The goal of this study is to evaluate if KRIYA-748 (RP-008) is safe, tolerable, and preliminary effective in treating trigeminal neuralgia (TN) when used in combination with varenicline tartrate. The study will also assess what doses of RP-008 are safe and tolerable for participants and how the severity of participants' TN pain and frequency of facial pain attacks are affected.
Participant is capable of providing signed informed consent.
Participant must be between 18 to 80 years of age (inclusive), at the time of signing the informed consent.
Confirmed diagnosis of classical or idiopathic TN according to the criteria of the International Classification of Headache Disorders-3rd edition (ICHD-3, 2018).
The diagnosis of TN established at least 6 months prior to Screening.
Participant has bilateral TN pain attacks.
Participants with secondary TN, defined by ICHD-3 as TN caused by an underlying disease (e.g., tumor in the cerebellopontine angle, arteriovenous malformation, or multiple sclerosis).
Participants with facial pain not meeting the ICHD-3 diagnostic criteria for either classical or idiopathic TN, including: trigeminal autonomic cephalalgias, cluster headache, hemicrania continua, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA).
Participants who had no change in pain after taking sodium channel blockers despite the use of a therapeutic dose for an adequate duration of time.