A Long-term Active Treatment Study of Mongersen (GED-0301) in Subjects With Crohn's Disease

This is a long-term active treatment study in patients with Crohn's disease (CD). Subjects
who met the early escape criteria in Study GED-0301-CD-002, or subjects who completed Study
GED-0301-002 or GED-0301-003, may be eligible for this study. Primary objective is to assess
long-term safety of GED 0301. Additional efficacy and patient reported outcomes will be
explored.

There are 5 possible treatment groups for GED-0301-CD-002 Subjects (Groups 1-5). There are 3
possible treatment groups for GED-0301-CD-003 subjects (Groups 1-3). Treatment is assigned
based on clinical improvement achieved or not achieved from the core GED-0301 study.

1. continuous GED-0301 160 mg once daily for 12 weeks, followed by alternating placebo once
daily for 4 weeks with GED-0301 160 mg once daily for 4 weeks, through Week 208;

2. alternating GED-0301 160 mg once daily for 4 weeks with placebo once daily for 4 weeks,
through Week 208;

3. alternating placebo once daily for 4 weeks with GED-0301 160 mg once daily for 4 weeks,
through Week 208;

4. continuous GED-0301 40 mg once daily through Week 208;

5. alternating placebo once daily for 4 weeks, followed by GED-0301 40 mg once daily for 4
weeks, through Week 208.

The GED-0301-CD-003 trial was not initiated; the GED-0301 program was terminated; no safety
findings were noted.

Inclusion Criteria for Adult Subjects:

Subjects must satisfy the following criteria to be screened and enrolled in the study:

- Male or female ≥ 18 years of age.

- Subject must have participated in the GED-0301-CD-002 or GED 0301 CD 003 study.

- Subject must use protocol approved contraception.

Inclusion Criteria for Adolescent Subjects:

Adolescent subjects must satisfy the following criteria to be screened and enrolled in the
study

- Male or female 12 to 17 years of age.

- Subject must have participated in the GED 0301 CD 003 study.

- Subject is able to swallow the IP tablets.

- Subject must use protocol approved contraception.

Exclusion Criteria for Adult and Adolescent Subjects:

The presence of any of the following will exclude a subject from screening and enrollment:

- Subject had experienced a serious adverse event (SAE) related to the investigational
product while participating in the previous Phase 3 GED-0301 study.

- Subject has initiated biologic agents, such as TNF-α blockers or integrin antagonists.

- Subject is pregnant or breastfeeding.

- Subject has developed a known hypersensitivity to oligonucleotides, GED 0301 or any
ingredient in the investigational product.