Phase 1 Results: Oral Ketamir-2 Safety and PK in Neuropathic Pain

Phase 1 Study Establishes Safety and Tolerability of Oral Ketamir-2

The first-in-human Phase 1 trial of Ketamir-2, a novel oral N-methyl-D-aspartate (NMDA) receptor antagonist, demonstrates that the compound is safe and well-tolerated at doses up to 600 mg in healthy adults. Conducted under the identifier MIRA-001, this randomized, double-blind, placebo-controlled study enrolled 57 participants who received either single ascending doses (50–600 mg) or repeated daily doses (150–600 mg for five days). Importantly, no serious adverse events, dose-dependent toxicity, or meaningful psychotomimetic (dissociative) or abuse-related signals were observed, as measured by standardized tools such as the Bowdle Visual Analog Scale (VAS), the Ketamine Side Effect Tool (KSET), and the Columbia-Suicide Severity Rating Scale (C-SSRS). Adverse events occurred in 37.2% of Ketamir-2 recipients and 50.0% of placebo recipients, with no Grade ≥3 events reported.

Mechanism: Selectivity and Pharmacokinetics Distinguish Ketamir-2

Ketamir-2 is engineered as a low-affinity, phencyclidine-site-selective NMDA antagonist, with an in vitro IC50 of approximately 100 µM, significantly lower than ketamine's low single-digit micromolar range. This selectivity is designed to retain analgesic efficacy while minimizing the dissociative and abuse liabilities that restrict ketamine's clinical use, especially in oral formulations. The pharmacokinetic (PK) profile of Ketamir-2 showed rapid absorption (Tmax 1.0–2.5 hours), dose-dependent plasma exposure, and no clinically meaningful accumulation over five days. Its primary metabolite, Norketamir, exhibited dose-proportional exposure and a longer half-life (6.4–8.6 hours) compared to the parent compound (2.5–7.2 hours). Notably, exposures at 300 and 600 mg met or exceeded plasma concentrations associated with efficacy in preclinical models of chemotherapy-induced peripheral neuropathy, supporting the rationale for advancing to Phase 2a studies.

Context: Addressing Ketamine's Limitations in Pain and Psychiatry

Ketamine, a high-affinity NMDA antagonist, is used off-label for neuropathic pain and treatment-resistant depression but is limited by poor oral bioavailability, a narrow therapeutic window, and significant dissociative side effects. Regulatory concerns over abuse potential and psychiatric risk further constrain its adoption. By contrast, Ketamir-2’s oral bioavailability and reduced psychotomimetic liability could offer a safer, more scalable alternative for non-opioid pain management and potentially for neuropsychiatric indications. The absence of dissociative or abuse signals in this Phase 1 study is particularly notable, as it may lower both clinical and legal barriers to broader therapeutic development and eventual commercialization. A key insight not widely discussed in competitor coverage is that the trial’s rigorous use of validated psychotomimetic and suicidality screening tools—rarely deployed in early-phase NMDA antagonist studies—provides a higher level of confidence in the compound’s safety profile, which could streamline regulatory review in subsequent phases.

Policy, Research, and Industry Implications

The favorable safety and PK results for Ketamir-2 in healthy volunteers have immediate implications for the design of Phase 2a trials in neuropathic pain and possibly other indications such as depression or post-traumatic stress disorder (PTSD). Should efficacy be demonstrated, Ketamir-2 could fill a significant gap in non-opioid pain therapeutics, a field under intense regulatory and public health scrutiny due to the opioid crisis. The compound’s differentiated risk profile may also facilitate a smoother path through regulatory agencies such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA), where concerns about dissociation and abuse liability have historically slowed or blocked NMDA antagonist approvals. For industry stakeholders, Ketamir-2’s progress signals renewed interest in next-generation dissociative therapeutics that avoid the pitfalls of first-generation agents like ketamine and phencyclidine (PCP).

Risks, Unknowns, and Next Steps

While the Phase 1 data are promising, several risks and unknowns remain. The trial involved healthy volunteers, not patients with neuropathic pain or psychiatric disorders, so efficacy and real-world tolerability are untested. Long-term safety, especially regarding cognitive effects or subtle psychiatric symptoms, requires further study. Additionally, the translation of preclinical efficacy to clinical benefit is not guaranteed, and the absence of abuse signals in a controlled setting may not fully predict outcomes in broader populations. Finally, the regulatory landscape for novel NMDA antagonists remains complex, with agencies likely to require robust post-marketing surveillance if approval is granted. The sponsor’s decision to use rigorous psychometric monitoring in Phase 1 may set a precedent for future trials, potentially lowering risk for both patients and investors.

Looking Forward: A New Chapter for Oral NMDA Antagonists?

With Phase 1 safety and pharmacokinetic data in hand, Ketamir-2 is positioned to enter Phase 2a clinical trials targeting neuropathic pain, with possible expansion to neuropsychiatric indications if early efficacy signals emerge. The compound’s oral formulation, selective mechanism, and clean safety profile distinguish it from ketamine and may represent a paradigm shift in non-opioid pain management. Continued vigilance regarding long-term effects and real-world abuse potential will be essential as development progresses. If subsequent trials confirm efficacy without significant psychiatric or abuse liability, Ketamir-2 could become a leading candidate in the next generation of dissociative therapeutics, with broad implications for clinical practice, regulatory policy, and pharmaceutical investment.

How we research: Reviewed by Dr. Alex Kim, MD, PhD (Neuropharmacology) on 2026-09-02. Primary data from OpenAlex record W7205009176. Regulatory context cross-checked with FDA and EMA guidelines as of August 2026.