Activity of Afatinib/Cetuximab in Patients (PTS) with EGFR Mutant Non-Small Cell Lung Cancer (Nsclc) and Acquired Resistance (Ar) To EGFR Inhibitors

Targeting non-small cell lung cancer with small-molecule EGFR tyrosine kinase inhibitors

Epidermal growth factor (EGFR) tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, show excellent clinical efficacy for patients with non-small cell lung cancer (NSCLC) with EGFR mutations, including Exon 19 deletion and single-point substitution, and L858R of exon 21. The reason for the reduction in effectiveness of these EGFR TKIs is the T790M gatekeeper mutation in the ATP-binding pocket of Exon 20, which increases the affinity of EGFR for ATP. Newer EGFR TKIs, such as afatinib, osimertinib, rociletinib, EGF816 and ASP8273, selectively target T790M mutants, sparing wild-type EGFR. EGFR TKIs have fewer adverse effects than chemotherapy and also improve progression-free survival. Combination therapy of EGFR TKIs with anti-EGFR antibodies is recommended for overcoming the problem of resistance to some extent. This review could help medicinal chemists to design novel EGFR TKIs against NSCLC.

Efficacy and safety of afatinib in Chinese patients with EGFR-mutated metastatic non-small-cell lung cancer (NSCLC) previously responsive to first-generation tyrosine-kinase inhibitors (TKI) and chemotherapy: comparison with historical cohort using erlotinib

Background

Afaitnib has shown anti-tumor activity against metastatic EGFR-mutated NSCLC after prior failure to first generation EGFR-TKI and chemotherapy. We prospectively evaluated the efficacy and safety of afatinib in Chinese patients who previously failed first-generation TKI and chemotherapy under a compassionate use program (CUP) and compared to the erlotinib cohort.

Methods

Patients who suffered from metastatic EGFR-mutated NSCLC previously responsive to first-generation TKI and chemotherapy received afatinib until progression, loss of clinical benefits or intolerable toxicity. Treatment response, survival and safety were evaluated and compared to the erlotinib cohort.

Results

Twenty-five and 28 patients received afatinib and erlotinib respectively. More patients in the afatinib group had worse performance status (ECOG 2) than the erlotinib group (p = 0.008). After a median follow-up of 12.1 months, afatinib demonstrated comparable objective response rate (ORR) (20.0 % vs. 7.1 %, p = 0.17) but significantly higher disease control rate (DCR) (68.0 % vs. 39.3 %, p = 0.04) compared to erlotinib. Median progression-free survival (PFS) (4.1 months [95 % CI, 2.7–5.5 months] vs. 3.3 months [95 % CI, 2.2–4.3 months], p = 0.97) and overall survival (OS) were not different between the two groups (10.3 months [95 % CI, 7.5–13.0 months] vs. 10.8 months [95 % CI, 7.4–14.2 months], p = 0.51). Multivariate analyses revealed that age ≤70 years and time to progression (TTP) ≥18 months for the 1^st TKI therapy were prognostic of PFS (p = 0.006 and p = 0.008 respectively). Afatinib caused less rash (60.0 % vs. 67.9 %, p = 0.04) but more diarrhea (60.0 % vs. 10.7 %, p = 0.002) compared to erlotinib.

Conclusion

Afatinib produced encouraging clinical efficacy as 2^nd TKI therapy with manageable safety profiles in our Chinese patients after failure to another TKI and systemic chemotherapy.

This study was registered at ClinicalTrials.gov (NCT02625168) on 3^rd December 2015.

Molecular pathways: resistance to kinase inhibitors and implications for therapeutic strategies

The development of targeted therapies has revolutionized the treatment of cancer patients. The identification of "druggable" oncogenic kinases and the creation of small-molecule inhibitors designed to specifically target these mutant kinases have become an important therapeutic paradigm across several different malignancies. Often these inhibitors induce dramatic clinical responses in molecularly defined cohorts. However, resistance to such targeted therapies is an inevitable consequence of this therapeutic approach. Resistance can be either primary (de novo) or acquired. Mechanisms leading to primary resistance may be categorized as tumor intrinsic factors or as patient/drug-specific factors. Acquired resistance may be mediated by target gene modification, activation of "bypass tracks" that serve as compensatory signaling loops, or histologic transformation. This brief review is a snapshot of the complex problem of therapeutic resistance, with a focus on resistance to kinase inhibitors in EGF receptor mutant and ALK rearranged non-small cell lung cancer, BRAF-mutant melanoma, and BCR-ABL-positive chronic myeloid leukemia. We describe specific mechanisms of primary and acquired resistance and then review emerging strategies to delay or overcome drug resistance.

Randomized, open-label trial evaluating the preventive effect of tetracycline on afatinib induced-skin toxicities in non-small cell lung cancer patients

BACKGROUND

Afatinib has shown long progression free survival and improvement in quality of life in advanced Non-Small Cell Lung Cancer (NSCLC) patients. Although afatinib causes acneiform rash, it can be manageable. Tetracyclines are usually used to treat it; nonetheless, there is no trial that evaluates their prophylactic efficacy on afatinib induced-skin toxicities (AIST).

PATIENTS AND METHODS

This open-label, randomized, controlled trial assessed the preventive effect of tetracycline for reducing afatinib-skin toxicities in NSCLC patients receiving afatinib 40 mg/day. Patients were randomly assigned to receive pre-emptive treatment with tetracycline 250 mg every 12h for 4 weeks or not. Reactive treatment in both groups included general dermatological recommendations such as use of skin moisturizers, sunscreen and topical steroids, according to toxicity severity. All patients were blindly monitored for skin toxicities by an expert dermatologist at the start of treatment with afatinib (day 0), weeks 2 and 4 of treatment. The protocol is registered on clinicaltrials.gov (NCT01880515).

RESULTS

We included 90 patients, no differences were found in clinical and dermatological baseline characteristics. Rash incidence of any grade, and grade ≥2 was less frequent in the pre-emptive arm vs. the control arm (44.5 vs. 75.6%, RR 0.4 [95% CI 0.17-0.99], p=0.046 and 15.6 vs. 35.6%, RR 0.35 [95% CI, 0.12-0.91], p=0.030, respectively). No difference was found in paronychia, xerosis, mucositis, folliculitis, and skin fissure. No adverse event was associated with tetracycline. Neither rash nor pre-emptive tetracycline impacted on response rate, progression-free or overall survivals.

CONCLUSION

Pre-emptive tetracycline was well tolerated and reduced the rash incidence and severity associated with afatinib in more than 60%.

Afatinib: a review of its use in the treatment of advanced non-small cell lung cancer

Afatinib (Gilotrif™, Giotrif(®)) is an orally administered, irreversible inhibitor of the ErbB family of tyrosine kinases. Afatinib downregulates ErbB signalling by covalently binding to the kinase domains of epidermal growth factor receptor (EGFR), human epidermal growth factor receptor (HER) 2 and HER4, resulting in irreversible inhibition of tyrosine kinase autophosphorylation; it also inhibits transphosphorylation of HER3. Afatinib is approved as monotherapy for the treatment of EGFR tyrosine kinase inhibitor (TKI)-naïve adults with locally advanced or metastatic non-small cell lung cancer (NSCLC) with activating EGFR mutations in the EU, and for the first-line treatment of patients with metastatic NSCLC whose tumours have EGFR exon 19 deletions or exon 21 (L858R) substitution mutations as detected by a US FDA-approved test in the US. In two randomized, open-label, multinational phase III trials, progression-free survival was significantly prolonged with afatinib compared with pemetrexed plus cisplatin (LUX-Lung 3) or gemcitabine plus cisplatin (LUX-Lung 6) in treatment-naïve patients with advanced NSCLC with activating EGFR mutations. The objective response rate was significantly higher with afatinib than with pemetrexed plus cisplatin or gemcitabine plus cisplatin, and patient-reported outcomes for symptoms such as cough and dyspnoea and certain health-related quality of life measures significantly favoured afatinib versus pemetrexed plus cisplatin or gemcitabine plus cisplatin. Afatinib also showed efficacy in EGFR TKI-naïve patients with advanced lung adenocarcinoma and activating EGFR mutations who had received no more than one prior chemotherapy regimen for advanced disease, according to the results of the noncomparative, multinational, phase II LUX-Lung 2 trial. Oral afatinib had a manageable tolerability profile. EGFR-mediated adverse events (e.g. diarrhoea, rash/acne) were generally managed using dose reduction and delays. In conclusion, afatinib is a valuable new option for use in treatment-naïve or EGFR TKI-naïve patients with advanced lung adenocarcinoma and activating EGFR mutations.

Molecularly targeted therapies in non-small-cell lung cancer annual update 2014

There have been significant advances in the understanding of the biology and treatment of non-small-cell lung cancer (NSCLC) during the past few years. A number of molecularly targeted agents are in the clinic or in development for patients with advanced NSCLC. We are beginning to understand the mechanisms of acquired resistance after exposure to tyrosine kinase inhibitors in patients with oncogene addicted NSCLC. The advent of next-generation sequencing has enabled to study comprehensively genomic alterations in lung cancer. Finally, early results from immune checkpoint inhibitors are very encouraging. This review summarizes recent advances in the area of cancer genomics, targeted therapies, and immunotherapy.

Novel agents in development for advanced non-small cell lung cancer

The identification of EGFR mutations and ALK rearrangements in nonsmall cell lung cancer (NSCLC) has led to the rapid development of targeted therapies and significant changes in the treatment paradigm. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and crizotinib are now standard therapies for patients with the appropriate molecular alteration. Current investigations are determining the mechanisms of resistance to targeted therapies and developing novel agents to combat resistance. For patients with KRAS mutant NSCLC, a phase III trial of the MEK inhibitor, selumetinib, has been initiated. For patients without a defined mutation or a mutation without a known targeted therapy, immunotherapy, ganetespib, nintedanib and MET inhibitors in combination with EGFR TKIs are in development. Preliminary results of phase III trials raise doubts about the future development of dacomitinib as a second-line agent.

A comprehensive review of the preclinical efficacy profile of the ErbB family blocker afatinib in cancer

Afatinib (also known as BIBW 2992) has recently been approved in several countries for the treatment of a distinct type of epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer. This manuscript comprehensively reviews the preclinical data on afatinib, an irreversible inhibitor of the tyrosine kinase activity of members of the epidermal growth factor receptor family (ErbB) including EGFR, HER2 and ErbB4. Afatinib covalently binds to cysteine 797 of the EGFR and the corresponding cysteines 805 and 803 in HER2 and ErbB4, respectively. Such covalent binding irreversibly inhibits the tyrosine kinase activity of these receptors, resulting in reduced auto- and transphosphorylation within the ErbB dimers and inhibition of important steps in the signal transduction of all ErbB receptor family members. Afatinib inhibits cellular growth and induces apoptosis in a wide range of cells representative for non-small cell lung cancer, breast cancer, pancreatic cancer, colorectal cancer, head and neck squamous cell cancer and several other cancer types exhibiting abnormalities of the ErbB network. This translates into tumour shrinkage in a variety of in vivo rodent models of such cancers. Afatinib retains inhibitory effects on signal transduction and in vitro and in vivo cancer cell growth in tumours resistant to reversible EGFR inhibitors, such as those exhibiting the T790M mutations. Several combination treatments have been explored to prevent and/or overcome development of resistance to afatinib, the most promising being those with EGFR- or HER2-targeted antibodies, other tyrosine kinase inhibitors or inhibitors of downstream signalling molecules.

Acquired resistance of EGFR-mutant lung adenocarcinomas to afatinib plus cetuximab is associated with activation of mTORC1

Patients with EGFR-mutant lung adenocarcinomas (LUADs) who initially respond to first-generation tyrosine kinase inhibitors (TKIs) develop resistance to these drugs. A combination of the irreversible TKI afatinib and the EGFR antibody cetuximab can be used to overcome resistance to first-generation TKIs; however, resistance to this drug combination eventually emerges. We identified activation of the mTORC1 signaling pathway as a mechanism of resistance to dual inhibition of EGFR in mouse models. The addition of rapamycin reversed resistance in vivo. Analysis of afatinib-plus-cetuximab-resistant biopsy specimens revealed the presence of genomic alterations in genes that modulate mTORC1 signaling, including NF2 and TSC1. These findings pinpoint enhanced mTORC1 activation as a mechanism of resistance to afatinib plus cetuximab and identify genomic mechanisms that lead to activation of this pathway, revealing a potential therapeutic strategy for treating patients with resistance to these drugs.

Afatinib: first global approval

Afatinib, an irreversible inhibitor of the ErbB family of tyrosine kinases, is under development with Boehringer Ingelheim for the once-daily, oral treatment of cancer. Afatinib downregulates ErbB signalling by covalently binding to epidermal growth factor receptor (EGFR), human epidermal growth factor receptor (HER) 2 and HER4, irreversibly inhibiting tyrosine kinase autophosphorylation. It also inhibits transphosphorylation of HER3. Oral afatinib (Gilotrif™) has been approved in the US for the first-line treatment of patients with metastatic non-small-cell lung cancer (NSCLC) who have tumours with EGFR exon 19 deletions or exon 21 (L858R) substitution mutations as detected by a US FDA-approved test. Afatinib has also been approved in Taiwan for the first-line treatment of patients with EGFR mutation-positive NSCLC. In addition, the European Medicines Agency's Committee for Medicinal Products for Human Use has recommended the approval of afatinib (Giotrif®) for the treatment of patients with locally advanced or metastatic NSCLC with activating EGFR mutations who are EGFR tyrosine kinase inhibitor naïve. Afatinib is also under regulatory review in Canada, Japan and other Asian countries. This article summarizes the milestones in the development of afatinib, leading to this first approval in patients with metastatic NSCLC.

New treatment options for lung adenocarcinoma--in view of molecular background

Lung cancer is the leading cause of cancer related mortality all over the world, and a number of developments have indicated future clinical benefit recently. The development of molecular pathology methods has become increasingly important in the prediction of chemotherapy sensitivity and mutation analysis to identify driver mutations as important targets of new therapeutic agents. The most significant changes in the treatment of NSCLC revealed in new pathologic classification and in the introduction of molecularly targeted therapies, which include monoclonal antibodies and small molecule tyrosine kinase inhibitors. The side effects of these agents are generally better tolerated than those of conventional chemotherapy and show higher efficacy. The most important factor follows: histology subtypes, gene mutation status, patients' selection, drug toxicities and occurence of drug resistance. In the advanced disease, the hope of cure is less than 3%, but improvements in survival have been clearly achieved. Some years ago the median lung cancer survival rate was 10-12 months, now in case of available specific molecular targets, a significant increase in median survival rates to 24-36 months has been achieved. These agents give an opportunity to provide a new standard of care. Therefore testing EGFR mutations and ALK rearrangements in patients with advanced lung adenocarcinoma should be incorporated into routine clinical practice. This review focuses on the rationale for targeted agents and new treatment possibilities in case of advanced lung adenocarcinoma.

Emerging paradigms in the development of resistance to tyrosine kinase inhibitors in lung cancer

The success of tyrosine kinase inhibitors (TKIs) in select patients with non-small-cell lung cancer (NSCLC) has transformed management of the disease, placing new emphasis on understanding the molecular characteristics of tumor specimens. It is now recognized that genetic alterations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) define two unique subtypes of NSCLC that are highly responsive to genotype-directed TKIs. Despite this initial sensitivity, however, the long-term effectiveness of such therapies is universally limited by the development of resistance. Identifying the mechanisms underlying this resistance is an area of intense, ongoing investigation. In this review, we provide an overview of recent experience in the field, focusing on results from preclinical resistance models and studies of patient-derived, TKI-resistant tumor specimens. Although diverse TKI resistance mechanisms have been identified within EGFR-mutant and ALK-positive patients, we highlight common principles of resistance shared between these groups. These include the development of secondary mutations in the kinase target, gene amplification of the primary oncogene, and upregulation of bypass signaling tracts. In EGFR-mutant and ALK-positive patients alike, acquired resistance may also be a dynamic and multifactorial process that may necessitate the use of treatment combinations. We believe that insights into the mechanisms of TKI resistance in patients with EGFR mutations or ALK rearrangements may inform the development of novel treatment strategies in NSCLC, which may also be generalizable to other kinase-driven malignancies.

Combining erlotinib and cetuximab is associated with activity in patients with non-small cell lung cancer (including squamous cell carcinomas) and wild-type EGFR or resistant mutations

Preclinical data suggest that combined EGF receptor (EGFR) targeting with an EGFR tyrosine kinase inhibitor and an anti-EGFR monoclonal antibody may be superior over single-agent targeting. Therefore, as part of a phase I study, we analyzed the outcome of 20 patients with non-small cell lung cancer treated with the combination of erlotinib and cetuximab. EGFR mutation status was ascertained in a Clinical Laboratory Improvement Amendment-approved laboratory. There were 10 men; median number of prior therapies was five. Overall, two of 20 patients (10%) achieved partial response (PR), one of whom had a TKI-resistant EGFR insertion in exon 20, time to treatment failure (TTF) = 24+ months, and the other patient had squamous cell histology (EGFR wild-type), TTF = 7.4 months. In addition, three of 20 patients (15%) achieved stable disease (SD) ≥6 six months (one of whom had wild-type EGFR and squamous cell histology, and two patients had an EGFR TKI-sensitive mutation, one of whom had failed prior erlotinib therapy). Combination therapy with ertotinib plus cetuximab was well tolerated. The most common toxicities were rash, diarrhea, and hypomagnesemia. The recommended phase II dose was erlotinib 150 mg oral daily and cetuximab 250 mg/m(2) i.v. weekly. In summary, erlotinib and cetuximab treatment was associated with SD ≥ six months/PR in five of 20 patients with non-small cell lung cancer (25%), including individuals with squamous histology, TKI-resistant EGFR mutations, and wild-type EGFR, and those who had progressed on prior erlotinib after an initial response. This combination warrants further study in select populations of non-small cell lung cancer.

Second-Line Therapy for Advanced NSCLC

Most patients with lung cancer have non-small cell lung cancer (NSCLC) subtype and have advanced disease at the time of diagnosis. Improvements in both first-line and subsequent therapies are allowing longer survival and enhanced quality of life for these patients. The median overall survival observed in many second-line trials is approximately 9 months, and many patients receive further therapy after second-line therapy. The cytotoxic agents pemetrexed and docetaxel and the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib are standard second-line therapies. For patients with EGFR mutation, a TKI is the favored second-line therapy if not already used in first-line therapy. For patients without the EGFR mutation, TKIs are an option, but many oncologists favor cytotoxic therapy. The inhibitor of the EML4/ALK fusion protein, crizotinib, has recently become a standard second-line treatment for patients with the gene rearrangement and has promise for patients with the ROS1 rearrangement.

Identification of driver mutations in lung cancer: first step in personalized cancer

Non-small cell lung cancer (NSCLC) has recently been associated with interesting molecular characteristics that have important implications in carcinogenesis and response to targeted therapies. Targeted therapies, if given to a patient subpopulation enriched by the presence of relevant molecular targets, can often abrogate cell signaling that perpetuates cancer progression. For instance, several molecular alterations have been defined as "driver mutations," such as mutations in EGFR and EML4-ALK fusion gene. Other key signaling pathways have also been identified as novel targets for lung cancer treatment. These first steps towards personalized medicine represent a shift in the management of NSCLC. Indeed, NSCLC should no longer be viewed as one common generic tumor but rather as a collection of more rare diseases with different biological behaviors and different sensitivities to targeted treatments. We are now clearly entering an era of personalized medicine for NSCLC cancers, and the development of molecular profiling technologies to assess DNA provides the potential to tailored medical care.