Cebranopadol Efficacy and Safety in Diabetic Patients Suffering From Chronic Pain Caused by Damage to the Nerves

Inclusion Criteria:

- written signed informed consent

- type 1 or type 2 diabetes mellitus

- clinical diagnosis of painful Diabetic Polyneuropathic Neuropathy (DPN) with symptoms
and signs for at least 3 months

- must require medication (e.g., non-opioids or opioids up to an equivalent dose of 160
mg oral morphine/day) for the treatment of pain due to DPN for at least 1 month prior
to Visit 1 and must be dissatisfied with the current treatment (in terms of efficacy
and/or tolerability). Medication for the treatment of pain due to DPN should be
required on at least 4 of 7 consecutive days.

- blood glucose to be controlled by a diet, oral anti-hyperglycemic medication, and/or
insulin for at least 3 months prior. Glycosylated hemoglobin (HbA1C) should not be
greater than 11%

- baseline pain intensity score greater or equal to 5 on the 11-point Numerical Rating
Scale (NRS) without intake of any analgesic at allocation. For each of the last 3
days prior to allocation of treatment, a 24 hour NRS score greater or equal to 4 is
required

- women of childbearing potential must have a negative urine pregnancy test at
enrollment

- using medically acceptable and highly effective methods of birth control (and willing
to use them during the trial).

Exclusion Criteria:

- presence of other pain that could confound the painful Diabetic Polyneuropathy (DPN)
assessments, e.g. pain due to nerve entrapment (tarsal tunnel syndrome,
osteoarthritis of the knee etc), peripheral vascular disease, radiculopathy, plantar
fasciitis, tendonitis, mononeuritis multiplex, postherpetic neuralgia, complex
regional pain syndrome, or fibromyalgia.

- neuropathy due to etiologies other than diabetes, e.g. autoimmune disorders,
inflammatory neuropathies (e.g. chronic inflammatory demyelinating polyneuropathy),
thyroid disease or endocrine disorders (other than diabetes), heavy metal or toxic
neuropathy, nutritional deficiency, metabolic disorders, vasculitis, infections,
injury, or paraneoplastic syndromes.

- severe or extensive diabetic ulcers or amputations due to diabetes

- Charcot's

- any clinically significant disease or laboratory findings, e.g., significant unstable
cardiac, vascular, pulmonary, gastrointestinal, endocrine, metabolic, neurological,
or psychiatric disorders.

- inability to comply with the protocol and with the intake of trial medication that,
in the investigator's opinion, might indicate that the participant is unsuitable for
the trial.

- conditions that require treatment with medication that is not allowed to be taken
during the trial

- previous or current alcohol or drug abuse or opioid dependency.

- severe functional hepatic impairment corresponding to Child-Pugh classification C.

- history of acute hepatitis

- impaired renal function, a creatinine clearance less than 60 mL/min at the enrollment
(Cockcroft-Gault calculated).

- history of any major gastrointestinal procedures (e.g., gastric bypass) or
gastrointestinal conditions (e.g. acute diarrhea, blind loop syndrome, gastric
dumping syndrome, Whipple's disease) that might affect the absorption or metabolism
of cebranopadol or pregabalin.

- risk factors for or history of torsade de pointes and/or marked prolongation of the
QT interval (e.g. heart failure, hypokalemia, or bradycardia).

- history of seizure disorder and/or epilepsy or any condition associated with a
significant risk for seizure disorder or epilepsy at the discretion of the
investigator.