A New Drug Could Halt Weight Gain in Patients Taking These Antipsychotics

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Source: Alkermes Plc

Alkermes Plc is developing a new antipsychotic drug that could remove a major side effect that is associated with atypical antipsychotic medicines, including Eli Lilly and Co.'s Zyprexa.

Atypical antipsychotics are used to combat a variety of conditions, including schizophrenia and bipolar disorder, but the class of drugs can cause significant weight gain in patients, which can result in patients discontinuing their treatment.

A big market with a need for better therapies
Atypical antipsychotics like Zyprexa, Seroquel, and Abilify are commonly prescribed therapies that generate billions of dollars in sales annually.

Eli Lilly's Zyprexa was one of the best selling of these drugs, generating peak sales of $5 billion per year before losing patent exclusivity in 2011. Even after facing off against generics for years, Zyprexa remains a top seller for Eli Lilly, producing more than $1 billion in revenue for the company in 2014.

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The significant need for therapies that address tough-to-treat conditions like schizophrenia is the reason why atypical antipsychotics like Zyprexa have been so successful.According to the U.S. National Institute of Mental Health, or NIMH, 1.1% of U.S. adults have schizophrenia, and despite the availability of first generation antipsychotics and atypical antipsychotics, just 60% of Americans with schizophrenia receive treatment.

The fact that the nature of schizophrenia can make it difficult to stick with continuous treatment makestreatment even more difficult, particularly when side effects like weight gain occur.

Schizophrenia often causes patients to have difficulty thinking, perceiving the world around them, and controlling emotional responses. Some patients may have delusions and hallucinations, while others may struggle to form social bonds. For these reasons, patient adherence to chronic treatment is a major obstacle that has proven difficult to overcome. According to the pharmacy benefit manager Express Scripts, just 42% of patients taking mental or neurological disorder drugs like Zyprexa take their medicine as prescribed.

Innovating treatment
As I've noted, one of the most common side effects associated with taking atypical antipsychotics is weight gain, and Zyprexa has one of the highest incidence rates of weight gain in the drug class.

As a result, Alkermes is developing ALKS-3831, a once daily pill that combines generic Zyprexa with samidorphan, a novel mu-opioid antagonist that Alkermes developed to control Zyprexa's potential to cause patients to gain weight.

In phase 2 studies, Alkermes' approach appears to work. The company reported top line study data earlier this year that show that ALKS-3831 works as well at controlling schizophrenia as Zyprexa, and additional results released this month show that ALKS-3831 successfully curbed weight gain, too.

Overall, patients who took ALKS-3831 for three months saw their weight increase by just 0.5%, while patients who took Zyprexa saw their weight increase by 4.3%. Additionally, patients who switched over from Zyprexa to ALKS-3831 after the three month period and then took ALKS-3831 for three more months only gained an additional 0.1% of their weight during the ALKS-3831 period.

Looking forward
The mid-stage results set the stage for a phase 3 trial for ALKS-3831 that should begin this year. If that trial delivers similar results, Alkermes will be able to seek FDA approval. That could still be a while away, but so far, the phase 2 success seems to indicate that Alkermes has built a better mousetrap that, if approved, could lead to ALKS-3831 becoming a best in class option within this multibillion dollar market. For that reason, investors might want to consider owning this one in their portfolios for the long haul.

The article A New Drug Could Halt Weight Gain in Patients Taking These Antipsychotics originally appeared on Fool.com.

Todd Campbell owns shares of Alkermes,. Todd owns E.B. Capital Markets, LLC. E.B. Capital's clients may or may not have positions in the companies mentioned. The Motley Fool recommends Express Scripts. The Motley Fool owns shares of Express Scripts. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.