Coppertone or Nibrozetone?

Aug 4, 2023

The new International Nonproprietary Name (INN) for RRx-001 is nibrozetone (pronunciation: NA-ih-broh-tseh-TOH-uun). See blog post EpicentRx Word of the Week: NO and press release United States Adopted Name (USAN) Council and International Nonproprietary Names (INN) Expert Committee Recognizes New Therapeutic Class by Granting “nibrozetone” as New Generic Name for EpicentRx’s Lead Small Molecule NLRP3 Inhibitor, RRx-001.

Fair to say, that’s a mouthful! Well, if it helps any, Coppertone, the sunscreen lotion, is sort of an approximation for nibrozetone, with some “butts” thrown in.

Wait, how is that?

Ok, so, outside of the “-tone” suffix that nibrozetone and Coppertone both share their mechanisms of action are kinda/sorta similar, heavy emphasis on kinda/sorta. Here’s why: all sunscreens carry a sun protection factor (SPF) number, referring to the degree to which they block ultraviolet (UV) radiation, as shown below.

Nibrozetone (RRx-001) is also associated with an SPF, not literally, of course, but figuratively because it potentially protects normal tissues from the side effects of radiation. A drug that protects normal tissues from the side effects of radiation is known as a radioprotector. Radioprotection is the basis for the use of nibrozetone (RRx-001) in head and neck cancer since a common complication of radiation treatment is severely painful inflammation and ulceration of the oropharyngeal cavity a.k.a. severe oral mucositis (SOM). Because of its antioxidant/anti-inflammatory properties (read more here in this manuscript entitled, A Review of RRx-001: A Late-Stage Multi-Indication Inhibitor of NLRP3 Activation and Chronic Inflammation), nibrozetone potentially prevents or mitigates SOM (read more here in this manuscript entitled PREVLAR: Phase 2a Randomized Trial to Assess the Safety and Efficacy of RRx-001 in the Attenuation of Oral Mucositis in Patients Receiving Head and Neck Chemoradiotherapy). SOM prevention/mitigation is a big deal and the basis for recently awarded FDA Fast Track designation for nibrozetone because SOM strongly, strongly impinges on quality of life and interferes with anticancer treatment continuation or adherence.

Unlike Coppertone, nibrozetone is intravenously administered not rubbed on the skin so it reaches all organs and tissues in the body including the brain and the gut; hence, in the case of nibrozetone, SPF stands not for sun protection factor but for systemic protection factor since several preclinical and clinical studies strongly suggest that nibrozetone dramatically reduces the side effects of both chemotherapy and radiation in the gastrointestinal tract, brain, and bone marrow.