Long-Acting Schizophrenia Tx Shows Long-Term Safety With Limited Relapses

NASHVILLE, Tenn. -- Every-6-month dosing of the long-acting injectable paliperidone palmitate (Invega Hafyera) for schizophrenia was effective and safe up to 3 years, researchers reported here.

In an intention-to-treat analysis that included 121 patients, 95.9% on the twice-a-year dose of the atypical antipsychotic remained relapse-free, reported Reina Benabou, MD, PhD, vice president and head of medical affairs at Janssen Neuroscience in New York City, during a poster presentation at Psych Congress 2023.

In addition, there were no new safety signals during the study, and no deaths.

"We're talking about patients with schizophrenia, which the main problem ... is the adherence to the treatment," Benabou told MedPage Today. "Sometimes, unfortunately, they don't have the overall cognition to really sustain taking pills every day."

When nonadherence to treatment becomes a constant for these patients, they tend to show up in emergency departments or may be incarcerated, Benabou said, noting that each relapse also means that patients can lose brain and physical function as well.

"Honestly, that's the beauty of any long-acting drug that provides the stability for the brain that's needed," she added. "We see that in Parkinson's. We see that in multiple sclerosis and many other things that the longer that you give the brain the stability that's needed -- and you don't kill any cells -- the better for the brain and for [patients'] function."

In this study, participants were clinically stable and well maintained on paliperidone palmitate every 6 months, based on scores on the Positive and Negative Syndrome Scale, the Clinical Global Impression-Severity scale, and the Personal and Social Performance scale.

Of the 121 participants in the study, mean age was 38.6 years, 68.6% were men, and mean length of illness was 11 years. In total, 4.1% of patients relapsed during the study period.

Most of the patients (80.2%) experienced at least one adverse event during treatment, but few patients experienced severe adverse events (5.8%). The most common adverse events included headache (18.2%), weight gain (12.4%), and an increase in blood prolactin (11.6%).

Participants had to have completed a prior 1-year double-blind randomized controlled trial with paliperidone palmitate once every 3 months (Invega Trinza) before being enrolled in this study.

The researchers noted that this analysis did not include data on patients who relapsed during the initial trial or on patients who did not opt into the every-6-month dosing study.

However, another poster presented during the meeting outlined safety data for patients who transitioned to paliperidone palmitate every 6 months from the 1-month (Invega Sustenna) and 3-month formulations.

These data showed that patients from both formulation groups experienced low relapse rates in transitioning to the twice-a-year formulation. The group that transitioned from the 1-month to 6-month formulation (n=231) had a relapse rate of 7.8%, while the group that transitioned from the 3-month to 6-month formulation (n=247) had a relapse rate of 7.3%.

The researchers said the safety shown with transitioning to the 6-month formulation in both groups suggests that clinicians may have flexibility in developing treatment plans for patients interested in switching.

Benabou noted that patients must be adequately treated with the 1- or 3-month formulations of paliperidone palmitate before switching to the every-6-month treatment, and the opportunity to take the long-term formulation can bring meaningful benefits to patients' lives.

"Unfortunately, the bar for schizophrenia is very low," she said. "The majority of those patients, when they have the diagnosis, they go straight to Medicaid. What this shows [is] when we see those patients [taking] those long-acting medications, it doesn't need to be that way. There's hope. There's treatment."