Phase 1 trial of everolimus and gefitinib in patients with advanced nonsmall-cell lung cancer

Pharmacokinetics, safety, tolerability, and feasibility of apatinib in combination with gefitinib in stage IIIB-IV EGFR-mutated non-squamous NSCLC: a drug-drug interaction study

PURPOSE

Apatinib combined with gefitinib was proven to benefit advanced EGFR-mutant NSCLC patients in first-line treatment. This study aimed to evaluate the drug-drug interaction of gefitinib and apatinib when coadministered in EGFR-mutated NSCLC patients.

METHODS

In this phase 1b, multi-center, open-label, fixed-sequence study, the drug-drug interaction of gefitinib and apatinib was evaluated when coadministered in EGFR-mutated NSCLC patients. Patients received single-agent apatinib 500 mg QD on days 1-4. Gefitinib 250 mg QD was given on days 5-15 and combined with apatinib 500 mg QD on days 12-15. Serial blood samples were drawn on days 4 and 15. The plasma concentrations and other pharmacokinetics parameters were measured for apatinib with and without gefitinib.

RESULTS

The study enrolled 22 patients and 20 were analyzed for pharmacokinetics. There were no distinct differences in apatinib Cmax and AUC0-τ with versus without gefitinib (geometric LSM ratio, 0.96 [90% CI 0.84-1.10] for Cmax and 1.12 [90% CI 0.96-1.30] for AUC0-τ). Similar PFS and grade of treatment-emergent adverse events (TEAEs) were found between different Cmax and AUC0-τ of apatinib and gefitinib at 500 mg apatinib and 250 mg gefitinib dose levels.

CONCLUSIONS

Apatinib pharmacokinetics parameters were not significantly changed when coadministered with gefitinib. All TEAEs were manageable, and there was no need to change the dose level when combining apatinib and gefitinib (ClinicalTrials.gov identifier: NCT04390984, May 18, 2020).

The Role of Proteomics and Phosphoproteomics in the Discovery of Therapeutic Targets and Biomarkers in Acquired EGFR-TKI-Resistant Non-Small Cell Lung Cancer

The discovery of potent EGFR-tyrosine kinase inhibitors (EGFR-TKIs) has revolutionized the treatment of EGFR-mutated lung cancer. Despite the fact that EGFR-TKIs have yielded several significant benefits for lung cancer patients, the emergence of resistance to EGFR-TKIs has been a substantial impediment to improving treatment outcomes. Understanding the molecular mechanisms underlying resistance is crucial for the development of new treatments and biomarkers for disease progression. Together with the advancement in proteome and phosphoproteome analysis, a diverse set of key signaling pathways have been successfully identified that provide insight for the discovery of possible therapeutically targeted proteins. In this review, we highlight the proteome and phosphoproteomic analyses of non-small cell lung cancer (NSCLC) as well as the proteome analysis of biofluid specimens that associate with acquired resistance in response to different generations of EGFR-TKI. Furthermore, we present an overview of the targeted proteins and potential drugs that have been tested in clinical studies and discuss the challenges of implementing this discovery in future NSCLC treatment.

High in vitro and in vivo synergistic activity between mTORC1 and PLK1 inhibition in adenocarcinoma NSCLC

Significant rational is available for specific targeting of PI3K/AKT/mTOR pathway in the treatment of non-small cell lung cancer (NSCLC). However, almost all clinical trials that have evaluated Pi3K pathway-based monotherapies/combinations did not observe an improvement of patient’s outcome. The aim of our study was therefore to define combination of treatment based on the determination of predictive markers of resistance to the mTORC1 inhibitor RAD001/Everolimus. An in vivo study showed high efficacy of RAD001 in NSCLC Patient-Derived Xenografts (PDXs). When looking at biomarkers of resistance by RT-PCR study, three genes were found to be highly expressed in resistant tumors, i.e., PLK1, CXCR4, and AXL. We have then focused our study on the combination of RAD001 + Volasertib, a PLK1 inhibitor, and observed a high antitumor activity of the combination in comparison to each monotherapy; similarly, a clear synergistic effect between the two compounds was found in an in vitro study. Pharmacodynamics study demonstrated that this synergy was due to (1) tumor vascularization decrease, increase of the HIF1 protein expression and decrease of the intracellular pH, and (2) decrease of the Carbonic Anhydrase 9 (CAIX) protein that could not correct intracellular acidosis. In conclusion, all these preclinical data strongly suggest that the inhibition of mTORC1 and PLK1 proteins may be a promising therapeutic approach for NSCLC patients.

PI3K-AKT-mTOR pathway alterations in advanced NSCLC patients after progression on EGFR-TKI and clinical response to EGFR-TKI plus everolimus combination therapy

Background

Several mechanisms including abnormal activation of PI3K-AKT-mTOR pathway have been proved to generate acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC). In this study, we investigated the genomic characteristics of PI3K pathway activated in NSCLC patients after progression on EGFR-TKIs and whether both targeting EGFR and PI3K pathway could overcome resistance.

Methods

A total of 605 NSCLC cases with a history of EGFR TKI treatment were reviewed, in which 324 patients harboring EGFR mutations were confirmed progression on at least one EGFR TKI and finally enrolled. Tumor tissues or blood samples were collected at the onset of TKI progression for next generation sequencing (NGS). Six EGFR mutant patients with co-occurring mutations in PI3K pathway were retrospectively collected to assess the effect of EGFR TKI plus everolimus, a mTOR inhibitor.

Results

Forty-nine (14.9%) patients resistant to EGFR TKIs have at least one genetic variation in PI3K pathway. PIK3CA, PTEN and AKT1 variations were detected in 31 (9.5%), 18 (5.5%) and 3 (0.9%) of patients, respectively. No significant differences were observed in distribution of PI3K pathway alterations among patients with different EGFR mutations (EGFR exon19 deletion mutations/EGFR L858R/uncommon EGFR mutations) and among patients resistant to different EGFR TKIs. For patients treated with everolimus and EGFR-TKI, five (5/6, 83.3%) achieved stable disease (SD) and one (1/6, 16.7%) didn’t receive disease control. The median progression-free survival (PFS) was 2.1 months (95% confidence interval, 1.35–4.3 months, range, 0.9–4.4 months). The most common adverse events were dental ulcer (6/6), rash (1/6).

Conclusions

Our study revealed that PI3K pathway was activated in at least 14.9% in EGFR-TKI resistant patients. EGFR-TKIs plus everolimus showed limited antitumor activity in EGFR mutant NSCLC patients with PI3K pathway aberrations.

Oral stomatitis and mTOR inhibitors: A review of current evidence in 20,915 patients

BACKGROUND

Traditional treatment of malignancies with chemotherapeutic agents is often affected by the damage inflicted on non-cancerous cells. Toxicities of the oral cavity, such as mucositis and stomatitis, are some of the most significant and unavoidable toxicities associated with anti-cancer therapies. For such reason, in the last decades, newer targeted agents have been developed aiming to decrease the rates of side effects on healthy cells. Unfortunately, targeted anti-cancer therapies also showed significant rate of toxicity on healthy tissues. mTOR inhibitors showed some adverse events, such as hyperglycemia, hyperlipidemia, hypophosphatemia, hematologic toxicities, and mucocutaneous eruption, but the most important are still stomatitis and skin rash, often reported as dose-limiting side effects.

PATIENTS AND METHODS

A search of the literature was performed by authors on the PubMed online database using the following key words: "sirolimus" OR "everolimus" OR "temsirolimus" OR "deforolimus" OR "ridaforolimus" combined with the Boolean operator AND with the terms: "stomatitis" OR "mucositis" OR "oral pain." Titles and abstracts of 382 potentially relevant studies were screened; of these, 114 studies were excluded because they did not report the inclusion criteria. In the second round, 268 studies were read full-text, but only 135 reported the inclusion criteria and were included for data extraction. Of the included studies, 95 referred to everolimus use, 16 to ridaforolimus, and 26 to temsirolimus (two studies referred to both everolimus and temsirolimus).

RESULTS

The incidence rate of stomatitis according to the agent used was 25.07% (3,959/15,787) for everolimus, 27.02% (724/2,679) for temsirolimus, and 54.76% (598/1,092) for ridaforolimus. All the three agents analyzed showed high rates of low-grade stomatitis (G1-G2), while the onset of severe stomatitis (G3-G4) was rare.

CONCLUSIONS

Analysis of the reports with patients treated with everolimus, temsirolimus, and ridaforolimus showed a clear prevalence of stomatitis grade 1 or 2. These data differ from that of patients treated with conventional chemotherapy in which mucositis is predominantly of grade 3 or 4.

Endoplasmic reticulum stress promotes autophagy and apoptosis and reverses chemoresistance in human ovarian cancer cells

Ovarian cancer presents the highest mortality rate among gynecological tumors. Here, we measured cell viability, proliferation, apoptosis, autophagy, and expression of endoplasmic reticulum stress (ERS)-related proteins, PI3K/AKT/mTOR pathway-related proteins, and apoptosis- and autophagy-related proteins in SKOV3 and SKOV3/CDDP cells treated with combinations of CDDP, tunicamycin, and BEZ235 (blank control, CDDP, CDDP + tunicamycin, CDDP + BEZ235, and CDDP + tunicamycin + BEZ235). Increasing concentrations of tunicamycin and CDDP activated ERS in SKOV3 cells, reduced cell viability and proliferation, increased apoptosis and autophagy, enhanced expression of ERS-related proteins, and inhibited expression of PI3K/AKT/mTOR pathway-related proteins. CDDP, tunicamycin, and BEZ235 acted synergistically to enhance these effects. We also detected lower expression of the ERS-related proteins caspase-3, LC3 II and Beclin 1 in ovarian cancer tissues than adjacent normal tissues. By contrast, expression of Bcl-2 and PI3K/AKT/mTOR pathway-related proteins was higher in ovarian cancer tissues than adjacent normal tissues. Lastly, expression of the ERS-related proteins Beclin 1, caspase-3 and LC3 II was higher in the sensitive group than the resistant group, while expression of Bcl-2, LC3 I, P62 and PI3K/AKT/mTOR pathway-related proteins was decreased. These results show that ERS promotes cell autophagy and apoptosis while reversing chemoresistance in ovarian cancer cells by inhibiting activation of the PI3K/AKT/mTOR signaling pathway.

Physakengose G induces apoptosis via EGFR/mTOR signaling and inhibits autophagic flux in human osteosarcoma cells

BACKGROUND

Physakengose G (PG) is a new compound first isolated from Physalis alkekengi var. franchetii, an anticarcinogenic traditional Chinese medicine. PG has shown promising anti-tumor effects, but its underlying mechanisms remain unknown.

PURPOSE

To investigate the anti-cancer effects of PG on human osteosarcoma cells and the underlying mechanisms.

METHODS

Cell viability was measured by MTT assay. Apoptosis rates, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) generation, and acidic vesicular organelles (AVOs) formation were determined by flow cytometry. Protein levels were analyzed by immunofluorescence and western blotting.

RESULTS

PG inhibited cell proliferation and induced apoptosis in human osteosarcoma cells. PG treatment blocked EGFR phosphorylation and suppressed epidermal growth factor (EGF)-induced activation of downstream signaling molecules, such as AKT and mTOR. PG treatment resulted in lysosome dysfunction by altering lysosome acidification and LAMP1 levels, which led to autophagosome accumulation and autophagic flux inhibition.

CONCLUSION

PG inhibits cell proliferation and EGFR/mTOR signaling in human osteosarcoma cells. Moreover, PG induces apoptosis through the mitochondrial pathway and impedes autophagic flux via lysosome dysfunction. Our findings indicate that PG has the potential to play a significant role in the treatment of osteosarcoma.

Sensitivity of imatinib-resistant T315I BCR-ABL CML to a synergistic combination of ponatinib and forskolin treatment

Tyrosine kinase inhibitors (TKIs) have dramatically improved the life expectancy of patients suffering from chronic myeloid leukemia (CML); however, patients will eventually develop resistance to TKI therapy or adverse side effects due to secondary off-target mechanisms associated with TKIs. CML patients exhibiting TKI resistance are at greater risk of developing an aggressive and drug-insensitive disease. Drug-resistant CML typically arises in response to spontaneous mutations within the drug binding sites of the targeted oncoproteins. To better understand the mechanism of drug resistance in TKI-resistant CML patients, the BCR-ABL transformed cell line KCL22 was grown with increasing concentrations of imatinib for a period of 6 weeks. Subsequently, a drug-resistant derivative of the parental KCL22 cell line harboring the T315I gatekeeper mutation was isolated and investigated for TKI drug sensitivity via multi-agent drug screens. A synergistic combination of ponatinib- and forskolin-reduced cell viability was identified in this clinically relevant imatinib-resistant CML cell line, which also proved efficacious in other CML cell lines. In summary, this study provides new insight into the biological underpinnings of BCR-ABL-driven CML and potential rationale for investigating novel treatment strategies for patients with T315I CML.

Expression and clinical significance of mTOR in surgically resected non-small cell lung cancer tissues: a case control study

AIMS

Mammalian target of rapamycin (mTOR) is master regulator of the PI3K/Akt/mTOR pathway and plays an important role in NSCLCs. Here we characterized mRNA and protein expression levels of mTOR and its functional associated molecules including PTEN, IGF-1R and 4EBP1 in surgically resected NSCLCs.

METHODS

Fifty-four patients with NSCLCs who underwent pulmonary resection were included in current study. mRNA levels of mTOR, PTEN, IGF-1R, and 4EBP1 were evaluated by RT-PCR and protein expression of mTOR, PTEN, and IGF-1R by immunohistochemistry (IHC). Association of expression of the relevant molecules with clinical characteristics, as well as correlations between mTOR and PTEN, 4EBP1 and IGF-1R were also assessed.

RESULTS

The results of RT-PCR showed that in NSCLCs, the expression level of mTOR increased, while PTEN, 4EBP1 and IGF-1R decreased. Statistical analysis indicated high IGF-1R expression was correlated with advanced clinical stage (stage III) and PTEN expression was reversely associated with tumor size (P=0.16). The results of IHC showed mTOR positive staining in 51.8% of cases, while IGF-1R positive staining was found in 83.3% and loss of PTEN in 46.3%. Protein expression of mTOR was correlated with its regulators, PTEN and IGF-1R, to some extent.

CONCLUSIONS

Abnormal activation of mTOR signaling, high expression of IGF-1R, and loss of PTEN were observed in resected NSCLC specimens. The poor expression agreement of mTOR with its regulators, PTEN, and IGF-1R, implied that combination strategy of mTOR inhibitors with other targets hold significant potential for NSCLC treatment.

[New targets and new drugs in thoracic oncology]

A number of mechanisms that drive oncogenesis have been deciphered over the last 20 years. The main oncogenic factors in the field of thoracic oncology are mutations of EGFR, KRAS, and EML4-ALK translocation, which are most often reported in adenocarcinomas. However, new molecular targets have been highlighted recently including BRAF mutations, HER2 or PI3K, new translocations such as ROS1 or KIF5B-RET. Molecular abnormalities have also been identified in tumors other than adenocarcinoma (squamous and small cell carcinoma). Therapeutic strategies have been designed to inhibit these signaling pathways including monoclonal antibodies and tyrosine kinase inhibitors. Some of these molecules are now approved as therapies, others are currently undergoing testing in clinical trials. We here present a review of novel targeted agents for lung cancer.

Phase II study of capecitabine and the oral mTOR inhibitor everolimus in patients with advanced pancreatic cancer

Purpose

The combination of an mTOR inhibitor with 5-fluorouracil-based anticancer therapy is attractive because of preclinical evidence of synergy between these drugs. According to our phase I study, the combination of capecitabine and everolimus is safe and feasible, with potential activity in pancreatic cancer patients.

Methods

Patients with advanced adenocarcinoma of the pancreas were enrolled. Eligible patients had a WHO performance status 0–2 and adequate hepatic and renal functions. The treatment regimen consisted of capecitabine 1000 mg/m² BID day 1–14 and everolimus 10 mg daily (5 mg BID) in a continuous 21-day schedule. Tumor assessment was performed with CT-scan every three cycles. Primary endpoint was response rate (RR) according to RECIST 1.0. Secondary endpoints were progression-free survival, overall survival and 1-year survival rate.

Results

In total, 31 patients were enrolled. Median (range) treatment duration with everolimus was 76 days (1–431). Principal grade 3/4 toxicities were hyperglycemia (45 %), hand-foot syndrome (16 %), diarrhea (6 %) and mucositis (3 %). Prominent grade 1/2 toxicities were anemia (81 %), rash (65 %), mucositis (58 %) and fatigue (55 %). RR was 6 %. Ten patients (32 %) had stable disease resulting in a disease control rate of 38 %. Median overall survival was 8.9 months (95 % CI 4.6–13.1). Progression-free survival was 3.6 months (95 % CI 1.9–5.3).

Conclusions

The oral regimen with the combination of capecitabine and everolimus is a moderately active treatment for patients with advanced pancreatic cancer, with an acceptable toxicity profile at the applied dose level.

A Translational, Pharmacodynamic, and Pharmacokinetic Phase IB Clinical Study of Everolimus in Resectable Non-Small Cell Lung Cancer

PURPOSE

The altered PI3K/mTOR pathway is implicated in lung cancer, but mTOR inhibitors have failed to demonstrate efficacy in advanced lung cancer. We studied the pharmacodynamic effects of everolimus in resectable non-small cell lung cancer (NSCLC) to inform further development of these agents in lung cancer.

EXPERIMENTAL DESIGN

We enrolled 33 patients and obtained baseline tumor biopsy and 2[18F]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) imaging followed by everolimus treatment (5 or 10 mg daily, up to 28 days), or without intervening treatment for controls. Target modulation by everolimus was quantified in vivo and ex vivo by comparing metabolic activity on paired PET scans and expression of active phosphorylated forms of mTOR, Akt, S6, eIF4e, p70S6K, 4EBP1, and total Bim protein between pretreatment and posttreatment tissue samples.

RESULTS

There were 23 patients on the treatment arm and 10 controls; median age 64 years; 22 tumors (67%) were adenocarcinomas. There was a dose-dependent reduction in metabolic activity (SUVmax: 29.0%, -21%, -24%; P = 0.014), tumor size (10.1%, 5.8%, -11.6%; P = 0.047), and modulation of S6 (-36.1, -13.7, -77.0; P = 0.071) and pS6 (-41.25, -61.57, -47.21; P = 0.063) in patients treated in the control, 5-mg, and 10-mg cohorts, respectively. Targeted DNA sequencing in all patients along with exome and whole transcriptome RNA-seq in an index patient with hypersensitive tumor was employed to further elucidate the mechanism of everolimus activity.

CONCLUSIONS

This "window-of-opportunity" study demonstrated measurable, dose-dependent, biologic, metabolic, and antitumor activity of everolimus in early-stage NSCLC.

mTOR pathway: A current, up-to-date mini-review (Review)

Mammalian target of rapamycin (mTOR) is a protein serine/threonine kinase that was initially identified as the cellular target of rapamycin. This kinase regulates cell growth, proliferation, motility and survival, as well as the gene transcription and protein synthesis that are activated in response to hormones, growth factors and nutrients. Results from preclinical studies have indicated that factors antagonizing the mTOR pathway exert an antitumor effect on lung cancer. Furthermore, primary clinical trials of mTOR inhibitors have demonstrated that the inhibitors may be effective against lung carcinoma. The present study explores the association between mTOR and lung carcinogenesis and describes the clinical trials of mTOR inhibitors.

Dual inhibition of EGFR with afatinib and cetuximab in kinase inhibitor-resistant EGFR-mutant lung cancer with and without T790M mutations

EGFR-mutant lung cancers responsive to reversible EGFR inhibitors (gefitinib/erlotinib) develop acquired resistance, mediated by second-site EGFR T790M mutation in >50% of cases. Preclinically, afatinib (irreversible ErbB family blocker) plus cetuximab (anti-EGFR monoclonal antibody) overcomes T790M-mediated resistance. This phase Ib study combining afatinib and cetuximab enrolled heavily pretreated patients with advanced EGFR-mutant lung cancer and acquired resistance to erlotinib/gefitinib. Patients provided post-acquired-resistance tumor samples for profiling EGFR mutations. Among 126 patients, objective response rate (overall 29%) was comparable in T790M-positive and T790M-negative tumors (32% vs. 25%; P = 0.341). Median progression-free survival was 4.7 months (95% confidence interval, 4.3-6.4), and the median duration of confirmed objective response was 5.7 months (range, 1.8-24.4). Therapy-related grade 3/4 adverse events occurred in 44%/2% of patients. Afatinib-cetuximab demonstrated robust clinical activity and a manageable safety profile in EGFR-mutant lung cancers with acquired resistance to gefitinib or erlotinib, both with and without T790M mutations, warranting further investigation.

SIGNIFICANCE

This article reports the results of a trial combining afatinib and cetuximab in patients with acquired resistance and details the first clinical proof-of-concept for the preclinical hypothesis that a significant proportion of tumors in patients with acquired resistance to gefitinib/erlotinib remain dependent on EGFR signaling for survival.

Phase II study of everolimus-erlotinib in previously treated patients with advanced non-small-cell lung cancer

BACKGROUND

Preclinical data suggest combining a mammalian target of rapamycin inhibitor with erlotinib could provide synergistic antitumor effects in advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

In this multicenter, open-label, phase II study, patients with advanced NSCLC that progressed after one to two previous chemotherapy regimens were randomized 1:1 to erlotinib 150 mg/day±everolimus 5 mg/day. Primary end point was the disease control rate (DCR) at 3 months; secondary end points included progression-free survival (PFS) and safety.

RESULTS

One hundred thirty-three patients received everolimus-erlotinib (n=66) or erlotinib alone (n=67). The DCR at 3 months was 39.4% and 28.4%, respectively. The probability for the difference in disease control at 3 months to be ≥15% was estimated to be 29.8%, which was below the prespecified probability threshold of ≥40%. Median PFS was 2.9 and 2.0 months, respectively. Grade 3/4 adverse events occurred in 72.7% and 32.3% of patients, respectively. Grade 3/4 stomatitis was observed in 31.8% of combination therapy recipients.

CONCLUSIONS

Everolimus 5 mg/day plus erlotinib 150 mg/day was not considered sufficiently efficacious per the predefined study criteria. The combination does not warrant further investigation based on increased toxicity and the lack of substantial improvement in disease stabilization.

Phase I study evaluating the combination of lapatinib (a Her2/Neu and EGFR inhibitor) and everolimus (an mTOR inhibitor) in patients with advanced cancers: South West Oncology Group (SWOG) Study S0528

PURPOSE

Everolimus, an oral inhibitor of mammalian target of rapamycin, can augment the efficacy of HER inhibitors in preclinical studies. This study was conducted to determine the safety and pharmacokinetics (PK) of the combination of lapatinib, a Her1 and 2 inhibitor, and everolimus and to describe its anti-tumor activity in the Phase I setting.

METHODS

In Part I, dose escalation to define the maximum tolerated dose (MTD) was performed. In Part II, PK of both drugs were analyzed to assess drug-drug interaction.

RESULTS

Twenty-three evaluable patients with advanced cancers were treated on six different dose levels in Part I of the study. The dose-limiting toxicities were diarrhea, rash, mucositis, and fatigue. The MTD of the combination was 1,250 mg of lapatinib and 5 mg of everolimus once daily. In Part II of the study, 54 patients were treated with the combination at the MTD. The mean everolimus time to maximum concentration was increased by 44 %, and mean clearance was decreased by 25 % when co-administered with lapatinib, though these differences were not statistically significant. There was no significant influence on the PK of lapatinib by everolimus. Two patients achieved a partial response [thymic cancer (45+ months) and breast cancer (unconfirmed PR; 7 months)]; 11 patients attained stable disease of at least 4 months.

CONCLUSIONS

Lapatinib and everolimus are well tolerated at doses of 1,250 and 5 mg po daily, respectively. Stable disease ≥4 months/PR was achieved in 13 of 78 patients (17 %).

Drug interactions with solid tumour-targeted therapies

Drug interactions are an on-going concern in the treatment of cancer, especially when targeted therapies, such as tyrosine kinase inhibitors (TKI) or mammalian target of rapamycin (mTOR) inhibitors, are being used. The emergence of elderly patients and/or patients with both cancer and other chronic co-morbidities leads to polypharmacy. Therefore, the risk of drug-drug interactions (DDI) becomes a clinically relevant issue, all the more so as TKIs and mTOR inhibitors are essentially metabolised by cytochrome P450 enzymes. These DDIs can result in variability in anticancer drug exposure, thus favouring the selection of resistant cellular clones or the occurrence of toxicity. This review provides a comprehensive overview of DDIs that involve targeted therapies approved by the FDA for the treatment of solid tumours for more than 3 years (sorafenib, sunitinib, erlotinib, gefitinib, imatinib, lapatinib, everolimus, temsirolimus) and medicinal herb or drugs. This review also provides some guidelines to help oncologists and pharmacists in their clinical practice.

Targeted therapies in non-small cell lung carcinoma: what have we achieved so far?

The search for innovative therapeutic agents in non-small cell lung cancer (NSCLC) has witnessed a swift evolution. The number of targeted drugs that can improve patient outcomes with an acceptable safety profile is steadily increasing. In this review, we highlight current drugs that have already been approved or are under evaluation for the treatment of patients with NSCLC, either in monotherapy or combined therapy for both the first- and second-line settings. Experience with drugs targeting the vascular endothelial growth factor and its receptor, as well as the epidermal growth factor receptor is summarized. Moreover, we provide an overview of more novel targets in NSCLC and initial experience with the respective therapeutic agents.

Safety and feasibility of targeted agent combinations in solid tumours

The plethora of novel molecular-targeted agents (MTAs) has provided an opportunity to selectively target pathways involved in carcinogenesis and tumour progression. Combination strategies of MTAs are being used to inhibit multiple aberrant pathways in the hope of optimizing antitumour efficacy and to prevent development of resistance. While the selection of specific agents in a given combination has been based on biological considerations (including the role of the putative targets in cancer) and the interactions of the agents used in combination, there has been little exploration of the possible enhanced toxicity of combinations resulting from alterations in multiple signalling pathways in normal cell biology. Owing to the complex networks and crosstalk that govern normal and tumour cell proliferation, inhibiting multiple pathways with MTA combinations can result in unpredictable disturbances in normal physiology. This Review focuses on the main toxicities and the lack of tolerability of some common MTA combinations, particularly where evidence of enhanced toxicity compared to either agent alone is documented or there is development of unexpected toxicity. Toxicities caused by MTA combinations highlight the need to introduce new preclinical testing paradigms early in the drug development process for the assessment of chronic toxicities resulting from such combinations.

Preclinical rationale for PI3K/Akt/mTOR pathway inhibitors as therapy for epidermal growth factor receptor inhibitor-resistant non-small-cell lung cancer

Mutations in the epidermal growth factor receptor gene (EGFR) are frequently observed in non-small-cell lung cancer (NSCLC), occurring in about 40% to 60% of never-smokers and in about 17% of patients with adenocarcinomas. EGFR tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, have transformed therapy for patients with EGFR-mutant NSCLC and have proved superior to chemotherapy as first-line treatment for this patient group. Despite these benefits, there are currently 2 key challenges associated with EGFR inhibitor therapy for patients with NSCLC. First, only 85% to 90% of patients with the EGFR mutation derive clinical benefit from EGFR TKIs, with the remainder demonstrating innate resistance to therapy. Second, acquired resistance to EGFR TKIs inevitably occurs in patients who initially respond to therapy, with a median duration of response of about 10 months. Mutant EGFR activates various subcellular signaling cascades, including the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, which demonstrates maintained activity in a variety of TKI-resistant cancers. Given the fundamental role of the PI3K/Akt/mTOR pathway in tumor oncogenesis, proliferation, and survival, PI3K pathway inhibitors have emerged as a possible solution to the problem of EGFR TKI resistance. However resistance to EGFR TKIs is associated with considerable heterogeneity and complexity. Preclinical experiments investigating these phenomena suggest that in some patients, PI3K inhibitors will have to be paired with other targeted agents if they are to be effective. This review discusses the preclinical data supporting PI3K/Akt/mTOR pathway inhibitor combinations in EGFR TKI-resistant NSCLC from the perspective of the various agents currently being investigated in clinical trials.

A review of oral toxicity associated with mTOR inhibitor therapy in cancer patients

Aphthous-like stomatitis has been identified as one of the most common dose-limiting toxicities associated with mTOR inhibitor therapy in cancer patients. The objective of this study was to summarize the cumulative oral toxicities associated with mTOR inhibitors in published oncology trials with respect to dose, schedule, and need for dose modifications. A review of all oncology-related clinical trials of mTOR inhibitors was conducted and standardized data was abstracted from each study. 44 studies were included in the analysis with a total of 2822 patients treated with temsirolimus (19 studies), everolimus (20 studies), and ridaforolimus (five studies) for a wide range of malignancies. At least one adverse event (AE) occurred in 74.4% of patients. Mucositis was the most frequent AE overall (73.4%), the third most frequent severe AE (20.7%), accounting for 27.3% dose reductions and 13.1% of discontinuations, and the most frequent dose limiting toxicity (52.5%). Mucositis typically occurred during the first cycle of therapy and was graded as mild to moderate in approximately 90% of the patients; severe mucositis generally occurred at higher doses. There were no clear differences in mucositis among the three agents and in most cases lesions resolved spontaneously. Oral mucositis is a frequent complication of mTOR inhibitor therapy and a significant cause of dose reductions and discontinuations in oncology trials. Prevention and management strategies should be investigated to improve tolerability and better permit effective long-term regimens.

The Biological Role of PI3K Pathway in Lung Cancer

Lung cancer is the primary cause of cancer-related mortality worldwide and although improvements in treatment have been achieved over the last few years, long-term survival rates for lung cancer patients remain poor. Therefore, there is an imperative need for molecularly targeted agents that will achieve long-term disease control. Numerous downstream molecular pathways, such as EGF/RAS/RAF/MEK/ERK and PI3K/AKT/mTOR are identified as having a key role in the pathogenesis of various forms of human cancer, including lung cancer. PI3K/AKT/mTOR signal pathway is an important intracellular signal transduction pathway with a significant role in cell proliferation, growth, survival, vesicle trafficking, glucose transport, and cytoskeletal organization. Aberrations in many primary and secondary messenger molecules of this pathway, including mutations and amplifications, are accounted for tumor cell proliferation, inhibition of apoptosis, angiogenesis, metastasis and resistance to chemotherapy-radiotherapy. In this review article, we investigate thoroughly the biological role of PI3K pathway in lung cancer and its contribution in the development of future therapeutic strategies.

The mTOR pathway in lung cancer and implications for therapy and biomarker analysis

Mammalian target of rapamycin (mTOR) is a serine/threonine kinase that functions as a key regulatory protein in normal cell growth, survival, metabolism, development, and angiogenic pathways. Deregulation of these processes is a required hallmark of cancer, and dysregulation of mTOR signaling frequently occurs in a wide variety of malignancies, including lung cancer. Targeting of mTOR is thus an attractive strategy in the development of therapeutic agents against lung cancer. In this review, the mTOR-signaling pathway is described, highlighting opportunities for therapeutic intervention and biomarker analysis, and clinical trials in lung cancer including both non-small cell lung cancer and small cell lung cancer.

Tankyrase and the canonical Wnt pathway protect lung cancer cells from EGFR inhibition

Lung cancer is the leading cause of death worldwide. Adenocarcinomas, the most common histologic subtype of non-small cell lung cancer (NSCLC), are frequently associated with activating mutations in the epidermal growth factor receptor (EGFR) gene. Although these patients often respond clinically to the EGFR tyrosine kinase inhibitors erlotinib and gefitinib, relapse inevitably occurs, suggesting the development of escape mechanisms that promote cell survival. Using a loss-of-function, whole genome short hairpin RNA (shRNA) screen, we identified that the canonical Wnt pathway contributes to the maintenance of NSCLC cells during EGFR inhibition, particularly the poly-ADP-ribosylating enzymes tankyrase 1 and 2 that positively regulate canonical Wnt signaling. Inhibition of tankyrase and various other components of the Wnt pathway with shRNAs or small molecules significantly increased the efficacy of EGFR inhibitors both in vitro and in vivo. Our findings therefore reveal a critical role for tankyrase and the canonical Wnt pathway in maintaining lung cancer cells during EGFR inhibition. Targeting the Wnt-tankyrase-β-catenin pathway together with EGFR inhibition may improve clinical outcome in patients with NSCLC.

Mammalian target of rapamycin (mTOR) inhibitors: potential uses and a review of haematological adverse effects

Mammalian target of rapamycin (mTOR) inhibitors (mTORis) constitute a relatively new category of immunosuppressive and antineoplastic drugs. These share a unique mechanism of action that is focused on the inhibition of the mTOR. Their clinical applications have recently expanded significantly to cover a wide spectrum of immune and non-immune-mediated disorders, including, apart from solid organ transplantation, various solid organ and haematological malignancies, rheumatological and auto-immune diseases such as rheumatoid arthritis, systemic lupus erythematosus, fibrotic conditions, e.g. pulmonary and hepatic fibrosis, and even metabolic problems such as diabetes mellitus and obesity. The most challenging and frequent adverse effects of the mTORis are the haematological ones, especially anaemia, leukopenia and thrombocytopenia. A unique characteristic of mTORi-induced anaemia is concurrent marked microcytosis. Recently, mechanisms have been proposed to explain the microcytic appearance of this anaemia; these include globin production defect, erythropoietin resistance, chronic inflammation, dysregulation of cellular iron metabolism and hepcidin-mediated iron homeostasis interference. As the differential diagnosis of microcytic anaemia includes pure iron deficiency, functional iron deficiency and haemoglobinopathies, characterization of the anaemia requires significant investigation, time and costs. Therefore, understanding of the likely interaction between mTORis and patients is valuable in clinical practice. Moreover, this could expand the drugs' therapeutic applications to other disorders, and suggest novel targets for further research.

Mammalian target of rapamycin (mTOR) inhibitors: potential uses and a review of haematological adverse effects

Mammalian target of rapamycin (mTOR) inhibitors (mTORis) constitute a relatively new category of immunosuppressive and antineoplastic drugs. These share a unique mechanism of action that is focused on the inhibition of the mTOR. Their clinical applications have recently expanded significantly to cover a wide spectrum of immune and non-immune-mediated disorders, including, apart from solid organ transplantation, various solid organ and haematological malignancies, rheumatological and auto-immune diseases such as rheumatoid arthritis, systemic lupus erythematosus, fibrotic conditions, e.g. pulmonary and hepatic fibrosis, and even metabolic problems such as diabetes mellitus and obesity. The most challenging and frequent adverse effects of the mTORis are the haematological ones, especially anaemia, leukopenia and thrombocytopenia. A unique characteristic of mTORi-induced anaemia is concurrent marked microcytosis. Recently, mechanisms have been proposed to explain the microcytic appearance of this anaemia; these include globin production defect, erythropoietin resistance, chronic inflammation, dysregulation of cellular iron metabolism and hepcidin-mediated iron homeostasis interference. As the differential diagnosis of microcytic anaemia includes pure iron deficiency, functional iron deficiency and haemoglobinopathies, characterization of the anaemia requires significant investigation, time and costs. Therefore, understanding of the likely interaction between mTORis and patients is valuable in clinical practice. Moreover, this could expand the drugs' therapeutic applications to other disorders, and suggest novel targets for further research.

Phase I and pharmacokinetic study of capecitabine and the oral mTOR inhibitor everolimus in patients with advanced solid malignancies

Background Everolimus is an oral mTOR-inhibitor. Preclinical data show synergistic effects of mTOR inhibition in combination with 5-fluorouracil-based anticancer therapy. The combination of everolimus with capecitabine seems therefore an attractive new, orally available, treatment regimen. Patients and methods Safety, preliminary efficacy and pharmacokinetics of everolimus in combination with capecitabine were investigated in patients with advanced solid malignancies. Patients were treated with fixed dose everolimus 10 mg/day continuously, plus capecitabine bid for 14 days in three-weekly cycles. Dose escalation of capecitabine proceeded according to the standard 3 × 3 phase I design in four predefined dose levels (500–1,000 mg/m² bid). Results In total, 18 patients were enrolled. Median (range) treatment duration with everolimus was 70 days (21–414). Capecitabine 1,000 mg/m² bid combined with 10 mg/day everolimus was declared the maximum tolerated dose, at which level one patient developed dose-limiting toxicity (stomatitis grade 3). Drug-related adverse events were mostly grade ≤2 and included mainly fatigue (56%), stomatitis (50%), and hand-foot syndrome (33%). Partial response was documented in three patients, and four had stable disease. There was no pharmacokinetic interaction between everolimus and capecitabine. Conclusion Everolimus 10 mg/day continuously combined with capecitabine 1,000 mg/m² bid for 14 days every 3 weeks is a patient-convenient, safe and tolerable oral treatment regimen. This is the first study to demonstrate feasibility of this combination at doses with proven single agent efficacy in a number of tumors. Prolonged clinical benefit was observed in an encouraging 39% of patients with advanced solid malignancies.

Overexpression of the mammalian target of rapamycin (mTOR) and angioinvasion are poor prognostic factors in early stage NSCLC: a verification study

BACKGROUND

A recent study by Dhillon et al. [12], identified both angioinvasion and mTOR as prognostic biomarkers for poor survival in early stage NSCLC. The aim of this study was to verify the above study by examining the angioinvasion and mTOR expression profile in a cohort of early stage NSCLC patients and correlate the results to patient clinico-pathological data and survival.

METHODS

Angioinvasion was routinely recorded by the pathologist at the initial assessment of the tumor following resection. mTOR was evaluated in 141 early stage (IA-IIB) NSCLC patients (67 - squamous; 60 - adenocarcinoma; 14 - others) using immunohistochemistry (IHC) analysis with an immunohistochemical score (IHS) calculated (% positive cells×staining intensity). Intensity was scored as follows: 0 (negative); 1+ (weak); 2+ (moderate); 3+ (strong). The range of scores was 0-300. Based on the previous study a cut-off score of 30 was used to define positive versus negative patients. The impact of angioinvasion and mTOR expression on prognosis was then evaluated.

RESULTS

101 of the 141 tumors studied expressed mTOR. There was no difference in mTOR expression between squamous cell carcinoma and adenocarcinoma. Angioinvasion (p=0.024) and mTOR staining (p=0.048) were significant univariate predictors of poor survival. Both remained significant after multivariate analysis (p=0.037 and p=0.020, respectively).

CONCLUSIONS

Our findings verify angioinvasion and mTOR expression as new biomarkers for poor outcome in patients with early stage NSCLC. mTOR expressing patients may benefit from novel therapies targeting the mTOR survival pathway.

Recent clinical developments and rationale for combining targeted agents in non-small cell lung cancer (NSCLC)

While chemotherapy has been the standard of care for patients with advanced non-small cell lung cancer (NSCLC), efforts have shifted toward evaluating novel targeted agents in an attempt to improve outcome. These targeted agents are directed toward key components in several signalling pathways such as vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR) and insulin-like growth factor 1 receptor (IGF-IR). There is also increasing interest in using combinations of targeted agents to inhibit more than one pathway; for example, inhibition of VEGFR + EGFR and VEGFR + PDGFR + EGFR. Further investigation is needed to identify the most appropriate combinations of these targeted agents in select patient subgroups, and to define optimal treatment doses to thereby achieve the best therapeutic index. This review outlines the rationale for combining targeted agents for the treatment of advanced NSCLC.

Targeted therapies for advanced non-small-cell lung cancer: current status and future implications

Lung cancer remains the leading cause of malignancy-related mortality worldwide, with over one million cases diagnosed yearly. Non-small-cell lung cancer (NSCLC) accounts for >80% of all lung cancers. Because lung cancer is typically diagnosed at an advanced stage, chemotherapy (CT) is the mainstay of management. Conventional treatment of NSCLC has apparently reached a plateau of effectiveness in improving survival of patients, and treatment outcomes must still be considered disappointing. Hence, considerable efforts have been made in order to identify novel targeted agents that interfere with other dysregulated pathways in advanced NSCLC patients. In order to further improve the results of targeted therapy, we should not forget that lung cancer is a heterogeneous disease with multiple mutations, and it is unlikely that any single signaling pathway drives the oncogenic behaviour of all tumours. The relative failure of some targeted therapies may be a result of multilevel cross-stimulation among the targets of the new biological agents along several pathways of signal transduction that lead to neoplastic events. Thus, blocking only one of these pathways allows others to act as salvage or escape mechanisms for cancer cells. We summarize the most promising research approaches to the treatment of NSCLC, with particular attention to drugs with multiple targets or combining targeted therapies.

Personalized medicine for non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is a heterogeneous illness associated with a high mortality rate. Personalized therapy may improve treatment outcomes by identification of a specific genotypic anomaly and target-specific therapy. The most significant development in recent years was the discovery of activated EGF receptor (EGFR) mutations at exons 19 and 21. Patients with EGFR mutations respond dramatically to EGFR tyrosine kinase inhibitors such as gefitinib or erlotinib, resulting in longer progression-free survival. Multiple randomized studies, including the Iressa Pan-Asia Study and WJTOG3405, have confirmed the role of EGFR tyrosine kinase inhibitors as standard first-line therapy for patients with the EGFR mutation. In this article, we summarize the current nonpersonalized therapies and examine the available and investigational personalized therapies for patients with resectable early-stage, unresectable locally advanced, or metastatic disease.

Novel compounds in the treatment of lung cancer: current and developing therapeutic agents

Lung cancer is the leading cause of cancer-related death in the United States. Though incremental advances have been made in the treatment of this devastating disease during the past decade, new therapies are urgently needed. Traditional cytotoxic agents have been combined with other modalities with improved survival for early-stage patients. Newer cytotoxic agents targeting the same or different mechanisms have been developed at different stages. Optimization of various chemotherapy regimens in different settings is one of the aims of current clinical trials. Some predictive biomarkers (eg, excision repair cross-complementing 1, ERCC1) and histotypes (eg, adenocarcinoma) are found to be associated with resistance/response to some cytotoxic drugs. Another notable advance is the addition of targeted therapy to lung cancer treatment. Targeted agents such as erlotinib and bevacizumab have demonstrated clinical benefits and gained Food and Drug Administration approval for lung cancer. More agents targeting various signaling pathways critical to lung cancer are at different stages of development. Along with the effort of new targeted drug discovery, biomarkers such as epidermal growth factor receptor and anaplastic lymphoma kinase mutations have proven useful for patient selection, and more predictive biomarkers have been actively evaluated in non-small cell lung cancer. The paradigm of lung cancer treatment has shifted towards biomarker-based personalized medicine.

Phase II trial of gefitinib and everolimus in advanced non-small cell lung cancer

INTRODUCTION

Concurrent signal transduction inhibition with the epidermal growth factor receptor (EGFR) inhibitor gefitinib and the mammalian target-of-rapamycin inhibitor everolimus has been hypothesized to result in enhanced antitumor activity in patients with non-small cell lung cancer (NSCLC). This phase II trial assessed the efficacy of the combination of gefitinib and everolimus in patients with advanced NSCLC.

METHODS

Two cohorts of 31 patients with measurable stage IIIB/IV NSCLC were enrolled: (1) no prior chemotherapy and (2) previously treated with cisplatin or carboplatin and docetaxel or pemetrexed. All patients received daily everolimus 5 mg and gefitinib 250 mg. Response was assessed after 1 month and then every 2 months. Pretreatment tumor specimens were collected for mutation testing.

RESULTS

Sixty-two patients were enrolled (median age: 66 years, 50% women, 98% stage IV, all current/former smokers, and 85% adenocarcinoma). Partial responses were seen in 8 of 62 patients (response rate: 13%; 95% confidence interval: 5-21%); five responders had received no prior chemotherapy. Three partial responders had an EGFR mutation. Both patients with a KRAS (G12F) mutation responded. The median time to progression was 4 months. Median overall survival was 12 months, 27 months for no prior chemotherapy patients, and 11 months for patients previously treated with chemotherapy.

CONCLUSIONS

The 13% partial response rate observed did not meet the prespecified response threshold to pursue further study of the combination of gefitinib and everolimus. The response rate in patients with non-EGFR mutant tumors was 8%, likely reflecting activity of everolimus. Further investigation of mammalian target-of-rapamycin inhibitors in patients with NSCLC with KRAS G12F-mutated tumors is warranted.

A phase I study of bevacizumab (B) in combination with everolimus (E) and erlotinib (E) in advanced cancer (BEE)

PURPOSE

VEGF, mTOR, and EGFR inhibitors have demonstrated anti-tumor and anti-angiogenic effects alone and in combination with each other. This study evaluated the safety, tolerability, and pharmacokinetics of bevacizumab, everolimus, and erlotinib combination.

METHODS

Doublet therapy consisted of bevacizumab at 10 mg/kg every 14 days and everolimus 5 mg daily which escalated to 10 mg daily. Erlotinib 75 mg daily was added to the phase II dose recommended phase II dose (RPTD) of bevacizumab and everolimus. Dose-limiting toxicity (DLT) was assessed in cycle 1.

RESULTS

Forty-eight patients with advanced solid malignancies were evaluable for DLT and efficacy. No DLTs were observed in the doublet dose escalation. Two DLTs (grade 3 mucositis and grade 3 rash) were observed with the addition of erlotinib 75 mg daily. Consequently, triplet doses were adjusted and were better tolerated. Four patients had a partial response. Median progression-free survival (PFS) for the doublet therapy was 6.0 months (0.5 to 32+ months) and 5.5 months (0.8 to 27+ months) for the triplet therapy. Systemic exposure of everolimus was significantly higher in combination with erlotinib (476 ± 161 ng h/mL) compared to when given alone (393 ± 156 ng h/mL; P = 0.020).

CONCLUSIONS

The RPTD for the doublet therapy is bevacizumab 10 mg/kg every 14 days and everolimus 10 mg daily, and the RPTD for the triplet therapy is bevacizumab 5 mg/kg every 14 days, everolimus 5 mg and erlotinib 75 mg daily. Prolonged disease stability was demonstrated in tumors known to respond to mTOR inhibition and potentially resistant to VEGF blockade.

Discovering Molecular Targets in Cancer with Multiscale Modeling

Multiscale modeling is increasingly being recognized as a promising research area in computational cancer systems biology. Here, exemplified by two pioneering studies, we attempt to explain why and how such a multiscale approach paired with an innovative cross-scale analytical technique can be useful in identifying high-value molecular therapeutic targets. This novel, integrated approach has the potential to offer a more effective in silico framework for target discovery and represents an important technical step towards systems medicine.

Identifying therapeutic targets in a combined EGFR-TGFβR signalling cascade using a multiscale agent-based cancer model

Applying a previously developed non-small cell lung cancer model, we assess 'cross-scale' the therapeutic efficacy of targeting a variety of molecular components of the epidermal growth factor receptor (EGFR) signalling pathway. Simulation of therapeutic inhibition and amplification allows for the ranking of the implemented downstream EGFR signalling molecules according to their therapeutic values or indices. Analysis identifies mitogen-activated protein kinase and extracellular signal-regulated kinase as top therapeutic targets for both inhibition and amplification-based treatment regimen but indicates that combined parameter perturbations do not necessarily improve the therapeutic effect of the separate parameter treatments as much as might be expected. Potential future strategies using this in silico model to tailor molecular treatment regimen are discussed.