G-POEM Data Show High Success Rates, Symptom Relief in Patients With Persistent Gastroparesis

Originally published by our sister publication Gastroenterology & Endoscopy News

VANCOUVER, B.C.—Gastric peroral endoscopic myotomy may greatly aid patients with persistent gastroparesis, according to two new studies presented at the 2023 annual meeting of the American College of Gastroenterology.

In a systematic review and meta-analysis of five studies conducted by researchers from George Washington University, G-POEM demonstrated an impressive clinical success rate of 75% for the management of refractory gastroparesis. With a 36-month follow-up, the findings also showed a reduction in the Gastroparesis Cardinal Symptom Index (GCSI) score and minimal adverse events. In a second single-center, retrospective study, researchers from University of Missouri–Columbia found the procedure resulted in an 88% clinical success rate and a significant improvement in symptoms.

Although the small studies may not give a full picture of G-POEM success rates, both research teams emphasized that these data affirm G-POEM as an effective long-term treatment for refractory gastroparesis.

“Given the limitations of existing interventions, G-POEM represents a breakthrough,” said researcher Justin P. Canakis, DO, a resident in the Department of Internal Medicine at George Washington University, in Washington, D.C. “Our analysis establishes, with robust evidence, that G-POEM facilitates significant symptom reduction in gastroparesis with a promising long-term outlook.”

Gastroparesis poses a consistent clinical challenge, with current therapies, including medications and surgical interventions, often falling short of providing lasting relief, Dr. Canakis said. However, G-POEM has emerged as a novel management option for patients with refractory gastroparesis by targeting pyloric distensibility, which is associated with delayed emptying and symptom severity.

For this systematic review and meta-analysis, which won an ACG Presidential Poster Award, Dr. Canakis and his co-investigators searched multiple databases for studies looking at long-term outcomes of at least three years for patients with gastroparesis treated with G-POEM (abstract P2745).

The primary outcome was clinical success three years after G-POEM. Secondary outcomes included changes in the GCSI score before and 26 months after G-POEM, technical success, adverse events, and hospital length of stay. The researchers included five studies involving 560 patients in the final analysis.

The pooled rate of clinical success at 36 months’ follow-up was 75% for G-POEM (95% CI, 68.2%-80.5%; I²=20%). Patients also exhibited a significant decrease in the GSCI score, indicating effective symptom management (standardized mean difference, 3.3; 95% CI, 1.8-4.7; I²=94%).

Sustained Relief

“G-POEM isn’t just about managing symptoms,” Dr. Canakis said. “It provides sustained relief, drastically improving patients’ quality of life over the long haul.”

Patients treated with G-POEM reported minimal adverse events, including perforation, bleeding and pain. In addition, the average hospital stay for patients was only three days, representing an additional benefit of shorter hospitalization periods.

While these results affirm G-POEM as a viable solution, Dr. Canakis said additional research is needed to identify patient selection factors that can predict long-term success. Further studies exploring G-POEM’s efficacy across varying patient profiles are underway to determine optimal procedural parameters.

Promise for Patient Relief

A second study also presented at the ACG meeting found similar results, especially highlighting patient symptom relief (abstract P3711). Lead researcher Muhammad Yousaf, MD, a clinical fellow gastroenterology at the University of Missouri–Columbia, called G-POEM a “feasible and effective treatment for patients with refractory gastroparesis, with a good short-term clinical success rate.”

Dr. Yousaf and his co-investigators conducted a single-center retrospective study of consecutive patients who underwent G-POEM between February 2020 and September 2022. Primary outcomes were the success rate of the procedure, which is defined as improvement in GCSI score by 25% and improvement in gastric emptying percentage at four hours.

Secondary outcomes were technical success rate, adverse event rates, frequency of hospitalization due to recurrent symptoms after G-POEM, and need for endoscopic or surgical re-interventions. Refractory gastroparesis was defined as persistent symptoms despite dietary modifications and pharmacologic therapy.

A total of 25 patients (72% female), who were a mean age of 58.5 years, were included in the study. As Dr. Yousaf reported, the clinical success rate was 88% and the technical success rate was 100%.

The researchers observed a significant improvement in mean GCSI score after G-POEM (32.8 vs. 12.0; P<0.001). There was also a trend toward a lower percentage of food retention on gastric emptying study at four hours (47.2% vs. 43.3%; P=0.30).

In addition, they found a significant reduction in mean ER visits due to gastroparesis-related symptoms after G-POEM (1.6 vs. 0.2 visits; P<0.03). No severe adverse events were reported.

Even with the positive results, Drs. Canakis and Yousaf underscored the importance of additional research. “Larger clinical trials are needed,” Dr. Yousaf said, “to evaluate the long-term benefits of this emerging endoscopic technique for the management of refractory gastroparesis.”

Long-Term Benefits Need to Be Confirmed

Asked to comment, Mohammad Al-Haddad, MD, MS, FASGE, FACG, AGAF, the Naga P. Chalasani Chair of Gastroenterology and Hepatology at Indiana University School of Medicine, in Indianapolis, who has performed nearly 180 G-POEM procedures over the past six years, was not convinced about the long-term sustainability of the results.

“At our center, our response rates—defined by a drop of 1 point on the GCSI scale—are in the low to mid-50s,” Dr. Al-Haddad said. “I am amazed by some of the very high response rates reported by some centers, as high as 80% or more in some series.”

According to Dr. Al-Haddad, larger multicenter studies that include academic and community centers are needed to more accurately assess this intervention.

“We see variation in response rates and also a drop in response beyond year 2 post-G-POEM,” said Dr. Al-Haddad, who noted that the main issue is the use of symptom-based, patient-reported tools such as the GCSI score as the sole determinant of success, which he called “insufficient.”

“Data from our center looked at alternative measures including well-validated [quality-of-life] questionnaires such as SF-36 [the 36-item Short Form Health Survey] and reported enhanced quality of life, even in patients who technically were ‘failures’ based on the mainstream definition that relies on GCSI,” Dr. Al-Haddad added. “We have recently submitted the largest data set yet to date to DDW [Digestive Disease Week] and are hoping to present this at 2024 DDW.”

—Chase Doyle

Drs. Al-Haddad, Canakis and Yousaf reported no relevant financial disclosures.