Afatinib

GILOTRIF is a kinase inhibitor indicated for: First-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have non-resistant epidermal growth factor receptor (EGFR) mutations as detected by an FDA-approved test ( 1.1 ) Limitations of Use : Safety and efficacy of GILOTRIF were not established in patients whose tumors have resistant EGFR mutations ( 1.1 ) Treatment of patients with metastatic, squamous NSCLC progressing after platinum-based chemotherapy ( 1.2 ) 1.1 EGFR Mutation-Positive, Metastatic Non-Small Cell Lung Cancer GILOTRIF is indicated for the first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have non-resistant epidermal growth factor receptor (EGFR) mutations as detected by an FDA-approved test [see Dosage and Administration (2.1) , Clinical Pharmacology (12.1) , Clinical Studies (14.1) ]. Limitations of Use : The safety and efficacy of GILOTRIF have not been established in patients whose tumors have resistant EGFR mutations [see Clinical Studies (14.1) ].

1.2 Previously Treated, Metastatic Squamous NSCLC GILOTRIF is indicated for the treatment of patients with metastatic squamous NSCLC progressing after platinum-based chemotherapy .

GILOTRIF is available as: 40 mg tablets: light blue, film-coated, round, biconvex, bevel-edged tablets debossed with "T40" on one side and the Boehringer Ingelheim company symbol on the other side. 30 mg tablets: dark blue, film-coated, round, biconvex, bevel-edged tablets debossed with "T30" on one side and the Boehringer Ingelheim company symbol on the other side. 20 mg tablets: white to slightly yellowish, film-coated, round, biconvex, bevel-edged tablets debossed with "T20" on one side and the Boehringer Ingelheim company symbol on the other side. Tablets: 40 mg, 30 mg, and 20 mg ( 3 )

None. None. ( 4 )

Diarrhea : Diarrhea may result in dehydration and renal failure. Withhold GILOTRIF for severe and prolonged diarrhea not responsive to anti-diarrheal agents. ( 2.3 , 5.1 ) Bullous and exfoliative skin disorders : Severe bullous, blistering, and exfoliating lesions occurred in 0.2% of patients. Discontinue for life-threatening cutaneous reactions. Withhold GILOTRIF for severe and prolonged cutaneous reactions. ( 2.3 , 5.2 ) Interstitial lung disease (ILD) : Occurs in 1.6% of patients. Withhold GILOTRIF for acute onset or worsening of pulmonary symptoms. Discontinue GILOTRIF if ILD is diagnosed. ( 2.3 , 5.3 ) Hepatic toxicity : Fatal hepatic impairment occurs in 0.2% of patients. Monitor with periodic liver testing. Withhold or discontinue GILOTRIF for severe or worsening liver tests. ( 2.3 , 5.4 ) Gastrointestinal perforation : Occurs in 0.2% of patients. Permanently discontinue GILOTRIF in patients who develop gastrointestinal perforation. ( 2.3 , 5.5 ) Keratitis : Occurs in 0.7% of patients. Withhold GILOTRIF for keratitis evaluation. Withhold or discontinue GILOTRIF for confirmed ulcerative keratitis. ( 2.3 , 5.6 ) Embryo-fetal toxicity : Can cause fetal harm when administered to a pregnant woman. Advise pregnant women and females of reproductive potential of the potential risk to the fetus and to use effective contraception. ( 5.7 )

5.1 Diarrhea Diarrhea has resulted in dehydration with or without renal impairment across the clinical experience; some cases were fatal. Grade 3-4 diarrhea occurred in 697 (16%) of the 4257 patients who received GILOTRIF across 44 clinical trials. In LUX-Lung 3, diarrhea occurred in 96% of patients treated with GILOTRIF (n=229), of which 15% were Grade 3 in severity and occurred within the first 6 weeks . Renal impairment as a consequence of diarrhea occurred in 6% of patients treated with GILOTRIF, of which 1.3% were Grade 3. In LUX-Lung 8, diarrhea occurred in 75% of patients treated with GILOTRIF (n=392), of which 10% were Grade 3 in severity and 0.8% were Grade 4 in severity . Renal impairment as a consequence of diarrhea occurred in 7% of patients treated with GILOTRIF, of which 2% were Grade 3 [see Adverse Reactions (6.1) ]. For patients who develop prolonged Grade 2 diarrhea lasting more than 48 hours or greater than or equal to Grade 3 diarrhea, withhold GILOTRIF until diarrhea resolves to Grade 1 or less and resume GILOTRIF with appropriate dose reduction [see Dosage and Administration (2.3) ]. Provide patients with an anti-diarrheal agent (e.g., loperamide) for self-administration at the onset of diarrhea and instruct patients to continue anti-diarrheal therapy until loose bowel movements cease for 12 hours.

5.2 Bullous and Exfoliative Skin Disorders Grade 3 cutaneous reactions characterized by bullous, blistering, and exfoliating skin lesions, occurred in 0.2% of the 4257 patients who received GILOTRIF across clinical trials . In LUX-Lung 3, the overall incidence of cutaneous reactions consisting of rash, erythema, and acneiform rash was 90%, and the incidence of Grade 3 cutaneous reactions was 16%. In addition, the incidence of Grade 1-3 palmar-plantar erythrodysesthesia syndrome was 7%. In LUX-Lung 8, the overall incidence of cutaneous reactions consisting of rash, erythema, and acneiform rash was 70%, and the incidence of Grade 3 cutaneous reactions was 7%. In addition, the incidence of Grade 1-3 palmar-plantar erythrodysesthesia syndrome was 1.5% [see Adverse Reactions (6.1) ] . Discontinue GILOTRIF in patients who develop life-threatening bullous, blistering, or exfoliating skin lesions . For patients who develop prolonged Grade 2 cutaneous adverse reactions lasting more than 7 days, intolerable Grade 2 cutaneous reactions, or Grade 3 cutaneous reactions, withhold GILOTRIF until the adverse reaction resolves to Grade 1 or less and resume GILOTRIF with appropriate dose reduction [see Dosage and Administration (2.3) ] . Postmarketing cases consistent with toxic epidermal necrolysis (TEN) and Stevens Johnson syndrome (SJS) have been reported in patients receiving GILOTRIF. The cases of TEN and SJS bullous skin reactions result from a distinct and separate mechanism of toxicity than the bullous skin lesions secondary to the pharmacologic action of the drug on the epidermal growth factor receptor. Discontinue GILOTRIF if TEN or SJS is suspected [see Dosage and Administration (2.3) ].

5.3 Interstitial Lung Disease Interstitial lung disease or ILD-like adverse reactions (e.g., lung infiltration, pneumonitis, acute respiratory distress syndrome, or alveolitis allergic) occurred in 1.6% of the 4257 patients who received GILOTRIF across clinical trials; of these, 0.4% were fatal. The incidence of ILD appeared to be higher in Asian patients (2.3%; 38/1657) as compared to Whites (1.0%; 23/2241). In LUX-Lung 3, the incidence of Grade ≥3 ILD was 1.3% and resulted in death in 1% of GILOTRIF-treated patients. In LUX-Lung 8, the incidence of Grade ≥3 ILD was 0.9% and resulted in death in 0.8% of GILOTRIF-treated patients. Withhold GILOTRIF during evaluation of patients with suspected ILD and discontinue GILOTRIF in patients with confirmed ILD [see Dosage and Administration (2.3) ] .

5.4 Hepatic Toxicity In 4257 patients who received GILOTRIF across clinical trials, 9.7% had liver test abnormalities, of which 0.2% were fatal. In LUX-Lung 3, liver test abnormalities of any grade occurred in 17.5% of the patients treated with GILOTRIF, of which 3.5% had Grade 3-4 liver test abnormalities. In LUX-Lung 8, liver test abnormalities of any grade occurred in 6% of the patients treated with GILOTRIF, of which 0.2% had Grade 3-4 liver test abnormalities. Obtain periodic liver testing in patients during treatment with GILOTRIF. Withhold GILOTRIF in patients who develop worsening of liver function [see Dosage and Administration (2.3) ] . In patients who develop severe hepatic impairment while taking GILOTRIF, discontinue treatment.

5.5 Gastrointestinal Perforation Gastrointestinal perforation, including fatal cases, has occurred with GILOTRIF. Gastrointestinal perforation has been reported in 0.2% of patients treated with GILOTRIF among 3213 patients across 17 randomized controlled clinical trials. Patients receiving concomitant corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs) or anti-angiogenic agents, or patients with increasing age or who have an underlying history of gastrointestinal ulceration, underlying diverticular disease or bowel metastases may be at increased risk of perforation. Permanently discontinue GILOTRIF in patients who develop gastrointestinal perforation [see Dosage and Administration (2.3) ] .

5.6 Keratitis Keratitis, characterized as acute or worsening eye inflammation, lacrimation, light sensitivity, blurred vision, eye pain, and/or red eye occurred in 0.7% of patients treated with GILOTRIF among 4257 patients across clinical trials, of which 0.05% of patients experienced Grade 3 keratitis. Keratitis was reported in 2.2% patients in LUX-Lung 3, with Grade 3 in 0.4%. In LUX-Lung 8, keratitis was reported in 0.3% patients; there were no patients with ≥Grade 3 keratitis. Withhold GILOTRIF during evaluation of patients with suspected keratitis, and if diagnosis of ulcerative keratitis is confirmed, interrupt or discontinue GILOTRIF [see Dosage and Administration (2.3) ] . If keratitis is diagnosed, the benefits and risks of continuing treatment should be carefully considered. GILOTRIF should be used with caution in patients with a history of keratitis, ulcerative keratitis, or severe dry eye [see Adverse Reactions (6.1) ] . Contact lens use is also a risk factor for keratitis and ulceration.

5.7 Embryo-Fetal Toxicity Based on findings from animal studies and its mechanism of action, GILOTRIF can cause fetal harm when administered to a pregnant woman. […]

The following clinically significant adverse reactions are described elsewhere in the labeling: Diarrhea [see Warnings and Precautions (5.1) ] Bullous and Exfoliative Skin Disorders [see Warnings and Precautions (5.2) ] Interstitial Lung Disease [see Warnings and Precautions (5.3) ] Hepatic Toxicity [see Warnings and Precautions (5.4) ] Gastrointestinal Perforation [see Warnings and Precautions (5.5) ] Keratitis [see Warnings and Precautions (5.6) ] Most common adverse reactions (≥20%) were diarrhea, rash/acneiform dermatitis, stomatitis, paronychia, dry skin, decreased appetite, nausea, vomiting, pruritus ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Boehringer Ingelheim Pharmaceuticals, Inc. at (800) 542-6257 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The data in the Warnings and Precautions section reflect exposure to GILOTRIF for clinically significant adverse reactions in 4257 patients enrolled in LUX-Lung 3 (n=229) and LUX-Lung 8 (n=392), and 3636 patients with cancer enrolled in 42 studies of GILOTRIF administered alone or in combination with other anti-neoplastic drugs at GILOTRIF doses ranging from 10-70 mg daily or at doses 10-160 mg in other regimens. The mean exposure was 5.5 months. The population included patients with various cancers, the most common of which were NSCLC, breast, colorectal, brain, and head and neck. The data described below reflect exposure to GILOTRIF as a single agent in LUX-Lung 3, a randomized, active-controlled trial conducted in patients with EGFR mutation-positive, metastatic NSCLC, and in LUX-Lung 8, a randomized, active-controlled trial in patients with metastatic squamous NSCLC progressing after platinum-based chemotherapy. EGFR Mutation-Positive Metastatic NSCLC The safety of GILOTRIF was evaluated in 229 EGFR-tyrosine kinase inhibitor-naïve patients with EGFR mutation-positive, metastatic non-squamous NSCLC enrolled in a randomized (2:1), multicenter, open-label trial (LUX-Lung 3). Patients received either GILOTRIF 40 mg daily until documented disease progression or intolerance to the therapy or pemetrexed 500 mg/m² followed after 30 minutes by cisplatin 75 mg/m² every three weeks for a maximum of six treatment courses. The median exposure was 11 months for patients treated with GILOTRIF and 3.4 months for patients treated with pemetrexed/cisplatin. The overall trial population had a median age of 61 years; 61% of patients in the GILOTRIF arm and 60% of patients in the pemetrexed/cisplatin arm were younger than 65 years. A total of 64% of patients on GILOTRIF and 67% of pemetrexed/cisplatin patients were female. More than two-thirds of patients were from Asia (GILOTRIF 70%; pemetrexed/cisplatin 72%). Serious adverse reactions were reported in 29% of patients treated with GILOTRIF. The most frequent serious adverse reactions reported in patients treated with GILOTRIF were diarrhea (6.6%); vomiting (4.8%); and dyspnea, fatigue, and hypokalemia (1.7% each). Fatal adverse reactions in GILOTRIF-treated patients in LUX-Lung 3 included pulmonary toxicity/ILD-like adverse reactions (1.3%), sepsis (0.43%), and pneumonia (0.43%). Dose reductions due to adverse reactions were required in 57% of GILOTRIF-treated patients. The most frequent adverse reactions that led to dose reduction in the patients treated with GILOTRIF were diarrhea (20%), rash/acne (19%), paronychia (14%), and stomatitis (10%). Discontinuation of therapy in GILOTRIF-treated patients for adverse reactions was 14.0%. The most frequent adverse reactions that led to discontinuation in GILOTRIF-treated patients were diarrhea (1.3%), ILD (0.9%), and paronychia (0.9%). Clinical trials of GILOTRIF excluded patients with an abnormal left ventricular ejection fraction (LVEF), i.e., below the institutional lower limit of normal. In LUX-Lung 3, all patients were evaluated for LVEF at screening and every 9 weeks thereafter in the GILOTRIF-treated group and as needed in the pemetrexed/cisplatin group. More GILOTRIF-treated patients (2.2%; n=5) experienced ventricular dysfunction (defined as diastolic dysfunction, left ventricular dysfunction, or ventricular dilation; all <Grade 3) compared to chemotherapy-treated patients (0.9%; n=1). Tables 1 and 2 summarize common adverse reactions and laboratory abnormalities in LUX-Lung 3. Table 1 Adverse Reactions Reported in ≥10% of GILOTRIF-Treated Patients in LUX-Lung 3* Adverse Reaction GILOTRIF n=229 Pemetrexed/Cisplatin n=111 All Grades (%) Grade 3 † (%) All Grades (%) Grade 3 † (%) *NCI CTCAE v 3.0 † None of the adverse reactions in this table except stomatitis (one patient on GILOTRIF [0.4%]) were Grade 4 in severity. 1 Includes stomatitis, aphthous stomatitis, mucosal inflammation, mouth ulceration, oral mucosa erosion, mucosal erosion, mucosal ulceration 2 Includes acne, acne pustular, dermatitis, acneiform dermatitis, dermatosis, drug eruption, erythema, exfoliative rash, folliculitis, rash, rash erythematous, rash follicular, rash generalized, rash macular, rash maculo-papular, rash pruritic, rash pustular, skin disorder, skin erosion, skin exfoliation, skin fissures, skin lesion, skin reaction, skin toxicity, skin ulcer 3 Includes paronychia, nail infection, nail bed infection Gastrointestinal disorders Diarrhea 96 15 23 2 Stomatitis 1 71 9 15 1 Cheilitis 12 0 1 0 Skin and subcutaneous tissue disorders Rash/acneiform dermatitis 2 90 16 11 0 Pruritus 21 0 1 0 Dry skin 31 0 2 0 Infections Paronychia 3 58 11 0 0 Cystitis 13 1 5 0 Respiratory, thoracic and mediastinal disorders Epistaxis 17 0 2 1 Rhinorrhea 11 0 6 0 Investigations Weight decreased 17 1 14 1 General disorders and administration site conditions Pyrexia 12 0 6 0 Eye disorders Conjunctivitis 11 0 3 0 Other clinically important adverse reactions observed in patients treated with GILOTRIF but that occurred at a higher incidence in pemetrexed/cisplatin-treated patients and not listed elsewhere in section 6 include: decreased appetite (29% Grades 1-4, 4% Grade 3), nausea (25% Grades 1-4, 4% Grade 3), and vomiting (23% Grades 1-4, 4% Grade 3). Table 2 Laboratory Abnormalities Occurring in ≥10% of GILOTRIF Arm and at ≥2% Higher Incidence than in Chemotherapy Arm in LUX-Lung 3* Laboratory Abnormality GILOTRIF n=229 Pemetrexed/Cisplatin n=111 All Grades (%) Grades 3-4 (%) All Grades (%) Grades 3-4 (%) *NCI CTCAE v

3.0 Increased alanine aminotransferase (ALT) 54 2 27 1 Increased alkaline phosphate 51 3 46 1 Decreased creatinine clearance 49 2 47 1 Increased aspartate aminotransferase (AST) 46 3 22 1 Decreased lymphocytes 38 9 32 14 Decreased potassium 30 8 11 3 Increased bilirubin 16 1 8 0 Previously Treated, Metastatic Squamous NSCLC The safety of GILOTRIF was evaluated in 392 GILOTRIF-treated patients with metastatic squamous NSCLC enrolled in a randomized, multicenter, open-label trial (LUX-Lung 8). Patients were required to have received at least four cycles of platinum-based chemotherapy, ECOG Performance Status (PS) 0 or 1, and normal left ventricular ejection fraction (LVEF). Patients received GILOTRIF 40 mg once daily (n=392) or erlotinib 150 mg once daily (n=395). Treatment continued until documented disease progression or intolerance to the therapy. The median exposure was 2.1 months for patients treated with GILOTRIF, 15% were exposed for at least 6 months, and 5% were exposed for at least 12 months. Among the 392 GILOTRIF-treated patients, the median age was 65 years, 53% were 65 years of age or older, 84% were male, 72% were White, 25% were Asian, ECOG PS 0 (32%) or 1 (68%). Serious adverse reactions occurred in 44% of patients treated with GILOTRIF. […]

P-glycoprotein (P-gp) Inhibitors : Co-administration of P-gp inhibitors can increase afatinib exposure. Reduce GILOTRIF by 10 mg per day if not tolerated. ( 2.5 , 7 ) P-gp Inducers : Co-administration of chronic P-gp inducers orally can decrease afatinib exposure. Increase GILOTRIF by 10 mg per day as tolerated. ( 2.5 , 7 ) Effect of P-glycoprotein (P-gp) Inhibitors and Inducers Concomitant taking of P-gp inhibitors (including but not limited to ritonavir, cyclosporine A, ketoconazole, itraconazole, erythromycin, verapamil, quinidine, tacrolimus, nelfinavir, saquinavir, and amiodarone) with GILOTRIF can increase exposure to afatinib [see Clinical Pharmacology (12.3) ]. Reduce GILOTRIF daily dose as recommended [see Dosage and Administration (2.5) ]. Concomitant taking of P-gp inducers (including but not limited to rifampicin, carbamazepine, phenytoin, phenobarbital, and St. John's wort) with GILOTRIF can decrease exposure to afatinib [see Clinical Pharmacology (12.3) ]. Increase GILOTRIF daily dose as recommended [see Dosage and Administration (2.5) ].

Lactation : Advise women not to breastfeed ( 8.2 )

8.1 Pregnancy Risk Summary Based on findings from animal studies and its mechanism of action [see Clinical Pharmacology (12.1) ] , GILOTRIF can cause fetal harm when administered to a pregnant woman. There are no available data on the use of GILOTRIF in pregnant women. Administration of afatinib to pregnant rabbits during organogenesis at exposures approximately 0.2 times the exposure in humans at the recommended dose of 40 mg daily resulted in embryotoxicity and, in rabbits showing maternal toxicity, increased abortions at late gestational stages (see Data ) . Advise a pregnant woman of the potential risk to a fetus . The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data In an embryo-fetal development study in rabbits, administration of afatinib to pregnant animals at doses of 5 mg/kg (approximately 0.2 times the exposure by AUC at the recommended human dose of 40 mg daily) or greater during the period of organogenesis caused increased post-implantation loss, and in animals showing maternal toxicity, abortion at late gestational stages. In the same study, at the high dose level of 10 mg/kg (approximately 0.7 times the exposure by AUC at the recommended human dose of 40 mg daily), there were reduced fetal weights, and increases in the incidence of runts, as well as visceral and dermal variations. In an embryo-fetal development study in rats, there were skeletal alterations consisting of incomplete or delayed ossifications and reduced fetal weight at a dose of 16 mg/kg (approximately twice the exposure based on AUC at the recommended human dose of 40 mg daily).

8.2 Lactation Risk Summary There are no data on the presence of afatinib in human milk or its effects on the breastfed infant or on milk production. Afatinib was present in the milk of lactating rats (see Data ) . Because of the potential for serious adverse reactions in breastfed infants from GILOTRIF, advise women not to breastfeed during treatment with GILOTRIF and for 2 weeks after the final dose. Data Afatinib was present in the milk of lactating rats at concentrations 80 and 150 times higher than those found in plasma at 1 and 6 hours after administration.

8.3 Females and Males of Reproductive Potential Contraception Females GILOTRIF can cause fetal harm when administered to a pregnant woman. Advise females of reproductive potential to use effective contraception during treatment with GILOTRIF and for at least 2 weeks after the last dose of GILOTRIF [see Use in Specific Populations (8.1) , Clinical Pharmacology (12.3) ]. Infertility Based on results from an animal fertility study, GILOTRIF may reduce fertility in females and males of reproductive potential. It is not known if the effects on fertility are reversible [see Nonclinical Toxicology (13.1) ].

8.4 Pediatric Use Safety and effectiveness of GILOTRIF in pediatric patients have not been established. The safety and efficacy of afatinib were assessed, but not established, in a single-arm, open-label, multicenter trial [NCT02372006] which included 37 pediatric patients 2 to <17 years of age with recurrent/refractory solid tumors with known ErbB pathway deregulation who received 80% of the adult dose per body surface area. No new safety signals were observed in pediatric patients in this trial. In these 37 patients, the pharmacokinetic parameters were within range of values in adults.

8.5 Geriatric Use LUX-Lung 3 did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In LUX-Lung 8, 53% of the 398 patients randomized to receive afatinib were 65 years of age or older and 11% were 75 years or older. In an exploratory subgroup analysis of LUX-Lung 8, the hazard ratio for overall survival (OS) in patients less than 65 years old was 0.68 (95% CI: 0.55, 0.85) and in patients 65 years or older was 0.95 (95% CI: 0.76, 1.19). No overall differences in safety were observed between patients 65 years and older and younger patients.

8.6 Renal Impairment Patients with severe renal impairment have a higher exposure to afatinib than patients with normal renal function. Administer GILOTRIF at a starting dose of 30 mg once daily in patients with severe renal impairment (eGFR 15 to 29 mL/min /1.73 m 2 as determined by Modification of Diet in Renal Disease formula) [see Dosage and Administration (2.4) , Clinical Pharmacology (12.3) ] . Adjustments to the starting dose of GILOTRIF are not necessary in patients with mild or moderate renal impairment (eGFR 30 to 89 mL/min /1.73 m 2 ). GILOTRIF has not been studied in patients with eGFR <15 mL/min/1.73 m 2 or on dialysis.

8.7 Hepatic Impairment GILOTRIF has not been studied in patients with severe (Child Pugh C) hepatic impairment. Adjustments to the starting dose of GILOTRIF are not necessary in patients with mild (Child Pugh A) or moderate (Child Pugh B) hepatic impairment [see Clinical Pharmacology (12.3) ] . Closely monitor patients with severe hepatic impairment and adjust GILOTRIF dose if not tolerated.

Afatinib covalently binds to the kinase domains of EGFR (ErbB1), HER2 (ErbB2), and HER4 (ErbB4) and irreversibly inhibits tyrosine kinase autophosphorylation, resulting in downregulation of ErbB signaling. Certain mutations in EGFR, including non-resistant mutations in its kinase domain, can result in increased autophosphorylation of the receptor, leading to receptor activation, sometimes in the absence of ligand binding, and can support cell proliferation in NSCLC. Non-resistant mutations are defined as those occurring in exons constituting the kinase domain of EGFR that lead to increased receptor activation and where efficacy is predicted by 1) clinically meaningful tumor shrinkage with the recommended dose of afatinib and/or 2) inhibition of cellular proliferation or EGFR tyrosine kinase phosphorylation at concentrations of afatinib sustainable at the recommended dosage according to validated methods. The most commonly found of these mutations are exon 21 L858R substitutions and exon 19 deletions. Afatinib demonstrated inhibition of autophosphorylation and/or in vitro proliferation of cell lines expressing wild-type EGFR and in those expressing selected EGFR exon 19 deletion mutations, exon 21 L858R mutations, or other less common non-resistant mutations, at afatinib concentrations achieved in patients. In addition, afatinib inhibited in vitro proliferation of cell lines overexpressing HER2. Treatment with afatinib resulted in inhibition of tumor growth in nude mice implanted with tumors either overexpressing wild type EGFR or HER2 or in an EGFR L858R/T790M double mutant model.