An open-label, randomised, multi-centre, dose evaluation study of the efficacy and safety of TLA Gut™ leukapheresis treatment in patients with UC. The aim of this trial is to evaluate the efficacy and safety of two different TLA Gut™ dose regimens in patients with acute exacerbation of UC. Enrolled patients will participate in a 6-week treatment phase and a 20- week follow-up phase. The treatment phase consists of two periods; 2 weeks in which patients will undergo two treatment sessions per week, followed by 4 weeks of a single treatment session per week. The follow-up phase consists of 2 visits, one visit at week 7 and the last visit at week 26. Telephone visits will be conducted between these visits. In all a patient will undergo 8 treatment visits and 2 follow-up visits. Only patients not having experienced an earlier recurrence will participate in the follow-up phase.

Inclusion Criteria:

Female or male patients 18 to 80 years of age

• Active UC without Ileorectal anastomosis (IRA)

• Active UC is defined as:

  • Total Mayo score of ≥ 6 to 11 points
  • Flexible rectosigmoidoscopy findings of 2 or 3 (0 inactive disease, 1; mild disease, 2; moderate disease or 3; severe disease)

• Minimum extension of inflammation 10 cm from anus.

• Active disease with no medical treatment OR Active disease despite receiving concomitant therapy with one or more of the following agents:

  • ≤20 mg prednisolone daily. Stable dose ≥1 week prior to the start of the investigation.
  • 5-Aminosalicylate (5-ASA) agents for ≥4 weeks and stable dose for ≥2 weeks (local or systemic administration)
  • Rectal administration of corticosteroids in a stable dose for ≥2 weeks
  • Azathioprine or 6-mercaptopurine for ≥8 weeks or stable dose ≥2 weeks

• No anti-tumour necrosis factor (TNF) treatment (Adalimumab, Infliximab, Golimumab, Certolizumab), anti-integrin-treatment (vedolizumab), Interleukin (IL)-12/23 inhibitor (Ustekinumab) or Janus Kinase (JAK) treatment (Tofacitinib) during the last 4 weeks prior to entering the study

• Patients with peripheral veins suitable for extracorporeal treatment - must be examined by the treating apheresis specialist

• Willing and able to give written informed consent

Exclusion Criteria:

Involvement in any investigational drug or device trial within 30 days prior to this investigation

• Patients with peripheral veins not suitable for extracorporeal treatment
• Fever, defined as a temperature of >38,5 Celsius degrees (ºC), at the Screening Visit
• Heart failure
• Coronary artery disease
• Cardiomyopathy
• Valvular heart disease
• Cardiac arrythmia class IV
• Underweight person (BMI < 19)
• Hypotension (< 90/55 mmHG)
• Hypoproteinemia
• Evidence of toxic megacolon
• History of hypersensitivity to heparin
• Heparin-induced thrombocytopenia
• History of cerebrovascular incident
• Known clinically significant bleeding disorder
• Colectomy planned within 6 months
• Concomitant anticoagulant therapy
• History of hypercoagulable disorders
• Severe anaemia or Leukopenia
• Patients with active viral hepatitis and/or human immunodeficiency virus (HIV) infections
• A positive urine pregnancy test at the screening visit
• Patients that are nursing Local intestinal treatments with suppositories, enemas, creams, ointments or foams during the last 2 weeks
• Current daily smoking habits
• Patients unwilling to meet the requirements of the clinical investigational plan
• Other medical or social reasons for exclusion at the discretion of the investigator