GTP-004 is a fixed-dose combination tablet for the treatment of the muscle weakness associated with myasthenia gravis. GTP-004 combines pyridostigmine with an antagonist of the gastrointestinal, or GI, side effects of pyridostigmine.

Myasthenia gravis is a chronic autoimmune disease of the neuromuscular junction characterized by muscle weakness. The disease occurs in all ethnic groups and both genders. The prevalence of the disease in the United States is estimated at 14 to 20 per 100,000 population, approximately 36,000 to 60,000 cases in the U.S. (Howard, 2015). Myasthenia gravis most commonly affects adult women (onset between 20 to 40 years) and older men (onset over 60), but it can occur at any age (Myasthenia Gravis Fact Sheet; National Institute of Neurological Disorders and Stroke, 2016).

Cholinesterase inhibitors, or ChEIs, that do not get into the brain (do not cross the blood-brain barrier), such as pyridostigmine and neostigmine are used to treat the muscular weakness associated with myasthenia gravis. However, ChEIs also act at cholinergic synapses in the gut to cause GI side effects such as diarrhea, nausea and vomiting, which are dose-limiting. The GI side effects associated with pyridostigmine or neostigmine are an important source of discomfort for the patient, may be the source of non-compliance, or may result in the need to decrease the dose of the ChEI to mitigate these side effects when these become dose-limiting. As a consequence, efficacy may be reduced. Mitigating the GI side effects of neostigmine or pyridostigmine with a drug that prevents diarrhea, nausea and vomiting should lead to greater patient comfort, safety, and compliance as well as to improved efficacy

Since GTP-004 is a combination tablet of two approved drugs, we anticipate that the new drug application, or NDA, will be a 505(B)2 NDA. This is an abbreviated and more streamlined form of NDA than a full application, which would generally require information about the safety and effectiveness of the drug to come from studies conducted by or for the applicant. This can result in a faster and less costly approval process.

Provisional patent applications protecting the combination of neostigmine or pyridostigmine with a number of antiemetic drugs were filed by GTP in early 2017.

We expect to complete a proof-of-concept clinical trial for GTP-004 in the first half of 2018.