Case Report: Dacomitinib May Not Benefit Patients Who Develop Rare Compound Mutations After Later-Line Osimertinib Treatment

The acquired EGFR C797X mutation has been identified as the most notable resistance to osimertinib, and novel secondary mutations of EGFR L718 and L792 residues have also been demonstrated to confer osimertinib resistance, making the choice of medication after osimertinib treatment a quandary. Dacomitinib has been reported to have potential impact on patients acquiring rare compound mutations after osimertinib resistance; however, little evidence is available to date. In five lung adenocarcinoma patients resistant to later-line osimertinib, recurrent mutations at EGFR L792 and/or L718 were identified using targeted next-generation sequencing of tissue or cell-free DNA from plasma or pleural effusion. Dacomitinib was initiated after osimertinib resistance; however, all patients progressed within 2 months. Molecular structural simulation revealed that L792H + T790M and L718Q mutations could interfere with the binding of dacomitinib to EGFR and potentially cause primary drug resistance. Our case series study, to our knowledge, is the first to report the clinical efficacy of dacomitinib in patients harboring rare complex mutations after later-line osimertinib resistance.

Dacomitinib as a retreatment for advanced non-small cell lung cancer patient with an uncommon EGFR mutation

In non‐small cell lung cancer (NSCLC), uncommon epidermal growth factor receptor (EGFR) mutations are mutations other than Ex19 deletion and Ex21 L858R, which are common mutations highly sensitive to EGFR‐tyrosine kinase inhibitors. Afatinib, a second‐generation EGFR‐tyrosine kinase inhibitor, has been shown to be effective in patients with uncommon mutations. Dacomitinib, another second‐generation EGFR‐tyrosine kinase inhibitor, has not previously been shown to be effective in patients with uncommon mutations. Here, we report the efficacy of dacomitinib for uncommon EGFR mutations in a 71‐year‐old woman diagnosed with metastatic lung adenocarcinoma with uncommon EGFR mutation (Ex18 G719A). Afatinib was administered as the first‐line treatment, and a remarkable antitumor effect was observed. However, the tumor grew after 14 months. Pemetrexed plus carboplatin followed by pemetrexed, docetaxel, atezolizumab and S‐1 were performed in sequence. Although approximately four years had passed since the start of treatment, her physical condition was good. The patient started dacomitinib as the sixth‐line treatment. Lesions were markedly reduced and treatment with dacomitinib was continued for 7.8 months. Dacomitinib is a possible treatment option for NSCLC with uncommon mutations.

Dacomitinib in first-line treatment of advanced EGFR-mutated non-small-cell lung cancer: a cost-effectiveness analysis

Aim: To assess the cost-effectiveness of first-line treatment with dacomitinib compared with gefitinib in patients newly diagnosed with advanced NSCLC EGFR-positive in the context of Spain. Materials & methods: A partitioned survival model was developed including costs, utilities and disutilities to estimate quality-adjusted life-year (QALY) and incremental cost-effectiveness ratio when treating with dacomitinib versus gefitinib. Results: Dacomitinib presented higher QALYs (0.51) compared with gefitinib (0.45). Dacomitinib costs were €33,061 in comparison with €26,692 for gefitinib arm. An incremental cost-effectiveness ratio of €111,048 was obtained for dacomitinib. Conclusion: Dacomitinib was more effective in terms of QALYs gained than gefitinib. However, to obtain a cost-effectiveness alternative, a discount greater than 25% in dacomitinib acquisition cost is required.

The patient's perspective on treatment with dacomitinib: patient-reported outcomes from the Phase III trial ARCHER 1050

Aim: Patient-reported symptoms, functioning and overall quality of life (QoL) were compared between dacomitinib and gefitinib in ARCHER 1050. Patients & methods: Patients (n = 448) with advanced EGFR mutation-positive non-small-cell lung cancer completed the EORTC-QLQ-C30 questionnaire and its lung-specific module, LC-13. Mean scores over time were analyzed using a mixed model for repeated measures. Results: Both treatments showed early improvement in disease-related symptoms that was maintained during treatment. Treatment-related diarrhea and sore mouth decreased following dose reduction with dacomitinib. There were no clinically meaningful changes in functioning and overall QoL in either treatment group. Conclusion: Longer treatment duration, enabled by dose reduction, allowed patients on dacomitinib to improve treatment-related symptoms and maintain functioning and overall QoL for longer than gefitinib.

Dramatic Response of Brain Metastasis from EGFR-mutation-positive NSCLC to Dacomitinib

The central nervous system efficacy of dacomitinib, a key agent used in the treatment of epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC), is unclear. We herein present our experience in the use of dacomitinib for the treatment of multiple brain metastatic lesions from EGFR-mutation-positive NSCLC in an elderly patient. This case report demonstrates that dacomitinib can be an essential treatment option for patients with brain metastases.

Safety and efficacy of first-line dacomitinib in Japanese patients with advanced non-small cell lung cancer

In a subgroup of Japanese patients in the ARCHER 1050 randomized phase 3 trial, we evaluated the efficacy and safety and determined the effects of dose modifications on adverse events (AE) and therapy management of first-line oral dacomitinib 45 mg compared with oral gefitinib 250 mg, each once daily in 28-d cycles, in patients with EGFR-activating mutation-positive (EGFR-positive; exon 19 deletion or exon 21 L858R substitution mutations) advanced non-small cell lung cancer (NSCLC). The primary endpoint was progression-free survival (PFS; RECIST, version 1.1, by blinded independent review). In 81 Japanese patients (40 dacomitinib, 41 gefitinib), PFS was longer with dacomitinib compared with gefitinib (hazard ratio [HR], 0.544 [95% confidence interval {CI}, 0.307-0.961]; 2-sided P = .0327; median 18.2 for dacomitinib [95% CI, 11.0-31.3] mo, 9.3 [95% CI, 7.4-14.7] mo for gefitinib). The most common Grade 3 AEs were dermatitis acneiform with dacomitinib (27.5%) and increased alanine aminotransferase with gefitinib (12.2%). A higher proportion of patients receiving dacomitinib (85.0%) compared with gefitinib (24.4%) had AEs leading to dose reduction. Incidence and severity of diarrhea, dermatitis acneiform, stomatitis and paronychia were generally reduced after dacomitinib dose reductions and dacomitinib treatment duration was generally longer in patients with a dose reduction in comparison with those without a dose reduction. Our results confirmed the efficacy and safety of first-line dacomitinib in Japanese patients with EGFR-positive advanced NSCLC.

Localization and Accumulation Studies of Dacomitinib in Rat Intestines and Skin by Immunohistochemistry

Dacomitinib, a second-generation tyrosine kinase inhibitor, was irreversible inhibitor forming covalent bonds with the kinase domains of EGFR and other ErbB family receptors. Dacomitinib has been approved for the treatment of locally advanced or metastatic non-small cell lung cancer. In this study, we aimed to develop an immunohistochemistry to detect dacomitinib-ErbB family receptor conjugates. Immunostaining was performed in rat intestine and skin tissues after oral administration of dacomitinib. Following a single oral dose of dacomitinib, strong staining was observed after 24 hr in the ileum and colon, with only slight staining in the duodenum and jejunum. In the skin, strong staining was observed in the epidermis, hair follicles, and sebaceous glands. Moreover, significant amounts of dacomitinib remained for up to 72 hr post-administration in the ileum, colon, and skin. This report is the first to elucidate the localization and accumulation of dacomitinib in the rat intestine and skin and should be valuable during efforts to clarify the mechanism dacomitinib-induced diarrhea or skin toxicities.

Clinical evaluation of dacomitinib for the treatment of metastatic non-small cell lung cancer (NSCLC): current perspectives

Systemic treatment of advanced non-small cell lung cancer (NSCLC) has undergone remarkable changes in the last decade, with the introduction of targeted therapies and immunotherapy. The identification of activating mutations in the epidermal growth factor receptor (EGFR) gene (deletions in exon 19 [Del19] and point mutation L858R in exon 21) has been the first important step toward molecularly guided precision therapy in lung cancer. Several randomized trials comparing EGFR tyrosine kinase inhibitors (TKIs) (gefitinib, erlotinib, and afatinib) to standard chemotherapy in first-line treatment of advanced EGFR-mutant NSCLC showed significant improvement in progression-free survival (PFS) and in response rate, with lower rates of adverse events (AEs) and better symptom control. However, none of these trials showed significant improvement in overall survival (OS). Despite impressive responses with EGFR-TKI, disease invariably progresses after 9 to 13 months, due to acquired resistance. Dacomitinib is a potent, irreversible, highly selective, second-generation EGFR-TKI, which inhibits the signaling from both heterodimers and homodimers of all the members of the human epidermal growth factor receptor (HER) family. Here, we review the clinical development of dacomitinib from phase I to phase III, with particular attention to its toxicity and on its activity on T790M mutation. Then, we critically examine the results of ARCHER 1050, a study that was crucial for Food and Drug Administration (FDA) approval. ARCHER 1050 was the first randomized phase III study comparing dacomitinib with gefitinib, in first-line treatment of patients with advanced EGFR-mutated NSCLC. Dacomitinib was superior to gefitinib in terms of primary end-point (14.7 vs 9.2 months) and OS (34.1 vs 26.8 months). The incidence of diarrhea, skin rash, mucositis and, consequently, dose reductions was higher with dacomitinib, while hepatic toxicity was higher with gefitinib. Dacomitinib constitutes one of the standard first-line options in patients with advanced EGFR-mutated NSCLC.

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Second-generation EGFR and ErbB tyrosine kinase inhibitors as first-line treatments for non-small cell lung cancer

The discovery that mutations in the EGFR gene are present in up to 50% of patients with lung adenocarcinoma, and the development of highly efficacious EGFR tyrosine kinase inhibitors (TKIs), has revolutionized the way this common malignancy is treated. Three generations of EGFR TKIs are now approved for use in EGFR mutation-positive non-small cell lung cancer (NSCLC); the first-generation agents erlotinib, gefitinib, and icotinib; the second-generation ErbB family blockers afatinib and dacomitinib; and most recently, osimertinib, a third-generation EGFR TKI. The second-generation agents have demonstrated impressive efficacy relative to both standard platinum-based chemotherapy and first-generation EGFR TKIs, significantly improving response and progression-free and overall survival. Data from real-world studies suggest that afatinib is as effective and well tolerated in routine clinical practice as it is in clinical studies and is effective in patients with certain uncommon EGFR mutations, patients with brain metastases, and older patients. Few real-world data are available for dacomitinib in the first-line setting. Afatinib and dacomitinib have similar safety profiles, with acne/skin dryzness, diarrhea, stomatitis, and paronychia the most common adverse events (AEs) reported in clinical and real-world studies. Numerous studies have shown that tolerability-guided dose reductions can help manage afatinib-related AEs without reducing efficacy. As the number of therapeutic options for advanced NSCLC increases, the optimal choice for first-line treatment will be determined by considering patient factors such as the presence of brain metastases, the type of EGFR mutation, tolerability, and subsequent therapy options for long-term treatment.

Dacomitinib in non-small-cell lung cancer: a comprehensive review for clinical application

Dacomitinib is a second-generation EGFR tyrosine kinase inhibitor (TKI) that irreversibly binds to and inhibits EGFR/Her1, Her2 and Her4 subtypes with an efficacy comparable to other TKIs. In the ARCHER 1050 trial, progression-free survival was improved by dacomitinib compared with gefitinib, supporting dacomitinib as a first-line treatment option for advanced non-small-cell lung cancer with sensitive EGFR mutation. Regarding to the higher adverse events rate, dose reductions did not reduce the efficacy of dacomitinib and could effectively decreased the incidence and severity of adverse events. Considering the evolving landscape of EGFR-mutant non-small-cell lung cancer, future head to head comparison between dacomitinib and osimertinib could provide key information to determine the optimal TKI treatment schedule.

Effects of dose modifications on the safety and efficacy of dacomitinib for EGFR mutation-positive non-small-cell lung cancer

Aim: We evaluated reasons for dacomitinib dose reduction (DR) and examined adverse event (AE) incidence, key efficacy end points (progression-free survival [PFS]/overall survival [OS]), and pharmacokinetics in dose-reducing patients in the ARCHER 1050 trial. Patients & methods: Newly diagnosed patients with EGFR mutation-positive, advanced non-small-cell lung cancer received oral dacomitinib (45 mg once-daily [QD]), with stepwise toxicity-managing DR (30 and 15 mg QD) permitted. Results: Skin toxicities (62.7%) were the most common DR-leading AEs. The AE incidence and severity decreased following DRs. Initial plasma dacomitinib exposure (45 mg QD) was generally lower in patients remaining at 45 mg QD compared with dose-reducing patients. Median PFS and OS were similar in all dacomitinib-treated patients and dose-reducing patients. Conclusion: Tolerability-guided dose modifications enabled patients to continue with dacomitinib and benefit from PFS/OS improvement. Trial registration number: NCT01774721.

Management of common adverse events related to first-line dacomitinib use in EGFR mutation-positive non-small-cell lung cancer: a pooled safety analysis

Aim: This pooled safety analysis was conducted to analyze incidence and management of key dacomitinib-associated adverse drug reactions (ADRs). Patients & methods: Patients with EGFR mutation-positive advanced non-small-cell lung cancer who received first-line dacomitinib at the 45 mg/day recommended starting dose were included. ADRs were identified based on reasonable association with EGFR tyrosine kinase inhibitors. Results: Overall, 251/255 patients (98%) experienced ADRs. The most common were diarrhea, rash, stomatitis, nail disorder and dry skin. Dose interruptions and dose reductions were reported in 47 and 52% of patients, respectively. Fewer grade 3 key ADRs were observed following dose reductions. Conclusion: Dacomitinib was generally tolerable. Most reported ADRs were known to be associated with EGFR tyrosine kinase inhibitors and were managed with standard medical management and dose modifications.

Phase II trial of dacomitinib, a pan-human EGFR tyrosine kinase inhibitor, in recurrent glioblastoma patients with EGFR amplification

Background

We conducted a multicenter, 2-stage, open-label, phase II trial to assess the efficacy and safety of dacomitinib in adult patients with recurrent glioblastoma (GB) and epidermal growth factor receptor gene (EGFR) amplification with or without variant III (EGFRvIII) deletion.

Methods

Patients with first recurrence were enrolled in 2 cohorts. Cohort A included patients with EGFR gene amplification without EGFRvIII mutation. Cohort B included patients with EGFR gene amplification and EGFRvIII mutation. Dacomitinib was administered (45 mg/day) until disease progression/unacceptable adverse events (AEs). Primary endpoint was progression-free survival (PFS; RANO criteria) at 6 months (PFS6).

Results

Thirty patients in Cohort A and 19 in Cohort B were enrolled. Median age was 59 years (range 39-81), 65.3% were male, and Eastern Cooperative Oncology Group Performance Status 0/1/2 were 10.2%/65.3%/24.5%, respectively. PFS6 was 10.6% (Cohort A: 13.3%; Cohort B: 5.9%) with a median PFS of 2.7 months (Cohort A: 2.7 mo; Cohort B: 2.6 mo). Four patients were progression free at 6 months and 3 patients were so at 12 months. Median overall survival was 7.4 months (Cohort A: 7.8 mo; Cohort B: 6.7 mo). The best overall response included 1 complete response and 2 partial responses (4.1%). Stable disease was observed in 12 patients (24.5%: eight in Cohort A and four in Cohort B). Diarrhea and rash were the most common AEs; 20 (40.8%) patients experienced grade 3-4 drug-related AEs.

Conclusions

Dacomitinib has a limited single-agent activity in recurrent GB with EGFR amplification. The detailed molecular characterization of the 4 patients with response in this trial can be useful to select patients who could benefit from dacomitinib.

Optimizing outcomes in EGFR mutation-positive NSCLC: which tyrosine kinase inhibitor and when?

Despite the efficacy of standard-of-care EGFR tyrosine kinase inhibitors (TKIs), erlotinib, gefitinib and afatinib, in EGFR mutation-positive non-small-cell lung cancer, resistance develops, most commonly due to the T790M mutation. Osimertinib showed clinical activity in the treatment of T790M-positive disease following progression on a first-line TKI, and is approved in this setting. Recently, osimertinib improved efficacy versus first-generation TKIs (erlotinib and gefitinib) in the first-line setting. Multiple factors can influence first-line treatment decisions, including subsequent therapy options, presence of brain metastases and tolerability, all of which should be considered in the long-term treatment plan. Further research into treatment sequencing is also needed, to optimize outcomes in EGFR mutation-positive non-small-cell lung cancer.

Phase 1 study to investigate the pharmacokinetic properties of dacomitinib in healthy adult Chinese subjects genotyped for CYP2D6

1. This study aimed to characterise the pharmacokinetics of dacomitinib, a pan-human epidermal growth factor receptor tyrosine kinase inhibitor, and its metabolite, PF-05199265, in healthy Chinese subjects. 2. In this open-label, single-centre, nonrandomised study (NCT02097433), 14 subjects received a single dacomitinib 45-mg oral dose. Pharmacokinetic samples for dacomitinib and PF-05199265 were collected pre- and postdose. Subjects were genotyped for cytochrome P450 (CYP)2D6 metaboliser status. Safety was assessed throughout the study. 3. The geometric mean (per cent coefficient of variability) area under the concentration-time curve from time zero to infinity (AUC_inf) and maximum plasma concentration (C_max) were 1662 ngċh/mL (26%) and 21.51 ng/mL (27%), respectively, for dacomitinib and 469 ngċh/mL (65%) and 5.54 ng/mL (79%) for PF-05199265. Median times to C_max were 8 and 4 h postdose for dacomitinib and PF-05199265, respectively; mean terminal half-life of dacomitinib was 62.7 h. Geometric mean apparent clearance and volume of distribution of dacomitinib were 27.06 L/h and 2415 L, respectively. The metabolite PF-05199265-to-dacomitinib ratios were 0.2907 for AUC_inf and 0.2656 for C_max. 4. Dacomitinib total (AUC_inf) and peak exposures (C_max) were similar among subjects with different CYP2D6 genotypes, whereas both parameters for PF-05199265 were higher in extensive metabolisers (n = 5) versus intermediate metabolisers (n = 8).

Novel combinations of PI3K-mTOR inhibitors with dacomitinib or chemotherapy in PTEN-deficient patient-derived tumor xenografts

PTEN inactivation occurs commonly in human cancers and putatively activates the PI3K/AKT/ mTOR pathway. Activation of this pathway has been involved in resistance to chemotherapy or anti-EGFR/HER2 therapies. We evaluated the combination of PI3K-mTOR inhibitors with chemotherapy or the pan-HER inhibitor dacomitinib in PTEN-deficient patient-derived tumor xenografts (PDX). Three PDXs were selected for their lack of PTEN expression by immunohistochemistry: a triple-negative breast cancer (TNBC), a KRAS G12R low-grade serous ovarian cancer (LGSOC), and KRAS G12C and TP53 R181P lung adenocarcinoma (LADC). Two dual PI3K-mTOR inhibitors were evaluated-PF-04691502 and PF-05212384-in combination with cisplatin, paclitaxel, or dacomitinib. The addition of PI3K-mTOR inhibitors to cisplatin or paclitaxel increased the activity of chemotherapy in the TNBC and LGSOC models; whereas no added activity was observed in the LADC model. Pharmacodynamic modulation of pS6 and pAKT was observed in the group treated with PI3K-mTOR inhibitor. Our research suggests that the addition of a PI3K-mTOR inhibitor may enhance tumor growth inhibition when compared to chemotherapy alone in certain PTEN-deficient PDXs. However, this benefit was absent in the KRAS and TP53 mutant LADC model. The role of PTEN deficiency in the antitumor activity of these combinations should be further investigated in the clinic.

Second-line Treatment of Non-Small Cell Lung Cancer: Focus on the Clinical Development of Dacomitinib

Dacomitinib is a second-generation, irreversible, covalent pan-HER tyrosine-kinase inhibitor (TKI). It showed potent EGFR signaling inhibition in experimental models, including first-generation TKI-resistant non-small cell lung cancer (NSCLC) cell lines. This preclinical efficacy did not translate into clinically meaningful treatment benefits for advanced, pretreated, molecularly unselected NSCLC patients enrolled in two parallel phase III trials. Dacomitinib and erlotinib showed overlapping efficacy data in chemotherapy-pretreated EGFR wild-type (WT) patients in the ARCHER 1009 trial. Similarly, it failed to demonstrate any survival benefits as compared to placebo in EGFR WT subsets progressing on chemotherapy and at least one previous first-generation TKI (erlotinib or gefitinib) in the BR.26 trial. In the case of EGFR-mutant NSCLCs, a pooled analysis of the ARCHER 1009 and ARCHER 1028 trials comparing the efficacy of dacomitinib vs. erlotinib in chemotherapy-pretreated, EGFR TKI-naïve patients showed a trend to a longer progression-free survival (PFS) and overall survival in favor of dacomitinib that did not reach statistical significance, with a higher rate of treatment related adverse events (mainly skin rash, paronychia, and gastrointestinal toxicities). On the other hand, the clinical activity in patients with EGFR-mutant NSCLCs with acquired TKI resistance that were included in phase II/III trials was equally poor (response rate <10%; PFS 3-4 months). Therefore, with the results of the ARCHER 1050 trial (NCT01774721) still pending, the current clinical development of dacomitinib is largely focused on EGFR-mutant, TKI-naïve patients. Here, we review the most relevant clinical data of dacomitinib in advanced NSCLC. We discuss the potential role of dacomitinib in pretreated EGFR WT and EGFR-mutant (TKI-naïve and TKI-resistant) patients. Finally, we briefly comment the available clinical data of dacomitinib in HER2-mutant NSCLC patients.

Dacomitinib-induced diarrhoea is associated with altered gastrointestinal permeability and disruption in ileal histology in rats

Dacomitinib-an irreversible pan-ErbB tyrosine kinase inhibitor (TKI)-causes diarrhoea in 75% of patients. Dacomitinib-induced diarrhoea has not previously been investigated and the mechanisms remain poorly understood. The present study aimed to develop an in-vitro and in-vivo model of dacomitinib-induced diarrhoea to investigate underlying mechanisms. T84 cells were treated with 1-4 μM dacomitinib and resistance and viability were measured using transepithelial electrical resistance (TEER) and XTT assays. Rats were treated with 7.5 mg/kg dacomitinib daily via oral gavage for 7 or 21 days (n = 6/group). Weights, and diarrhoea incidence were recorded daily. Rats were administered FITC-dextran 2 hr before cull, and serum levels of FITC-dextran were measured and serum biochemistry analysis was conducted. Detailed histopathological analysis was conducted throughout the gastrointestinal tract. Gastrointestinal expression of ErbB1, ErbB2 and ErbB4 was analysed using RT-PCR. The ileum and the colon were analysed using multiplex for expression of various cytokines. T84 cells treated with dacomitinib showed no alteration in TEER or cell viability. Rats treated with dacomitinib developed severe diarrhoea, and had significantly lower weight gain. Further, dacomitinib treatment led to severe histopathological injury localised to the ileum. This damage coincided with increased levels of MCP1 in the ileum, and preferential expression of ErbB1 in this region compared to all other regions. This study showed dacomitinib induces severe ileal damage accompanied by increased MCP1 expression, and gastrointestinal permeability in rats. The histological changes were most pronounced in the ileum, which was also the region with the highest relative expression of ErbB1.

A phase II study (ARCHER 1042) to evaluate prophylactic treatment of dacomitinib-induced dermatologic and gastrointestinal adverse events in advanced non-small-cell lung cancer

BACKGROUND

ARCHER 1042, a randomized phase II trial, explored the impact of prophylactic treatment on select dermatologic adverse events of interest (SDAEI), diarrhea, and mucositis associated with dacomitinib, an oral irreversible pan-human epidermal growth factor receptor (HER) inhibitor, in development for advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Patients with advanced NSCLC treated with dacomitinib were enrolled in two cohorts. Cohort I patients were randomized 1:1 to receive oral doxycycline or placebo (4 weeks). Cohort II patients received oral VSL#3 probiotic plus topical alclometasone. Primary end points for Cohorts I and II were incidence of all grade and grade ≥2 SDAEI in the first 8 weeks of treatment and quality of life (QoL) assessed by the Skindex-16 survey. Additional primary end points for Cohort II were incidence of all grade and grade ≥2 diarrhea and mucositis in the first 8 weeks of treatment; QoL regarding diarrhea and mucositis incidence was assessed by the modified-Oral Mucositis Daily Questionnaire.

RESULTS

Cohort I randomized 114 evaluable patients: 56 in the doxycycline arm, 58 in the placebo arm. Cohort II enrolled 59 evaluable patients. Doxycycline significantly reduced the incidence of grade ≥2 SDAEI by 50% (P = 0.016) compared with placebo. The incidence of all grade SDAEI was lower with doxycycline than with placebo but did not reach statistical significance. Doxycycline was associated with less deterioration in QoL compared with placebo. Alclometasone was associated with less deterioration in QoL compared with placebo but did not statistically significantly reduce the incidence of all grade or grade ≥2 SDAEI. VSL#3 did not reduce the incidence of all grade or grade ≥2 diarrhea and did not impact mucositis scores.

CONCLUSIONS

Doxycycline was effective as a prophylactic treatment for dacomitinib-induced grade ≥2 SDAEI. Both doxycycline and alclometasone reduced the negative impact in patient-reported dermatologic AEs. The probiotic was not effective for preventing diarrhea or mucositis.

Dacomitinib versus erlotinib in patients with EGFR-mutated advanced nonsmall-cell lung cancer (NSCLC): pooled subset analyses from two randomized trials

BACKGROUND

The irreversible epidermal growth factor receptor (EGFR) inhibitors have demonstrated efficacy in NSCLC patients with activating EGFR mutations, but it is unknown if they are superior to the reversible inhibitors. Dacomitinib is an oral, small-molecule irreversible inhibitor of all enzymatically active HER family tyrosine kinases.

METHODS

The ARCHER 1009 (NCT01360554) and A7471028 (NCT00769067) studies randomized patients with locally advanced/metastatic NSCLC following progression with one or two prior chemotherapy regimens to dacomitinib or erlotinib. EGFR mutation testing was performed centrally on archived tumor samples. We pooled patients with exon 19 deletion and L858R EGFR mutations from both studies to compare the efficacy of dacomitinib to erlotinib.

RESULTS

One hundred twenty-one patients with any EGFR mutation were enrolled; 101 had activating mutations in exon 19 or 21. For patients with exon19/21 mutations, the median progression-free survival was 14.6 months [95% confidence interval (CI) 9.0-18.2] with dacomitinib and 9.6 months (95% CI 7.4-12.7) with erlotinib [unstratified hazard ratio (HR) 0.717 (95% CI 0.458-1.124), two-sided log-rank, P = 0.146]. The median survival was 26.6 months (95% CI 21.6-41.5) with dacomitinib versus 23.2 months (95% CI 16.0-31.8) with erlotinib [unstratified HR 0.737 (95% CI 0.431-1.259), two-sided log-rank, P = 0.265]. Dacomitinib was associated with a higher incidence of diarrhea and mucositis in both studies compared with erlotinib.

CONCLUSIONS

Dacomitinib is an active agent with comparable efficacy to erlotinib in the EGFR mutated patients. The subgroup with exon 19 deletion had favorable outcomes with dacomitinib. An ongoing phase III study will compare dacomitinib to gefitinib in first-line therapy of patients with NSCLC harboring common activating EGFR mutations (ARCHER 1050; NCT01774721).

CLINICAL TRIALS NUMBER

ARCHER 1009 (NCT01360554) and A7471028 (NCT00769067).

Advances in molecular-based personalized non-small-cell lung cancer therapy: targeting epidermal growth factor receptor and mechanisms of resistance

Molecularly targeted therapies, directed against the features of a given tumor, have allowed for a personalized approach to the treatment of advanced non-small-cell lung cancer (NSCLC). The reversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib had undergone turbulent clinical development until it was discovered that these agents have preferential activity in patients with NSCLC harboring activating EGFR mutations. Since then, a number of phase 3 clinical trials have collectively shown that EGFR-TKI monotherapy is more effective than combination chemotherapy as first-line therapy for EGFR mutation-positive advanced NSCLC. The next generation of EGFR-directed agents for EGFR mutation-positive advanced NSCLC is irreversible TKIs against EGFR and other ErbB family members, including afatinib, which was recently approved, and dacomitinib, which is currently being tested in phase 3 trials. As research efforts continue to explore the various proposed mechanisms of acquired resistance to EGFR-TKI therapy, agents that target signaling pathways downstream of EGFR are being studied in combination with EGFR TKIs in molecularly selected advanced NSCLC. Overall, the results of numerous ongoing phase 3 trials involving the EGFR TKIs will be instrumental in determining whether further gains in personalized therapy for advanced NSCLC are attainable with newer agents and combinations. This article reviews key clinical trial data for personalized NSCLC therapy with agents that target the EGFR and related pathways, specifically based on molecular characteristics of individual tumors, and mechanisms of resistance.

Dacomitinib in lung cancer: a "lost generation" EGFR tyrosine-kinase inhibitor from a bygone era?

EGFR tyrosine-kinase inhibitors (TKIs) have now been firmly established as the first-line treatment for non-small-cell lung cancer (NSCLC) patients harboring activating EGFR mutations, based on seven prospective randomized Phase III trials. However, despite significantly improved overall response rate and improved median progression-free survival when compared to platinum-doublet chemotherapy, EGFR-mutant NSCLC patients treated with EGFR TKIs invariably progress due to the emergence of acquired resistances, with the gatekeeper T790M mutation accounting for up to 60% of the resistance mechanisms. Second-generation irreversible EGFR TKIs were developed in part to inhibit the T790M mutation, in addition to the common activating EGFR mutations. Dacomitinib is one such second-generation EGFR TKI designed to inhibit both the wild-type (WT) EGFR and EGFR T790M. Afatinib is another second-generation EGR TKI that has been now been approved for the first-line treatment of EGFR-mutant NSCLC patients, while dacomitinib continues to undergo clinical evaluation. We will review the clinical development of dacomitinib from Phase I to Phase III trials, including the two recently published negative large-scale randomized Phase III trials (ARCHER 1009, NCIC-BR-26). Results from another large-scale randomized trial (ARCHER 1050) comparing dacomitinib to gefitinib as first-line treatment of advanced treatment-naïve EGFR-mutant NSCLC patients will soon be available and will serve as the lynchpin trial for the potential approval of dacomitinib in NSCLC. Meanwhile, third-generation EGFR TKIs (eg, CO-1686 [rociletinib], AZ9291, HM61713, EGF816, and ASP8273) that preferentially and potently inhibit EGFR T790M but not WT EGFR are in full-scale clinical development, and some of these EGFR TKIs have received “breakthrough” designation by the US Food and Drug Administration and will likely be approved in late 2015. Given the rapid development of third-generation EGFR TKIs and the approval of gefitinib, erlotinib, and afatinib as first-line treatment of EGFR-mutant NSCLC patients, the future role of dacomitinib in the treatment of NSCLC seems to be limited.

Effect of food or proton pump inhibitor treatment on the bioavailability of dacomitinib in healthy volunteers

This phase 1, open-label crossover study evaluated the relative bioavailability of dacomitinib in healthy volunteers under fed and fasted conditions and following coadministration with rabeprazole, a potent acid-reducing proton pump inhibitor (PPI). Twenty-four male subjects received a single dacomitinib 45-mg dose under 3 different conditions separated by washout periods of ≥ 16 days: coadministered with rabeprazole 40 mg under fasting conditions; alone under fasting conditions; and alone after a high-fat, high-calorie meal. Increased peak exposure of 23.7% (90% confidence interval [CI], 5.3%-45.2%) was detected with dacomitinib taken after food versus fasting. The adjusted geometric mean ratio (fed/fasted) for area under the plasma concentration-time curve from time zero to infinity (AUCinf ) was 114.2% (90%CI, 104.7%-124.5%) and not considered clinically meaningful. In the fasted state, a decrease in dacomitinib AUCinf was observed following rabeprazole versus dacomitinib alone (PPI+fasted/fasted alone): 71.1% (90%CI, 61.7%-81.8%). Dacomitinib was generally well tolerated. Dacomitinib may be taken with or without food. Use of long-acting acid-reducing agents, such as PPIs with dacomitinib should be avoided if possible. Shorter-acting agents such as antacids and H2-receptor antagonists may have lesser impact on dacomitinib exposure and may be preferable to PPIs if acid reduction is clinically required.

Targeting HER2 aberrations as actionable drivers in lung cancers: phase II trial of the pan-HER tyrosine kinase inhibitor dacomitinib in patients with HER2-mutant or amplified tumors

BACKGROUND

HER2 mutations and amplifications have been identified as oncogenic drivers in lung cancers. Dacomitinib, an irreversible inhibitor of HER2, EGFR (HER1), and HER4 tyrosine kinases, has demonstrated activity in cell-line models with HER2 exon 20 insertions or amplifications. Here, we studied dacomitinib in patients with HER2-mutant or amplified lung cancers.

PATIENTS AND METHODS

As a prespecified cohort of a phase II study, we included patients with stage IIIB/IV lung cancers with HER2 mutations or amplification. We gave oral dacomitinib at 30-45 mg daily in 28-day cycles. End points included partial response rate, overall survival, and toxicity.

RESULTS

We enrolled 30 patients with HER2-mutant (n = 26, all in exon 20 including 25 insertions and 1 missense mutation) or HER2-amplified lung cancers (n = 4). Three of 26 patients with tumors harboring HER2 exon 20 mutations [12%; 95% confidence interval (CI) 2% to 30%] had partial responses lasting 3+, 11, and 14 months. No partial responses occurred in four patients with tumors with HER2 amplifications. The median overall survival was 9 months from the start of dacomitinib (95% CI 7-21 months) for patients with HER2 mutations and ranged from 5 to 22 months with amplifications. Treatment-related toxicities included diarrhea (90%; grade 3/4: 20%/3%), dermatitis (73%; grade 3/4: 3%/0%), and fatigue (57%; grade 3/4: 3%/0%). One patient died on study likely due to an interaction of dacomitinib with mirtazapine.

CONCLUSIONS

Dacomitinib produced objective responses in patients with lung cancers with specific HER2 exon 20 insertions. This observation validates HER2 exon 20 insertions as actionable targets and justifies further study of HER2-targeted agents in specific HER2-driven lung cancers.

CLINICALTRIALSGOV

NCT00818441.

Irreversible EGFR-TKIs: dreaming perfection

In the last few years, the treatment of Non-Small-Cell Lung Cancer (NSCLC) has dramatically changed. Presence of activating mutations in the Epidermal Growth Factor Receptor (EGFR) identified a particular group of NSCLC patients with different clinical characteristics and outcome. For EGFR mutant patients first-generation EGFR tyrosine-kinase inhibitors (TKIs), such as gefitinib and erlotinib, represent the best therapeutic option in first, second and maintenance setting. Unfortunately, all patients develop acquired resistance and despite an initial benefit, virtually all patients progress due to the development of resistance. Several molecular mechanisms are responsible for acquired resistance and the two prominent are the up-regulation of the downstream signal by mesenchymal-epidermal transition (MET) amplification and the emergence of T790M EGFR gatekeeper mutation. Preclinical and early clinical trials suggested a potential efficacy of a new class of panHER inhibitor, also called irreversible or covalent inhibitor, in overcome acquired resistance related to T790M. Afatinib, dacomitinib and neratinib, are currently in development in different setting and results from these trials are awaited in order to establish the role of these new compounds in the treatment of NSCLC.