Diarrhea a barrier to using common ALS medication: Surveys

Questionnaire sponsored by Napo Pharmaceuticals, which markets Mytesi

Lindsey Shapiro, PhD avatar

by Lindsey Shapiro, PhD |

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Note: This story was updated Aug. 22, 2023, to correct there are four ALS approved therapies widely available in the U.S.

Diarrhea associated with a common amyotrophic lateral sclerosis (ALS) treatment could be a substantial barrier to complying with the medication, according to surveys by Napo Pharmaceuticals.

While the name of the ALS therapy was not disclosed — the survey referred only to the “ALS drug” — only four therapies are now widely available in the U.S. These include riluzole (sold as Rilutek and generics Tiglutik and Exservan) and edaravone (sold as Radicava and Radicava ORS), as well as the more recently approved Relyvrio (sodium phenylbutyrate and taurursodiol) and Qalsody (tofersen).

Doctors, patients, and caregivers who were surveyed reported diarrhea as a substantial burden with the medication and it influenced patients’ quality of life, leading to discontinuing treatment in many cases.

“The results of both surveys indicate that chronic diarrhea may be a substantial compliance issue of patients receiving the ALS drug, and that the severity of the diarrhea — and its impact on patient quality of life, dignity, and the ability of patients to remain on the drug — may be higher than previously understood,” Lisa Conte, president and CEO of Napo’s parent company Jaguar Health, said in a company press release.

Napo markets a treatment called crofelemer under the brand name Mytesi for diarrhea in adults with HIV/AIDS who are on anti-retroviral therapy. The company is investigating crofelemer for other indications, including ALS.

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Impact of diarrhea

Napo conducted two survey studies, one of 15 neurologists who treat ALS patients in the U.S. and another involving 15 patients or caregivers, to learn more about the burden of diarrhea with the disease.

Most neurologists (87%) said the severity of diarrhea linked to the ALS medication was moderate or severe for their patients and 13% said their patients had been hospitalized or required medical interventions for diarrhea while taking it.

This aligned with the patient and caregiver survey, where 93% reported diarrhea severity as moderate or higher and 27% said it was severe. The need for hospitalization or medical intervention was reported by 40%.

About two-thirds of patients and caregivers reported experiencing diarrhea throughout their time on the ALS medication, with 20% saying the symptoms increased over time.

These side effects were associated with significant quality of life impacts, with 79% of doctors saying diarrhea had a moderate to severe effect on their patients’ quality of life and 93% of patients and caregivers reporting moderate or greater life quality impacts.

More than half of physicians said they’d stopped prescribing the medication due to diarrhea and 40% said their patients had skipped doses. Nearly half of respondents in the patient/caregiver survey said the treatment was stopped because of diarrhea. Less than half of the patients took medications for managing it.

“The data from the Napo-sponsored survey of individuals who are either ALS patients or caregivers of an ALS patient underscores the importance of real-world patient reported outcomes (PRO) data and the importance of managing side effects for critical diseases such as ALS,” Conte said.

Potential of crofelemer

Napo believes crofelemer could help ALS patients. The therapy is a plant-based medication purified from red bark sap — known as “dragon’s blood” — from the Croton lechleri tree in the Amazon rainforest.

The company notes it has established a sustainable harvesting program under fair trade practices that ensure high quality, ecological integrity, and support for indigenous communities in the rainforest.

The molecule inhibits channels in the gastrointestinal tract that mediate the movement of chloride into and out of cells. It works to help normalize the electrolyte and fluid balance in the gut to prevent diarrhea.

“We believe it is important to evaluate the potential of crofelemer’s novel mechanism of action to improve the quality of life of patients treated with the ALS drug and help prevent discontinuations and dose reductions of their disease modifying medications due to diarrhea,” Conte said.

While there’s no clinical trial involving ALS patients, a Phase 3 trial called OnTarget (NCT04538625) is evaluating crofelemer as a preventive treatment in adult cancer patients.