#NACFC2021 – Trikafta Treatment Helps CF Patients Gain Weight

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by Marisa Wexler, MS |

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Treatment with Trikafta can help people with cystic fibrosis (CF) to put on weight, according to new data from a small clinical trial.

These findings indicate that traditional guidelines for CF nutrition — which urge a protein-heavy, calorie-packed diet to counter the malnutrition common among patients with the genetic disease — may need to be updated in light of newly available treatments.  

“The universal CF high-calorie, high-fat diet recommendation potentially needs to be revised,” Julianna Bailey, a registered dietitian at the University of Alabama, said at the 2021 North American Cystic Fibrosis Conference (NACFC), in a presentation on the study, titled “Nutritional and metabolic effects of elexacaftor/tezacaftor/ivacaftor in adults and adolescents with cystic fibrosis.”

The annual NACFC is being held virtually this year from Nov. 2–5.

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CF can have substantial impacts on digestive health, and many people with the disease have difficulty getting enough nutrients from their food. 

“Malnutrition is one of the common clinical features of CF, and it is associated with both lower lung function and poorer survival,” Bailey said at NACFC.

To ensure appropriate nutrition, CF patients have generally been recommended a diet that’s high in calories, fats, proteins, and salts. However, nutritional care for CF is changing with the availability of new, highly effective medicines.

In fact, Bailey noted, emerging data indicate that, while malnutrition is becoming less common among people with CF, issues like obesity are becoming more prevalent — and affecting both children and adults with the disease.

Trikafta, by Vertex Pharmaceuticals, is an oral therapy containing three CFTR modulators (elexacaftor, tezacaftor, and ivacaftor), which are medications that work to improve the functionality of the CFTR protein whose defect causes CF

When Trikafta was first approved in the U.S. in 2019, scientists launched an observational study called PROMISE (NCT04038047) to study the medication’s clinical efficacy.

At NACFC, Bailey shared data on how Trikafta affected nutritional status in 22 participants in a sub-study of PROMISE. The participants ranged in age from 16 to 54 and 68% were female. Nearly all (95%) were Caucasian. Exactly half had previously been on another type of CFTR modulator, or other CF therapy, while the other half had not been eligible for CFTR modulators prior to Trikafta because of their specific disease-causing mutation.

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Participants were assessed prior to starting on Trikafta, and again after 28 days on the therapy. The researchers’ plan had been to do a third assessment at six months, but due to scheduling issues caused by the COVID-19 pandemic, the third visit occurred after an average of 10 months on the treatment. Of the 22 participants, 17 completed all three visits.

At the first visit after one month of treatment, participants’ body mass index (BMI) increased significantly, by a mean of 0.46 kilograms per square meter (kg/m2). BMI is a measure of body weight relative to height. Since people with CF often have poor nutrition, they tend to have low BMIs; thus, an increase in this measure is likely reflective of better nutritional status.

“BMI has long been the main marker for nutritional status” in people with CF, Bailey said, noting that BMI is closely linked to lung function.

At the longer follow-up after an average of 10 months, the mean BMI increase was 0.92 kg/m2.

Trikafta “improved weight and BMI status rapidly, which was sustained with chronic treatment at greater than six months,” Bailey said.

Prior to starting on Trikafta, 41% of participants were underweight and 23% were overweight or obese. By the third study visit, the proportion of underweight participants had decreased to 29%, while the number of overweight participants had increased to 29%. Of note, the one participant who was classified as “obese” at the start of the study lost some weight during it, so that by the end, this person was classified as “overweight.”

Long-term Trikafta treatment was associated with significant increases in daily calorie intake (by 297 kcal per day after 10 months, on average) and daily fat intake (19.4 grams per day). The treatment also led to a decrease in energy expenditure, which was abnormally high at the study’s start. 

There were no noted changes in dietary habits or the use of pancreatic enzyme replacement therapies, which are treatments used to improve digestion in CF patients. 

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One issue Bailey highlighted, which was noted in the study findings, is that diet quality appears to be lacking for most people with CF.

Indeed, the researchers noted that patients historically have been given “little guidance related to nutrient density or quality of foods consumed to meet elevated metabolic needs.”

“Diet quality was poor at [the start of the study], and did not improve despite there being increases in total calorie and total fat intake,” Bailey said.

This result suggests that the traditional recommendation that people with CF should always try to maintain a high-calorie, high-fat diet “potentially needs to be revised, given these findings of rising BMI, increased intake, and poor diet quality,” Bailey said.

“These findings also highlight the need for individualized nutrition counseling to improve diet quality and manage weight changes” among people treated with Trikafta, she added.

Editor’s note: The Cystic Fibrosis News Today team is providing coverage of the virtual 2021 North American Cystic Fibrosis Conference (NACFC) Nov. 2-5. Go here to see the latest stories from the conference.