SMaRT Replacement Therapy™
BackgroundOur SMaRT Replacement Therapy is based on the creation of a genetically modified strain of bacteria that colonizes in the oral cavity and replaces native bacteria that cause tooth decay. Our SMaRT Replacement Therapy product candidate is designed to be a painless, one-time, five-minute topical treatment applied to the teeth that has the potential to offer lifelong protection against dental caries, or tooth decay.
Market OpportunityDental diseases are the most prevalent chronic infectious diseases in the world, affecting up to 90% of schoolchildren and the vast majority of adults. Annual expenditures on the treatment of dental caries in the U.S. are estimated to be $40 billion a year according to the Dental, Oral and Craniofacial Data Resource Center. Tooth decay is characterized by the demineralization of enamel and dentin, eventually resulting in the destruction of the teeth. Dietary sugar is often misperceived as the cause of tooth decay; however, the immediate cause of tooth decay is lactic acid produced by microorganisms that metabolize sugar on the surface of the teeth. Studies suggest that of the approximately 700 oral microorganisms, S. mutans, a bacterium found in virtually all humans, is the principal causative agent in the development of tooth decay. Residing within dental plaque on the surface of teeth, S. mutans derives energy from carbohydrate metabolism as it converts dietary sugar to lactic acid which, in turn, promotes demineralization in enamel and dentin, eventually resulting in a cavity. The rate at which mineral is lost depends on several factors, most importantly the frequency and amount of sugar that is consumed.
Fluoride is used to reduce the effect of lactic acid-based demineralization of enamel and dentin. Despite the widespread use of fluoride in public water systems, toothpastes, dental treatments and sealants, and the use of antiseptic mouth rinses, over 50% of 5-to-9-year olds and almost 80% of 17-year-olds in the United States have at least one cavity or filling, according to the U.S. Surgeon General. In addition to non-compliance with the behavioral guidelines of the American Dental Association such as routine brushing and flossing, there are several factors that are likely to increase the incidence and frequency of tooth decay, including increasing consumption of both dietary sugar and bottled water. Bottled water generally does not contain fluoride, and thus does not impart any of the protective effects of fluoridated water from public systems.
Our SolutionOur SMaRT Replacement Therapy technology is based on the creation of a genetically altered strain of S. mutans, called SMaRT, which does not produce lactic acid. Our SMaRT strain is engineered to have a selective colonization advantage over native S. mutans strains in that SMaRT produces minute amounts of a lantibiotic that kills off the native strains but leaves the SMaRT strain unharmed. Thus SMaRT Replacement Therapy can permanently replace native lactic acid-producing strains of S. mutans in the oral cavity, thereby potentially providing lifelong protection against the primary cause of tooth decay. The SMaRT strain has been extensively and successfully tested for safety and efficacy in laboratory and animal models.
SMaRT Replacement Therapy is designed to be applied topically to the teeth by a dentist, pediatrician or primary care physician during a routine office visit. A suspension of the SMaRT strain is administered using a cotton-tipped swab during a single five-minute, pain-free treatment. Following treatment, the SMaRT strain should displace the native, decay-causing S. mutans strains over a six to twelve month period and permanently occupy the niche on the tooth surfaces normally occupied by native S. mutans.
Tooth decay is a largely preventable disease through implementation of an appropriate oral care hygiene program including brushing, flossing, irrigation, sealants and antiseptic mouth rinses. Nevertheless, tooth decay remains the most common chronic infectious disease in the world, which indicates that the lack of patient compliance with an overall oral care regimen remains a critical issue in tooth decay prevention. We believe that SMaRT Replacement Therapy addresses the issue of patient compliance by requiring only a one-time, five-minute treatment for the potential lifelong prevention of tooth decay.
Regulatory StatusWe initiated our first Phase 1 clinical trial in April 2005, but we found it difficult to find subjects who fit the trial’s highly cautious inclusion and exclusion criteria, particularly with respect to the subjects’ lack of dentition. We concluded this trial early after enrolling only two of the 15 planned subjects. The FDA then recommended that we revise the protocol for the evaluation of ten healthy male subjects, ranging from 18 to 30 years old and with normal dentition, in an institutionalized setting. After we submitted additional information, the FDA issued a clinical hold letter in June 2007 for the proposed trial with the attenuated strain, citing the need for a plan with respect to serious adverse effects; a plan for the eradication of the attenuated strain in trial subjects’ offspring; and a required pregnancy test for female partners of subjects. We submitted additional protocols in response to the FDA’s concerns. In August 2007, the FDA issued a clinical hold letter with required revisions to the protocol for offspring of subjects. We submitted a response to the clinical hold letter in September 2007, and the FDA removed the clinical hold for our Phase 1 trial in the attenuated strain in October 2007.
While we commenced a Phase 1b clinical trial for SMaRT Replacement Therapy during the first quarter of 2011, the very restrictive study enrollment criteria required by the FDA made the enrollment of candidates meeting the restrictive criteria difficult. Due to the enrollment difficulty we encountered with our initial our Phase 1a clinical trial and now with our phase 1b clinical trial, we determined to discontinue pursuit of our Phase 1b clinical trial. Our current efforts are primarily focused on possible partnering opportunities that may exist for our SMaRT Replacement Therapy. It is possible that we will be unable to negotiate acceptable terms with a licensee or partner.
ManufacturingThe SMaRT strain grows readily in a variety of cultivation media and under a variety of common growth conditions including both aerobic and anaerobic incubations. The SMaRT strain can also utilize various carbon and nitrogen sources and is highly acid tolerant. There is no significant limitation to the manufacturing scale of our SMaRT strain other than the size of the containment vessel. In connection with our clinical trial, we engaged a contract manufacturer to produce an attenuated version our SMaRT strain, using a standard operating procedure provided by us that we believe is readily transferable to outside contract manufacturers with large scale GMP fermentation capabilities.