NLS Pharmaceutics Ltd. announced positive data from five recently completed in vitro drug-drug interaction studies investigating the potential for DDI of mazindol, a triple monoamine reuptake inhibitor and partial orexin-2 agonist, as well as its hydrolyzed metabolite (M6). Typical DDI studies include Cytochrome P450 (CYP), UDP glucuronosyltransferase (UGT) and transporter inhibition and induction studies to evaluate whether mazindol affects the pharmacokinetic (PK) effect of other drugs (mazindol as a "perpetrator"). In addition, in vitro studies are conducted with CYP and transporter substrates to evaluate whether other drugs can affect mazindol PK (mazindol as a "victim").

Following U.S. Food and Drug Administration (FDA) guidelines, the in vitro DDI studies were designed to evaluate the drug interaction potential across a wide range of metabolic enzymes and transporters when co-administered with mazindol. The mazindol in vitro studies examined the following: CYP Inhibition in Human Liver Microsomes. CYP Induction in Cultured Human Hepatocytes.

CYP and UGT Reaction Phenotyping. UGT Inhibition in Human Liver Microsomes. ATP-binding case (ABC) and solute carrier (SLC) Transporter Inhibition and Substrate Potential in Cells and Vesicles.

Results of the in vitro victim studies showed that mazindol is not metabolized by CYPs or UGTs and is not transported by BCRP, OAT1, OAT3 and OCT2. Only the hydrolysis metabolite (but not mazindol) is a P-glycoprotein (Pgp) substrate; thus a clinical DDI study of mazindol is planned to quantify the potential for an increase in the hydrolyzed metabolite (M6) exposure in the presence of a Pgp inhibitor (e.g., Itraconazole). Otherwise, concomitant medications are not expected to affect the PK of mazindol.

DDI studies are a standard and necessary step required by the FDA and other regulatory agencies globally for approving a new drug to market. DDI studies help identify potential adverse reactions that may be caused by interactions between multiple drugs, leading to unintended reactions, toxic side effects, or in some cases, a lack of therapeutic efficacy. With the rise in polypharmacy to treat comorbidities, alongside prevalent substance abuse, drug-drug interactions have become a critical factor to consider when treating narcolepsy.

Approximately 50% of prescribed drugs currently on the market are known to cause drug interactions with CYP3A4 inhibitors and can lead to side effects. Findings from DDI studies help to inform drug labeling that is then used by healthcare providers to aid in therapeutic decision-making. Currently available medications used to treat narcolepsy can have significant DDI effects which prevent co-administration or require dose adjustments of drugs like hormonal contraceptives, proton-pump inhibitors or anti-epileptic drugs.