Ustekinumab was evaluated in two randomized, double-blind, placebo-controlled clinical trials [UC-1 and UC-2 (
NCT02407236)] in adult subjects with moderately to severely active ulcerative colitis who had an inadequate response to or failed to tolerate a biologic (i.e., TNF blocker and/or vedolizumab), corticosteroids, and/or 6-MP or AZA therapy. The 8-week intravenous induction trial (UC-1) was followed by the 44-week subcutaneous randomized withdrawal maintenance trial (UC-2) for a total of 52 weeks of therapy.
Disease assessment was based on the Mayo score, which ranged from 0 to 12 and has four subscores that were each scored from 0 (normal) to 3 (most severe): stool frequency, rectal bleeding, findings on centrally-reviewed endoscopy, and physician global assessment. Moderately to severely active ulcerative colitis was defined at baseline (Week 0) as Mayo score of 6 to 12, including a Mayo endoscopy subscore ≥2. An endoscopy score of 2 was defined by marked erythema, absent vascular pattern, friability, erosions; and a score of 3 was defined by spontaneous bleeding, ulceration. At baseline, subjects had a median Mayo score of 9, with 84% of subjects having moderate disease (Mayo score 6–10) and 15% having severe disease (Mayo score 11–12).
Subjects in these trials may have received other concomitant therapies including aminosalicylates, immunomodulatory agents (AZA, 6-MP, or MTX), and oral corticosteroids (prednisone).
Trial UC-1
In UC-1, 961 subjects were randomized at Week 0 to a single intravenous administration of ustekinumab of approximately 6 mg/kg, 130 mg (a lower dose than recommended), or placebo. Subjects enrolled in UC-1 had to have failed therapy with corticosteroids, immunomodulators or at least one biologic. A total of 51% had failed at least one biologic and 17% had failed both a TNF blocker and an integrin receptor blocker. Of the total population, 46% had failed corticosteroids or immunomodulators but were biologic-naïve and an additional 3% had previously received but had not failed a biologic. At induction baseline and throughout the trial, approximately 52% subjects were receiving oral corticosteroids, 28% subjects were receiving immunomodulators (AZA, 6-MP, or MTX) and 69% subjects were receiving aminosalicylates.
The primary endpoint was clinical remission at Week 8. Clinical remission with a definition of: Mayo stool frequency subscore of 0 or 1, Mayo rectal bleeding subscore of 0 (no rectal bleeding), and Mayo endoscopy subscore of 0 or 1 (Mayo endoscopy subscore of 0 defined as normal or inactive disease and Mayo subscore of 1 defined as presence of erythema, decreased vascular pattern and no friability) is provided in Table 15.
The secondary endpoints were clinical response, endoscopic improvement, and histologic-endoscopic mucosal improvement. Clinical response with a definition of (≥ 2 points and ≥ 30% decrease in modified Mayo score, defined as 3-component Mayo score without the Physician's Global Assessment, with either a decrease from baseline in the rectal bleeding subscore ≥1 or a rectal bleeding subscore of 0 or 1), endoscopic improvement with a definition of Mayo endoscopy subscore of 0 or 1, and histologic- endoscopic mucosal improvement with a definition of combined endoscopic improvement and histologic improvement of the colon tissue [neutrophil infiltration in <5% of crypts, no crypt destruction, and no erosions, ulcerations, or granulation tissue]) are provided in Table 15.
In UC-1, a significantly greater proportion of subjects treated with ustekinumab (at the recommended dose of approximately 6 mg/kg dose) were in clinical remission and response and achieved endoscopic improvement and histologic-endoscopic mucosal improvement compared to placebo (see Table 15).
Table 15: Proportion of Subjects Meeting Efficacy Endpoints at Week 8 in UC-1 | Endpoint | Placebo N = 319 | Ustekinumab†
N = 322 | Treatment difference and 97.5% CIa
|
| N | % | N | % |
| Clinical Remission* | 22 | 7% | 62 | 19% | 12% (7%, 18%)b
|
| Bio-naïve⸸
| 14/151 | 9% | 36/147 | 24% | |
| Prior biologic failure | 7/161 | 4% | 24/166 | 14% |
| Endoscopic Improvement§
| 40 | 13% | 80 | 25% | 12% (6%, 19%)b
|
| Bio-naïve⸸
| 28/151 | 19% | 43/147 | 29% | |
| Prior biologic failure | 11/161 | 7% | 34/166 | 20% |
| Clinical Response¶
| 99 | 31% | 186 | 58% | 27% (18%, 35%)b
|
| Bio-naïve⸸
| 55/151 | 36% | 94/147 | 64% | |
| Prior biologic failure | 42/161 | 26% | 86/166 | 52% |
Histologic-Endoscopic Mucosal Improvement‡
| 26 | 8% | 54 | 17% | 9% (3%, 14%)b
|
| Bio-naïve⸸
| 19/151 | 13% | 30/147 | 20% | |
| Prior biologic failure | 6/161 | 4% | 21/166 | 13% | |
† Infusion dose of ustekinumab using the weight-based dosage regimen specified in Table 4.
⸸ An additional 7 subjects on placebo and 9 subjects on ustekinumab (6 mg/kg) had been exposed to, but had not failed, biologics.
* Clinical remission was defined as Mayo stool frequency subscore of 0 or 1, Mayo rectal bleeding subscore of 0, and Mayo endoscopy subscore of 0 or 1 (modified so that 1 does not include friability).
§ Endoscopic improvement was defined as Mayo endoscopy subscore of 0 or 1 (modified so that 1 does not include friability).
¶ Clinical response was defined as a decrease from baseline in the modified Mayo score by ≥30% and ≥2 points, with either a decrease from baseline in the rectal bleeding subscore ≥1 or a rectal bleeding subscore of 0 or 1.
‡ Histologic-endoscopic mucosal improvement was defined as combined endoscopic improvement (Mayo endoscopy subscore of 0 or 1) and histologic improvement of the colon tissue (neutrophil infiltration in <5% of crypts, no crypt destruction, and no erosions, ulcerations, or granulation tissue).
a Adjusted treatment difference (97.5% CI)
b p < 0.001
The relationship of histologic-endoscopic mucosal improvement, as defined in UC-1, at Week 8 to disease progression and long-term outcomes was not evaluated during UC-1.
Rectal Bleeding and Stool Frequency Subscores
Decreases in rectal bleeding and stool frequency subscores were observed as early as Week 2 in ustekinumab-treated subjects.
Trial UC-2
The maintenance trial (UC-2) evaluated 523 subjects who achieved clinical response 8 weeks following the intravenous administration of either induction dose of ustekinumab in UC-1. These subjects were randomized to receive a subcutaneous maintenance regimen of either 90 mg ustekinumab every 8 weeks, or every 12 weeks (a lower dose than recommended), or placebo for 44 weeks.
The primary endpoint was the proportion of subjects in clinical remission at Week 44. The secondary endpoints included the proportion of subjects maintaining clinical response at Week 44, the proportion of subjects with endoscopic improvement at Week 44, the proportion of subjects with corticosteroid-free clinical remission at Week 44, and the proportion of subjects maintaining clinical remission at Week 44 among subjects who achieved clinical remission 8 weeks after induction.
Results of the primary and secondary endpoints at Week 44 in subjects treated with ustekinumab at the recommended dosage (90 mg every 8 weeks) compared to the placebo are shown in Table 16.
Table 16: Efficacy Endpoints of Maintenance at Week 44 in UC-2 (52 Weeks from Initiation of the Induction Dose) | Endpoint | Placebo* N = 175†
| 90 mg ustekinumab every 8 weeks N = 176 | Treatment difference and 95% CI |
| N | % | N | % |
| Clinical Remission** | 46 | 26% | 79 | 45% | 19% (9%, 28%) a
|
| Bio-naïve⸸
| 30/84 | 36% | 39/79 | 49% | |
| Prior biologic failure | 16/88 | 18% | 37/91 | 41% |
| Maintenance of Clinical Response at Week 44†
| 84 | 48% | 130 | 74% | 26% (16%, 36%) a
|
| Bio-naïve⸸
| 49/84 | 58% | 62/79 | 78% | |
| Prior biologic failure | 35/88 | 40% | 64/91 | 70% |
| Endoscopic Improvement§
| 47 | 27% | 83 | 47% | 20% (11%, 30%) a
|
| Bio-naïve⸸
| 29/84 | 35% | 42/79 | 53% | |
| Prior biologic failure | 18/88 | 20% | 38/91 | 42% |
| Corticosteroid-free Clinical Remission‡
| 45 | 26% | 76 | 43% | 17% (8%, 27%) a
|
| Bio-naïve⸸
| 30/84 | 36% | 38/79 | 48% | |
| Prior biologic failure | 15/88 | 17% | 35/91 | 38% |
| Maintenance of Clinical Remission at Week 44 in subjects who achieved clinical remission 8 weeks after induction | 18/50 | 36% | 27/41 | 66% | 31% (12%, 50%) b
|
| Bio-naïve⸸
| 12/27 | 44% | 14/20 | 70% | |
| Prior biologic failure | 6/23 | 26% | 12/18 | 67% | |
⸸ An additional 3 subjects on placebo and 6 subjects on ustekinumab had been exposed to, but had not failed, biologics.
* The placebo group consisted of subjects who were in response to ustekinumab and were randomized to receive placebo at the start of maintenance therapy.
** Clinical remission was defined as Mayo stool frequency subscore of 0 or 1, Mayo rectal bleeding subscore of 0, and Mayo endoscopy subscore of 0 or 1 (modified so that 1 does not include friability).
† Clinical response was defined as a decrease from baseline in the modified Mayo score by ≥30% and ≥2 points, with either a decrease from baseline in the rectal bleeding subscore ≥1 or a rectal bleeding subscore of 0 or 1.
§ Endoscopic improvement was defined as Mayo endoscopy subscore of 0 or 1 (modified so that 1 does not include friability).
‡ Corticosteroid-free clinical remission was defined as subjects in clinical remission and not receiving corticosteroids at Week 44.
a p =<0.001
b p=0.004
Other Endpoints
Week 16 Responders to Ustekinumab Induction
Subjects who were not in clinical response 8 weeks after induction with ustekinumab in UC- 1 were not included in the primary efficacy analyses for trial UC-2; however, these subjects were eligible to receive a 90 mg subcutaneous injection of ustekinumab at Week 8. Of these subjects, 55/101 (54%) achieved clinical response eight weeks later (Week 16) and received ustekinumab 90 mg subcutaneously every 8 weeks during the UC-2 trial. At Week 44, there were 97/157 (62%) subjects who maintained clinical response and there were 51/157 (32%) who achieved clinical remission.
Histologic-Endoscopic Mucosal Improvement at Week 44
The proportion of subjects achieving histologic-endoscopic mucosal improvement during maintenance treatment in UC-2 was 75/172 (44%) among subjects on ustekinumab and 40/172 (23%) in subjects on placebo at Week 44. The relationship of histologic-endoscopic mucosal improvement, as defined in UC-2, at Week 44 to progression of disease or long-term outcomes was not evaluated in UC-2.
Endoscopic Normalization
Normalization of endoscopic appearance of the mucosa was defined as a Mayo endoscopic subscore of 0. At Week 8 in UC-1, endoscopic normalization was achieved in 25/322 (8%) of subjects treated with ustekinumab and 12/319 (4%) of subjects in the placebo group. At Week 44 of UC-2, endoscopic normalization was achieved in 51/176 (29%) of subjects treated with ustekinumab and in 32/175 (18%) of subjects in placebo group.