Canakinumab for Pyoderma Gangrenosum

Inclusion criteria: Patients fulfilling all of the following inclusion criteria may be enrolled in the study 1. Age = 18 years of age at visit 0 and 2. Subjects are capable of giving informed consent 3. Non-healing ulcer with primarily neutrophil infiltration, regardless of size and location 4. Diagnosis of pyoderma gangrenosum as confirmed by clinical and histological examination (see exclusion criteria). In case of doubt, a steering committee consisting of experts of the participating centers is going to evaluate whether inclusion is possible or not Exclusion criteria: * Other etiologies of ulcers 15, namely venous insufficiency, arterial occlusion, microcirculatory disorders, physical or chemical injury, infection, neuropathy, vasculitis, haematological disorders, neoplasia, other ulcerating diseases: Diseases with cutaneous manifestations mimicking pyoderma gangrenosum, including but not limited to Wegener's granulomatosis, polyarteritis nodosa, lymphoma, sporotrichosis and antiphospholipid syndrome. * Classical systemic therapy (including but not limited to: corticosteroids, methotrexate, mycophenolate mofetil, azathioprine, tacrolimus, dapsone, cyclophosphamide) affecting pyoderma gangrenosum less than 14 days prior to enrollment. * Therapy with other biologics (TNF antagonists, intravenous immunoglobulins) less than 3 months or 5 half-lives prior to enrollment, whichever is longer. * Any other investigational drugs, other than investigational biologic treatment, within 30 days (or 3 months for investigational monoclonal antibodies) or 5 half-lives prior to the baseline visit, whichever is longer. Washout period may be longer according to local requirements. * Topical therapy affecting pyoderma gangrenosum for a period of 14 days prior to enrollment. * Having a history of recurring bacterial, viral, fungal, atypical mycobacterial infection, especially active or latent granulomatous infections (incl. tuberculosis, histoplasmosis) or currently undergoing treatment for tuberculosis. * A positive quantiferon test indicating possible latent tuberculosis infection. * An abnormal chest x-ray indicating a possible infection or malignoma for a period of 3 months prior to enrollment. * Known Human Immunodeficiency Virus (HIV)-, Hepatitis B (HBV)-, or Hepatitis C (HCV)-infection. * Having a severe medical condition that, in the judgment of the investigator, would jeopardize in any way the subject's safety following exposure to study drug. * Pregnant or lactating women, patients (men or women) planning a pregnancy during the duration of the study, lack of safe contraception. Safe contraception is defined as follows: Double-barrier contraception such as oral, injectable, or implantable contraceptives, or intrauterine contraceptive devices together with condom use. Both men and women must use safe contraception (double-barrier as defined above) during the duration of the study and until 6 months after the study. Please note that female subjects who are surgically sterilized/hysterectomized or post-menopausal for longer than 2 years are not considered as being of child bearing potential. * Having the presence or history of malignancy, including lymphoproliferative disorders. Subjects with a history of fully resolved basal or squamous cell skin cancer may be enrolled. * Contraindications to monoclonal or polyclonal antibodies, e.g. known hypersensitivity or allergy to class of drugs or the investigational product. * Known or suspected non-compliance, drug or alcohol abuse. * Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia or confusional state of the subject. * Participation in another treatment study within the 30 days preceding and during the present study. * Previous enrollment into the current study. * Enrollment of the investigator, his/her family members, employees and other dependent persons.