IVIG Therapy Shows Promise in Reducing Symptom Severity for AGID

New research presented at this year’s American College of Gastroenterology (ACG) Conference indicates that intravenous immunoglobulin (IVIG) therapy can reduce symptom severity for patients with autoimmune gastrointestinal dysmotility (AGID), also known as gastroparesis.

The chronic digestive condition is characterized by a delay in gastric emptying and is associated with many symptoms including early satiety, excessive fullness, nausea, vomiting, and abdominal pain. While small, open-label studies of IVIG have demonstrated symptom improvement for patients with autoimmune markers, the new study evaluated how IVIG therapy affects symptom severity.

Madison Simons, PsyD, a gastrointestinal psychologist and the lead author of the study, explains, “Gastroparesis has historically been divided into two classes: diabetic and idiopathic. Over the last several years, we’ve become aware of autoimmune causes of gastroparesis. As there are few effective treatments for gastroparesis, this study was important in understanding whether patients with known autoimmunity benefit from IVIG therapy.”

The research was presented at ACG by Madison Simons, PsyD, as part of research conducted with Michael Cline, DO, Andrew Grubic, DO, Matthew Allemang, MD, and Anthony Lembo, MD in the Gastroparesis Center at Cleveland Clinic.

Study design

The retrospective case study included patients who were identified through medical chart review as having gastroparesis and seropositive autoimmune dysfunction identified through bloodwork. These markers included glutamic acid decarboxylase (GAD), neuronal voltage-gated calcium channel, acetylcholine receptor and neuronal voltage-gated potassium channel autoantibodies. All patients included in the study received at least 12 weeks of IVIG therapy. Before the treatment, the researchers collected the group’s Gastroparesis Cardinal Symptom Index (GCSI) scores to compare their post-treatment scores.

“Our study was limited to patients with seromarkers of autoimmune dysfunction associated with gastroparesis, as these are the only patients right now who have a chance of receiving insurance coverage for IVIG,” explains Dr. Simons. “Even then, many patients are being denied coverage for this treatment. There is emerging evidence that even antibody-negative individuals may benefit from IVIG, but more evidence is needed to confirm this.”

The final sample included 27 patients (96.3% female; 81.5% white; mean age=39.0 [SD=13.4]) with AGID. Just under half (44.4%) of the cohort had a per-oral pyloromyotomy (POP) prior to IVIG therapy. Gastric scintigraphy mean 4-hour retention was 38.6% (SD=24.4%). The mean wireless motility capsule gastric emptying time (GET) was 677.0 minutes (SD=585.5).

“Prior to receiving IVIG therapy, the patients indicated in their GCSI scores that early satiety was the most problematic symptom,” says Dr. Simons. “However, following treatment, the group’s mean GCSI scores significantly improved by more than 1.5 points, and two-thirds of the patients had GCSI scores that improved by at least 1 point after receiving IVIG therapy.”

Looking ahead

Based on their findings, the research group believes that IVIG therapy should be considered for AGID treatment. Although the study showed significant improvement in symptoms for patients, more work is still necessary. The group suggests that future randomized, placebo-controlled trials would provide more clarity on the effectiveness of IVIG in treating AGID.

Dr. Simons says that the researchers hope their findings, in collaboration with other centers doing similar research, may lead to funding opportunities for a randomized trial to better demonstrate the efficacy of this treatment. More work is also needed to predict who will most likely respond to IVIG treatment.

“We are one of few centers looking for autoimmune causes of gastroparesis and pursuing IVIG as a treatment option,” she says. “We hope that by publishing and presenting our findings, other centers begin to adopt a similar model so providers can feel more confident in their approach to gastroparesis and more patients can benefit from this treatment.”