Gilotrif

1 INDICATIONS AND USAGE 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 Limitations of Use : Safety and efficacy of GILOTRIF were not established in patients whose tumors have resistant EGFR mutations Treatment of patients with metastatic, squamous NSCLC progressing after platinum-based chemotherapy

1.1EGFR 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 . Limitations of Use : The safety and efficacy of GILOTRIF have not been established in patients whose tumors have resistant EGFR mutations .

1.2Previously Treated, Metastatic Squamous

NSCLC GILOTRIF is indicated for the treatment of patients with metastatic squamous NSCLC progressing after platinum-based chemotherapy .

Recommended dosage : 40 mg orally once daily Renal impairment : 30 mg orally once daily in patients with severe renal impairment ( 2.4 , 8.6 , 12.3 ) Instruct patients to take GILOTRIF at least 1 hour before or 2 hours after a meal

2.1Patient Selection for Non-Resistant

EGFR Mutation-Positive Metastatic NSCLC Select patients for first-line treatment of metastatic NSCLC with GILOTRIF based on the presence of non-resistant EGFR mutations in tumor specimens . Information on FDA-approved tests for the detection of EGFR mutations in NSCLC is available at: http://www.fda.gov/CompanionDiagnostics .

2.2Recommended Dosage The

recommended dosage of GILOTRIF is 40 mg orally once daily until disease progression or no longer tolerated by the patient. Take GILOTRIF at least 1 hour before or 2 hours after a meal. Do not take a missed dose within 12 hours of the next dose.

2.3Dosage Modifications for Adverse Reactions Withhold

GILOTRIF for: Grade* 3 or higher adverse reactions Diarrhea of Grade 2 persisting for 2 or more consecutive days while taking anti-diarrheal medication Cutaneous reactions of Grade 2 that are prolonged (lasting more than 7 days) or intolerable * National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), v

3.0Resume

treatment when the adverse reaction fully resolves, returns to baseline, or improves to Grade 1. Reinstitute GILOTRIF at a reduced dose, i.e., 10 mg per day less than the dose at which the adverse reaction occurred. Permanently discontinue GILOTRIF for: Life-threatening bullous, blistering, or exfoliating skin lesions Confirmed interstitial lung disease (ILD) Severe drug-induced hepatic impairment Gastrointestinal perforation Persistent ulcerative keratitis Symptomatic left ventricular dysfunction Severe or intolerable adverse reaction occurring at a dose of 20 mg per day

2.4Dosage Modification for Pre-Existing Severe Renal

Impairment The recommended dosage of GILOTRIF in patients with pre-existing severe renal impairment (estimated glomerular filtration rate [eGFR*] 15 to 29 mL/min /1.73 m 2 ) is 30 mg orally once daily . * Use the Modification of Diet in Renal Disease [MDRD] formula to estimate eGFR.

2.5Dosage Modifications for Drug Interactions P-glycoprotein

Inhibitors Reduce GILOTRIF daily dose by 10 mg if not tolerated for patients who require therapy with a P-glycoprotein (P-gp) inhibitor. Resume the previous dose after discontinuation of the P-gp inhibitor as tolerated . P-glycoprotein Inducers Increase GILOTRIF daily dose by 10 mg as tolerated for patients who require chronic therapy with a P-gp inducer. Resume the previous dose 2 to 3 days after discontinuation of the P-gp inducer .

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.

5.1Diarrhea 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 . 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 . 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.

5.2Bullous 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% . 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 . 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 .

5.3Interstitial 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 .

5.4Hepatic 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 . In patients who develop severe hepatic impairment while taking GILOTRIF, discontinue treatment.

5.5Gastrointestinal 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 .

5.6Keratitis 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 . 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 . Contact lens use is also a risk factor for keratitis and ulceration.

5.7Embryo-Fetal Toxicity Based on

findings from animal studies and its mechanism of action, GILOTRIF can cause fetal harm when administered to a pregnant woman. 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. Advise pregnant women and females of reproductive potential of the potential risk to a fetus . Advise females of reproductive potential to use effective contraception during treatment and for at least 2 weeks after the last dose of GILOTRIF .

None. None.

8.1Pregnancy Risk Summary Based on

findings from animal studies and its mechanism of action , 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 . 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).

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

6.1Clinical 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

3.0Increased

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. The most frequent serious adverse reactions in patients treated with GILOTRIF were pneumonia (6.6%), diarrhea (4.6%), and dehydration and dyspnea (3.1% each). Fatal adverse reactions in GILOTRIF-treated patients included ILD (0.5%), pneumonia (0.3%), respiratory failure (0.3%), acute renal failure (0.3%), and general physical health deterioration (0.3%). The most frequent adverse reactions that led to discontinuation in GILOTRIF-treated patients were diarrhea (4.1%) and rash/acne (2.6%).

Dose reductions due to adverse reactions were required in 27% of GILOTRIF-treated patients and discontinuation of GILOTRIF for adverse reactions was required for 20%. The most frequent adverse reactions that led to dose reduction in the patients treated with GILOTRIF were diarrhea (15%), rash/acne (5.9%), and stomatitis (3.1%). Tables 3 and 4 summarize common adverse reactions and laboratory abnormalities in LUX-Lung 8. Table 3 Adverse Reactions Reported in ≥10% of GILOTRIF-Treated Patients in LUX-Lung 8* Adverse Reaction GILOTRIF n=392 Erlotinib n=395 All Grades (%) Grade 3-4 (%) All Grades (%) Grade 3-4 (%) *NCI CTCAE v 3.0 1 Includes stomatitis, aphthous stomatitis, mucosal inflammation, mouth ulceration, oral mucosa erosion, mucosal erosion, mucosal ulceration 2 Includes acne, dermatitis, acneiform dermatitis, eczema, erythema, exfoliative rash, folliculitis, rash, rash generalized, rash macular, rash maculo-papular, rash pruritic, rash pustular, skin exfoliation, skin fissures, skin lesion, skin reaction, skin toxicity, skin ulcer 3 Includes paronychia, nail infection, nail bed infection Gastrointestinal disorders Diarrhea 75 11 41 3 Stomatitis 1 30 4 11 1 Nausea 21 2 16 1 Vomiting 13 1 10 1 Skin and subcutaneous tissue disorders Rash/acneiform dermatitis 2 70 7 70 11 Pruritus 10 0 13 0 Metabolism and nutrition disorders Decreased appetite 25 3 26 2 Infections Paronychia 3 11 1 5 0 Table 4 Laboratory Abnormalities Occurring in ≥10% of GILOTRIF Arm and at ≥2% Higher Incidence than in Erlotinib Arm in LUX-Lung 8* Laboratory Abnormality GILOTRIF n=392 Erlotinib n=395 All Grades (%) Grades 3-4 (%) All Grades (%) Grades 3-4 (%) *NCI CTCAE v

3.0Increased

alkaline phosphate 34 2 31 0 Decreased white blood cell count 12 1 8 1 Decreased potassium 11 1 8 1 Other clinically important laboratory abnormalities observed in patients treated with GILOTRIF that are not listed in Table 4 are: increased alanine aminotransferase (10% Grade 1-4; 1% Grade 3-4), increased aspartate aminotransferase (7% Grade 1-4; 1% Grade 3-4), and increased bilirubin (3% Grade 1-4; 0 Grade 3-4). Less Common Adverse Reactions Other adverse reactions reported in patients treated with GILOTRIF in LUX-Lung 3 and LUX-Lung 8 include: Skin and subcutaneous disorders: nail disorders occurred in 9.2% and 2.8% of patients, respectively.

6.2Postmarketing Experience The

following adverse reactions have been identified during postapproval use of GILOTRIF. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Pancreatitis Toxic epidermal necrolysis/Stevens Johnson syndrome