Delpor is sketching out late-stage clinical trial plans for its drug-device combination implant DLP-114 (risperidone) in schizophrenia.
After presenting topline results from a Phase Ib/IIa trial (NCT04418466) in November, the US-based biopharma company is currently making some changes to the product based on the learnings from the previous study, CEO Tassos Nicolaou told Clinical Trials Arena.
The company is set to launch the Phase IIb study in Q1 2024, which is expected to go on until the end of the year. Afterwards, Delpor plans to initiate both a registrational Phase III trial and a safety study in parallel, which should be sufficient for product approval.
The CEO shared that the US Food and Drug Administration (FDA) has accepted the idea of approving the drug using pharmacokinetics (PKs) as a surrogate endpoint for safety and efficacy. The recently completed and upcoming trials all have the same structure as a single-sequence PK comparability study.
In addition, Delpor will measure secondary efficacy endpoints such as the Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression (CGI) scores.
In the Phase IIb study, Delpor will enrol approximately 35-40 schizophrenia patients across sites based in the US. Around 50-80 participants will be enrolled into the registrational trial and 100-150 participants in the safety study, with a possibility to include countries outside of the US.
Nicolaou explained that the trials will focus only on stable schizophrenia patients as the company aims to get DLP-114 approved as a maintenance therapy.
DLP-114 is an investigational matchstick-long implant device that provides continuous dosing of risperidone, an antipsychotic medication approved for the treatment of schizophrenia. The device is implanted into the abdominal area and lasts for six to 12 months.
In addition to schizophrenia, Delpor is also investigating its drug-device combo approach in opioid use disorder with DLP-160 (naltrexone). The company has already completed a Phase I study in Australia and plans to file for a new investigational drug (IND) application in the US early next year. The next Phase Ib trial is expected to start in the first half of 2024.
Continuous delivery edges over competitors
The drug development landscape has stagnated in schizophrenia over the past few years, whereas the substance use disorder field is neglected by the pharma industry. However, Delpor is aiming to make a mark in the field with its product longevity and stability.
The currently available long-acting formulations for risperidone and naltrexone are long-acting injectables (LAIs), but typically LAIs last for up to two months. Delpor’s implantable devices shoot for up to a year.
The implants are also reversible and can be removed if the therapy causes unexpected adverse events, pregnancy or the patient’s preference to switch to another therapeutic agent. According to Nicolaou, plasma levels drop to zero within the day after the removal whereas the washout period is longer with injectables.
The reason why Delpor can extend the dosing period up to a year is because of a stable and flat PK profile. Whereas long-acting injectables cause big bursts after the administration, followed by a fast drop before the end of the dosing period.
However, Delpor sees its product as a complementary addition to injectables, as some patients may be suitable more for one rather than the other, Nicolaou added.
