Insys Therapeutics commercially launched Syndros (dronabinol oral solution) on July 31, 2017, becoming the first marketed, FDA-approved liquid dronabinol.
The agent was FDA-approved in July 2016 for chemotherapy-induced nausea and vomiting (CINV) patients who have not responded to conventional antiemetic therapies, and for treating anorexia associated with weight loss in acquired immune deficiency syndrome (AIDS) patients. Syndros is a liquid version of dronabinol, which was originally FDA-approved in 1985 in capsule form, and is marketed by AbbVie under the brand name Marinol. Dronabinol is a synthetic, pharmaceutically manufactured version of the cannabinoid tetrahydrocannabinol (THC).
Insys utilised the 505(b)(2) development pathway for Syndros, which allows much of the data needed for a New Drug Approval (NDA), including safety and efficacy data on the active ingredient, to come from previously completed studies by other parties, thereby reducing the costs and time required for development. Thus, Insys only had to carry out a Phase I study that assessed the bioequivalence and pharmacokinetics of Syndros compared with Marinol.
The open-label study enrolled 52 healthy volunteers and concluded that single-dose Syndros 4.25mg was bioequivalent to dronabinol capsule 5mg under fasting conditions. The study also indicated that Syndros may provide an easy-to-swallow administration option with lower intraindividual variability compared with dronabinol capsules (13.5% versus 36.8%, respectively), and more rapid absorption (nine minutes versus two hours, respectively). The liquid formulation of Syndros also allows for the dosage to be titrated to clinical effect. Insys hopes that these attributes will differentiate its offering from Marinol and dronabinol generics. The company estimates that approximately 9,500 prescribers account for 70% of dronabinol prescriptions, and hopes to convert a large portion of these prescribers through direct detailing to physicians, highlighting the improved product profile of Syndros.
The long journey
The launch of Syndros marks the culmination of a long journey to approval and commercialisation. Insys first submitted a NDA for the agent in August 2014, but was rejected in October of that year due to providing an inadequate plan to study the safety and efficacy of the agent in pediatric patients. Insys submitted a subsequent NDA in June 2015, which the FDA accepted in August of that year. However, in March 2016, the FDA announced that it would extend its decision date from April 2016 to July 2016, as it had received new, non-clinical information from Insys.
In July 2016, the FDA announced its decision to grant approval for Syndros. Subsequently, the Department of Health and Human Services provided the Drug Enforcement Administration (DEA) with a scheduling recommendation, and the DEA issued its interim final ruling in March 2017, which resulted in Syndros being placed in Schedule II of the Controlled Substances Act (CSA). Insys received final labelling approval from the FDA in May 2017 and finally launched Syndros at the end of July 2017. A delay of one year between approval and commercialisation is atypical for cancer related therapies; however, with Syndros, the main cause of the delay was the time needed for the DEA to determine scheduling for the agent. This is not surprising, given the fact that Syndros is a synthetic derivative of THC and its liquid formulation was determined to be easier to abuse than Marinol, as Syndros can be manipulated for abuse by inhalation; thus, it was not placed in the same Schedule as Marinol.
In its financial results for its third quarter, which ended September 30, 2017, Insys announced that Syndros generated $0.7M in revenue in its first two months. Within the CINV indication, GlobalData believes its overall market potential is small, as it is indicated for use after traditional antiemetics, of which there are many options available, have failed. It remains to be seen whether Syndros’ purported advantages are enough to convince prescribers to switch from Marinol and generics.
GlobalData (2017). PharmaFocus: Supportive Care in Oncology, to be published