Randomized phase II trial of three schedules of pemetrexed and gemcitabine as front-line therapy for advanced non-small-cell lung cancer

Modeling tumor measurement data to predict overall survival (OS) in cancer clinical trials

Introduction

Longitudinal tumor measurements (TM) are commonly recorded in cancer clinical trials of solid tumors. To define patient response to treatment, the Response Evaluation Criteria in Solid Tumors (RECIST) categorizes the otherwise continuous measurements, which results in substantial information loss. We investigated two modeling approaches to incorporate all available cycle-by-cycle (continuous) TM to predict overall survival (OS) and compare the predictive accuracy of these two approaches to RECIST.

Material and methods

Joint modeling (JM) for longitudinal TM and OS and two-stage modeling with potential time-varying coefficients were utilized to predict OS using data from three trials with cycle-by-cycle TM. The JM approach incorporates TM data collected throughout the course of the clinical trial. The two-stage modeling approach incorporates information from early assessments (before 12 weeks) to predict subsequent OS outcome. The predictive accuracy was quantified by c-indices.

Results

Data from 577, 337, and 126 patients were included for the analysis (from two stage IV colorectal cancer trials (N9741, N9841) and an advanced non-small cell lung cancer trial (N0026), respectively). Both the JM and two-stage modeling reached a similar conclusion, i.e. the baseline covariates (age, gender, and race) were mostly not predictive of OS (p-value > 0.05). Quantities derived from TM were strong predictors of OS in the two colorectal cancer trials (p < 0.001 for both association in JM and two-stage modeling parameters); but less so in the lung cancer trial (p = 0.053 for association in JM and p = 0.024 and 0.160 for two-stage modeling parameters). The c-indices from the two-stage modeling were higher than those from a model using RECIST (range: 0.611–0.633 versus 0.586–0.590). The dynamic c-indices from the JM were in the range of 0.627–0.683 indicating good predictive accuracy.

Conclusion

Both modeling approaches provide highly interpretable and clinical meaningful results; the improved predictive performance compared with RECIST indicates the possibility of deriving better trial endpoints from these approaches.

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Two-stage modeling incorporating time-varying coefficients achieves better predictive accuracy than RECIST-alone.

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Two–stage modeling offers the possibility of alternative endpoint definition.

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Serial tumor measurements can be incorporated in OS prediction using joint modeling.

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Joint modeling can potentially guide individualized medicine.

Missing tumor measurement (TM) data in the search for alternative TM-based endpoints in cancer clinical trials

PURPOSE

Missing data commonly occur in cancer clinical trials (CCT) and may hinder the search for alternative trial endpoints. We consider reasons for missing tumor measurement (TM) data in CCT and how missing TM data are typically handled. We explore the potential impact of missing TM data on predictive ability of a set of TM-based endpoints.

METHODS

Literature review identifies reasons for and approaches to handling missing TM data. Data from 3 actual clinical trials were used for illustration. A sensitivity analysis of the potential impact of missing TM data was performed by comparing overall survival (OS) predictive ability of alternative endpoints using observed and imputed data.

RESULTS

Reasons for missing TM data in CCT are presented, based on the literature review and the three trials. Although missing TM data impacted individual objective status (e.g. 12-week status changed for 53% of patients in one imputation set), it surprisingly only minimally impacted endpoint predictive ability (e.g. median c-indices of 500 imputed datasets ranged from 0.566 to 0.570 for N9741, 0.592-0.616 for N9841, and 0.542-0.624 for N0026).

CONCLUSION

By understanding the reasons for missingness, we can better anticipate them and minimize their occurrence. Our preliminary analysis suggests missing TM data may not impact endpoint predictive ability, but could impact objective response status classification; however these findings require further validation. With response status accepted as an important phase II endpoint in the development of new cancer therapies (including immunotherapy), we urge that in CCT complete TM data collection and adherence to protocol-defined disease evaluation as closely as possible be a priority.

Pemetrexed and gemcitabine as combination therapy for the treatment of Group3 medulloblastoma

We devised a high-throughput, cell-based assay to identify compounds to treat Group3 medulloblastoma (G3 MB). Mouse G3 MBs neurospheres were screened against a library of approximately 7,000 compounds including US Food and Drug Administration-approved drugs. We found that pemetrexed and gemcitabine preferentially inhibited G3 MB proliferation in vitro compared to control neurospheres and substantially inhibited G3 MB proliferation in vivo. When combined, these two drugs significantly increased survival of mice bearing cortical implants of mouse and human G3 MBs that overexpress MYC compared to each agent alone, while having little effect on mouse MBs of the sonic hedgehog subgroup. Our findings strongly suggest that combination therapy with pemetrexed and gemcitabine is a promising treatment for G3 MBs.

The place of pemetrexed in the management of non-small-cell lung cancer patients

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer death worldwide. Chemotherapy is included in the management of the majority of NSCLC patients either in addition to a local treatment (surgery/radiotherapy) or alone. In this setting, pemetrexed has become one of the most important partners of current chemotherapy regimens for nonsquamous NSCLC patients. Indeed, pemetrexed demonstrated a comparable efficacy to other previously available drugs in NSCLC, with however a better safety profile and an easier schedule of administration. In addition, pemetrexed demonstrated a greater efficacy in nonsquamous NSCLC that lead to an exploration of the underlying potential biological background. It is now suggested that the tumor thymidylate synthase level may act as a predictor of pemetrexed efficacy, therefore potentially providing clinicians in the future with a predictor of efficacy, which it is usually lacking with standard chemotherapies.

Efficacy of pemetrexed as second-line therapy in advanced NSCLC after either treatment-free interval or maintenance therapy with gemcitabine or erlotinib in IFCT-GFPC 05-02 phase III study

INTRODUCTION

Maintenance therapy in advanced non-small-cell lung cancer (NSCLC) might lead to resistance to subsequent treatments. IFCT-GFPC 0502 study showed a progression-free survival (PFS) benefit with gemcitabine or erlotinib maintenance compared with observation after cisplatin-gemcitabine chemotherapy. The trial included a pre-defined pemetrexed second-line therapy, allowing post-hoc assessment of its efficacy according to previous maintenance treatment or treatment-free interval.

METHODS

Stage IIIB/IV NSCLC patients were randomized after four cycles of cisplatin-gemcitabine chemotherapy to either observation or to receive maintenance therapy with gemcitabine or erlotinib. Pemetrexed was given as second-line treatment on disease progression in all arms. PFS and overall survival (OS) were assessed from the beginning of pemetrexed therapy according to randomization arm.

RESULTS

Of the 464 randomized patients, 360 (78 %) received second-line pemetrexed (130 [84%], 114 [74%], and 116 [75%] in observation, gemcitabine, and erlotinib arm, respectively). Median number of pemetrexed cycles was 3 (1-40) in all arms. Median PFS did not differ between gemcitabine and observation arms (4.2 versus 3.9 months, hazard ratio [HR] [95% confidence interval [CI] 0.81 [0.62-1.06]) or between erlotinib and observation arms (4.2 versus 3.9 months, HR 0.83 [0.64-1.09]). OS data showed a non-significant improvement with gemcitabine arm versus observation arm (8.3 versus 7.5 months, HR 0.81 [0.61-1.07]) or erlotinib arm versus observation arm (9.1 versus 7.5 months, HR 0.80 [0.61-1.05]). Results were similar for non-squamous patients. Grade 3 to 4 treatment-related adverse events (AEs) were comparable in all arms.

CONCLUSIONS

Maintenance therapy with gemcitabine continuation or erlotinib does not seem to impair efficacy of second-line pemetrexed comparatively to administration after a treatment-free interval.

Preclinical rationale for synergistic interaction of pemetrexed and cytotoxic nucleoside analogues

Cytotoxic nucleoside analogues are widely used in cancer chemotherapy. We used the cytosine arabinoside (Ara-C)-resistant erythroleukaemia cell line K562 and the Ara-C-sensitive myeloid leukaemia cell line HL60 to examine the differential expression of molecular markers. We found increased expression levels of deoxycytidine kinase (dCK) and human equilibrative nucleoside transporter 1 (hENT1) and decreased levels of multidrug resistance protein 5 (ABCC5) and ribonucleoside reductase subunit M1 (RRM1) expression in Ara-C-sensitive HL60 cells. We previously established the pemetrexed (MTA)-resistant small cell lung cancer cell lines PC6/MTA-0.4 and PC6/MTA-1.6 and found that MTA-resistant cells are more sensitive to gemcitabine (GEM) and Ara-C compared with parental PC-6 cells. We examined the molecular markers for GEM and Ara-C sensitivity in MTA-resistant cells and found increased gene expression of dCK and hENT1. Furthermore, treatment with MTA resulted in increased expression of dCK and hENT1 and decreased expression of ABCC5 and RRM1, concomitant with the alteration of the resistance to Ara-C in Ara-C-resistant K562 cells. These results provide evidence that the chemotherapeutic activity of the combination of MTA and cytotoxic nucleoside analogues is synergistic with regard to the alteration of metabolic molecules.

Impact of disease progression date determination on progression-free survival estimates in advanced lung cancer

BACKGROUND

In patients with advanced lung cancer, overall survival is largely influenced by progression status. Because progression-free survival (PFS)-based endpoints are controversial, the authors evaluated the impact of the progression date (PD) determination approach on PFS estimates.

METHODS

Individual patient data from 21 trials (14 North Central Cancer Treatment Group trials and 7 Southwest Oncology Group trials) were used. The reported PD (RPD) was defined as either the radiographic scan date or the clinical deterioration date. PD was determined using Method 1 (M1), the RPD; M2, 1 day after the last progression-free scan; M3, midpoint between the last progression-free scan and the RPD; and M4, an interval-censoring approach. PFS was estimated using Kaplan-Meier (M1-M3), and maximum-likelihood (M4) methods. Simulation studies were performed to understand the impact of the length of time elapsed between the last progression-free scan and the PD on time-to-progression estimates.

RESULTS

PFS estimates using the RPD were the highest, and M2 was the most conservative. M3 and M4 were similar because the majority of progressions occurred during treatment (ie, frequent disease assessments). M3 was influenced less by the length of the assessment schedules (percentage difference from the true time-to-progression, <1.5%) compared with M1 (11% to 30%) and M2 (-8% to -29%). The overall study conclusion was unaffected by the method used for randomized trials.

CONCLUSIONS

The magnitude of difference in the PFS estimates was large enough to alter trial conclusions in patients with advanced lung cancer. The results indicate that standards for PD determination, the use of sensitivity analyses, and randomized trials are critical when designing trials and reporting efficacy using PFS-based endpoints.

Upfront association of carboplatin plus pemetrexed in patients with brain metastases of lung adenocarcinoma

Approximately 10% of patients with non-small cell lung cancer (NSCLC) have brain metastases at the time of diagnosis. When surgical resection is not possible, whole brain radiotherapy is the standard of care, with a cerebral response rate of approximately 30%. We report our experience with an upfront association of carboplatin and pemetrexed (areas under the curve, 5 and 500 mg/m(2), respectively), every 3 weeks, in 30 patients presenting with newly diagnosed brain metastases and NSCLC. Cerebral MRIs were performed every 6-9 weeks. The radiologic response rates were assessed according to Response Evaluation Criteria in Solid Tumors. Overall survival was also determined. Twenty-six patients were evaluable for response, and the objective cerebral response rate (complete and partial response) in the intent-to-treat population was 40% (12 of 30 patients). Event-free survival was 31 weeks, and median overall survival was 39 weeks. The upfront association of carboplatin plus pemetrexed allows simultaneous treatment of cerebral and systemic disease in patients with NSCLC with newly diagnosed brain metastases and appears to be particularly interesting in terms of radiologic response and overall survival. Further clinical studies are warranted.

A retrospective study of pemetrexed combined with oxaliplatin as second-line treatment for advanced non-small-cell lung cancer: Comparable toxicity, better outcome

BACKGROUND

  The outcomes of single-agent regimens as second-line chemotherapy for metastatic non-small-cell lung cancer (NSCLC) are poor. Pemetrexed combined with oxaliplatin has been reportedly well-tolerated and active in chemotherapy-naïve NSCLC. The current study aimed to evaluate the therapeutic effect and toxicity of the regimen of pemetrexed plus oxaliplatin for pretreated advanced NSCLC.

PATIENTS AND METHODS

  The clinical records of consecutive patients with metastatic NSCLC who received pemetrexed after failed first-line chemotherapy were reviewed.

RESULTS

  The medical records of 79 eligible patients were examined. Thirty-four of them were treated with a regimen of pemetrexed plus oxaliplatin (PEMOX). Another 45 patients were administered pemetrexed alone (PEM). Both regimens were well-tolerated and there was no therapy-related death. Comparable response rates (15.2% vs. 11.1%) and tumor control rates (63.6% vs. 47.5%) were observed between the two groups. Median time to progression and overall survival of the PEMOX and PEM groups were 18 weeks (95% confidence interval (CI): 13.72-22.28 weeks) versus 13 weeks (95%CI: 12.28-13.72 weeks; P= 0.002), and 31 weeks (95%CI: 15.56-46.44 weeks) versus 21 weeks (95%CI: 18.37-23.63 weeks; P= 0.006), respectively.

CONCLUSIONS

  The current retrospective study suggests that pemetrexed combined with oxaliplatin as second-line treatment for advanced NSCLC has comparable safety and response with a pemetrexed alone regimen, but better survival.

Comparison of continuous versus categorical tumor measurement-based metrics to predict overall survival in cancer treatment trials

PURPOSE

The categorical definition of response assessed via the Response Evaluation Criteria in Solid Tumors has documented limitations. We sought to identify alternative metrics for tumor response that improve prediction of overall survival.

EXPERIMENTAL DESIGN

Individual patient data from three North Central Cancer Treatment Group trials (N0026, n = 117; N9741, n = 1,109; and N9841, n = 332) were used. Continuous metrics of tumor size based on longitudinal tumor measurements were considered in addition to a trichotomized response [TriTR: response (complete or partial) vs. stable disease vs. progression). Cox proportional hazards models, adjusted for treatment arm and baseline tumor burden, were used to assess the impact of the metrics on subsequent overall survival, using a landmark analysis approach at 12, 16, and 24 weeks postbaseline. Model discrimination was evaluated by the concordance (c) index.

RESULTS

The overall best response rates for the three trials were 26%, 45%, and 25%, respectively. Although nearly all metrics were statistically significantly associated with overall survival at the different landmark time points, the concordance indices (c-index) for the traditional response metrics ranged from 0.59 to 0.65; for the continuous metrics from 0.60 to 0.66; and for the TriTR metrics from 0.64 to 0.69. The c-indices for TriTR at 12 weeks were comparable with those at 16 and 24 weeks.

CONCLUSIONS

Continuous tumor measurement-based metrics provided no predictive improvement over traditional response-based metrics or TriTR; TriTR had better predictive ability than best TriTR or confirmed response. If confirmed, TriTR represents a promising endpoint for future phase II trials.

Chemotherapy and targeted therapies for unresectable malignant mesothelioma

The global burden of mesothelioma is expected to increase in the coming decades. As a result the development of more effective therapies with an emphasis on personalized treatments based on validated prognostic and predictive biomarkers is an essential requirement. Progress has been made in the last decade with the development of newer generation anti-folates leading to the current standard of care of pemetrexed and cisplatin in patients with unresectable disease. However, the median overall survival of patients with this combination treatment is only 12 months. There is no consensus regarding second line therapy for patients who have progressed or not responded to pemetrexed based therapies although gemcitabine in combination with a platinum compound or single agent vinorelbine is a reasonable option. The development of effective targeted agents that are active in mesothelioma has to date been disappointing. Strategies involving the addition of bevacizumab to pemetrexed and cisplatin in the frontline setting, the histone deacetylase inhibitor vorinostat as second line therapy and studies evaluating the utility of maintenance therapy in mesothelioma are all ongoing and appear promising. In addition clinical trials investigating immunotherapy and gene therapy in combination with chemotherapy could potentially improve the prognosis of patients with mesothelioma.

Correlation between polymorphisms of the reduced folate carrier gene (SLC19A1) and survival after pemetrexed-based therapy in non-small cell lung cancer: a North Central Cancer Treatment Group-based exploratory study

PURPOSE

To correlate polymorphisms in genes involved in the transport, activation, and inactivation of pemetrexed with the outcome of patients with advanced non-small cell lung cancer (NSCLC) treated with pemetrexed.

EXPERIMENTAL DESIGN

Data from a phase II NSCLC trial evaluating the optimal schedule of gemcitabine and pemetrexed were used. All patients with available DNA were genotyped for polymorphisms in FPGS, GGH, and SLC19A1 genes. Patients with various genotypes were compared for efficacy and adverse events resulting from pemetrexed.

RESULTS

Fifty-four patients had genotype results for all polymorphisms studied. Patients with the homozygous variant genotypes for SLC19A1 IVS4(2117) C>T, IVS5(9148) C>A, and wild-type genotype for exon6(2522) C>T had a significantly better overall survival compared with their counterparts (median overall survival in months: 8.9 [CC] versus 14.0 [CT] versus 16.7 [TT]; 9.4 [CC] versus 10.3 [CA] versus 22.7 [AA]; and 22.7 [CC] versus 10.3 [CT] versus 9.4 [TT] respectively; all log rank p = 0.03). Patients with the heterozygous TC genotype for GGH IVS5(1042) T>C had greater rates of confirmed response + stable disease compared with the TT genotype (85% versus 60%; odds ratio = 4.0; p = 0.06). A greater risk for grade 3/4 SGPT (ALT) elevation was observed in patients heterozygous (GA) for the FPGS IVS1 (28) G>A polymorphism compared with the GG genotype (43% versus 13%; odds ratio = 5.0, p = 0.07). All results were largely consistent within patients with nonsquamous (n = 40) histology.

CONCLUSION

Polymorphisms in SLC1A91 seem to predict for survival differences in pemetrexed-treated NSCLC. Additionally, polymorphisms in GGH and FPGS have marginal associations with response and adverse event. These results should be validated in larger prospective studies using pemetrexed.

Phase II study of biweekly pemetrexed and gemcitabine in patients with previously untreated advanced non-small cell lung cancer

INTRODUCTION

Pemetrexed and gemcitabine are safe and active non-small cell lung cancer (NSCLC) therapies when administered every 3 weeks. Biweekly scheduling was studied in this phase II trial.

METHODS

The primary objective was to assess the overall response rate in chemotherapy-naive patients with unresectable stage III/IV NSCLC. Patients received 500 mg/m(2) of pemetrexed intravenously and 1500 mg/m(2) of gemcitabine intravenously every 2 weeks for 8 to 12 cycles with restaging every 4 cycles. Patients also received supplemental folate/B12 therapy. Entry criteria included the following: all non-small cell histologies, measurable disease, Eastern Cooperative Oncology Group 0 to 2, and informed consent.

RESULTS

Seventy-two patients were enrolled. Baseline characteristics included the following: median age: 66 years (41-85 years); male/female: 65%/35%; Eastern Cooperative Oncology Group 0/1/2: 19%/67%/14%; and histology: adenocarcinoma (36%), large cell (18%), squamous (13%), and mixed or not specified (34%). The median number of cycles was 7 (range, 1-12). The most common (> or =5%) grade 3/4 toxicities were as follows: neutropenia (47%), leukopenia (31%), fatigue (25%), dyspnea (18%), pain (11%), and anemia (8%). Complete/partial responses for all patients: 1 patient/18 patients, respectively, for an overall response rate of 26% (95% confidence interval, 17-38%). Thirty-nine percentage of patients had stable disease, and 21% had disease progression (10 patients were not evaluable). Median progression-free survival was 6.2 months. One-year overall survival was 37.5%.

CONCLUSION

Biweekly administration of pemetrexed and gemcitabine seems to be well tolerated with activity comparable with other first-line NSCLC regimens. Further study addressing whether biweekly scheduling could be an effective strategy to shorten overall treatment duration will require a randomized design.

In vitro study on the schedule-dependency of the interaction between pemetrexed, gemcitabine and irradiation in non-small cell lung cancer and head and neck cancer cells

Background

Based on their different mechanisms of action, non-overlapping side effects and radiosensitising potential, combining the antimetabolites pemetrexed (multitargeted antifolate, MTA) and gemcitabine (2',2'-difluorodeoxycytidine, dFdC) with irradiation (RT) seems promising. This in vitro study, for the first time, presents the triple combination of MTA, dFdC and irradiation using various treatment schedules.

Methods

The cytotoxicity, radiosensitising potential and cell cycle effect of MTA were investigated in A549 (NSCLC) and CAL-27 (SCCHN) cells. Using simultaneous or sequential exposure schedules, the cytotoxicity and radiosensitising effect of 24 h MTA combined with 1 h or 24 h dFdC were analysed.

Results

Including a time interval between MTA exposure and irradiation seemed favourable to MTA immediately preceding or following radiotherapy. MTA induced a significant S phase accumulation that persisted for more than 8 h after drug removal. Among different MTA/dFdC combinations tested, the highest synergistic interaction was produced by 24 h MTA followed by 1 h dFdC. Combined with irradiation, this schedule showed a clear radiosensitising effect.

Conclusions

Results from our in vitro model suggest that the sequence 24 h MTA → 1 h dFdC → RT is the most rational design and would, after confirmation in an in vivo setting, possibly provide the greatest benefit in the clinic.

Pemetrexed in advanced non-small-cell lung cancer

IMPORTANCE OF THE FIELD

Current therapeutic options for advanced non-small-cell lung cancer (NSCLC) yield relatively modest improvements in survival leading to an ongoing search for new active treatment agents. In the past decade, pemetrexed has had an increasingly established role in the treatment of advanced NSCLC in both first- and second-line settings.

AREAS COVERED IN THIS REVIEW

Currently available published data on mechanism of action, pharmacokinetics, safety and efficacy of pemetrexed in the treatment of advanced NSCLC are described. Peer-reviewed publications on the development of pemetrexed and its clinical use in NSCLC were reviewed (1995 - 2009).

WHAT THE READER WILL GAIN

Pemetrexed is a multitargeted antifolate cytotoxic agent. Key Phase II and Phase III trials are described that have shown pemetrexed's efficacy in both the first- and second-line treatment of advanced NSCLC. The efficacy of pemetrexed seems to vary between squamous and nonsquamous histologies. Possible reasons for this are explored. Additionally, the potential role of pemetrexed in maintenance therapy is discussed.

TAKE HOME MESSAGE

Pemetrexed is an effective treatment for advanced NSCLC, with an overall favorable toxicity profile. There is growing evidence that, in patients treated with pemetrexed, nonsquamous tumors have improved outcomes compared to squamous cell tumors. Pemetrexed may also have a role in maintenance therapy for NSCLC.

Feasibility study of dose-dense biweekly administered pemetrexed in patients with non-small cell lung cancer

BACKGROUND AND OBJECTIVES

Pemetrexed is a multitargeted folate pathway inhibitor with documented activity in non-small cell lung cancer (NSCLC). The presumed maximum tolerated dose is 500 mg/m2 every 3 weeks, but pemetrexed-related toxicity is ameliorated when folate and B12 supplementation is provided and therefore a higher dose intensity may be tolerated. The current exploratory study assessed the feasibility of administration of pemetrexed at a fixed dose of 1000 mg every 2 weeks in patients with relapsed or refractory NSCLC.

PATIENTS AND METHODS

The first cohort of 12 patients received pemetrexed monotherapy. No dose-limiting grade 4 toxicity was noted after 4 cycles, so the subsequent cohort of 14 patients received additional anticancer agents (bevacizumab, erlotinib, carboplatin, docetaxel, vinorelbine) given along with dose-dense pemetrexed.

RESULTS

Toxicity overall was reversible and manageable. Among 19 patients who received pemetrexed either alone or with non-myelosuppressive targeted agents, there were only 2 instances of grade 4 neutropenia after prolonged treatment. Grade 3-4 hematologic toxicity was eventually noted in 11 of the 26 patients (42%; 95% confidence interval, 23% to 61%) after a median of 4 cycles (range, 2-14 cycles). There was no significant additional toxicity nor any treatment-related deaths.

CONCLUSION

Our preliminary observations indicate that dose-dense pemetrexed every 2 weeks is feasible and this regimen can be used as monotherapy. These data may serve as a scaffold for combination studies.

Emerging role of pemetrexed in ovarian cancer

The current treatment of choice of epithelial ovarian cancer involves aggressive tumor cytoreductive surgery followed by platinum- and taxane-based chemotherapy; however, despite the encouraging activity of these agents, most ovarian carcinomas relapse and many patients die from drug-resistant disease. After the failure of platinum- and taxane-based schedules, several cytotoxic agents have demonstrated activity in advanced ovarian cancer but none were able to induce significant and durable responses. Among the new cytotoxic agents, pemetrexed plays an emerging role in different tumors, demonstrating competitive activity and a promising safety profile. In ovarian cancer, pemetrexed has been investigated, with encouraging results, as a single agent and in association with platinum compounds; moreover, the drug has shown interesting activity both in platinum-sensitive and platinum-resistant ovarian cancer. According to these clinical results it appears reasonable to explore the combination of pemetrexed with other cytotoxic agents and also with targeted therapies in relapsed ovarian cancer patients.

Endpoints in phase II trials for advanced non-small cell lung cancer

INTRODUCTION

We investigated the relationships between progression-free survival (PFS), response, confirmed response, and failure-free survival (FFS) with overall survival (OS) to assess their suitability as primary endpoints in phase II trials for advanced non-small cell lung cancer.

METHODS

Individual data of 284 patients from four phase II trials were pooled. Progression status and response were modeled as time dependent variables in a multivariable (adjusted for baseline age, gender, stage, and performance status) Cox proportional hazards model for OS, stratified by trial. Subsequently, Cox proportional hazards models were used to assess the impact of PFS, response, confirmed response, and FFS on subsequent survival, using landmark analysis at 8, 12, 16, 20, and 24 weeks. Model discrimination was evaluated using the concordance index (c-index).

RESULTS

The overall median OS, PFS, and FFS were 9.6, 3.7, and 2.8 months, and the response and confirmed response rates were 21 and 15%, respectively. Both progression status and response as time dependent covariates were significantly associated with OS (p < 0.0001; p = 0.009). PFS and FFS at 12 weeks significantly predicted for subsequent survival with the strongest c-index and hazard ratio combination in landmark analyses (hazard ratio, c-index: PFS: 0.39, 0.67; FFS: 0.37, 0.67). The c-indices for response and confirmed response were low (0.59-0.60), indicating their inability to sufficiently discriminate subsequent patient survival outcomes.

CONCLUSIONS

FFS or PFS at 12 weeks is a stronger predictor of subsequent patient survival compared with tumor response and should be routinely used as endpoints in phase II trials for advanced non-small cell lung cancer.

Pemetrexed as first-line therapy for non-squamous non-small cell lung cancer

Pemetrexed is a new cytotoxic agent that is a standard of care for the second-line treatment of non-small cell lung cancer (NSCLC) and in combination with cisplatin in treatment of malignat pleural mesothelioma. It has been studied in numerous phase II and III trials in combination with different drugs or as single agent. Recently, pemetrexed has been approved in combination with cisplatin for the first-line treatment of patients with locally advanced or metastatic NSCLC other than squamous cell histology. The toxicity is acceptable and similar to that of other NSCLC regimens. The postinduction maintenance therapy with pemetrexed is being evaluated in a phase III, double-blind, placebo-controlled study.

Gemcitabine combined with either pemetrexed or paclitaxel in the treatment of advanced non-small cell lung cancer: a randomized phase II SICOG trial

PURPOSE

To estimate the safety, activity, and impact on quality of life of a combination of gemcitabine and pemetrexed in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) in the context of a randomized two-stage phase II study.

PATIENTS AND METHODS

Patients in stage IIIB or IV NSCLC were randomly allocated to receive either gemcitabine 1250 mg/m(2) on day 1, and pemetrexed (Alimta) 500 mg/m(2) followed by gemcitabine 1250 mg/m(2) on day 8 of a 3-weekly cycle (GA arm), or paclitaxel 120 mg/m(2) followed by gemcitabine 1000 mg/m(2), both given on days 1 and 8 of a 3-weekly cycle (PG arm).

RESULTS

105 (GA arm, 51; PG arm, 54) eligible patients (stage IV, 32 and 30, respectively) were enrolled into this study; thereafter, accrual was stopped due to first-stage analysis. The response rate was 20% (95% confidence interval [CI], 10-33%) in the GA arm, and 32% (95% CI, 20-46%) in the PG arm. Median progression-free survival was 5.1 (95% CI, 3.7-6.5) months in the GA arm, and 8.3 (95% CI, 5.9-10.7) months in the PG arm, while median overall survival was 10.5 (95% CI 7.1-13.9), and 13.3 (95% CI 11.7-14.9) months, respectively. Severe neutropenia (36% vs 22%), and febrile neutropenia (14% vs 7%) were more common with the GA regimen, while hair loss (52% vs 16%) and any grade peripheral neuropathy (31% vs 2%) occurred more frequently with PG regimen. Other severe side effects of GA regimen were diarrhoea (10%), liver enzyme derangement (10%), and fatigue (8%).

CONCLUSION

The GA regimen was tolerated and moderately active in advanced or metastatic NSCLC. However, this combination did not yield any advantage in comparison with the PG regimen, and does not deserve further evaluation.

Pemetrexed in the treatment of advanced non-squamous lung cancer

Pemetrexed, a new cytotoxic agent, is a potent inhibitor of thymidylate synthase and other folate-dependent enzymes. Firstly, pemetrexed was approved in combination with cisplatin for the treatment of malignant pleural mesothelioma. Successively, it has been studied, as single-agent, in phase II and III trials for second-line therapy of non-small cell lung cancer (NSCLC). Based on these results, pemetrexed has been registered for the treatment of recurrent NSCLC. The next step was to test pemetrexed plus cisplatin versus gemcitabine plus cisplatin, as first-line therapy in advanced NSCLC patients, in a phase III, non-inferiority, randomized trial. This trial reported the pemetrexed plus cisplatin regimen to be not inferior, in terms of activity and efficacy, to the control arm but statistically better tolerated. The role of pemetrexed as maintenance therapy after first-line therapy for advanced NSCLC is currently being evaluated into a phase III trial. The consistency of the results of these recent studies has identified a predictive effect of NSCLC non-squamous histology for pemetrexed. To date, pemetrexed is registered, at the dose of 500 mg/m(2) on day 1 of a 3-week schedule, in combination with cisplatin, for first-line therapy and, as single-agent, for second-line treatment of patients with non-squamous NSCLC.This review shows the latest and indicates the future developments of pemetrexed in the treatment of advanced NSCLC patients.

Tailoring treatment of nonsmall cell lung cancer by tissue type: role of pemetrexed

Pemetrexed (ALIMTA, LY231514, MTA) is a novel multitargeted antifolate that is currently approved for the treatment of metastatic nonsmall cell lung cancer (NSCLC). Recent evidence reveals that the drug's efficacy is limited to nonsquamous lung cancer histology. As we further understand the drug's mechanisms of action, new genomic and proteomic evidence is shedding light on why some patients respond while others do not. The first goal of this review is to briefly review pemetrexed's mechanism of action, resistance patterns, toxicity profile, and pharmacokinetics. We will also review the clinical trials that led to its use in NSCLC, with special attention to data showing that pemetrexed has greater efficacy in nonsquamous histologies of NSCLC. Furthermore, we will discuss the hypotheses for the genomic and proteomic basis for this variation in efficacy. Finally, we will report the future directions for pemetrexed as a personalized agent for nonsquamous NSCLC.

Pemetrexed in first-line treatment of non-small cell lung cancer

Pemetrexed is an antitumor agent traditionally used as monotherapy for the second-line treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) as well as in combination with cisplatin for the treatment of chemonaïve patients with unresectable malignant pleural mesothelioma. Recently, pemetrexed has been approved in combination with cisplatin for the first-line treatment of patients with locally advanced or metastatic NSCLC other than predominantly squamous cell histology. Studies that support the development of this indication are detailed in this review. We performed a PubMed/Medline database search to identify relevant literature from 1998 until August 2008. Bibliographies from identified references were searched, as well as were abstracts from the most relevant congresses in lung cancer area (American Society of Clinical Oncology Congress, World Conferences of Lung Cancer). We detailed pemetrexed studies in the first-line setting of NSCLC treatment, in monotherapy, in combination with platinum and also, with other agents. Data regarding efficacy differences related to different histologic types were also analyzed.

Adult onset Still's disease after first cycle of pemetrexed and gemcitabine for non-small cell lung cancer

Pemetrexed is a multitargeted antifolate approved for the second-line treatment of locally advanced or metastatic non-small cell lung cancer. The combination of pemetrexed with gemcitabine has been studied in several clinical trials showing a promising antitumor activity with a mild toxicity profile. We present the case of a patient who experienced fever, arthralgia, skin rash and high serum ferritin levels after first cycle of this chemotherapy combination, compatible with an adult onset Still's disease. This adverse event has not been previously reported.

Clinical efficacy and predictive molecular markers of neoadjuvant gemcitabine and pemetrexed in resectable non-small cell lung cancer

BACKGROUND

A trial of neoadjuvant gemcitabine and pemetrexed (GP) chemotherapy in patients with resectable non-small cell lung cancer was conducted. The goal was to achieve a disease response rate of 50% and to determine if the expression levels of genes associated with GP metabolism are predictive of response.

METHODS

Patients had staging with a computed tomography scan, whole body F-18 fluorodeoxyglucose positron emission tomography, and mediastinoscopy. Four biweekly cycles of GP were given. Patients were restaged, and those with resectable stage IB-III disease had thoracotomy. Fresh frozen tumor specimens were collected before and after chemotherapy and the mRNA levels of 14 target genes determined by real-time reverse transcription polymerase chain reaction.

RESULTS

Fifty-two patients started therapy. The radiographic disease response rate was 35% (95% confidence interval 21.7-49.6%), and the progression rate was 6%. Forty-six patients had a thoracotomy. The complete tumor resection rate was 77% (40/52). There were no perioperative deaths or deaths related to chemotherapy. Tumor response to chemotherapy was inversely correlated with the level of expression of RRM1 (p < 0.001; regulatory subunit of ribonucleotide reductase) and TS (p = 0.006; thymidylate synthase); i.e., the reduction in tumor size was greater in those with low levels of expression.

CONCLUSIONS

Neoadjuvant GP is well tolerated and produces an objective response rate of 35%. Tumoral RRM1 and TS mRNA levels are predictive of disease response and should be considered as parameters for treatment selection in future trials with this regimen.

Phase II trial of pemetrexed and gemcitabine in chemotherapy-naive malignant pleural mesothelioma

PURPOSE

Pemetrexed and gemcitabine have single-agent activity in malignant pleural mesothelioma (MPM). The combination of pemetrexed/gemcitabine has not previously been studied in MPM to our knowledge.

PATIENTS AND METHODS

Patients with histologic or cytologic diagnosis of MPM were included. Cohort 1 received gemcitabine 1,250 mg/m(2) on days 1 and 8, with pemetrexed 500 mg/m(2) on day 8, and cohort 2 received gemcitabine 1,250 mg/m(2) on days 1 and 8, with pemetrexed 500 mg/m(2) on day 1. Cycles were repeated every 21 days; all patients were supplemented with folic acid and vitamin B(12) and received dexamethasone.

RESULTS

One hundred eight patients (cohort 1, n = 56; cohort 2, n = 52) with pleural mesothelioma were enrolled. Among assessable patients, response rate was 26.0% in cohort 1 and 17.1% in cohort 2. Median time to disease progression was 4.34 months for cohort 1 and 7.43 months for cohort 2. Median survival was 8.08 months for cohort 1 (1-year survival = 31.14%) and 10.12 months for cohort 2 (1-year survival = 45.80%). In cohorts 1 and 2, incidence of grade 4 neutropenia was 25.0% and 29.4%, grade 4 thrombocytopenia was 14.3% and 3.9%, grade 3 or 4 anemia was 5.4% and 5.9%, and grade 3 or 4 fatigue was 23.2% and 15.7%, respectively.

CONCLUSION

The combination of pemetrexed and gemcitabine resulted in moderate clinical activity in MPM. However, the median survival times are similar to those with single-agent pemetrexed and inferior to outcomes observed with cisplatin in combination with an antifolate.

Review of the pemetrexed and gemcitabine combination in patients with advanced-stage non-small cell lung cancer

Pemetrexed is a new multitargeted antifolate that can be easily administered as a 10-min infusion every 3 weeks. The use of folic acid, vitamin B(12), and corticoid prophylaxis has significantly reduced pemetrexed-induced toxicity. Single-agent pemetrexed has shown antitumor activity in a wide range of solid tumors, including non-small cell lung cancer (NSCLC). Association with vinorelbine, cisplatin, carboplatin, and oxaliplatin have been tried, but the pemetrexed and gemcitabine combination, an easy to administer cisplatin-free doublet, has been documented in many phase 2 trials in the first-line treatment of advanced NSCLC. In vitro cytotoxic assays and phase I studies have defined several schedules of administration for pemetrexed and gemcitabine. The recommended dose is pemetrexed 500 mg/m(2) on day 1 or 8, and gemcitabine 1250 mg/m(2) on day 1 and 8, but it is unknown if pemetrexed should precede or follow gemcitabine and at what time interval. Published studies have failed to show significant differences in overall survival times despites response rates oscillating between 15% and 41%. The main toxicities are neutropenia, fatigue, skin rashes and elevated transaminases and seem to occur with similar rates in the many phase 2 trials. Hopes for the future are in tailored chemotherapy, since molecular markers of sensitivity are available for gemcitabine and pemetrexed, allowing to determinate in the future which patients will be most likely to benefit from the gemcitabine-pemetrexed doublet.

Pemetrexed: biochemical and cellular pharmacology, mechanisms, and clinical applications

Pemetrexed is a new-generation antifolate, approved for the treatment of mesothelioma and non-small cell lung cancer, currently being evaluated for the treatment of a variety of other solid tumors. This review traces the history of antifolates that led to the development of pemetrexed and describes the unique properties of this agent that distinguish it from other antifolates. These include (a) its very rapid conversion to active polyglutamate derivatives in cells that build to high levels and are retained for long intervals to achieve prolonged and potent inhibition of its major target enzyme thymidylate synthase, (b) its high affinity for three folate transporters, and (c) its marked sensitivity to the level of physiologic folates in cells. The latter results in the unique and paradoxical finding that when transport mediated by the major folate transporter (the reduced folate carrier) is impaired, pemetrexed activity is preserved. This is due to concurrent contraction of competing cellular physiologic folates and utilization of a novel second transport carrier for which pemetrexed has high affinity, recently identified as the proton-coupled folate transporter (PCFT). Laboratory studies are reviewed that raise the possibility of new approaches to the use of folic acid supplementation in clinical regimens with pemetrexed.

Clinical activity of pemetrexed: a multitargeted antifolate anticancer agent

Pemetrexed is a new generation antifolate anticancer agent that inhibits several folate-dependent enzymes required for production of DNA and RNA intermediates. Early studies showed significant hematologic and nonhematologic toxicities with this agent. However it was found that many of these toxicities related to functional folate status and could be markedly reduced through routine supplementation with folic acid and vitamin B(12), without adversely affecting efficacy. Phase III studies with pemetrexed have established a clinical role for this drug as a single agent in the second-line treatment of non-small cell lung cancer and in combination with cisplatin for the frontline treatment of unresectable malignant pleural mesothelioma. Clinical trials of pemetrexed alone or in combination with other chemotherapeutic agents have shown considerable activity in many tumor types including colorectal, pancreatic and breast cancer, and urothelial tumors.

A Dose Escalation Study of Gemcitabine plus Pemetrexed Administered Biweekly in Patients with Solid Tumors

PURPOSE

The study aimed to determine the maximum tolerated doses (MTDs) and identify the dose-limiting toxicities of the biweekly administration of pemetrexed plus gemcitabine in patients with solid tumors.

PATIENTS AND METHODS

Patients with advanced malignancies were treated with escalated doses of gemcitabine and pemetrexed (starting doses 1,250 and 300 mg/m(2), respectively) both given on days 1 and 15 in cycles of 4 weeks.

RESULTS

Forty-one patients were treated at 7 dose levels. The MTD was reached at the dose of 1,750 mg/m(2) for gemcitabine and 450 mg/m(2) for pemetrexed. Dose-limiting events were grade IV neutropenia, febrile neutropenia and treatment delay due to grade III hematological toxicities. One partial response in a pretreated patient with ovarian cancer was observed, while 4 other patients experienced stable disease.

CONCLUSIONS

The biweekly administration of gemcitabine plus pemetrexed at the recommended MTDs is safe, well tolerated and demonstrates antitumor activity which merits further evaluation in phase II studies.

Role of pemetrexed in non-small cell lung cancer

Pemetrexed was approved for the treatment of relapsed or chemotherapy refractory non-small cell lung cancer patients, as it produced similar response and survival outcomes and less toxicity as compared to taxotere. Pemetrexed in combination with platinum analogs or with gemcitabine or vinorelbine, produce equivalent responses and overall survival results compared to combinations of platinum analogs with other drugs. The role of bevacizumab and the inhibitors of epithelial growth factor receptor also should be evaluated in selected patients with NSCLC treated with pemetrexed combinations. Further increases in drug dose may be possible using transfer of drug resistance genes in hematopoietic stem cells.

Phase II study of gemcitabine and carboplatin in patients with advanced non-small-cell lung cancer

PURPOSE

To evaluate the efficacy and safety of gemcitabine in combination with carboplatin at standard rate or fixed dose rate infusion in patients with advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

In this prospective study, patients with chemonaive advanced NSCLC were randomized to receive gemcitabine at a standard rate (gemcitabine 1,200 mg/m2 over 30 min, the standard arm) or a fixed dose rate (gemcitabine 1,200 mg/m2 over 120 min, the FDR arm) on days 1 and 8 every 3 week cycle. In both treatment arms, carboplatin at AUC of 5 was administered over 4 h following gemcitabine on day 1 of each cycle.

RESULTS

From November 2003 to June 2005, a total of 42 patients, in which 7 (17%) patients had stage III(B) disease and 35 (83%) had stage IV disease, were enrolled into this study. All patients were included in efficacy and toxicity assessment. No patient had a complete response. Seven (33%) patients in the standard arm and 10 (48%) in the FDR arm had a partial response. The median time to progression and median overall survival time in the standard arm was 5.4 months (95% CI, 3.8-7 months) and 11.5 months (95% CI, 8.2-14.8 months), respectively, while in the FDR arm was 6.5 (95% CI, 4.4-8.6 months) months, 12.0 months (95% CI, 11.3-12.7 months), respectively. The most frequently reported grade 3 or 4 hematological toxicities were thrombocytopenia (38% patients in the standard arm and 43% in the FDR arm) and neutropenia (24% in the standard arm and 33% in the FDR arm). Although hematological toxicity occurred in a little higher percent of patients in the FDR arm than in the standard arm, there were no discernible differences by statistical analysis in both treatment arms (P > 0.05). And significant nonhematologic toxicities were infrequent and tolerable in both arms. No significant difference existed also (P > 0.05).

CONCLUSION

In this phase II study, gemcitabine in combination with carboplatin either at standard rate or fixed dose rate infusion was clinically effective and well tolerated in patients with advanced NSCLC.

Phase I trial and pharmacokinetic study of pemetrexed in children with refractory solid tumors: the Children's Oncology Group

PURPOSE

We report results of a phase I trial and pharmacokinetic study of pemetrexed (LY231514) in children and adolescents with refractory solid tumors. Pemetrexed is a novel antifolate that inhibits multiple enzymes necessary for the biosynthesis of thymidine and purine nucleotides. The purpose of this study was to determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetic properties of pemetrexed in children.

PATIENTS AND METHODS

Pemetrexed was administered as a 10-minute intravenous infusion every 21 days. Patients received vitamin B12 and folic acid supplementation as well as dexamethasone prophylaxis. Cohorts of three to six children were enrolled at dose levels of 400, 520, 670, 870, 1,130, 1,470, 1,910, and 2,480 mg/m2. Pharmacokinetic studies were performed during the first course of treatment.

RESULTS

Thirty-three patients (31 assessable) with a median age of 12 years were enrolled. DLT occurred in one of six patients at 1,470 mg/m2 and two of four patients at 2,480 mg/m2. The MTD was 1,910 mg/m2. The primary DLTs were neutropenia and rash. No objective antitumor responses were seen. Mean plasma clearance, half-life, and steady-state volume of distribution values were 2.3 L/h/m2, 2.5 hours, and 5.4 L/m2, respectively.

CONCLUSION

Pemetrexed is well-tolerated in children with refractory solid tumors at doses similar to the MTD in adults. The recommended dose for phase II studies is 1,910 mg/m2 administered every 21 days with dexamethasone, folic acid, and vitamin B12 supplementation.

Single-Agent Pemetrexed or Sequential Pemetrexed/Gemcitabine as Front-Line Treatment of Advanced Non-small Cell Lung Cancer in Elderly Patients or Patients Ineligible for Platinum-Based Chemotherapy: A Multicenter, Randomized, Phase II Trial

INTRODUCTION

This randomized phase II trial evaluated single-agent pemetrexed or sequential pemetrexed/gemcitabine in patients with non-small cell lung cancer (NSCLC) who were elderly (> or = 70 years) or younger than 70 years and ineligible for platinum-based chemotherapy.

METHODS

Chemonaive patients with stage IIIB/IV NSCLC and an Eastern Cooperative Oncology Group performance status of 0 to 2 received either 500 mg/m2 of pemetrexed (day 1, every 3 weeks) for eight cycles, or the same dosage of pemetrexed for cycles 1 and 2 and then 1200 mg/m2 of gemcitabine (days 1 and 8, every 3 weeks) for cycles 3 and 4 (repeated once for a total of eight cycles). All patients were given vitamin B12 and folic acid supplementation.

RESULTS

From July 2003 to July 2004, 87 patients (44 pemetrexed; 43 pemetrexed/gemcitabine) received treatment. The median time to progression was 4.5 (95% confidence interval: 3.0-9.3) and 4.1 months (95% confidence interval: 1.7-5.8) for the pemetrexed and pemetrexed/gemcitabine arms, respectively, and the median progression-free survival time was 3.3 months for both arms. Tumor response rates for the pemetrexed and pemetrexed/gemcitabine arms were 4.5% and 11.6%, respectively. The median overall survival time was 4.7 months for the pemetrexed arm and 5.4 months for the pemetrexed/gemcitabine arm, with respective 1-year survival rates of 28.5% and 28.1%. Grade 3/4 hematologic toxicity consisted of neutropenia (4.5% pemetrexed; 2.3% pemetrexed/gemcitabine), febrile neutropenia (4.5% pemetrexed; 4.7% pemetrexed/gemcitabine), thrombocytopenia (4.5% pemetrexed; 7.0% pemetrexed/gemcitabine), and anemia (6.8% pemetrexed; 4.7% pemetrexed/gemcitabine). No grade 3/4 nonhematologic toxicities exceeded 4.7% in either arm.

CONCLUSIONS

Single-agent pemetrexed and sequential pemetrexed/gemcitabine have shown moderate activity and are well tolerated as first-line treatments for advanced NSCLC in elderly patients or patients unsuitable for platinum-based combination chemotherapy.

A prognostic model for advanced stage nonsmall cell lung cancer. Pooled analysis of North Central Cancer Treatment Group trials

BACKGROUND

A pooled analysis was performed to examine the impact of pretreatment factors on overall survival (OS) and time to progression (TTP) in patients with advanced-stage nonsmall cell lung cancer (NSCLC) and to construct a prediction equation for OS using pretreatment factors.

METHODS

A pooled data set of 1053 patients from 9 North Central Cancer Treatment Group trials was used. Age, gender, Eastern Cooperative Oncology Group performance status (PS), tumor stage (Stage IIIB vs. Stage IV), body mass index (BMI), creatinine level, hemoglobin (Hgb) level, white blood cell (WBC) count, and platelet count were evaluated for their prognostic significance in both univariate and multivariate analyses by using a Cox proportional-hazards model.

RESULTS

Patients who had high WBC counts, low Hgb levels, PS >0, BMI < 18.5 kg/m2, and TNM Stage IV disease had significantly worse TTP and OS. Patients who had Stage IV disease with a high WBC count had a particularly poor prognosis. An equation to predict the OS of patients with Stage IV NSCLC based on pretreatment PS, BMI, Hgb level, and WBC count was constructed.

CONCLUSIONS

In addition to the widely accepted prognostic factors of PS, BMI, and disease stage, both of the readily available laboratory parameters of Hgb level and WBC count were found to be significant prognostic factors for OS and TTP in patients with advanced-stage NSCLC. The authors' prediction equation can be used to evaluate the benefit of a treatment in Phase II trials by comparing the observed survival of a cohort with its expected survival by using the patients' own prognostic factors in place of comparisons with historic data that may have substantially different baseline patient characteristics.