Arikayce (liposomal amikacin for inhalation, or LAI) is an investigational liposomal formulation of the antibiotic amikacin being developed by Insmed.

It is being assessed as a treatment for lung infections caused by non-tuberculous mycobacteria (NTM) in patients with cystic fibrosis (CF) as well as other lung diseases. Amikacin is currently approved for intravenous or intramuscular use to treat serious bacterial infections.

How Arikayce works

Liposomes are microscopic spheres that contain water. In liposome drug delivery systems, water-soluble substances such as amikacin are contained inside those spheres. The goal of inhaled liposomal amikacin is to deliver the treatment directly to the site of the lung infection.

NTM invade macrophages — special cells of the immune system — and multiply, causing lung infections. When non-liposomal amikacin is inhaled, it does not achieve the same level of intracellular delivery as does liposomal amikacin.

This is because the bacteria produce negatively charged materials to protect themselves called biofilms, so positively charged antibiotics (such as amikacin) are attracted to the opposite charge and bind to that. As a result, the antibiotic cannot efficiently reach the site where the bacteria are multiplying.

Insmed reports that the liposomal packaging of amikacin allows it to be delivered to the macrophages at high concentrations. In other words, the particle nature of the liposomes could be the key to its effectiveness.

Arikayce in clinical trials

A completed Phase 2 clinical trial (NCT01315236) testing Arikayce in patients with NMT showed that the treatment did not reach its primary endpoint, or goal, of a change in mycobacterial density on a seven-point scale from the study’s start, according to a 2014 report.

But a key secondary goal, that of culture conversion to negative, did reach statistical significance, with 11 out of 44 patients given Arikayce plus standard care demonstrating negative cultures by day 84, compared to three patients out of 45 given placebo plus standard care.

After the completion of the trial, participants had the option to enroll in an open-label, 84-day extension study, during which all received Arikayce plus standard care (an anti-mycobacterial regimen), and were monitored for 12 months.

In total, 59 patients completed the extension trial, and results showed that most participants continued to have negative sputum cultures in both the open-label and follow-up phases. Patients who were assigned Arikayce in the Phase 2 study showed a continued improvement in the six-minute walk test, while those who switched from placebo to treatment in the open-label trial demonstrated a reduced rate of decline from baseline.

An open-label Phase 3 clinical trial (NCT02344004) in people with NTM lung infections is now underway at sites in the U.S., U.K., Europe, Canada, and parts of Asia, but is not currently recruiting participants. Its primary goal is culture conversion brought about by treatment with Arikayce plus standard care. As an open-label study, it has no placebo arm.

A second Phase 2 open label extension study started in 2017 and is currently recruiting participants (NCT03038178). The trial will evaluate the safety, efficacy, and tolerability of Arikayce taken once daily for 12 months. The study will assess the change in baseline sputum culture (a test of lung infection) and the change in the six-minute walk test as well as monitoring for side effects.

Arikayce is also being studied as a treatment for cystic fibrosis patients with chronic Pseudomonas aeruginosa infection. In a Phase 3 study (NCT01315678), the effectiveness and safety of Arikayce were compared to that of Tobi (tobramycin, an inhaled antibiotic).

Results reported in 2014 showed that the drug is generally safe and well-tolerated, with no adverse events observed. Participants taking Arikayce improved their respiratory system compared to tobramycin.

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