Advancements in Cystic Fibrosis Treatment

Triple Drug Combination Under Investigation

A new triple drug combination aimed at treating the root cause of cystic fibrosis is currently being researched. Preliminary findings indicate a notable enhancement in lung function among participants.

Understanding Cystic Fibrosis

Cystic fibrosis is a hereditary disorder that impacts the chloride channels in the body, specifically known as cystic fibrosis transmembrane conductance regulator (CFTR). The primary body systems affected by this genetic mutation are the respiratory and gastrointestinal systems. This condition predominantly presents as chronic lung disease along with a deficiency in digestive enzymes.

Effects on Lung Function and Digestion

In individuals with cystic fibrosis, chronic lung disease is characterized by an excess of thick, sticky mucus and persistent lower respiratory tract infections. Patients are required to take digestive enzymes before meals to aid in nutrient absorption, and children with this condition often face challenges in gaining and maintaining a healthy weight.

New Drug Developments Targeting CFTR Mutations

Innovative Therapies for Common Mutations

Two novel drugs have been created to specifically target prevalent mutations of the CFTR channel. These medications bind to distinct locations on the CFTR channels, potentially enhancing health outcomes and survival rates for individuals with the most common mutations of cystic fibrosis.

Clinical Trials of VX-659 and VX-445

Researchers conducted two clinical studies to evaluate the safety and efficacy of the new drugs, referred to as VX-659 and VX-445. These drugs are combined with tezacaftor and ivacaftor, both of which are existing CFTR corrector therapies.

In the first study, VX-659 combined with tezacaftor and ivacaftor was administered to 12 patients sharing the same CFTR genetic alteration. The second study involved randomly assigning 117 patients with the same genotype to either a placebo group or a treatment group, followed over four weeks.

Positive Outcomes from Drug Combinations

After four weeks, researchers reported significant improvements in lung function tests among patients in the treatment group, with these findings published in the New England Journal of Medicine. The second study, which evaluated VX-445 in combination with tezacaftor and ivacaftor, yielded similar positive results compared to the placebo group. Both drug combinations not only enhanced respiratory function but also improved scores on the respiratory section of the Cystic Fibrosis Questionnaire. Although side effects were noted in both studies, only three out of the total 122 patients discontinued therapy due to serious adverse effects.

Future Research Directions

Need for Phase III Clinical Trials

These newly developed CFTR-targeted drugs hold the potential to address the fundamental cause of cystic fibrosis by correcting dysfunctional chloride channels. However, the current trials primarily focused on the short-term efficacy of these drugs on respiratory function.

It remains uncertain whether these medications are safe and effective over extended periods or if they can rectify digestive dysfunctions associated with cystic fibrosis. Therefore, researchers must conduct Phase III clinical trials to validate the long-term safety of these treatments and explore their potential to reverse other non-respiratory symptoms of cystic fibrosis.

References

Mayor, S. Cystic fibrosis: triple drug regimens that target defective ion channel improve lung function, studies show. BMJ Research News. 2018.
Rosenstein, BJ. Cystic Fibrosis. Merck Manual Professional Version. 2017. https://www.merckmanuals.com/en-ca/professional/pediatrics/cystic-fibrosis-cf/cystic-fibrosis
Symdeko. Vertex Pharmaceuticals Incorporated. https://www.symdeko.com/