Iclaprim is a novel diaminopyrimidine antibiotic that inhibits an essential bacterial enzyme called ‘‘dihydrofolate reductase’’ (DHFR). Diaminopyrimidines are a class of chemical compounds that inhibit different enzymes in the production of tetrahydrofolate, a form of folic acid, which is required for the production of bacterial DNA and RNA.
The inhibition of DHFR represents a differentiated and underutilized mechanism of action compared with other antibiotics. We acquired iclaprim from Nuprim Inc., or Nuprim, following the completion of our merger with the company on April 1, 2015. Arpida AG, or Arpida, one of the previous owners of iclaprim, completed a comprehensive development program for iclaprim, including two successful Phase 3 trials in complicated skin and skin structure infections (cSSSI).
Iclaprim has been administered to more than 600 patients and healthy volunteers in Phase 1, 2 and 3 clinical trials and in contrast to vancomycin, a standard of care antibiotic in hospitalized patients with ‘‘Gram-positive’’ infections, no evidence of nephrotoxicity (i.e., damage to the kidneys caused by exposure to a toxic chemical, toxin or medication) has been observed with iclaprim, and, therefore, therapeutic monitoring or dosage adjustment in renally impaired patients is not required with iclaprim. ‘‘Gram-positive’’ or ‘‘Gram-negative’’ refer to how bacteria react to the Gram stain test based on the outer casing of the bacteria, and the bacteria’s cell wall structure. Each type of bacteria may be associated with different diseases. Iclaprim has also demonstrated rapid bactericidal activity and a low propensity for resistance development in vitro.
We believe that iclaprim is an attractive potential candidate for use as a first-line empiric monotherapy, the initial therapy administered prior to the identification of the pathogen, in severely ill patients who are hospitalized with ABSSSI caused by MRSA and have comorbidities, or also suffer from other health issues, such as diabetes or renal impairment. Renal impairment affects up to an estimated 936,000 of the approximately 3.6 million patients hospitalized with ABSSSI annually in the United States.
On March 2, 2016 we announced the dosing of the first patient in our two REVIVE (Randomized Evaluation intraVenous Iclaprim Vancomycin trEatment) Phase 3 clinical trials in ABSSSI. Data from the first REVIVE trial (REVIVE-1) is expected in the second quarter of 2017. Data from the second REVIVE trial (REVIVE-2) is expected in the second half of 2017. If successful, we believe the data from the two REVIVE trials will satisfy the requirements to submit a New Drug Application (NDA) in the United States and a Marketing Authorization Application (MAA) in Europe to obtain marketing approval for an IV formulation of iclaprim in the treatment of ABSSSI caused by Gram-positive pathogens, including resistant strains such as MRSA. If approved, we believe that iclaprim can become a valuable addition to the formulary of life-saving antibiotics used by hospital physicians.
We plan to complete preparations for our INSPIRE (Iclaprim for NoSocomial PneumonIa gRam- positive pathogEns) Phase 3 clinical trial with iclaprim in patients with HABP, including patients with VABP, by the end of 2016. Subject to the availability of funding, we would look to start dosing patients thereafter. There are approximately 1.4 million patients hospitalized annually in the United States with HABP, including patients with VABP. We believe that iclaprim is well suited for use as a first-line empiric therapy for patients with HABP, including patients with VABP, based on data from a Phase 2 clinical trial, which demonstrated iclaprim’s efficacy in this patient population. Additionally, in a Phase 1 healthy volunteer trial, concentrations of iclaprim at the site of infection in the lungs were considerably higher than concentrations in plasma.
In July 2015, the U.S. Food and Drug Administration, or FDA, designated the IV formulation of iclaprim as a Qualified Infectious Disease Product (QIDP) for ABSSSI and HABP. QIDP status grants iclaprim regulatory Fast Track designation, Priority Review and, if approved, a five-year extension to the statutory market exclusivity period in the United States, resulting in 10 years of market exclusivity from the date of approval. If approved by the European Medicines Agency, or EMA, we expect that iclaprim will qualify for eight years of data exclusivity and an additional two years of market exclusivity in the EU. If approved by the Pharmaceuticals and Medical Devices Agency (PDMA) in Japan, we expect that iclaprim will qualify for eight years of data exclusivity (which may be extended to 10 years for orphan or pediatric indications) and an additional two years of market exclusivity in Japan.
We believe that iclaprim is well suited for use as a first-line empiric monotherapy in patients with ABSSSI who are comorbid with renal impairment for the following reasons:
- iclaprim achieved high cure rates against the common Gram-positive causal organisms, including MRSA, in patients with cSSSI in completed Phase 2 and 3 trials;
- although the FDA has not yet made any determination regarding the safety and efficacy of iclaprim, in clinical trials involving over 600 patients and healthy volunteers, iclaprim exhibited a safety and tolerability profile comparable to that demonstrated by vancomycin and linezolid;
- iclaprim has demonstrated no nephrotoxicity, eliminating the requirement for therapeutic monitoring or dosage adjustment in renally impaired patients;
- no cases of symptomatic hypoglycemia have been reported in iclaprim-treated patients with diabetes mellitus receiving insulin or oral hypoglycemic agents;
- iclaprim has demonstrated no clinically significant drug-drug interactions (DDIs) with selective serotonin reuptake inhibitors (SSRIs), or vasopressors; and
- no cases of myopathy or rhabdomyolysis have been reported in iclaprim-treated patients who received recent prior or concomitant therapy with an HMG-CoA reductase inhibitor or in whom elevations in CPK occur during treatment.
We also believe that iclaprim is well positioned as a first-line empiric therapy for patients with HABP, including patients with VABP, for the following reasons:
- iclaprim achieved high cure rates against the common Gram-positive causal organisms, including MRSA, in patients with HABP, including patients with VABP, in a completed Phase 2 trial;
- iclaprim has demonstrated high and sustained concentrations in epithelial lining fluid (ELF) and alveolar macrophages which were 20-30 times the plasma concentration, respectively, throughout an entire 7-hour sampling period; and
- iclaprim has demonstrated no clinically significant DDIs with commonly used antibiotics in patients with combined Gram-positive and Gram-negative infections.