.

CONCLUSIONS

CHM is well tolerated and may improve the QOL of advanced NSCLC patients. CHM is worth studying in future investigations.

Maintenance treatment with oral cyclophosphamide and bevacizumab in patients with recurrent epithelial ovarian cancer

Aim: To evaluate the efficacy and safety of maintenance treatment with oral cyclophosphamide (Cy) and bevacizumab (Bev) in patients with recurrent ovarian cancer. Patients & methods: Induction treatment consisted of cisplatin, epirubicin, Cy and Bev every 3 weeks, for a maximum of six cycles. Maintenance treatment consisted of oral Cy 50 mg, days 1–14 and Bev 15 mg/kg, every 3 weeks until disease progression occurred. Results: In total, 39 patients were enrolled: after induction chemotherapy, the objective response was 74.3%. The median progression-free survival was 13.3 months, and the median overall survival was 33.2 months. Toxicity during maintenance treatment was mild. Conclusion: Maintenance with Cy and Bev may achieve encouraging results in terms of progression-free survival and overall survival in recurrent ovarian cancer patients.

PA28gamma emerges as a novel functional target of tumour suppressor microRNA-7 in non-small-cell lung cancer

BACKGROUND

MicroRNA-7 (miR-7) has been reported to be a tumour suppressor gene. However, whether it has a role in the growth of non-small-cell lung cancer (NSCLC) and what is its target involved in the tumour growth is still under investigation.

METHODS

NSCLC tissue sample, NSCLC cell lines and tissue microarray were investigated in this study. Total RNA, miRNA and protein were used for RT-PCR and western blot analysis. Immunohistochemistry was performed in tissues microarray. Cell culture and intervention experiments were performed in vitro and in vivo. Bioinformatics prediction, western blot and luciferase assay were identified the target of miR-7.

RESULTS

In this study, we found that the expression of miR-7 was significantly downregulated not only in NSCLC cell lines, but also in human NSCLC tissues compared with the matched adjacent tissues. Restoration of its expression through miR-7 mimics in A549 and H1299 NSCLC cells inhibited cell proliferation, colony formation, and cell-cycle progression in vitro. More importantly, the tumorigenicity in nude mice was reduced after administration of miR-7 in vivo. In advance, through bioinformatic analysis, luciferase assay and western blot, we identified a novel target of miR-7, PA28gamma (a proteasome activator) to be enrolled in the regulation with tumour. PA28gamma mRNA and protein levels are markedly upregulated in NSCLC cell lines and tumour samples, exhibiting a strong inverse relation with that of miR-7. In addition, knockdown of PA28gamma induced similar effects as overexpression of miR-7 in NSCLC cells. Furthermore, miR-7 overexpression or silencing of PA28gamma reduced the cyclinD1 expression at mRNA and protein level in NSCLC cell lines.

CONCLUSION

All these findings strongly imply that the overexpression of PA28gamma resulted from miR-7 downexpression in NSCLC has an important role in promoting cancer cell progress and consequently results in NSCLC growth. Thus, strategies targeting PA28gamma and/or miR-7 may become promising molecular therapies in NSCLC treatment.

Maintenance therapy with pemetrexed versus docetaxel after induction therapy with carboplatin and pemetrexed in chemotherapy-naïve patients with advanced non-squamous non-small-cell lung cancer: a randomized, phase II study

PURPOSE

The optimal strategy for maintenance chemotherapy is controversial. We evaluated the efficacy and safety of continuation maintenance with pemetrexed and switch maintenance with docetaxel in advanced non-squamous non-small-cell lung cancer (NSCLC).

METHODS

Chemotherapy-naïve patients with non-squamous NSCLC were enrolled in this randomized phase II study. Patients who achieved disease control after four cycles of induction therapy with carboplatin (AUC 6) and pemetrexed (500 mg/m(2)) were randomized to maintenance therapy with pemetrexed (500 mg/m(2)) or docetaxel (60 mg/m(2)). The primary endpoint was survival without toxicity, defined as the time from the initiation of maintenance therapy to the first date of any grade 3/4 toxicity or death due to any cause.

RESULTS

A total of eighty-five patients were enrolled in the induction phase, and 26 patients were assigned to the pemetrexed maintenance therapy and 25 patients were assigned to the docetaxel maintenance therapy. Survival without toxicity was significantly longer in the pemetrexed group (median 20.8 months, 95 % confidence interval (CI) 0.7-not estimable) than in the docetaxel group (median 0.5 months, 95 % CI 0.2-2.0, hazard ratio 0.36, 95 % CI 0.17-0.74).

CONCLUSIONS

Continuation maintenance with pemetrexed may be a feasible treatment option for patients with non-squamous NSCLC who have achieved disease control after induction therapy with carboplatin and pemetrexed. Switch maintenance with docetaxel may also be efficacious but frequently causes severe hematologic toxicity.

Identifying the target NSCLC patient for maintenance therapy: an analysis from a placebo-controlled, phase III trial of maintenance pemetrexed (H3E-MC-JMEN)

Background

This was a post hoc analysis of patients with non-squamous histology from a phase III maintenance pemetrexed study in advanced non-small cell lung cancer (NSCLC).

Patients and methods

The six symptom items' [average symptom burden index (ASBI)] mean at baseline was calculated using the lung cancer symptom scale (LCSS). Low and high symptom burden (LSB, ASBI < 25; HSB, ASBI ≥ 25) and performance status (PS: 0, 1) subgroups were analyzed for treatment effect on progression-free survival (PFS) and overall survival (OS) using the Cox proportional hazard models adjusted for demographic/clinical factors.

Results

Significantly longer PFS and OS for pemetrexed versus placebo occurred in LSB patients [PFS: median 5.1 versus 2.4 months, hazard ratio (HR) 0.49, P < 0.0001; OS: median 17.5 versus 11.0 months, HR 0.63, P = 0.0012] and PS 0 patients (PFS: median 5.5 versus 1.7 months, HR 0.36, P < 0.0001; OS: median 17.7 versus 10.3 months, HR 0.54, P = 0.0019). Significantly longer PFS, but not OS, occurred in HSB patients (median 3.7 versus 2.8 months, HR 0.50, P = 0.0033) and PS 1 patients (median 4.4 versus 2.8 months, HR 0.60, P = 0.0002).

Conclusions

ASBI and PS are associated with survival for non-squamous NSCLC patients, suggesting that maintenance pemetrexed is useful for LSB or PS 0 patients following induction.

Treatment of lung cancer

Lung cancer is a heterogenous disease with 2 main subtypes: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Early-stage NSCLC is managed primarily by surgical resection, with adjuvant chemotherapy for selected patients with stage IB, II, and III disease. Patients with locally advanced stage III NSCLC are usually treated with combined modality therapy. Advanced NSCLC remains an incurable disease. Further advances will rely on improvements in understanding of the molecular events driving the malignant phenotype and the development of novel, targeted therapeutic strategies.

Chemotherapy beyond first-line in stage IV metastatic non-small cell lung cancer

OBJECTIVE

Platinum-based doublet chemotherapy is considered the standard of care for advanced non-small cell lung cancer (NSCLC). However, prognosis after recurrent or progressive disease following first-line chemotherapy is usually poor. Maintenance chemotherapy, second line treatment and even third line chemotherapy are available for patients with advanced NSCLC. Unfortunately, few patients are candidates for chemotherapy beyond first line. The present study evaluated characteristics of patients with NSCLC and outcomes of the treatment of their metastatic disease, with emphasis on second and third-line chemotherapy.

METHODS

This was a retrospective observational study of 2,673 patients with metastatic, stage IV, non-small cell lung cancer admitted for treatment in two São Paulo institutions. First-line chemotherapy was defined as the first chemotherapeutic approach administered to the patient. Second and third-line chemotherapy were defined as the systemic treatment administered after discontinuing first-line chemotherapy, either for intolerance or for progressive or recurrent disease.

RESULTS

Most patients (57.9%) received first-line chemotherapy, and approximately 23.4% received second-line and 8% third-line regimens. Only 2.5% received fourth-line chemotherapy. Median overall survival (OS) was 8 months (95% CI: 8-9 months). At univariate analyses, gender (p < 0.05), histology, first-line chemotherapy, objective response to first-line chemotherapy and second-line chemotherapy (p < 0.01) were prognostic factors related to overall survival. At multivariate analysis, only performance status (p = 0.04), receiving any second-line chemotherapy (p < 0.01) and response to first-line chemotherapy (p < 0.01) were independent predictors of overall survival.

CONCLUSION

Second-line chemotherapy is a therapeutic strategy that should be considered for a selected group of patients. Performance status and response to first-line chemotherapy could be determinant characteristics to select patients who might be treated beyond first-line chemotherapy.

Single agent maintenance therapy for advanced stage non-small cell lung cancer: a meta-analysis

BACKGROUND

Maintenance therapy is a new treatment paradigm for advanced non-small cell lung cancer (NSCLC). We conducted a meta-analysis of randomized studies with single agent maintenance therapy.

METHODS

An electronic literature search of public databases (MEDLINE, EMBASE, Cochrane library) and manual search of relevant conference proceedings was performed. A formal meta-analysis was conducted using Comprehensive Meta Analysis software (Version 2.0). Outcome data were pooled and reported as hazard ratio (HR). The primary outcome of interest was overall survival (OS) and secondary outcome was progression free survival (PFS).

RESULTS

Twelve studies were included (5 meeting abstracts, 7 full manuscripts) with a total of 4286 patients (maintenance arm/control arm - 2449/1837, median age 61 years, males - 69%). The OS (HR 0.86, 95% confidence intervals [CI] 0.80-0.92; P=0.0003) and PFS (HR 0.80, 95% CI 0.77-0.84; P<0.0001) were superior with maintenance therapy. 'Switch' maintenance was associated with significant OS and PFS improvement (OS HR 0.84, 95% CI 0.77-0.91; P=0.00026; PFS HR 0.62, 95% CI 0.57-0.67; P<0.0001). Despite a modest improvement in PFS (HR 0.90, 95%CI 0.85-0.95; P=0.007), "continuation" maintenance was not associated with survival benefit (HR 0.927, 95%CI 0.78-1.09; P=0.33). Improvements in OS and PFS were observed with both EGFR-targeted agents (HR 0.83, 95% CI 0.74-0.92; P=0.004; HR 0.64, 95% CI 0.58-0.71 P<0.0001) and cytotoxic agents (HR 0.89, 95% CI 0.80-0.98; P=0.018; HR 0.85, 95% CI 0.80-0.89; P<0.0001).

CONCLUSIONS

Single agent maintenance therapy improves overall survival, though statistical significance was only noted with 'switch' maintenance.

Five-year survival does not equal cure in non-small cell lung cancer: a Surveillance, Epidemiology, and End Results-based analysis of variables affecting 10- to 18-year survival

OBJECTIVE

Five-year survival after the diagnosis of non-small cell lung cancer is the most common benchmark used to evaluate long-term survival. Data on survival beyond 5 years are sparse. We sought to elucidate variables affecting 10- to 18-year survival.

METHODS

A total of 31,206 patients alive at least 5 years after diagnosis of non-small cell lung cancer who were registered in the Surveillance, Epidemiology, and End Results database from 1988 to 2001 were examined. Primary end points were disease-specific survival and overall survival. Survival analysis was performed with Kaplan-Meier estimates, multivariable Cox proportional hazards regression, and competing risk models.

RESULTS

Overall survival at 10, 15, and 18 years was 55.4%, 33.1%, and 24.3%, respectively. Disease-specific survival at 10, 15, and 18 years was 76.6%, 65.4%, and 59.4%, respectively. In multivariable regression analysis, squamous cell cancers had a disease-specific survival advantage (hazard ratio, 0.88; P < .0001) but an overall survival disadvantage (hazard ratio, 1.082; P = .0002) compared with adenocarcinoma. Pneumonectomy (hazard ratio, 0.44) and lobectomy (hazard ratio, 0.474) had improved disease-specific survival compared with no surgery (P < .0001). Left-sided tumors (hazard ratio, 0.723; P = .036) and node-negative cancers (hazard ratio, 0.562; P < .001) also had a better disease-specific survival and, to a lesser extent, overall survival advantage.

CONCLUSIONS

Five-year survivors of non-small cell lung cancer have a persistent risk of death from lung cancer up to 18 years from diagnosis. More than one half of all deaths in 5-year survivors are related to lung cancer. In multivariable regression analysis, age, node-negative disease, and lobar or greater resection were strong predictors of long-term survival (ie, 10-18 years).

Synergistic activity of the Hsp90 inhibitor ganetespib with taxanes in non-small cell lung cancer models

Systemic chemotherapy using two-drug platinum-based regimens for the treatment of advanced stage non-small cell lung cancer (NSCLC) has largely reached a plateau of effectiveness. Accordingly, efforts to improve survival and quality of life outcomes have more recently focused on the use of molecularly targeted agents, either alone or in combination with standard of care therapies such as taxanes. The molecular chaperone heat shock protein 90 (Hsp90) represents an attractive candidate for therapeutic intervention, as its inhibition results in the simultaneous blockade of multiple oncogenic signaling cascades. Ganetespib is a non-ansamycin inhibitor of Hsp90 currently under clinical evaluation in a number of human malignancies, including NSCLC. Here we show that ganetespib potentiates the cytotoxic activity of the taxanes paclitaxel and docetaxel in NSCLC models. The combination of ganetespib with paclitaxel, docetaxel or another microtubule-targeted agent vincristine resulted in synergistic antiproliferative effects in the H1975 cell line in vitro. These benefits translated to improved efficacy in H1975 xenografts in vivo, with significantly enhanced tumor growth inhibition observed in combination with paclitaxel and tumor regressions seen with docetaxel. Notably, concurrent exposure to ganetespib and docetaxel improved antitumor activity in 5 of 6 NSCLC xenograft models examined. Our data suggest that the improved therapeutic indices are likely to be mechanistically multifactorial, including loss of pro-survival signaling and direct cell cycle effects resulting from Hsp90 modulation by ganetespib. Taken together, these findings provide preclinical evidence for the use of this combination to treat patients with advanced NSCLC.

Maintenance therapy in NSCLC: why? To whom? Which agent?

Maintenance therapy is emerging as a treatment strategy in the management of advanced non small cell lung cancer (NSCLC). Initial trials addressing the question of duration of combination chemotherapy failed to show any overall survival benefit for the prolonged administration over a fixed number of cycles with an increased risk for cumulative toxicity. Nowadays several agents with different ways of administration and a different pattern of toxicity have been formally investigated in the maintenance setting. Maintenance strategies include continuing with an agent already present in the induction regimen or switching to a different one. Taking into consideration that no comparative trials of maintenance with different chemotherapy drugs or targeted agents have been conducted, the choice and the duration of maintenance agents is largely empirical. Furthermore, it is still unknown and it remains an open question if this approach needs to be proposed to every patient in the case of partial/complete response or stable disease after the induction therapy. Here, we critically review available data on maintenance treatment, discussing the possibility to tailor the right treatment to the right patient, in an attempt to optimize costs and benefits of an ever-growing panel of different treatment options.

Maintenance chemotherapy: an evolving and increasingly acceptable strategy in cancer management

Individual randomized phase 3 trials and meta-analyses of previously published studies have provided support for the general concept of the clinical utility of extending the duration of antineoplastic drug therapy in an effort to prolong ("maintain") a favorable clinical state. This commentary briefly reviews data from several of these reports.

Pemetrexed indirectly activates the metabolic kinase AMPK in human carcinomas

The chemotherapeutic drug pemetrexed, an inhibitor of thymidylate synthase, has an important secondary target in human leukemic cells, aminoimidazolecarboxamide ribonucleotide formyltransferase (AICART), the second folate-dependent enzyme of purine biosynthesis. The purine intermediate aminoimidazolecarboxamide ribonucleotide (ZMP), which accumulates behind this block, transmits an inhibitory signal to the mTORC1 complex via activation of the cellular energy sensor AMP-activated kinase (AMPK). Given that the PI3K-AKT-mTOR pathway is frequently deregulated during carcinogenesis, we asked whether the indirect activation of AMPK by pemetrexed offers an effective therapeutic strategy for carcinomas with defects in this pathway. Activation of AMPK by ZMP in pemetrexed-treated colon and lung carcinoma cells and the downstream consequences of this activation were strikingly more robust than previously seen in leukemic cells. Genetic experiments demonstrated the intermediacy of AICART inhibition and the centrality of AMPK activation in these effects. Whereas AMPK activation resulted in marked inhibition of mTORC1, other targets of AMPK were phosphorylated that were not mTORC1-dependent. Whereas AMPK activation is thought to require AMPKα T172 phosphorylation, pemetrexed also activated AMPK in carcinoma cells null for LKB1, the predominant AMPKα T172 kinase whose deficiency is common in lung adenocarcinomas. Like rapamycin analogs, pemetrexed relieved feedback suppression of PI3K and AKT, but the prolonged accumulation of unphosphorylated 4E-BP1, a tight-binding inhibitor of cap-dependent translation, was seen following AMPK activation. Our findings indicate that AMPK activation by pemetrexed inhibits mTORC1-dependent and -independent processes that control translation and lipid metabolism, identifying pemetrexed as a targeted therapeutic agent for this pathway that differs significantly from rapamycin analogs.

Approval summary: erlotinib maintenance therapy of advanced/metastatic non-small cell lung cancer (NSCLC)

On April 16, 2010, the U. S. Food and Drug Administration (FDA) approved erlotinib tablets (Tarceva®; OSI Pharmaceuticals, Inc., Melville, NY) for maintenance treatment of patients with stage IIIB/IV non-small cell lung cancer (NSCLC) whose disease had not progressed after four cycles of platinum-based first-line chemotherapy. In total, 889 patients received either erlotinib (150 mg) or placebo once daily. Progression-free survival (PFS), in all patients and in patients with epidermal growth factor receptor (EGFR)(+) tumors by immunohistochemistry (IHC), was the primary efficacy endpoint. Overall survival (OS) was a secondary sponsor endpoint but was the primary regulatory endpoint. Median PFS times were 2.8 months and 2.6 months in the erlotinib and placebo arms, respectively (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.62-0.82; p < .001). Median OS times were 12.0 months and 11.0 months, favoring erlotinib (HR, 0.81; 95% CI, 0.70-0.95). The PFS and OS HRs in patients with EGFR(+) tumors by IHC were 0.69 (95% CI, 0.58-0.82) and 0.77 (95% CI, 0.64-0.93), respectively. The PFS and OS HRs in patients with EGFR(-) tumors by IHC were 0.77 (95% CI, 0.51-1.14) and 0.91 (95% CI, 0.59-1.38), respectively. Following disease progression, 57% of placebo-treated patients received additional chemotherapy, compared with 47% of erlotinib-treated patients. Fourteen percent of placebo-treated patients received erlotinib or gefitinib, 31% received docetaxel, and 14% received pemetrexed. In total, 59% of placebo-treated patients who received treatment received FDA approved second-line NSCLC drugs. The most common adverse reactions in patients receiving erlotinib were rash and diarrhea.