Efficacy and Safety Results of the Afatinib Expanded Access Program
Abstract
Introduction
Afatinib is an oral, irreversible ErbB family blocker approved for first-line treatment of metastatic epidermal growth factor receptor (EGFR) mutation–positive non–small cell lung cancer (NSCLC). The expanded access program (EAP) allowed early access to afatinib and provided additional data on its safety, tolerability, and efficacy.
Methods
The afatinib EAP was an open-label, multicenter, single-arm program in the United States that treated and followed patients with locally advanced or metastatic NSCLC harboring EGFR mutations. Afatinib 40 mg was administered orally once daily until discontinuation due to disease progression, adverse events (AEs), or transition to commercially available drug.
Results
Three hundred twenty-two patients received ≥1 dose of afatinib. Most patients had received prior therapies. Drug-related AEs occurred in 89.4% of patients, including 7.8% with serious AEs. The most common afatinib-related AEs (all grades) were diarrhea (77.0%) and rash (36.0%). Dose reductions occurred in 31.1% of patients. Discontinuation rates due to diarrhea (1.6%) or rash/acne (0.3%) were low. Efficacy data were collected and analyzed when available, with 17.1% and 69.9% of patients achieving objective response and disease control, respectively, in this highly pretreated population.
Conclusions
No additional or unexpected safety concerns were revealed, and afatinib demonstrated antitumor activity in a heavily pretreated NSCLC patient population in a routine clinical setting.
Trial Registration
ClinicalTrials.gov Identifier: NCT01649284.
Funding
Boehringer Ingelheim Pharmaceuticals, Inc.
Keywords
Afatinib EGFR Expanded access program Non–small cell lung cancer SafetyIntroduction
Afatinib (GILOTRIF®, Boehringer Ingelheim; Ingelheim, Germany) is an oral, irreversible ErbB family blocker approved by the US Food and Drug Administration (FDA) for first-line treatment of metastatic non–small cell lung cancer (NSCLC) in patients whose tumors harbor epidermal growth factor receptor (EGFR) mutations, specifically exon 19 deletions (Del19) or exon 21 (L858R) substitutions, as identified by an FDA-approved test [1]. Afatinib is also approved for the treatment of patients with metastatic, squamous NSCLC progressing after platinum-based chemotherapy [1]. It has been evaluated in several NSCLC clinical trials, including tyrosine kinase inhibitor (TKI)–naïve and TKI-exposed patients [2, 3, 4]. Results from two global phase 3 trials, LUX-Lung 3 and LUX-Lung 6, demonstrated significant progression-free survival (PFS) benefit with afatinib versus cisplatin/pemetrexed and cisplatin/gemcitabine, respectively, as first-line therapy among patients with common EGFR mutations (Del19/L858R) [5, 6]. In both studies, a significant overall survival (OS) benefit was also observed with afatinib in patients with Del19 mutations [7].
Expanded access, or “compassionate use,” makes investigational drugs available to patients in the United States who are ineligible for ongoing clinical trials [8]. This expanded access program (EAP) was developed to provide afatinib access before FDA approval for patients with locally advanced or metastatic NSCLC harboring EGFR mutations, regardless of the line of therapy (not limited to Del19 or L858R mutations in the first-line setting, as currently indicated). The aim of this study was to collect additional information on afatinib safety, tolerability, and efficacy in a real-world clinical setting.
Methods
Patients/Program Design
The afatinib EAP was an open-label, multicenter, single-arm program conducted at 66 US sites. Adult patients with locally advanced or metastatic NSCLC harboring EGFR mutations (identified per the institution’s testing methodology), adequate organ function, and an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0–2 were eligible regardless of line of therapy. Patients with symptomatic brain metastases were excluded from participation, but patients with previously treated asymptomatic brain metastases were eligible, provided they had stable disease for ≥4 weeks on stable doses of medication.
Patients were instructed to take a single oral dose of afatinib 40 mg with a glass of water at approximately the same time each day, with no food for ≥3 h before and ≥1 h after taking afatinib. Dose escalation was prohibited. Dose reductions in 10-mg steps were allowed based on tolerability. Adverse events (AEs) were categorized and graded using the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0. For patients with any grade ≥3 treatment-related AEs, prolonged grade 2 diarrhea (≥48 h), grade ≥2 worsening renal function, or acute onset and/or unexplained worsening of pulmonary symptoms, afatinib treatment was withheld while supportive care was administered or clinical assessment was completed. After the AE fully resolved, returned to baseline, or improved to grade 1, afatinib was reinstituted at a dose reduced by 10 mg; the dose could not be increased. For unrelated AEs, the treating physician could pause medication for ≤14 days without dose reduction. Patients were discontinued from the EAP if afatinib was paused >6 weeks.
Patients were followed monthly until discontinuation due to disease progression, unacceptable AEs, or transition to commercially available drug. The EAP was stopped when afatinib became commercially available. Palliative radiation therapy was permitted for symptom control.
The protocol received institutional review board approval, and the study was conducted in accordance with the principles of the Declaration of Helsinki of 1964, as revised in 2013 and the International Conference on Harmonisation guidelines for Good Clinical Practice. All patients provided written informed consent.
Assessments
The primary objective was to provide afatinib access to patients who might benefit from it. There were no primary or secondary efficacy objectives, but disease assessments were performed per local standard of care. Safety was assessed descriptively.
Statistical Analysis
Exploratory, descriptive analyses of demographic, safety, and efficacy data were planned based on the treated set (all patients who were dispensed medication and were documented to have taken ≥1 afatinib dose), with two subgroups divided by previous TKI exposure.
Results
Patients
Disposition of patients (enrolled set).a EAP expanded access program, AE adverse event. a Enrolled set included all patients who signed the informed consent. b Transition to commercially available drug
Demographic Data (Treated Set)
| Characteristic | Afatinib 40 mg, N = 322 |
|---|---|
| Gender, n (%) | |
| Female | 221 (68.6) |
| Male | 101 (31.4) |
| Race, n (%)a | |
| White | 237 (73.6) |
| Asian | 56 (17.4) |
| Black/African American | 24 (7.5) |
| Native Hawaiian/Pacific Islander | 2 (0.6) |
| American Indian/Alaska Native | 2 (0.6) |
| Age, mean (SD), years | 64.6 (12.1) |
| Min; max | 35; 94 |
| Smoking status, n (%) | |
| Never smoked | 201 (62.4) |
| Ex-smoker | 113 (35.1) |
| Currently smokes | 8 (2.5) |
| Baseline ECOG score, n (%) | |
| 0 | 112 (34.8) |
| 1 | 168 (52.2) |
| 2 | 42 (13.0) |
| TKI status, n (%) | |
| Exposedb | 281 (87.3) |
| Naïve | 41 (12.7) |
| First-line afatinib | 23 (7.1) |
| Common EGFR mutation, n (%) | 267 (82.9) |
| Uncommon EGFR mutation, n (%)c | 55 (17.1) |
| T790M | 25 (7.8) |
| Exon 20 insertions | 22 (6.8) |
| G719S, G719A, G719C | 20 (6.2) |
| L861Q | 13 (4.0) |
| S768I | 4 (1.2) |
| Other—not specified | 13 (4.0) |
| Time since first diagnosis, mean (SD), months | 32.8 (28.0) |
| Min; max | 1; 152 |
| Histologic classification, n (%) | |
| Predominantly adenocarcinoma | 303 (94.1) |
| NOS | 8 (2.5) |
| Predominantly squamous cell carcinoma | 7 (2.2) |
| Large cell/undifferentiated carcinoma | 4 (1.2) |
| Clinical stage at initial diagnosis, n (%)d | |
| 0–IIB | 54 (16.8) |
| IIIA | 24 (7.5) |
| IIIB | 23 (7.1) |
| IV | 218 (67.7) |
Exposure
Median treatment duration was 86 days (maximum, 393 days). Nearly half of the patients (48.1%) received afatinib for ≥90 days. Dose reductions occurred in 100 (31.1%) patients, with 98 patients reduced from 40 to 30 mg (including 30 patients subsequently reduced to 20 mg) and two patients reduced from 40 to 20 mg.
Safety
AE Overall Summary (Treated Set)
| Number of patients, n (%) | Afatinib 40 mg, N = 322 |
|---|---|
| Any AE | 310 (96.3) |
| Drug-related AEsa | 288 (89.4) |
| AEs reported in >10% of treated patients (all grades; grade 3/4)b | |
| Diarrhea | 248 (77.0); 32 (9.9) |
| Rash | 116 (36.0); 6 (1.9) |
| Mucosal inflammation | 54 (16.8); 4 (1.2) |
| Stomatitis | 43 (13.4); 4 (1.2) |
| Nausea | 41 (12.7); 1 (0.3) |
| Dry skin | 40 (12.4); 2 (0.6) |
| Fatigue | 36 (11.2); 4 (1.2) |
| Paronychia | 34 (10.6); 0 |
| AEs leading to discontinuation | 39 (12.1) |
| Drug-related AEs leading to discontinuation | 17 (5.3) |
| AEs leading to dose reduction | 69 (21.4) |
| Serious AEsc | 109 (33.9)d |
| Required hospitalization | 89 (27.6) |
| Resulted in deathe | 48 (14.9) |
| Prolonged hospitalization | 15 (4.7) |
| Life threatening | 6 (1.9) |
| Persistent/significant disability | 4 (1.2) |
| Other | 4 (1.2) |
The most common drug-related AEs were diarrhea (77.0%) and rash (36.0%); the majority were grade 1 or 2. Afatinib-related grade 3 AEs occurred in 18.0% of patients, including diarrhea (9.9%); rash (1.9%); dehydration (1.6%); stomatitis, mucosal inflammation, and fatigue (each 1.2%); and acute renal failure (0.9%). Grade 4 afatinib-related AEs occurred in 4 (1.2%) patients (peripheral edema, multi-organ failure, dehydration, and acute renal failure; n = 1 each), but only one required discontinuation (peripheral edema).
The majority of afatinib-related serious AEs were grade 3, with diarrhea (n = 9), dehydration (n = 6), and acute renal failure (n = 3) the most common. Disease progression was responsible for most fatal events; no fatal event was considered related to afatinib.
Supportive care measures were implemented for 66.8% of patients with diarrhea and 33.9% with rash. Dose reductions occurred in 31.1% of patients: 16.8% due to diarrhea, and 3.7% due to rash. With dose reduction and treatment, few patients discontinued because of diarrhea (1.6%) or rash (0.3%).
Efficacy
Efficacy End Points (Treated Set)
| Overall, N = 322 | TKI-naïve,a n = 41 | TKI-exposed, n = 281 | |
|---|---|---|---|
| Response,b n (%) [95% CI] | |||
| Disease controlc | 225 (69.9) [64.5–74.8] | 34 (82.9) [67.9–92.8] | 191 (68.0) [62.2–73.4] |
| Objective responsed | 55 (17.1) [13.1–21.6] | 14 (34.1) [20.1–50.6] | 41 (14.6) [10.7–19.3] |
| Stable disease | 170 (52.8) [47.2–58.4] | 20 (48.8) [32.9–64.9] | 150 (53.4) [47.4–59.3] |
| Median duration of objective response,d months [95% CI] | 4.1 [3.4–5.3] | 3.4 [2.1–NE] | 4.2 [3.0–5.8] |
| Median duration of disease control,c months [95% CI] | 4.7 [4.4–5.2] | 5.9 [3.5–NE] | 4.6 [4.2–5.0] |
| Median PFS, months [95% CI] | 3.6 [3.1–4.2] | 5.8 [3.4–8.1] | 3.6 [2.9–3.9] |
Discussion
This EAP provided early access to afatinib and collected additional prospective safety and efficacy information. Despite most patients being heavily pretreated, the safety profile was consistent with earlier trials of afatinib monotherapy, with no new safety concerns [2, 5, 6]. The most common AEs were gastrointestinal and dermatologic, which is similar to those reported for other EGFR-targeted therapies. Most cases of diarrhea and rash/acne were adequately managed by pausing treatment, dose reduction, and supportive treatment and infrequently required discontinuation. These findings suggest that, with proper dose optimization and diarrhea and rash/acne management, patients can remain on afatinib treatment.
Although this EAP was not designed with specific efficacy aims, afatinib demonstrated antitumor activity, with disease control achieved in 69.9% of patients and objective tumor response in 17.1%. This response rate is slightly higher compared to the LUX-Lung 1 trial of afatinib after failure of erlotinib, gefitinib, or both [2]. PFS durations were shorter compared to LUX-Lung 3 (11.1 months) and LUX-Lung 6 (11.0 months) [5, 6]; however, only 7.1% of patients in this EAP received afatinib as first-line treatment, and many patients were not fully documented until disease progression. Patients also had an extensively longer time since first diagnosis in this EAP.
Findings of this EAP must be tempered against several limitations. Subgroup analyses must be interpreted with caution due to small sample size and widely different durations of drug exposure. EGFR mutation testing was not standardized across sites, which may have resulted in varying sensitivity levels for identification of mutations between sites. Lastly, although the majority of patients were alive at the end of the program, the EAP was not designed to follow patients through death, and OS data are immature and not reliably interpretable.
Conclusion
The results of the afatinib EAP confirm that, in a broad patient population, afatinib is not associated with unexpected safety signals and has safety and antitumor activity profiles similar to those observed in earlier clinical trials.
Notes
Acknowledgements
We would like to acknowledge the contributions of all participants of the afatinib EAP, especially the patients and their treating physicians. This manuscript was previously presented as an abstract/poster at Chicago Multidisciplinary Symposium in Thoracic Oncology; October 30–November 1, 2014; Chicago, IL, USA. Alexander I. Spira reports grant support from Boehringer Ingelheim to conduct the present study. Journal article processing charges were funded by the study sponsor, Boehringer Ingelheim Pharmaceuticals, Inc. (BIPI). All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship for this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval to the version to be published. The authors received no direct compensation related to the development of the manuscript. All authors had full access to all of the data in this study and take complete responsibility for the integrity of the data and accuracy of the data analysis. Writing, editorial support, and formatting assistance were provided by Lauren Fink, PhD, of MedErgy, which was contracted and funded by BIPI. BIPI was given the opportunity to review the manuscript for medical and scientific accuracy as well as intellectual property considerations.
Disclosures
Edward S. Kim reports consulting for AstraZeneca, Boehringer Ingelheim, Celgene, and Eli Lilly. Balazs Halmos reports consulting fees from AstraZeneca, Boehringer Ingelheim, Celgene, and Genentech. Alexander I. Spira reports grant support and fees from Novartis and Roche and grant support from Boehringer Ingelheim. Agnieszka Cseh, John McKay, and Gudrun Wallenstein are employees of Boehringer Ingelheim. Kathryn F. Mileham has served on an advisory board for Boehringer Ingelheim, has consulted with Covidien, and reports research funding from Celgene. Ingrid F. Kohut, Taral Patel, and Regan D. Rostorfer have nothing to disclose.
Compliance with Ethics Guidelines
The protocol received institutional review board approval, and the study was conducted in accordance with the principles of the Declaration of Helsinki of 1964, as revised in 2013 and the International Conference on Harmonisation guidelines for Good Clinical Practice. All patients provided written informed consent.
Data Availability
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Open Access
This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
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