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

Pan-Cancer Characterization Identifies SLC19A1 as an Unfavorable Prognostic Marker and Associates It with Tumor Infiltration Features

Background: Recent studies have identified solute carrier family 19 member 1 (SLC19A1) as a second messenger transporter that regulates massive immune-related signaling cascades, but current studies provide limited information. This study aims to evaluate its role and the potential mechanisms across various cancers. Methods: We analyzed multi-omics data from a pan-cancer cohort to evaluate SLC19A1 expression and its association with multiple features, including prognosis, tumor stemness, genome instability, and immune infiltration. Immunofluorescence staining was performed to validate SLC19A1 expression in tumor tissues and its relationship M2 macrophages. In addition, we used web tools such as ROCplotter to evaluate the association between SLC19A1 and response to chemotherapy and immunotherapy. Results: SLC19A1 was found to be overexpressed in multiple cancer types compared to normal tissues, correlating with poor prognosis. High SLC19A1 levels were associated with increased genomic instability and immune suppression. In addition, SLC19A1 was negatively correlated with CD8+ T-cell infiltration and positively correlated with M2 macrophage infiltration. The association of SLC19A1 with M2 macrophages was confirmed in multiple immunofluorescence staining. Finally, SLC19A1 was associated with the response to chemotherapy and immunotherapy in a variety of tumors. Conclusions: Our findings position SLC19A1 as a novel unfavorable prognostic marker in cancer, closely linked to immune suppression and genomic instability. This study highlights the need for further exploration of SLC19A1 as a therapeutic target and its implications in cancer treatment strategies.

X-ray cross-complementing family: the bridge linking DNA damage repair and cancer

Genomic instability is a common hallmark of human tumours. As a carrier of genetic information, DNA is constantly threatened by various damaging factors that, if not repaired in time, can affect the transmission of genetic information and lead to cellular carcinogenesis. In response to these threats, cells have evolved a range of DNA damage response mechanisms, including DNA damage repair, to maintain genomic stability. The X-ray repair cross-complementary gene family (XRCC) comprises an important class of DNA damage repair genes that encode proteins that play important roles in DNA single-strand breakage and DNA base damage repair. The dysfunction of the XRCC gene family is associated with the development of various tumours. In the context of tumours, mutations in XRCC and its aberrant expression, result in abnormal DNA damage repair, thus contributing to the malignant progression of tumour cells. In this review, we summarise the significant roles played by XRCC in diverse tumour types. In addition, we discuss the correlation between the XRCC family members and tumour therapeutic sensitivity.

Correlation of toxicities and efficacies of pemetrexed with clinical factors and single-nucleotide polymorphisms: a prospective observational study

BACKGROUND

Pemetrexed is an efficacious multi-targeted antifolate with acceptable toxicity for non-squamous non-small cell lung cancer (non-Sq NSCLC) and malignant pleural mesothelioma. Vitamin B12 and folic acid as premedication can reduce the frequency of severe toxicities of pemetrexed chemotherapy. However, adverse effects are frequent in clinical settings. In this study, we aimed to identify the clinical factors and single-nucleotide polymorphisms (SNPs) associated with the toxicity and efficacy of pemetrexed chemotherapy.

METHODS

This observational study was conducted from October 2012 to December 2019; we evaluated the toxicities and efficacies of pemetrexed chemotherapy using multivariate logistic or Cox regression analysis. In total, 106 patients received pemetrexed chemotherapy. SNPs were analyzed for four patients with malignant pleural mesothelioma and 67 with non-Sq NSCLC.

RESULTS

The median progression-free survival (PFS) and overall survival of 63 patients with non-Sq NSCLC, excluding four in the adjuvant setting, were 6.8 and 33.3 months, respectively. Per propensity-score-adjusted multivariate Cox analyses, favorable factors for PFS were folic acid level ≥ 9.3 ng/mL before premedication, platinum combination, bevacizumab combination, vitamin B12 level < 1136 pg/mL before chemotherapy, A/A + A/G of BHMT (742 G > A), and A/A + A/C of DHFR (680 C > A). Favorable prognostic factors included good performance status, low smoking index, body mass index ≥ 20.66 kg/m2, folic acid level ≥ 5.55 ng/mL before premedication, higher retinol-binding protein before chemotherapy, and A/G of MTRR (66 A > G). Among the 71 patients who were analyzed for SNPs, the frequencies of hematologic toxicities and non-hematologic toxicities in Grades 3-4 were 38% and 36.6%, respectively. Per propensity-score-adjusted multivariate logistic analyses, risk factors for Grades 3-4 hematologic toxicities were vitamin B12 level < 486 pg/mL before premedication, leucocyte count < 6120 /µL before chemotherapy, folic acid level < 15.8 ng/mL before chemotherapy, status with a reduced dose of chemotherapy, and C/T + T/T of MTHFR (677 C > T). Risk factors for Grades 2-4 non-hematologic toxicities were homocysteine levels ≥ 11.8 nmol/mL before premedication, transthyretin level < 21.5 mg/dL before chemotherapy, C/C + T/T of MTHFR (677 C > T), and A/A + G/G of SLC19A1 [IVS2 (4935) G > A].

CONCLUSION

The information on metabolites and SNPs of the folate and methionine cycle will help predict the toxicities and efficacies of pemetrexed.

TRIAL REGISTRATION

This trial was retrospectively registered with the University hospital Medical Information Network (UMIN000009366) on November 20, 2012.

Polymorphisms in solute carrier genes (SLC19A1, SLCO1B1, and SLCO1B3) predicts survival and toxicity in North Indian lung cancer patients undergoing platinum-based doublet chemotherapy

WHAT IS KNOWN AND OBJECTIVE

Solute Carrier (SLC) transporters are known mediators of drug disposition that facilitate the influx of substrates and various chemotherapeutic agents into cells. Polymorphisms in the SLC19A1, SLCO1B1, and SLCO1B3 gene influence the prognosis in the cancer patients, but little is known about their role in lung cancer in Asians. So, the current study aims to investigate the polymorphisms in SLC19A1, SLCO1B1, and SLCO1B3 genes in Northern Indian lung cancer patients.

METHODS

Patients with lung cancer who had a confirmed histology and cytology diagnosis were enrolled in the study. SLC polymorphisms were assessed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) for variations in SLC19A1 (G80 A), SLCO1B1 (A388 G, T521 C), and SLCO1B3 (A1683-5676 G).

RESULTS AND DISCUSSION

Our results showed that mutant genotype for SLC19A1 G80 A polymorphism had higher median survival time (MST) compared to wild genotype. ADCC patients with mutant genotype showed better survival compared to wild genotype for SLC19A1 G80 A. SCLC patients G80 A polymorphism showed increased survival in patients with mutant genotype (p = 0.04). In SLCO1B3, A1683-5676 G patients carrying heterozygous alleles and administered with platinum and docetaxel showed inferior survival (p = 0.006). In T521 C variant, patients with carrier genotype had reduced chances of developing anaemia (p = 0.04). Patients with SLC19A1 and SLCO1B3 variants showed lower incidence of thrombocytopenia and nephrotoxicity.

WHAT IS NEW AND CONCLUSION

Our findings imply that Solute Carrier gene polymorphisms modulate the overall survival in lung cancer patients undergoing platin-based doublet chemotherapy, also these polymorphisms have a modifying impact on the associated adverse events/toxicity.

Mechanisms of resistance to chemotherapy in non-small cell lung cancer

Non-small cell lung cancer (NSCLC), which represents 80-85% of lung cancer cases, is one of the leading causes of human death worldwide. The majority of patients undergo an intensive and invasive treatment regimen, which may include radiotherapy, chemotherapy, targeted therapy, immunotherapy, or a combination of these, depending on disease stage and performance status. Despite advances in therapeutic regimens, the 5-year survival of NSCLC is approximately 20-30%, largely due to diagnosis at advanced stages. Conventional chemotherapy is still the standard treatment option for patients with NSCLC, especially those with advanced disease. However, the emergence of resistance to chemotherapeutic agents (chemoresistance) poses a significant obstacle to the management of patients with NSCLC. Therefore, to develop efficacious chemotherapeutic approaches for NSCLC, it is necessary to understand the mechanisms underlying chemoresistance. Several mechanisms are known to mediate chemoresistance. These include altered cellular targets for chemotherapy, decreased cellular drug concentrations, blockade of chemotherapy-induced cell cycle arrest and apoptosis, acquisition of epithelial-mesenchymal transition and cancer stem cell-like phenotypes, deregulated expression of microRNAs, epigenetic modulation, and the interaction with tumor microenvironments. In this review, we summarize the mechanisms underlying chemoresistance and tumor recurrence in NSCLC and discuss potential strategies to avoid or overcome chemoresistance.

Mechanisms of resistance to pemetrexed in non-small cell lung cancer

Currently, lung cancer has remained the most common cause of cancer death while non-small cell lung cancer (NSCLC) accounts for the most of all lung cancer cases. Regardless of multiple existing managements, chemotherapy regimens are still the mainstay of treatment for NSCLC, where pemetrexed has shown cytotoxic activity and has increasingly been used, especially for advanced cases. However, chemo-resistance may inhibit clinical efficacy after long-term use. Mechanisms responsible for chemo-resistance to pemetrexed in NSCLC are plethoric but can be separated into two categories to be discussed: tumor cells and their interactions with drugs. Phenomena relevant to tumor cells such as oncogene or oncoprotein alterations, DNA synthesis, DNA repair, and tumor cell biology behavior are discussed, as well as processes associated with drug dynamics, including drug uptake, drug elimination, and antifolate polyglutamylation. This review will focus on clinical trials and the basic biomedical mechanisms of NSCLC treated with pemetrexed and will describe the underlying mechanisms of resistance to facilitate more efficient clinical therapies to treat patients.

Discovery of Novel Biomarkers of Therapeutic Responses in Han Chinese Pemetrexed-Based Treated Advanced NSCLC Patients

Pemetrexed, one of the most commonly used drugs in advanced non–small cell lung cancer (NSCLC) therapies, often leads to various therapeutic responses in patients. These therapeutic responses to pemetrexed, including adverse drug reactions (ADRs) and its intended therapeutic effects, have been demonstrated to be highly individual-specific. Such difference in therapeutic responses across individuals may be caused by the unique genetic variations in each patient. However, only a few pemetrexed-based studies have been performed using Han Chinese patients. In this study, we aimed to identify genetic signatures of therapeutic responses of pemetrexed-based treatment using 203 Han Chinese patients with advanced NSCLC. All the participants received two different types of therapies: 1) treatment with only pemetrexed and 2) treatment with both pemetrexed and platinum (mainly cisplatin and carboplatin). We then performed a genetic association analysis on 16 selected single-nucleotide polymorphisms (SNPs) in 7 genes using these 2 groups. The analysis of patients receiving only pemetrexed suggests that the SNP rs1051298 on the SLC19A1 gene (c.*746C > T) increased the risk of all ADRs (collected all types of ADRs) in different cycles of pemetrexed therapy [1-2 cycles: P = 0.0059, odds ratio (OR) = 3.143; 1-4 cycles: P = 0.0072, OR = 2.340; 1-6 cycles: P = 0.0071, OR = 2.243]. This influence of rs1051298 is particularly significant in terms of liver injury (1-4 cycles: P = 0.0056, OR = 3.863; 1-6 cycles: P = 0.0071, OR = 3.466). In all the patients, including patients who received both pemetrexed and platinum, SNP rs1801133 on the MTHFR gene (665C > T) was found to be significantly associated with hematological ADRs in 1 to 2 cycles (P = 0.0079, OR = 3.566). Additionally, we discovered that SNP rs12995526 (c.815-102T > C) in the ATIC gene and SNP rs11545077 (c.91G > T) in the GGH gene were associated with both ADRs and therapeutic effects. In summary, our study identified several potential biomarkers that were significantly associated with ADRs and therapeutic effects of pemetrexed-related treatments using Han Chinese patients. Our discoveries will provide important clues for personalized pemetrexed-based treatment design for Han Chinese NSCLC patients in the future.

Pharmacogenetics of platinum-based chemotherapy: impact of DNA repair and folate metabolism gene polymorphisms on prognosis of non-small cell lung cancer patients

Chemotherapy based on platinum compounds is the standard treatment for NSCLC patients with EGFR wild type, and is also used as second line in mutated EGFR patients. Nevertheless, this therapy presents poor clinical outcomes. ERCC1, ERCC2, XRCC1, MDM2, MTHFR, MTR, and SLC19A1 gene polymorphisms may contribute to individual variation in response and survival to platinum-based chemotherapy. The aim of this study was to investigate the influence of these polymorphisms on response and survival of NSCLC patients treated with platinum-based chemotherapy. A retrospective-prospective cohorts study was conducted, including 141 NSCLC patients. Polymorphisms were analyzed by PCR real-time with Taqman® probes. Patients with ERCC1 rs3212986-GG (p = 0.0268; OR = 2.50; CI_95% = 1.12-5.69) and XRCC1 rs25487-GG (p = 0.0161; OR = 2.99; CI_95% = 1.26-7.62) genotype showed significantly better ORR. Cox survival analysis revealed that patients carrying the MDM2 rs1690924-GG genotype (p = 0.0345; HR = 1.99; CI_95% = 1.05-3.80) presented higher risk of death. Furthermore, carriers of MTR rs1805087-A alleles (p = 0.0060; HR = 8.91; CI_95% = 1.87-42.42) and SLC19A1 rs1051266-AA genotype (p = 0.0130; HR = 1.74; CI_95% = 1.12-2.68) showed greater risk of progression. No influence of ERCC1 rs11615, ERCC2 rs13181, ERCC2 rs1799793, XRCC1 rs1799782, MDM2 rs1470383, MTHFR rs1801131, and MTHFR rs1801133 on platinum-based chemotherapy clinical outcomes was found. In conclusion, our results suggest that ERCC1 rs3212986, XRCC1 rs25487, MDM2 rs1690924, MTR rs1805087, and SLC19A1 rs1051266 gene polymorphisms may significantly act as predictive factors in NSCLC patients treated with platinum-based chemotherapy.

Combined effect of ERCC1 and ERCC2 polymorphisms on overall survival in non-squamous non-small-cell lung cancer patients treated with first-line pemetrexed/platinum

OBJECTIVES

Polymorphisms of DNA repair genes may affect DNA repair capacity and the sensitivity of platinum doublets chemotherapy in non-small-cell lung cancer (NSCLC). We prospectively evaluated whether single nucleotide polymorphisms (SNPs) of ERCC1, ERCC2, XRCC1, and XRCC3 were associated with treatment outcome in advanced non-squamous NSCLC patients receiving pemetrexed/platinum as their first-line chemotherapy.

MATERIALS AND METHODS

Genotyping of six SNPs in four DNA repair genes in 58 patients treated with first-line pemetrexed/platinum was performed using TaqMan SNP Genotyping Assays.

RESULTS

The wild-type ERCC1 8092 (C/C) was significantly associated with a better objective response compared to the variant genotypes (C/A + A/A) (48% vs 10%, P = .005). In the multivariate Cox proportional hazards model, we found that individuals with a wild-type genotype of ERCC1 Asn118Asn, ERCC1 C8092A and ERCC2 Asp312Asn had significantly better overall survival (OS) than those with a heterozygous or homozygous variant genotype. On the other hand, the heterozygous variant genotype of ERCC2 Lys751Gln was associated with better OS than that of the wild-type genotype. We further explored the combined effect of SNPs on OS, and found a significant allele/dose-dependent trend toward decreasing OS in patients with an increasing number of unfavorable alleles among four SNPs in ERCC1 and ERCC2. The median OS of patients with two or three unfavorable alleles (30.1 and 30.5 months, respectively) was significantly longer than that of patients with 4 unfavorable alleles (11.8 months, log-rank test for trend, P = .001).

CONCLUSION

A combination of ERCC1 and ERCC2 polymorphisms may predict OS among pemetrexed/platinum treated advanced non-squamous NSCLC patients.

Influx transporter variants as predictors of cancer chemotherapy-induced toxicity: systematic review and meta-analysis

AIM

Chemotherapeutic agents have been shown to increase lung patient survival, however their use may be limited by their serious adverse effects. We aimed to assess int impact of pharmacogenetic variation of influx transporters on inter-individual patient variation in adverse drug reactions.

PATIENTS & METHODS

We conducted a meta-analysis and systemic review and identified 16 publications, totaling 1510 patients, to be eligible for review.

RESULTS

Meta-analysis showed east-Asian patients expressing SLCO1B1 521T>C or 1118G>A to have a two- to fourfold increased risk of irinotecan-induced neutropenia but not diarrhea. American patients, expressing SLC19A1 IVS2(4935) G>A, were further associated with pemetrexed/gemcitabine-induced grade 3+ leukopenia.

CONCLUSION

Future studies should look to robust validation of SLCO1B1 and SLC19A1 as prognostic markers in the management of lung cancer patients.

Efflux transporter variants as predictors of drug toxicity in lung cancer patients: systematic review and meta-analysis

Chemotherapeutic drugs are underutilized in lung cancer management due in part to serious adverse drug reactions (ADRs).

AIM

With studies revealing an association between interindividual patient ADR variation and efflux transporter variants, we carried out a meta-analysis and systemic review, in order to highlight current knowledge regarding the strength of association between efflux transporter SNPs variants and chemotherapeutic-drug induced ADRs.

MATERIALS & METHODS

Papers were sourced from MEDLINE, Cochrane Library, CINHL, EMBASE, Web of Knowledge, Scopus. The Cochrane Collaboration Risk of Bias Tool v13 was used to evaluate six types of bias domains for each of the publications reviewed.

RESULTS

Twenty-five publications comprising three randomised control trials, two retrospective case-controls and 20 clinical observation studies, totalling 3578 patients, were deemed eligible for review. Of the known efflux drug transporters, we report findings on the ABC members ABCB1, ABCC1, ABCC2, ABCG2, ABCA1, ABCC4 and ABCC5. Meta-analysis showed an decreased risk of irinotecan-induced neutropenia in patients expressing ABCB1 2677G>T/G (odds ratio [OR]: 0.24; 95% CI: 0.1-0.59; p = 0.002) but increased risk for ABCC2 3972T>T (OR: 1.67; 95% CI: 1.01-2.74; p = 0.04). ABCG2 34G>A was associated with a threefold increased risk of irinotecan-induced diarrhea (95% CI: 1.00-6.24; p = 0.05).

CONCLUSION

The majority of studies have identified a role for variants in effluxdrug transporters in contributing to lung cancer treatment-associated ADRs. However, for implementation of use of these transporter genetic variants as prognostic markers for ADR risk, future studies must incorporate larger patient numbers.

On the pharmacogenetics of non-small cell lung cancer treatment

Despite many clinical efforts, non-small-cell lung cancer (NSCLC) has a dismal 5-year survival rate of 16%, and high incidence of recurrence. The success of biologically targeted agents, as well as the activity of well-established chemotherapeutic regimens, has been limited by inherited/acquired resistance, and biomarkers to adapt the prescription of anticancer drugs to patients' features are urgently warranted. Areas covered. In oncology, pharmacogenetics should provide the way to select patients who may benefit from a specific therapy that best match the individual and tumor genetic profile, thus allowing maximum activity and minimal toxicity. The present review summarizes the main findings on NSCLC pharmacogenetics, critically reappraising the most important studies on polymorphisms correlated with outcome of pemetrexed and EGFR-inhibitors, and provides perspective on clinical application of genomic tests for treatment decision-making. Expert Opinion. A major challenge in NSCLC is the identification of subgroups of diseases/patients that will truly benefit from specific treatments. Ideally, convenient and minimally invasive tests to decipher biomarkers of chemosensitivity/resistance and toxicity should be developed alongside novel anticancer treatments. Integration with the latest generation of whole-genome analyses and liquid biopsies as well as prospective validation in large cohorts of patients will overcome the limitations of the traditional pharmacogenetic approaches.

NCCTG N0821 (Alliance): a phase II first-line study of pemetrexed, carboplatin, and bevacizumab in elderly patients with advanced nonsquamous non-small-cell lung cancer with good performance status

BACKGROUND

We hypothesized that the combination of bevacizumab, carboplatin, and pemetrexed will be an effective first-line regimen in fit, elderly patients with nonsquamous non-small-cell lung cancer.

METHODS

Treatment-naïve, stage IIIB/IV nonsquamous non-small-cell lung cancer patients more than 70 years old with good performance status (Eastern Cooperative Oncology Group performance status 0-1) and adequate organ function were eligible. Carboplatin area under the curve 6, pemetrexed 500 mg/m, and bevacizumab 15 mg/kg were administered on day 1 of each 21-day cycle (up to six cycles) followed by maintenance pemetrexed and bevacizumab. The primary end point of 6-month progression-free survival rate of at least 70% was assessed using a one-stage binomial design. Quality of life (QOL) questionnaires were administered. Polymorphisms in genes encoding relevant proteins (drug targets, transport, and metabolism proteins) were correlated with treatment outcome.

RESULTS

Fifty-seven eligible patients were enrolled. Median age was 74.5 years. Median treatment cycles received was 6. The most common grade 3 or higher non-hematologic adverse events were fatigue (26%) and hypertension (11%); 16% had grade 4 neutropenia and 6.5% had grade 4 thrombocytopenia. Three patients experienced grade 3/4 hemorrhagic events (one pulmonary, two gastrointestinal). Primary end point of PFS6 was 60% (95% confidence interval [CI]: 45.9-73%). Median PFS was 7.0 months (95% CI: 5.9-10.1), median overall survival was 13.7 months (95% CI: 9.4-16.8). Polymorphic KDR and VEGFA variants correlated with survival and toxicity, respectively. There was no significant change in overall QOL scores over time.

CONCLUSION

This regimen is feasible and did not decrease the QOL in this study population. However, it did not meet the primary efficacy end point.

Phase II study of perioperative chemotherapy with cisplatin and pemetrexed in non-small-cell lung cancer

INTRODUCTION

Pathologic complete response (pCR) with neoadjuvant chemotherapy is associated with improved survival in many solid tumors. We evaluated pCR rate of cisplatin with pemetrexed in non-small-cell lung cancer.

METHODS

Patients with stages IB to IIIA non-small-cell lung cancer, Eastern Cooperative Oncology Group performance status 0 to 1 were enrolled in this single-arm phase II trial using two-stage design with 90% power to detect pCR rate of more than or equal to 10%. Pretreatment mediastinal lymph node biopsy was required. Patients received three cycles of cisplatin 75 mg/m with pemetrexed 500 mg/m (day 1 every 21 days) preoperatively and additional two cycles within 60 to 80 days after surgery. The primary end point was pCR. Polymorphisms in FPGS, GGH, SLC19A1, and TYMS genes were correlated with treatment outcomes.

RESULTS

Thirty-eight patients were enrolled, with median age of 62.5 years. Preoperatively, 26% had squamous histology, and 34% had biopsy-proven N2 involvement. R0 resection was achieved in 94% of the 34 patients who underwent surgery, and 54% had documented N2 clearance. There was no pCR seen. Median disease-free survival (DFS) and overall survival of these patients have not yet been reached in contrast to median of 13.8 and 24.2 months, respectively, in patients with persistent N2 disease (p = 0.3241 and p = 0.1022, respectively). There was a statistically significant association between DFS and postoperative tumor, node, metastasis stage (p = 0.0429), SLC19A1 rs3788189 TT genotype (p = 0.0821), and viable tumor defined as less than or equal to 10% of resected specimen (p = 0.026).

CONCLUSION

The primary end point was not met. Patients with N2 clearance, less than or equal to 10% viable tumor in the resected specimen, and SLC19A1 rs3788189 TT genotype have favorable DFS outcomes.

Pemetrexed in non-small-cell lung cancer

SUMMARY 

Pemetrexed, a multitargeted antifolate agent, is currently used in the treatment of non-small-cell lung cancer. Strong evidence has shown a treatment-by-histology interaction, with pemetrexed acting significantly better in the nonsquamous cell subtype. Therefore, all pemetrexed indications are restricted to this histology. Associated initially with somewhat high toxicity, the use of vitamin supplementation and corticoid premedication turned pemetrexed into one of the most convenient chemotherapy agents. At present pemetrexed is recommended as one of the preferred platinum partners in first line and as a single agent in the second-line setting for nonsquamous histology. The particular efficacy/toxicity profile has confirmed pemetrexed as the only chemotherapy agent approved for both continuation and switch maintenance therapy.

Polymorphisms in folate pathway and pemetrexed treatment outcome in patients with malignant pleural mesothelioma

INTRODUCTION

A combination of pemetrexed and cisplatin has been shown to improve the outcome in patients with malignant pleural mesothelioma (MPM), however, there is a great heterogeneity in treatment response among patients. The aim of our study was to evaluate the influence of polymorphisms in folate pathway and transporter genes on pemetrexed treatment outcome in Slovenian patients with MPM.

METHODS

MPM patients treated with pemetrexed in the course of a prospective randomized clinical trial were genotyped for nineteen polymorphisms in five genes of folate pathway and six transporter genes. Logistic regression was used to assess the influence of polymorphisms on treatment efficacy and toxicity, while Cox regression was used to determine their influence on progression-free and overall survival.

RESULTS

Patients with at least one polymorphic MTHFD1 rs2236225 allele had a significantly lower response rate (p = 0.005; odds ratio [OR] = 0.12; 95% confidence interval [CI] = 0.03-0.54) and shorter progression-free survival (p = 0.032; hazard ratio [HR] = 3.10; 95% CI = 1.10-8.74) than non-carriers. Polymorphisms in transporter genes did not influence survival; however, several were associated with toxicity. Liver toxicity was significantly lower in carriers of polymorphic ABCC2 rs2273697 (p = 0.028; OR = 0.23; 95% CI = 0.06-0.85), SLCO1B1 rs4149056 (p = 0.028; OR = 0.23; 95% CI = 0.06-0.85) and rs11045879 (p = 0.014; OR = 0.18; 95% CI = 0.05-0.71) alleles compared to non-carriers, as well as in patients with SLCO1B1 GCAC haplotype (p = 0.048; OR = 0.17; 95% CI = 0.03-0.98). Gastrointestinal toxicity was much more common in patients with polymorphic ABCC2 rs717620 allele (p = 0.004; OR = 10.67; 95% CI = 2.15-52.85) and ABCC2 CAG haplotype (p = 0.006; OR = 5.67; 95% CI = 1.64-19.66).

CONCLUSIONS

MTHFD1 polymorphism affected treatment response and survival, while polymorphisms in ABCC2 and SLCO1B1 transporter genes influenced the risk for toxicity. These polymorphisms could serve as potential markers of pemetrexed treatment outcome in patients with MPM.

Significance of thymidylate synthase expression for resistance to pemetrexed in pulmonary adenocarcinoma

Pemetrexed (PEM), a multi-targeted antifolate, has promising clinical activity in non-squamous non-small cell lung cancer. However, the majority of patients eventually acquire resistance to PEM. To evaluate the resistant mechanisms, the A549 lung adenocarcinoma cell line was exposed to stepwise increasing PEM concentrations of 1.6, 6.4 and 16 μM to establish three PEM-resistant lung cancer cell lines, A549/PEM-1.6, -6.4 and -16. Growth inhibition was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Expression of the genes encoding thymidylate synthase (TS), reduced folate carrier (RFC) and folypoly-γ-glutamate synthetase (FPGS) were analyzed by quantitative real-time reverse transcription polymerase chain reaction. The three A549 cell lines showed more resistance to PEM (3.7-, 17.3^- and 38.0-fold, respectively) compared with that of the parental cell line, which also showed cross-resistance to cisplatin, but not to docetaxel, vinorelbine and 5-Fluorouracil (5-FU). TS gene expression was significantly increased in three PEM-resistant cells, relative to that of the parental cells, in a PEM dose-dependent manner. Knockdown of TS expression with siRNA enhanced the cytotoxicity of PEM in A549/PEM-16 cells. By contrast, the levels of RFC and FPGS gene expression in A549/PEM-1.6 and -6.4 cells were significantly decreased, whereas the levels of the two genes were restored in A549/PEM-16 cells. In summary, PEM-resistant A549 cells remained sensitive to docetaxel, vinorelbine and 5-FU. TS expression appeared to be associated with resistance to PEM, which may be a predictive marker for PEM sensitivity in lung adenocarcinoma.

Polymorphisms in thymidylate synthase and reduced folate carrier (SLC19A1) genes predict survival outcome in advanced non-small cell lung cancer patients treated with pemetrexed-based chemotherapy

The aim of this study was to evaluate the association between thymidylate synthase (TS), methylenetetrahydrofolate reductase (MTHFR) and reduced folate carrier (SLC19A1) gene polymorphisms and the treatment efficacy of pemetrexed-based chemotherapy in advanced non-small cell lung cancer (NSCLC). Advanced NSCLC patients received pemetrexed and cisplatin every three weeks. Polymorphisms in the TS, MTHFR and SLC19A1 genes were detected in peripheral blood samples using DNA sequencing and Taqman PCR. An analysis of gene polymorphisms was performed with respect to the progression-free survival (PFS), response rate (RR) and overall survival (OS) of patients treated with pemetrexed. The median PFS times for patients with the TS 2R/2R, 2R/3C or 3C/3C genotypes were significantly longer than those of patients with the 2R/3G, 3C/3G or 3G/3G genotypes (P=0.036). Patients with the SLC19A1 CC genotype had a significantly longer median OS compared with individuals with the homozygous and heterozygous genotypes (12.2 vs. 8.9 and 7.3 months, respectively; P=0.022). The PFS and OS did not differ for the three genotypes of MTHFR assessed. The RR was higher in patients with the TS 2R/2R, 2R/3C or 3C/3C genotypes than in the other groups (P=0.044). The polymorphisms of the 5'-UTR of the TS gene and exon 6 (2522) C/T of the SLC19A1 gene predict the survival of advanced NSCLC patients treated with pemetrexed. However, a large scale clinical trial is required to validate these findings.

Pharmacogenetic study of patients with advanced non-small cell lung cancer (NSCLC) treated with second-line pemetrexed or pemetrexed-carboplatin

PURPOSE

To correlate candidate polymorphisms affecting pemetrexed and carboplatin activity with clinical outcome of patients with advanced non-small cell lung cancer (NSCLC) treated in second-line with pemetrexed or pemetrexed plus carboplatin.

METHODS

Functional polymorphisms in thymidylate synthase (TS), reduced folate carrier (RFC), gamma-glutamyl hydrolase (GGH), methylenetetrahydrofolate reductase (MTHFR) and xeroderma pigmentosum group D (XPD) genes were evaluated in 208 patients either treated within randomized phase II trials NVALT-7 and GOIRC-02.2006, comparing second-line pemetrexed with pemetrexed plus carboplatin, or with the same regimens outside of these trials. Univariate and multivariate analyses correlated genotyping data with response, clinical benefit, toxicity, progression-free (PFS) and overall survival (OS) using Pearson-χ2 test, log-rank test and Cox proportional hazards model.

RESULTS

Patients harboring the MTHFR-T667T variant had significantly longer PFS (5.4 versus 3.4 months; p=0.012) and OS (16.4 versus 8.5 months; p=0.026) than patients with CC-CT genotypes. No correlation was observed for other polymorphisms, except for XPD-Gln751Gln, which was associated with shorter PFS (p=0.021) and OS (p=0.044) in the subgroup of patients treated with pemetrexed plus carboplatin. Multivariate analysis confirmed the independent prognostic significance of MTHFR-C677T both in risk of disease progression (CC-CT genotypes hazard ratio [HR] 1.94, 95%CI 1.15-3.28; p=0.012) and of death (HR 2.00, 95% CI 1.12-3.54; p=0.018).

CONCLUSIONS

MTHFR-C667T polymorphisms appear to predict survival differences in pemetrexed-treated NSCLC. These results should be validated in larger and adequately designed prospective studies using pemetrexed.

Pharmacogenetics of conventional chemotherapy in non-small-cell lung cancer: a changing landscape?

Pharmacogenetics might be used to select patients who may benefit from specific chemotherapy that best matches the individual and tumor genetic profile, thus allowing maximum activity and minimal toxicity. Even if most studies in non-small-cell lung cancer yielded contradictory results, several potential biomarkers for sensitivity/resistance to platinum compounds, gemcitabine, taxanes and pemetrexed have been proposed. However, these markers need to be validated within larger prospective randomized trials of customized chemotherapy in homogeneous populations. Other critical points include the optimization/standardization of technical procedures, and further studies to unravel the extremely complex regulation of gene function. From this perspective, the evaluation of key factors influencing genotype-phenotype relationships, such as miRNAs, and functional studies to clarify pharmacokinetic/pharmacodynamic interactions, are fundamental for the pharmacogenetic optimization of cancer chemotherapy. Finally, limitation of the traditional pharmacogenetic approach relying only on candidate genes suspected of affecting drug response is now being overcome by the use of novel genome-wide studies.

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.

Phase II Study of S-1 Plus Either Irinotecan or Docetaxel for Non-small Cell Lung Cancer Patients Treated with More Than Three Lines of Treatment

Purpose

This study was designed to evaluate the efficacy of a combination treatment of S-1 plus either irinotecan or docetaxel for advanced/metastatic non-small cell lung cancer (NSCLC) patients who have already failed 3 or more lines of treatment.

Materials and Methods

This was a prospective single center phase II study. The eligible patients received S-1 40 mg/m² twice a day orally on days 1 though 14 combined with irinotecan 150 mg/m²on D1 only or docetaxel 35 mg/m² on D1 and D8. The treatment was repeated every 3 weeks until disease progression, unacceptable toxicity, or patient refusal. The choice between the two regimens was made at the discretion of the treating physician.

Results

A total of 14 patients participated in the study. There were 3 patients with squamous cell carcinoma, 9 with adenocarcinoma, and 2 with NSCLC, NOS. Eight of the patients were male. There were 8 patients with an Eastern Cooperative Oncology Group (ECOG) of 1, and 6 patients with an ECOG of 2. All the patients had already been treated with platinum-based chemotherapy and epidermal growth factor receptor tyrosine kinase inhibitor therapy. Out of the 14 patients, 10 received irinotecan and S-1 and the other 4 received docetaxel and S-1. Twelve patients had also received pemetrexed. Disappointingly, there were no response from 2 patients with a stable disease, and therefore, as per the protocol, we stopped the study early. With a median follow-up time of 49 months, the median survival time was 5.6 months (95% confidence interval, 4.3 to 6.9 months).

Conclusion

S-1 containing doublets did not show activity in this population as a salvage treatment and further investigation cannot be recommended.