Safety Study of RMJH-111b to Treat Essential Hypertension

This was a phase 1/2, single center, randomized, double-blind, placebo-controlled study to assess the safety and tolerability of RMJH-111b in adult subjects with essential hypertension. Assessments of pharmacokinetics and efficacy were secondary objectives. RMJ Holdings LLC (doing business as RMJH Rx) is developing RMJH-111b (magnesium citrate, tribasic anhydrous) soft gelatin capsules for the treatment of essential hypertension. The rationale for developing RMJH-111b for essential hypertension is based on reported calcium channel blocker and vasodilator effects of magnesium cation (Mg++). Given this hypothesized mechanism of action, RMJH-111b may not be effective for subjects with other causes or forms of hypertension, and thus the diagnosis of essential hypertension was a key inclusion criterion for this trial. In order to avoid confounding the results of the trial, subjects who were already taking anti-hypertensive medications to manage their hypertension were taken off of those medications and underwent a 7-day washout period. Subjects that met the specified blood pressure criteria after the washout \[systolic blood pressure (SBP) ≥ 150 and ≤ 200 mmHg and diastolic blood pressure (DBP) ≥ 95 and ≤ 115 mmHg\] received placebo orally twice a day (bid) for a 3-day run-in period (Days 1-3). Subjects that were recently diagnosed or previously diagnosed and off treatment for \> 1 week before starting the study and who met the blood pressure criteria proceeded directly to the 3-day run-in period (i.e., without the 7-day washout period). During the 3-day run-in period, the subjects remained in the clinical research unit (CRU) on a low salt (2.5 g/24 hours) diet. Subjects that remained eligible after the run-in period were randomized to receive either 440 mg of RMJH-111b or placebo orally bid (i.e., total daily dose of 880 and 0 mg elemental magnesium, respectively) for a 7-day treatment period (Days 4-10). A total of 21 subjects randomized 15:6 to RMJH-111b or placebo was planned. Subjects were randomized on either June 10th or 23rd of 2016. Based on the screen failure rate of the 1st cohort, the number of subjects needed for the 2nd cohort was projected. The actual number of subjects eligible for randomization at the end of the run-in period in the 2nd cohort exceeded the projection by 1 and all eligible subjects were randomized. Thus, the actual number of subjects randomized was 22, with 16 subjects in the RMJH-111b group and 6 subjects in the placebo group (i.e., 16:6 rather than 15:6). Subjects remained in the CRU on a low salt (2.5 g/24 hours) diet for the entire 7-day treatment period and through the 24-hour post treatment assessments (Day 11). Subjects returned to the clinic 8 days (±3 days) after the last dose of Study Drug (active or placebo) for their Final Study Visit. Protocol-specified reasons for discontinuing a subject from the study included, but were not limited to: 1) subject's blood pressure was too elevated for them to safely continue in the study (subjects who experienced SBP \>200 mmHg or DBP \>115 mmHg had to have these measurements repeated approximately 1 hour later, and if the SBP or DBP remained elevated, the subject was to be removed from the study and treated accordingly), 2) subject experienced a sharp drop in blood pressure (SBP \< 110 mmHg or DBP \< 60 mmHg); 3) subject's patellar reflex (knee jerk) disappeared, and 4) subject's total serum magnesium levels increased to ≥ 5 mg/dL (twice the upper limit of normal). As a conservative measure for this first trial of RMJH-111b, the criterion regarding drop in blood pressure did not require any associated clinical symptoms. For the pivotal trial, RMJH Rx will incorporate orthostatic hypotension monitoring and refine the discontinuation criterion regarding drop in blood pressure to allow for continued Study Drug treatment in the absence of clinical symptoms, so as to avoid unnecessarily removing a subject that is experiencing therapeutic benefit. All measurements used for the safety assessments in this study are widely used, and generally recognized as reliable, accurate, and relevant. Further, they included standard parameters used in the evaluation of drugs with the potential for anti-hypertensive and magnesium toxicity effects. Because blood pressure varies at daytime compared to nighttime, mean daytime (8 AM to 4 PM), nighttime (10 PM to 6 AM), and 24-hour ambulatory blood pressure monitor (ABPM) parameters were used to assess the efficacy effects of RMJH-111b on blood pressure in this trial. While 24-hour ambulatory blood pressure monitoring is considered as a more precise method for the evaluation of drug effects on blood pressure than clinic visit (seated) blood pressures, this trial also included efficacy evaluations of seated SBP and DBP parameters for informational purposes and in particular to facilitate the design of the larger pivotal trial where ABPM monitoring will not be practical. The pharmacokinetic (PK) evaluation of magnesium is complicated by pre-existing endogenous levels of magnesium, other ingested sources of magnesium (daily diet and supplements; supplements with total daily dose of magnesium ≤ 150 mg were allowed in this study), and the tight regulation of magnesium in the body (magnesium homeostasis) with relatively high levels of magnesium in bones and soft tissues compared to approximately 1% in the blood. Thus, the total serum magnesium exposure was anticipated to be minimally effected with RMJH-111b intake, but evidence of urinary magnesium excretion coupled with maintained total serum magnesium exposure was expected to provide an indication of intake rather than magnesium wasting.