Dordaviprone (ONC201) is a novel, small-molecule imipridone with antitumor activity in patients with a glioma. Six healthy male participants received a single 625-mg (100-µCi) oral dose of [14C]-dordaviprone. Blood, plasma, urine, and feces were collected up to 288 hours after dosing and analyzed by liquid scintillation counting. Metabolite profiles were evaluated using liquid chromatography-radiometric detection, and metabolite identification was accomplished by liquid chromatography with tandem mass spectrometry. Concentrations of drug-derived radioactivity in blood and plasma peaked at 1 hour after dosing and were below the limit of quantitation by 72 hours (whole blood) to 96 hours (plasma) after dosing. Seventy-one percent of the administered radioactivity was recovered in urine and 20% in feces. In plasma, the major circulating compounds were dordaviprone and the inactive metabolite ONC207, each contributing approximately one third of the total radioactivity area under the curve. Of the 19 metabolites identified in plasma, no other single metabolite contributed more than 10% to the total radioactivity area under the curve. Unchanged dordaviprone was a minor component in excreta (less than 0.3%), with multiple metabolites identified in urine and feces. Given the lack of dordaviprone in excreta and the metabolites formed, the primary route for dordaviprone elimination was through urinary excretion of oxidative metabolites.

Dordaviprone (ONC201) is a novel, small molecule imipridone with antitumor effects in glioma patients. This study evaluated the pharmacokinetics and safety of dordaviprone following single escalating doses (Part A), as a capsule content mixed with applesauce or Gatorade (sports drink) [Part B1]), and with or without food [Part B2]. The most common treatment-emergent adverse events pooled across study parts (Parts A, B1, and B2) were headache, dizziness, and headache, respectively; all were mild. Systemic dordaviprone exposure increased dose proportionally following administration of 125-625 mg of dordaviprone. Following dordaviprone capsule contents sprinkled on applesauce or dissolved in sports drink, the geometric mean ratios, and 90% confidence intervals (CIs) of the dordaviprone area under the concentration versus time curve (AUC) fell within the bioequivalence (BE) limits of 80.00%-125.00%; however, for Cmax the 90% CI lower limit (0.70) fell below BE limits when sprinkled on applesauce. The geometric mean ratios and 90% CIs of dordaviprone administered under fed versus fasted conditions fell within BE limits of 80.00%-125.00% for the AUC, indicating no food effect on total exposure; however, maximum concentration (Cmax) (90% CI 0.55, 0.67) fell below BE limits.

Dordaviprone (ONC201) is a novel, orally administered, anti-cancer, small molecule imipridone with demonstrated antitumor effects in patients with glioma. Dordaviprone in vitro solubility is significantly reduced at pH >4.5. Concomitant use of acid reducing agents (ARAs) may therefore impact dordaviprone solubility and bioavailability. This open-label, single-sequence, three-period crossover study evaluated the effect of proton-pump inhibitor rabeprazole on dordaviprone pharmacokinetics (PK). Periods were consecutive and comprised of period 1 (days 1-3), period 2 (days 4-9), and period 3 (days 10-13). In period 1, participants received a single oral 625 mg dose of dordaviprone on day 1. In period 2, participants received six consecutive days of QD 20 mg rabeprazole alone. In period 3, patients received one oral dose of 20 mg rabeprazole (the seventh consecutive daily dose), followed 2 h later by a single 625 mg dordaviprone oral dose. PK blood samples were collected and analyzed from pre-dose 72 h following dordaviprone administration in periods 1 and 3. Dordaviprone exposure PK parameters were similar following administration of dordaviprone alone or with rabeprazole. Geometric mean ratios and 90% CIs for dordaviprone exposure parameters with and without rabeprazole following dordaviprone administration fell within bioequivalence limits of 80.00%-125.00% for Cmax (97.19% [86.43-109.28]), AUClast (102.21% [95.19-109.75]), and AUCinf (102.27% [95.21-109.86]), indicating no effect of multiple oral doses of rabeprazole on dordaviprone relative bioavailability. Six of the 16 participants reported treatment-emergent adverse events (TEAEs); dordaviprone-related TEAEs were reported by three participants and were limited to mild nausea and dizziness. No dordaviprone dose adjustment or ARA treatment modification is warranted.

Abstract PURPOSE H3 K27M-mutant diffuse midline glioma (DMG) has a poor prognosis, with a median overall survival of 1 year and no proven treatments beyond radiotherapy. ONC201 (dordaviprone), a first-in-class imipridone, previously demonstrated durable responses in patients with recurrent H3 K27M-mutant DMG. The present analysis reports safety data from ONC028, a compassionate use program (CUP) for patients with previously treated H3 K27M-mutant glioma. METHODS ONC028 is an expanded access program that provides ONC201 monotherapy to patients with H3 K27M-mutant glioma. Eligible patients are adults or pediatric patients with H3 K27M-mutant glioma, prior therapy including at least radiation, and adequate organ function. Patients must be ineligible for enrollment in other ongoing clinical studies evaluating ONC201. ONC201 is administered orally once weekly at 625 mg or dose-equivalent based on body weight for pediatric patients. MRIs are performed every two 28-day cycles for the initial 12 months, thereafter every 2-3 cycles. Treatment continues until disease progression, unacceptable adverse events (AEs), or withdrawal of consent. Treatment may continue post-progression at the discretion of the treating physician. Bevacizumab use for radiation necrosis or symptom management is acceptable. AEs are assessed by NCI CTCAE v5.0 criteria. RESULTS The 422 enrolled patients include 191 adults (45.2%) and 231 children (54.7%); 87.1% had a performance score ≥60 and the most common tumor location was the pons (57.3%). Any-causality Grade ≥3 AEs have been reported in 200 patients (47.4%). Grade ≥3 treatment-related AEs (TR-AEs) were reported in 19 (4.5%) patients; the commonest was decreased lymphocyte count, occurring in 3 (0.7%) patients. Any-causality serious AEs (SAE) were reported in 43.1% (n=182) patients. There were 10 (2.4%) patients with reports of treatment-related SAEs, the commonest were ascites, nausea, vomiting, and seizure, each occurring in 2 patients (0.2%). CONCLUSIONS ONC028 provides expanded access to ONC201 treatment for patients with previously treated H3 K27M-mutant glioma who are ineligible for enrollment in ongoing trials of ONC201. ONC201 treatment remains well-tolerated.

The COVID-19 global pandemic caused by the novel coronavirus, SARS-CoV-2, and the consequent morbidity and mortality attributable to progressive hypoxemia and subsequent respiratory failure threaten to overrun hospital critical care units globally. New agents that address the hyperinflammatory “cytokine storm” and hypercoagulable pathology seen in these patients may be a promising approach to treat patients, minimize hospital stays, and ensure hospital wards and critical care units are able to operate effectively. Dociparstat sodium (DSTAT) is a glycosaminoglycan derivative of heparin with robust anti-inflammatory properties, with the potential to address underlying causes of coagulation disorders with substantially reduced risk of bleeding compared to commercially available heparin. This study is a randomized, double-blind, placebo-controlled, phase 2/3 trial to determine the safety and efficacy of DSTAT added to standard of care in hospitalized adults with COVID-19 who require supplemental oxygen. Phase 2 will enroll 12 participants in each of two dose-escalating cohorts to confirm the safety of DSTAT in this population. Following review of the data, an additional 50 participants will be enrolled. Contingent upon positive results, phase 3 will enroll approximately 450 participants randomized to DSTAT or placebo. The primary endpoint is the proportion of participants who survive and do not require mechanical ventilation through day 28. Advances in standard of care, recent emergency use authorizations, and positive data with dexamethasone have likely contributed to an increasing proportion of patients who are surviving without the need for mechanical ventilation. Therefore, examining the time to improvement in the NIAID score will be essential to provide a measure of drug effect on recovery. Analysis of additional endpoints, including supportive biomarkers (e.g., IL-6, HMGB1, soluble-RAGE, D-dimer), will be performed to further define the effect of DSTAT in patients with COVID-19 infection. ClinicalTrials.gov identifier; NCT04389840, Registered 13 May 2020

Abstract Background BCV is a lipid conjugated nucleotide analog that has shown rapid viral clearance with oral administration in patients with adenovirus infection, and improved survival in animal models of smallpox. Phase I single ascending dose evaluation of IV BCV demonstrated that 2 hour infusions of 10, 25, and 50 mg were well tolerated and not associated with significant adverse events (AEs) or laboratory abnormalities. This study evaluated the safety and PK of multiple ascending doses of IV BCV in healthy subjects. Methods Twenty-eight subjects were to be randomized 3:1 to receive blinded IV BCV or placebo in sequential MAD cohorts (Table A). Study drug was given twice a week (BIW) for 2 weeks or once a week (QW) for 4 weeks. Plasma PK samples were collected on Day 1 and after the last dose and assayed by HPLC-MS. Plasma BCV PK parameters were determined by noncompartmental analysis and dose proportionality and accumulation was assessed. Safety assessments were performed during the dosing period through 14 days post last dose. Results Twenty-seven male and female subjects (29–65 years, 93% White) were enrolled and 26 completed the study. Plasma BCV Cmax and AUC∞ increased in proportion to dose with no accumulation (Table A). AEs were generally mild and included diarrhea and headache. Alanine aminotransferase (ALT) elevations were asymptomatic and resolved upon cessation of dosing. No serious AEs occurred.Table A. BCV PK on Day 1 and Safety Plasma BCV PK1 BCV 10 mg BIW 2-hour Infusion (n = 9) BCV 20 mg QW 2-hour Infusion (n = 6) BCV 20 mg QW 1-hour Infusion (n = 5) Pooled Placebo (n = 7) C max (ng/mL) 553 (33%) 1,110 (19%) 1,720 (19%) NA AUC∞ (ng*h/mL) 1,374 (34%) 2,982 (23%) 2,919 (18%) NA Drug-related AEs in >2 subjects Diarrhea 0 3 (50%) 1 (20%) 0 Headache 4 (44%) 3 (50%) 3 (60%) 4 (57%) Fatigue 0 2 (33%) 0 2 (29%) 1. Cmax and AUC∞: geometric means (%CVb). Conclusion Multiple doses of IV BCV given as 10 mg BIW or 20 mg QW were generally safe and well tolerated. Mild diarrhea was reported only after IV BCV 20 mg QW. As seen with oral BCV, ALT increases were reversible upon cessation of drug, and were not associated with hyperbilirubinemia. BCV exposure was dose-proportional and no accumulation was observed. The data support evaluation of repeat dose administration in virally infected patients. Disclosures O. Naderer, Chimerix: Employee, Salary. V. Schuck, Chimerix: Research Contractor, Consulting fee. M. Morrison, Chimerix: Employee, Salary. M. Anderson, Chimerix: Employee, Salary. T. Arumugham, Chimerix: Employee, Salary. J. Dunn, Chimerix: Employee, Salary.

Cytomegalovirus (CMV) infection is a common complication of allogeneic hematopoietic cell transplantation (HCT). In this trial, we randomized adult CMV-seropositive HCT recipients without CMV viremia at screening 2:1 to receive brincidofovir or placebo until week 14 post-HCT. Randomization was stratified by center and risk of CMV infection. Patients were assessed weekly through week 15 and every third week thereafter through week 24 post-HCT. Patients who developed clinically significant CMV infection (CS-CMVi; CMV viremia requiring preemptive therapy or CMV disease) discontinued the study drug and began anti-CMV treatment. The primary endpoint was the proportion of patients with CS-CMVi through week 24 post-HCT; patients who discontinued the trial or with missing data were imputed as primary endpoint events. Between August 2013 and June 2015, 452 patients were randomized at a median of 15 days after HCT and received study drug. The proportion of patients who developed CS-CMVi or were imputed as having a primary endpoint event through week 24 was similar between brincidofovir-treated patients and placebo recipients (155 of 303 [51.2%] versus 78 of 149 [52.3%]; odds ratio, .95 [95% confidence interval, .64 to 1.41]; P = .805); fewer brincidofovir recipients developed CMV viremia through week 14 compared with placebo recipients (41.6%; P < .001). Serious adverse events were more frequent among brincidofovir recipients (57.1% versus 37.6%), driven by acute graft-versus-host disease (32.3% versus 6.0%) and diarrhea (6.9% versus 2.7%). Week 24 all-cause mortality was 15.5% among brincidofovir recipients and 10.1% among placebo recipients. Brincidofovir did not reduce CS-CMVi by week 24 post-HCT and was associated with gastrointestinal toxicity.

Brincidofovir (BCV, CMX001) is an orally available, long-acting, broad-spectrum antiviral that has been evaluated in healthy subjects in Phase I studies and in hematopoietic cell transplant recipients and other immunocompromised patients in Phase II/III clinical trials for the prevention and treatment of cytomegalovirus and adenovirus infections. BCV has also shown in vitro activity against orthopoxviruses such as variola (smallpox) virus, and is under advanced development as a treatment for smallpox under the US FDA's 'Animal Rule'. The anticipated treatment regimen for smallpox is a total weekly dose of 200 mg administered orally for 3 consecutive weeks. To assess the benefit-to-risk profile of BCV for the treatment of smallpox, we evaluated short-term safety data associated with comparable doses from Phase I studies and from adult and pediatric subjects in the cytomegalovirus and adenovirus clinical programs. When administered at doses and durations similar to that proposed for the treatment of smallpox, BCV was generally well tolerated in both adults and pediatric subjects. The most common adverse events were mild gastrointestinal events and asymptomatic, transient, and reversible elevations in serum transaminases. The data presented herein indicate a favorable safety profile for BCV for the treatment of smallpox, and support its continued development for this indication.

Adenovirus infection in immunocompromised patients contributes to significant morbidity and mortality, especially after allogeneic hematopoietic cell transplantation (HCT). Brincidofovir (BCV, CMX001) is an orally bioavailable lipid conjugate of cidofovir that has in vitro activity against adenoviruses and other double stranded DNA viruses. This randomized placebo-controlled phase II trial evaluated pre-emptive treatment with BCV for the prevention of adenovirus disease in pediatric and adult allogeneic HCT recipients with asymptomatic adenovirus viremia. Allogeneic HCT recipients with adenovirus viremia were randomized 1:1:1 to receive oral BCV 100 mg (2 mg/kg if < 50 kg) twice weekly (BIW), BCV 200 mg (4 mg/kg if < 50 kg) once weekly (QW), or placebo for 6 to 12 weeks, followed by 4 weeks of post-treatment follow-up. For randomization, subjects were stratified by screening absolute lymphocyte count (< 300 cells/mm(3) versus >= 300 cells/mm(3)). Assignment to BCV or placebo was double blinded; dose frequency was unblinded. The primary endpoint was the proportion of subjects experiencing treatment failure, defined as either progression to probable or definitive adenovirus disease or confirmed increasing adenovirus viremia (>= 1 log(10) copies/mL) during randomized therapy. Between June 2011 and December 2012, 48 subjects were randomized to the BCV BIW (n = 14), BCV QW (n = 16), or placebo (n = 18) groups. The proportion of subjects with treatment failure in the BCV BIW group was 21% (odds ratio, .53; 95% confidence interval [CI], .11 to 2.71; P =.45), 38% (odds ratio, 1.23; 95% CI, .30 to 5.05, P =.779) in the BCV QW group, and 33% in the placebo group. All-cause mortality was lower in the BCV BIW (14%) and BCV QW groups (31%) relative to the placebo group (39%), but these differences were not statistically significant. After 1 week of therapy, 8 of 12 subjects (67%) randomized to BCV BIW had undetectable adenovirus viremia (< 100 copies/mL), compared with 4 of 14 subjects (29%) randomized to BCV QW and 5 of 15 subjects (33%) randomized to placebo. In a post hoc analysis of subjects with viremia >= 1000copies/mL at baseline, 6 of 7 BCV BIW subjects (86%) achieved undetectable viremia compared with 2 of 8 placebo subjects (25%; P =.04). Early treatment discontinuation because of adverse events was more common in subjects treated with BCV than with placebo. Diarrhea was the most common event in all groups (57% BCV BIW, 38% BCV QW, 28% placebo), but it led to treatment discontinuation in only 1 subject receiving BCV QW. Events diagnosed as acute graft-versus-host disease, primarily of the gastrointestinal tract, were more frequent in the BCV BIW group (50%) than in the BCV QW (25%) and placebo (17%) groups. There was no evidence of myelotoxicity or nephrotoxicity in BCV-treated subjects. The results of this trial confirm the antiviral activity of BCV against adenoviruses. Further investigation is ongoing to define the optimal treatment strategy for HCT recipients with serious adenovirus infection and disease. (c) 2017 American Society for Blood and Marrow Transplantation.

Abstract Background BCV is a lipid conjugate nucleotide that has shown rapid viral clearance in patients with adenovirus infection and improved survival in animal models of smallpox. In preclinical studies in rats, IV BCV dosed twice weekly for up to 29 days was not associated with gastrointestinal (GI), hematopoietic, hepatic, or renal toxicity. This study evaluated the safety and PK of IV BCV in healthy subjects. Methods In this double-blind study, subjects were randomized 3:1 to receive IV BCV or placebo in sequential single ascending dose cohorts (Table 1). Plasma PK samples were collected over 7 days and assayed by HPLC-MS. Plasma BCV PK parameters were determined by non-compartmental analysis and dose proportionality was assessed. Safety assessments were collected over 14 days. Results Forty healthy male subjects (18–46 years, 83% White) were enrolled and completed the study. Plasma BCV Cmax and AUC∞ increased in proportion to dose (Table 1). AEs and alanine aminotransferase (ALT) elevations were dose- and infusion duration-related (Table 1). GI AEs were mild. All AEs and ALT elevations were transient and no serious AEs occurred. Conclusion Single doses of BCV 10–50 mg administered as a 2h IV infusion were well tolerated and not associated with significant clinical or laboratory abnormalities. BCV IV 10 mg and BCV IV 50 mg achieved geometric mean plasma BCV AUC∞ similar to and 4.5-fold, respectively, values achieved with BCV oral 100 mg tablets (Cmax = 251 ng/mL and AUC∞ = 1394 ng hours/mL). These data support evaluation of repeat dose administration in healthy subjects and virally-infected patients. Disclosures M. B. Wire, Chimerix: Employee and Shareholder, Salary. M. Morrison, Chimerix: Employee and Shareholder, Salary.M. Anderson, Chimerix: Employee and Shareholder, Salary. T. Arumugham, Chimerix: Employee and Shareholder, Salary. J. Dunn, Chimerix: Employee and Shareholder, Salary. O. Naderer, Chimerix: Employee and Shareholder, Salary.

Background: Brincidofovir (BCV) is an orally bioavailable lipid conjugate of cidofovir (CDV) with increased in vitro potency relative to CDV against all 5 families of double-stranded DNA viruses that cause human disease. After intravenous (IV) administration of CDV, the organic anion transporter 1 (OAT1) transports CDV from the blood into the renal proximal tubule epithelial cells with resulting dose-limiting nephrotoxicity.Objective: To study whether OAT1 transports BCV and to evaluate the pharmacokinetic and renal safety profile of oral BCV compared with IV CDV.Methods: The cellular uptake of BCV and its major metabolites was assessed in vitro. Renal function at baseline and during and after treatment in subjects in BCV clinical studies was examined.Results: In OAT1-expressing cells, uptake of BCV and its 2 major metabolites (CMX103 and CMX064) was the same as in mock-transfected control cells and was not inhibited by the OAT inhibitor probenecid. In human pharmacokinetic studies, BCV administration at therapeutic doses resulted in detection of CDV as a circulating metabolite; peak CDV plasma concentrations after oral BCV administration in humans were,1% of those observed after IV CDV administration at therapeutic doses. Analysis of renal function and adverse events from 3 BCV clinical studies in immunocompromised adult and pediatric subjects indicated little to no evidence of associated nephrotoxicity. Over 80% of subjects who switched from CDV or foscarnet to BCV experienced an improvement in renal function as measured by maximum on-treatment estimated glomerular filtration rate.Conclusions: The lack of BCV uptake through OAT1, together with lower CDV concentrations after oral BCV compared with IV CDV administration, likely explains the superior renal safety profile observed in immunocompromised subjects receiving BCV compared with CDV.