Inclusion Criteria:

- Written informed consent in advance of any study-specific procedure

- Histologically (not cytologically) confirmed diagnosis of metastatic pancreatic
adenocarcinoma (stage IV according to UICC 2009 classification: each T, each N, M1)

- Availability of tumour samples

- Informed consent that tumour- and blood samples are centrally collected and will
serve for translational analyses according to the study protocol.

- Age >= 18 years

- ECOG 0-1

- Life expectancy at least 3 months

- No option for surgical resection or radiation in curative intent

- At least one measurable tumour lesion (CT-scan or MRI) according to RECIST Version
1.1

- Possibility of long-term follow-up

- Negative pregnancy test in fertile females

- Given legal capacity of the patient

- Adequate hepatic, renal and bone marrow function

Exclusion Criteria:

- Evidence of weight loss > 15% within one month

- Active brain metastases (stable for <28 days, symptomatic, or requiring concurrent
steroids) or leptomeningeal disease. Patients who have received prior whole brain
irradiation and whose brain metastases are stable according to the criteria above
will not be excluded

- Previous gemcitabine treatment is allowed only if applied as monotherapy in the
adjuvant setting and if the adjuvant single-agent gemcitabine chemotherapy was
terminated at least 6 months before study entry

- Previous systemic treatment with chemotherapy or radiotherapy for locally advanced,
non resectable or metastatic pancreatic cancer

- Radiotherapy within four weeks prior to randomization or radiation of target lesions

- Prior treatment with EGFR targeting therapies or treatment with EGFR- or HER2
inhibiting drugs within the past 4 weeks before start of therapy or concomitantly
with this trial

- Hypersensitivity to afatinib or to gemcitabine or to any of the excipients or to
compounds with similar chemical or biologic composition

- Contraindications against the use of gemcitabine

- Severe renal insufficiency (baseline creatinine clearance < 30 ml/mi)

- LDH elevated by > 2.5 ULN

- Severe hepatic dysfunction

- Any disease e. g. active infection, uncontrolled hypertension, clinically significant
cardiovascular disease for example CVA (<= 6 months before study start), myocardial
infarction (<= 6 months before study start), unstable angina, NYHA >= grade 2 CHF,
arrhythmia requiring medication, metabolic dysfunction giving reasonable suspicion of
a disease or condition that contra-indicates the use of the study drugs or puts the
patient at high risk for treatment-related complications

- Significant or recent acute gastrointestinal disorders with diarrhoea as a major
symptom e.g. Crohn's disease, malabsorption or CTC grade > 2 diarrhoea of any
aetiology

- Pregnant or lactating females, non-effective contraception in men and women of
childbearing potential (an effective contraceptive measure has a Pearl Index < 1)

- Any major surgery within the last 2 weeks before study entry

- Chemo- or immunotherapy within the past 4 weeks

- Treatment with an investigational drug in another clinical study within the past 28
days prior to the start of therapy or concomitantly with this study

- Any persisting toxicities which are deemed to be clinically significant from the
previous therapy

- Patients with pre-existing interstitital lung disease

- Psychological, familial, social or geographic conditions that may prevent an adequate
compliance with the study protocol

- Known or suspected alcohol- or drug abuse

- Patients unable to comply with the protocol

- Known hepatitis B infection, known hepatitis C infection or HIV carrier

- Requirement for treatment with any of the prohibited concomitant medications

- Any other malignancies within the last 5 years before study start, except for
adequately treated carcinoma in situ of the cervix, basal or squamous cell skin
cancer