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Long-Acting Injectable Helped Adults With Schizophrenia Remain Relapse-Free

— 96% of patients who made it through the first year were relapse-free for the next 2 years

Ƶ MedicalToday

A study showed that 96% of patients with schizophrenia remained relapse-free with every-6-month dosing of the long-acting injectable paliperidone palmitate (Invega Hafyera) through up to 3 years, researchers reported during a poster presentation at the recent Psych Congress 2023.

In this exclusive Ƶ video, study author , of the Feinstein Institutes for Medical Research at Northwell Health in Manhasset, New York, explains the study's design, results, and conclusions.

Following is a transcript of his remarks:

Hi, everyone. I'm going to present the poster titled, "Efficacy and safety of paliperidone palmitate 6-month formulation, a 3-year analysis in adults with schizophrenia."

In terms of background, patients with schizophrenia do require long-term treatment with antipsychotics. However, individuals with schizophrenia often struggle -- as you know and I know -- with consistent medication adherence and that can lead to poor outcomes, mainly driven by relapses. Long-acting injectable antipsychotics, or LAIs, have the potential to improve adherence and thereby symptom control in patients with schizophrenia who are then able to also achieve more of their long-term goals.

Paliperidone palmitate once every 6 months (or PP6M) is the first LAI with a substantially longer dosing interval of every 6 months (twice yearly). The analysis we presented were of patients who were followed from a double-blind randomized controlled trial through a 2-year single-arm open-label extension study, and that assessed the long-term efficacy and safety of PP6M in adults with schizophrenia for up to 3 years, a period that's rarely assessed that long.

Patients were 18 to 70 years of age that had a DSM-5 diagnosis of schizophrenia and a PANSS [Positive and Negative Syndrome Scale] total score of less than 70. So they were already stabilized in the first year of that randomized double-blind trial, comparing 6-monthly and 3-monthly paliperidone, which were non-inferior, both compared together.

Patients receiving the PP6M arm who completed the 1-year double-blind study continued for up to 2 years in an open-label extension phase. And those were then included in the analysis.

The primary efficacy endpoint was assessment of relapse events. Secondary assessments included the PANSS total and subscale scores, CGI [Clinical Global Impression] severity, so that's illness severity score, and the PSP, or Personal and Social Performance Score looking at the functionality. Furthermore, safety assessments were also included.

A total of 121 patients were included in this 3-year intention-to-treat analysis, meaning everyone who finished the 1-year double-blind study was then followed for however long they stayed in up until the duration of 3 years. Mean age of the patients was 39 years, most were male, and the mean duration of illness was 11 years. So these were your multi-episode patients.

In terms of the survival rate, the relapse rate over the 3 years after 1-year stabilization was an amazingly low 4.1%. So, 96% of patients who had made it through the first year then remained relapse-free for the next 2 years. That's an enormously low number. Participants also treated with PP6M were clinically stable and well-maintained, which was evidenced by the PANSS total, the CGI severity, and the PSP -- the functional scores, that are very well remaining stable.

Overall, 80.2% of patients had at least one adverse event, but these were usually mild and did not lead to discontinuation. The most common TEAEs [treatment-emergent adverse events] occurring at least 10% were headache, weight increase, prolactin increase -- or hyperprolactinemia, nasopharyngitis, and injection site pain. But those [that] were related to the PP6M were very few, and also leading to drug withdrawal in only 5.8% and 5.0%.

Some limitations need to be mentioned, and there was no comparative group in the 3-year study. And basically, additionally, patients who started on PP6M and relapsed or discontinued during the double-blind phase were not included, and also those not opting to go into the open-label extension phase. Then the open-label extension phase was limited to six participating countries, so the data may not be fully generalizable to all countries.

In conclusion, a 3-year intent-to-treat analysis of 121 patients on PP6M demonstrated that 95.9% of patients remained relapse-free beyond the 1 year up to the end of 3 years. There were no new safety signals identified, no deaths were reported. So these results support the long-term efficacy and safety of the 2-yearly, or twice-a-year, dosing of PP6M up to 3 years in adults with schizophrenia who can benefit from the long-term stability of their illness.

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    Greg Laub is the Senior Director of Video and currently leads the video and podcast production teams.