Is histological remission feasible in UC patients?

A study presented at AIBD 2023 provides strong evidence that histological remission may be achievable in patients with ulcerative colitis (UC).

Histological remission, defined as microscopic normalization in mucosal biopsies or absence of acute inflammation characterized by the presence of intraepithelial neutrophils, is a sought-after objective in UC patients, the researchers noted.

“Histological remission has become very important since those who achieve it have fewer long-term complications, including the development of intestinal dysplasia. Currently, biological therapies represent a promising option to achieve this goal,” they continued.

The investigators retrospectively evaluated histological responses to biologic therapy in 40 patients diagnosed with UC (average age 50.13 years, 57.5 percent women). [AIBD 2023, abstract S144]

In terms of clinical activity, 42.5 percent of participants were considered in remission while more than a third (37.5 percent) were in the active phase.

When stratifying by type of remission, a little over 40 percent were in deep remission, 10 percent were in biochemical and histological remission, 7.5 percent in biochemical and endoscopic remission, while 5 percent were in histological and endoscopic remission. About 8 percent were in biochemical remission only; 2.5 percent were in endoscopic remission only.

The researchers noted that there were differences observed in the types of remission achieved with different therapeutic agents. “Infliximab and 5-aminosalicylic acid were most frequently associated with deep remission, while certolizumab and adalimumab were more common in biochemical and histological remission.”

An important treatment goal

“These findings are encouraging, since histological remission is an important goal in the treatment of UC, as it indicates complete healing of the intestinal mucosa and is associated with better long-term results,” the researchers explained.

Despite the relatively small sample size, the findings support the importance of histological remission as a therapeutic goal, as it is tied to significant clinical improvement.

Clinical importance of histological healing

“In UC patients who achieve endoscopic mucosal healing, histological healing is further protective against disease flares, medical escalation, hospitalization, surgery, and corticosteroid use,” said Dr Britt Christensen from The Royal Melbourne Hospital, Melbourne, Australia, in a separate report. [Gastroenterol Hepatol (NY) 2022;18:466-468]

However, most UC patients cannot achieve histological healing, Christensen stressed. “Many patients cannot even achieve mucosal healing. Mucosal healing rates of 40 percent are considered impressive in large biologic and small molecule clinical trials. Rates can be higher in the real world, particularly if patients are treated with a biologic early in their disease course; however, there remains a significant treatment gap.”

Moreover, even if mucosal healing is achieved, a fraction of patients may still have ongoing histological activity, she continued. “[H]istological healing is optimistically achieved in only approximately one-third of patients.”

She added that there remains various research gaps in this area, hence the need for better prospective trials to establish the types of patients who can achieve histological healing.

“Histological healing is a good prognostic marker, but it is not clear how achievable it is as a treatment target … If [UC] patients achieve both mucosal and histological healing, [they may] have a high probability of doing very well clinically on follow-up. These patients may benefit from less-intense monitoring,” noted Christensen.