Last updated June 27, 2022, by Teresa Carvalho, MS
Fact-checked by José Lopes, PhD
What is Trikafta for CF?
Developed by Vertex Pharmaceuticals, Trikafta is the first triple therapy approved for CF.
How does Trikafta work?
A genetic disease, CF is caused by mutations in the CFTR gene. This gene provides the instructions necessary for cells to make the CFTR protein, which is a transporter that controls the movement of charged ions across cell membranes.
Mutations in CFTR mean that salts cannot cross cell membranes normally. This leads to the buildup of thick, sticky mucus in different tissues and organs, especially the lungs and the digestive tract. In the lungs, this mucus can interfere with breathing, and make patients more susceptible to respiratory infections.
While nearly 2,000 mutations have been identified in the CFTR gene, the F508del mutation is the most common CF-causing genetic defect. It is seen in about 90% of all people with the disease.
This mutation results in a premature stop signal in the genetic code, causing cells to make a truncated or shorter-than-normal CFTR protein. The cells cannot shuttle this truncated protein to the surface as efficiently as normal CFTR, resulting in abnormal ion transport.
Trikafta is a CFTR modulator that helps defective CFTR proteins work more effectively. Both elexacaftor and tezacaftor work as correctors. They bind to the faulty CFTR protein and help it fold correctly. This way, cells can shuttle more of it to the membrane instead of degrading the newly formed protein. Ivacaftor — also marketed independently as Kalydeco — is a potentiator: it binds to the CFTR protein and holds the channel open so that more salt can pass through it.
With a combination of all three therapies, more active and functional CFTR proteins reach the cell membrane.
Who can use Trikafta?
Trikafta has been approved in more than 30 countries, including the U.S., Canada, and Australia. It is widely available in Europe.
The treatment was approved by the U.S. Food and Drug Administration (FDA) in October 2019 to treat CF patients, ages 12 and older, with at least one F508del mutation. The FDA expanded the number of eligible mutations for Trikafta in December 2020.
The therapy’s approval was once again expanded in 2021 by the FDA, to cover children as young as 6.
Before Trikafta’s FDA approval, Kalydeco was approved in 2012, while Orkambi — which contains lumacaftor and ivacaftor — received approval in 2015. In addition, the combination of tezacaftor and ivacaftor, called Symdeko (marketed as Symkevi in the EU) was approved in 2018.
Health Canada approved the therapy in 2021 for people ages 12 and up who have at least one copy of the F508del mutation. The Canadian regulatory agency recently also expanded the therapy’s approval to cover children as young as 6.
In the EU, the European Commission (EC) approved the Vertex triple combo — marketed there under the brand name Kaftrio — in combination with Kalydeco in 2020 for patients with two F508del mutations or one F508del and one minimal function mutation, or a mutation in which the resulting CFTR protein works minimally. The EC in 2021 also expanded the list of approved secondary mutations that can be treated with the triple combination.
Who should not use Trikafta?
There currently are no contraindications for Trikafta, according to the treatment’s FDA label.
People with hypersensitivity to any of Kaftrio’s inactive ingredients — those used alongside its active components — should avoid Trikafta.
How is Trikafta administered?
Trikafta is available in four-weekly blister cards. Each card contains 21 tablets: orange tablets to be taken in the morning, and blue tablets for the evening. All tablets should be taken with fat-containing food to help with absorption. Fat-containing foods include butter, peanut butter, eggs, meat, nuts, and whole-milk dairy products. Foods and drinks that contain grapefruit should be avoided.
For children ages 6 to 11 and weighing less than 30 kg (66 lbs.), the recommended dose is:
- two light orange tablets, sized 12 mm by 6 mm, debossed with “T50” on one side and plain on the other, containing 50 mg of elexacaftor, 25 mg of tezacaftor, and 37.5 mg of ivacaftor
- one light blue capsule-shaped tablet, sized 13 mm by 7 mm, printed with “V75” in black ink on one side and plain on the other, containing 75 mg of ivacaftor
For children ages 6 to 11 weighing 30 kg (66 lbs.) or more, and people ages 12 years and older, the recommended dose is:
- two orange capsule-shaped tablets, sized 16 mm by 8 mm, debossed with “T100” on one side and plain on the other, containing 100 mg of elexacaftor, 50 mg, and 75 mg of ivacaftor
- one light blue capsule-shaped tablet, sized 17 mm by 8 mm, printed with “V 150” in black ink on one side and plain on the other, containing 150 mg of ivacaftor
Trikafta in clinical trials
People ages 12 and older
The first trial enrolled 403 CF patients, 12 years and older, with one F508del mutation (F) and one minimal function mutation (MF). The study tested the effect of Trikafta against a placebo for 24 weeks, or about six months.
In the second trial, 107 patients with two F508del mutations (F/F) received Symdeko for the first four weeks. Then, participants were randomly split into two groups for more four weeks of treatment: one group switched to Trikafta and the other group was maintained on Symdeko.
The primary outcome or goal of both trials was the change in percent predicted forced expiratory volume in one second (ppFEV1), a measure of lung function. Secondary measures included the number of pulmonary exacerbations, levels of sweat chloride — a way to assess CFTR function — and change in the CF Questionnaire Revised respiratory domain score, which assesses respiratory symptoms relevant to people with CF.
Data from both studies showed significant improvements in lung function in Trikafta-treated patients, with ppFEV1 improving by an average of 14.3% in AURORA F/MF, and by 10% in those in AURORA F/F. Patients generally tolerated the treatment well.
In the first trial, the number of pulmonary exacerbations was significantly reduced by 63% in patients taking Trikafta compared with those on placebo. A significant decrease in sweat chloride and CF respiratory symptom score also was also observed in both trials.
Children ages 6 to 11
Vertex also unveiled positive results from another Phase 3 trial (NCT03691779). That study investigated the pharmacokinetics (movement into, through, and out of the body), pharmacodynamics (effect on the body), safety, tolerability, and efficacy of Trikafta in children, ages 6 to 11. This open-label study recruited 66 children with either F/F or F/MF mutations for 24 weeks of treatment. All patients were treated with Trikafta and assessed before and after the treatment.
This study found that children tolerated Trikafta well. When compared with the pre-treatment results, patients showed improvements in ppFEV1, by 10.2 percentage points, and sweat chloride. The CF Questionnaire-Revised respiratory domain score increased by seven points and the lung clearance index (a measure of lung ventilation) had a reduction of approximately two points.
An observational study called PROMISE (NCT04038047) has enrolled 490 CF patients, 12 years and older, to assess the long-term impact of Trikafta on pulmonary function, sweat chloride, body weight and overall health over two years of treatment.
Preliminary results from this study showed that long-term treatment with Trikafta significantly increased daily calorie intake and also led to a reduction in energy expenditure. This is particularly important for most CF patients as malnutrition is common in this patient population. The study is expected to be completed in September 2022.
The long-term effect of Trikafta on those CF-related manifestations also will be assessed in younger children in the PROMISE Pediatric study (NCT04613128). This two-year study is now recruiting up to 180 children, ages 6 to 11, at multiple sites in the U.S. The study is estimated to be concluded in July 2023.
The BEGIN study (NCT04509050) is being conducted at 34 sites across the U.S. and involves about 210 CF children up to 5 years old. It aims to evaluate the effect of Trikafta on several health parameters, such as gastrointestinal, lung, liver, and pancreatic functions, as well as sweat chloride, inflammation, and bone health. Other factors include gut and respiratory bacteria, as well as growth and height. The estimated duration of the study is six years; it is expected to end in October 2025.
Common side effects of Trikafta
Common side effects of Trikafta include:
- upper respiratory infection
- common cold
- nasal congestion
- runny nose
- high levels of liver enzymes
- abdominal pain
Trikafta is not recommended for patients with advanced liver disease unless the benefit for the patient is expected to exceed the risks.
One of the signs of liver damage is the elevation of liver enzymes. Evaluation of liver enzymes levels is recommended for all patients before starting Trikafta, every three months during the first year of treatment, and yearly thereafter.
Cases of cataracts — a clouding of the eye lens — have been observed in children treated with ivacaftor-containing therapies. Eye assessments at the beginning of the study and during follow-up are recommended in children who start the treatment with Trikafta.
Trikafta may cause dizziness in some people. As such, patients should not drive a car, use machinery, or do any task that needs them to be alert until they know if they experience this issue.
Use with other medications
Trikafta may affect the way other medications work, and vice versa. Therefore, patients should not take Trikafta when using antibiotics such as rifampin and rifabutin, seizure treatments, and St. John’s wort.
Patients treated with strong or moderate CYP3A inhibitors should use a reduced dose of Trikafta.
Use in pregnancy and breastfeeding
Results from animal studies on each of Trikafta’s active components did not show treatment-related adverse effects on the fetus or offspring development. However, there are limited data from clinical trials on pregnant women. As such, it is not known if this treatment will harm the developing fetus. It is currently unknown if Trikafta can pass to breast milk. Trikafta’s label states that patients should inform their healthcare team if they are pregnant or plan to become pregnant, are breastfeeding, or plan to do so.
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