KMRC011, an agonist of toll-like receptor 5, mitigates irradiation-induced tissue damage and mortality in cynomolgus monkeys

The Role of the Innate Immune Response in Oral Mucositis Pathogenesis

Oral mucositis (OM) is a significant complication of cancer therapy with limited management strategies. Whilst inflammation is a central feature of destructive and ultimately ulcerative pathology, to date, attempts to mitigate damage via this mechanism have proven limited. A relatively underexamined aspect of OM development is the contribution of elements of the innate immune system. In particular, the role played by barriers, pattern recognition systems, and microbial composition in early damage signaling requires further investigation. As such, this review highlights the innate immune response as a potential focus for research to better understand OM pathogenesis and development of interventions for patients treated with radiotherapy and chemotherapy. Future areas of evaluation include manipulation of microbial-mucosal interactions to alter cytotoxic sensitivity, use of germ-free models, and translation of innate immune-targeted agents interrogated for mucosal injury in other regions of the alimentary canal into OM-based clinical trials.

Looking for the phoenix: the current research on radiation countermeasures

PURPOSE

Ionizing radiation (IR) is widely applied in radiotherapy for the treatment of over 50% of cancer patients. IR is also intensively used in medical diagnostics on a daily basis in imaging. Moreover, recent geopolitical events have re-ignited the real threat of the use of nuclear weapons. Medical radiation countermeasures represent one of the effective protection strategies against the effects of IR. The aim of this review was to summarize the most commonly used strategies and procedures in the development of radiation countermeasures and to evaluate the current state of their research, with a focus on those in the clinical trial phase.

METHODS

Clinical trials for this review were selected in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. The search was performed in the clinicaltrials.gov database as of May 2022.

RESULTS

Our search returned 263 studies, which were screened and of which 25 were included in the review. 10 of these studies had been completed, 3 with promising results: KMRC011 increased G-CSF, IL-6, and neutrophil counts suggesting potential for the treatment of hematopoietic acute radiation syndrome (H-ARS); GC4419 reduced the number of patients with severe oral mucositis and its duration; the combination of enoxaparin, pentoxifylline, and ursodeoxycholic acid reduced the incidence of focal radiation-induced liver injury.

CONCLUSION

The agents discovered so far show significant side effects or low efficacy, and hence most of the tested agents terminate in the early stages of development. In addition, the low profitability of this type of drug demotivates the private sector to invest in such research. To overcome this problem, there is a need to involve more public resources in funding. Among the technological opportunities, a deeper use of in silico approaches seems to be prospective.

Clinical evaluation of toll-like receptor-5 agonist for radiation-induced oral mucositis in beagle dogs

This study aimed to evaluate the clinical safety and validate the radiomitigative effect of KMRC011, against radiation-induced oral mucositis in beagle dogs. Clinical safety was evaluated by assessing tolerability, complete blood tests, and plasma biochemistry after drug administration. The radiomitigative effect of KMRC011 was evaluated macropathologically and histopathologically after inducing oral mucositis iatrogenically using 20 Gy irradiation. The plasma concentration of interleukin-6 was measured via enzyme-linked immunosorbent assay, as a biomarker of KMRC011 bioreactivity. Decreased tolerability, increased neutrophil count, hepatic enzyme concentration, C-reactive protein concentration, and interleukin-6 concentration after the administration was observed and ceased within 24 h without additional treatment. Although all animals included in the present study developed severe mucositis in the late course of the study, animals administered KMRC011 showed less erythema, ulcer, inflammatory infiltration. These results suggest that KMRC011 may be used as an adjuvant for radiotherapy without severe adverse effects, especially during short-term radiotherapy, such as hypofractionated radiotherapy or stereotactic radiotherapy.

A first-in-human study of KMRC011, a potential treatment for acute radiation syndrome, to explore tolerability, pharmacokinetics, and pharmacodynamics

KMRC011 is a novel Toll-like receptor 5 agonist under development as a treatment for acute radiation syndrome (ARS). The aim of this first-in-human study was to investigate the tolerability, pharmacokinetics, and pharmacodynamics of a single intramuscular dose of KMRC011 in healthy subjects. A randomized, single-blind, placebo-controlled, single dose-escalation study was conducted with the starting dose of 5 μg. Eight (4 only for 5 μg cohort) subjects per cohort were randomly assigned to KMRC011 or placebo in a 3:1 ratio. Dose-limiting toxicity (DLT) was assessed throughout the study. Serum concentrations of KMRC011, granulocyte colony-stimulating factor (G-CSF), and interleukin-6 (IL-6) were measured up to 48 h postdose. Based on safety review, the dose of KMRC011 escalated up to 20 μg, and consequently, a total of 4 dose levels (5, 10, 15, and 20 μg) were explored. The most common adverse event was injection site reaction, showing no dose-related trend. Three DLTs (2 cases of hepatic enzyme increased and 1 of pyrexia) were observed; 1 in the 15 μg cohort and 2 in the 20 μg cohort. A developed method could not detect any KMRC011 in serum. KMRC011 15 μg and 20 μg showed significant increases of G-CSF, IL-6, and absolute neutrophil counts, compared with the placebo. A single intramuscular administration of KMRC011 ranging from 5 to 15 μg was tolerated in healthy subjects. Doses of KMRC011 equal to or greater than 15 μg exerted TLR5 agonist-like activities by increasing serum G-CSF and IL-6. It suggests that KMRC011 has the potential for a treatment for ARS.