A Phase Ib/IIa Study of the Pan-BET Inhibitor ZEN-3694 in Combination with Enzalutamide in Patients with Metastatic Castration-resistant Prostate Cancer.

PURPOSE: ZEN-3694 is a bromodomain extraterminal inhibitor (BETi) with activity in androgen-signaling inhibitor (ASI)-resistant models. The safety and efficacy of ZEN-3694 plus enzalutamide was evaluated in a phase Ib/IIa study in metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: Patients had progressive mCRPC with prior resistance to abiraterone and/or enzalutamide. 3+3 dose escalation was followed by dose expansion in parallel cohorts (ZEN-3694 at 48 and 96 mg orally once daily, respectively). RESULTS: Seventy-five patients were enrolled (N = 26 and 14 in dose expansion at low- and high-dose ZEN-3694, respectively). Thirty (40.0%) patients were resistant to abiraterone, 34 (45.3%) to enzalutamide, and 11 (14.7%) to both. ZEN-3694 dosing ranged from 36 to 144 mg daily without reaching an MTD. Fourteen patients (18.7%) experienced grade ≥3 toxicities, including three patients with grade 3 thrombocytopenia (4%). An exposure-dependent decrease in whole-blood RNA expression of BETi targets was observed (up to fourfold mean difference at 4 hours post-ZEN-3694 dose; P ≤ 0.0001). The median radiographic progression-free survival (rPFS) was 9.0 months [95% confidence interval (CI), 4.6-12.9] and composite median radiographic or clinical progression-free survival (PFS) was 5.5 months (95% CI, 4.0-7.8). Median duration of treatment was 3.5 months (range, 0-34.7+). Lower androgen receptor (AR) transcriptional activity in baseline tumor biopsies was associated with longer rPFS (median rPFS 10.4 vs. 4.3 months). CONCLUSIONS: ZEN-3694 plus enzalutamide demonstrated acceptable tolerability and potential efficacy in patients with ASI-resistant mCRPC. Further prospective study is warranted including in mCRPC harboring low AR transcriptional activity.

Discovery of ANA975: an oral prodrug of the TLR-7 agonist isatoribine.

ANA975, a 5-amino-3-beta -D-ribofuranosyl-3H-thiazolo[4,5-d]pyrimidin-2-one derivative, was synthesized in the search of an oral prodrug of isatoribine, a small molecule toll-like receptor 7 (TLR-7) agonist. Several strategies were studied to enable the kilogram-scale synthesis of ANA975. Three general total syntheses are described. In the phase I clinical study of ANA975 against hepatitis C virus (HCV), conversion to isatoribine in plasma was rapid and effective, delivering levels of isatoribine that have been shown to be clinically relevant.

The peak atrioventricular pressure gradient to transmitral flow relation: kinematic model prediction with in vivo validation.

Physiologists and cardiologists estimate peak transvalvular pressure gradients (DeltaP) by Doppler echocardiographic imaging of peak flow velocities using the simplified Bernoulli relationship: DeltaP (mm Hg) = 4V(2) (m/s). Because left ventricular filling is initiated by mechanical suction, V can be predicted by the motion of a simple harmonic oscillator by the parametrized diastolic filling formalism that characterizes E-wave contours by 3 unique simple harmonic oscillator parameters: initial displacement (x(o) cm); spring constant (k g/s(2)); and damping constant (c g/s). Parametrized diastolic filling predicts peak atrioventricular pressure gradient as kx(o), the peak simple harmonic oscillator force. For validation, simultaneous (micromanometric) left ventricular pressure and E-wave data from 19 patients were analyzed. Model-predicted peak gradient (kx(o)) was compared with actual gradient (DeltaP(cath)) and with 4V(2). Multiple linear regression results for all patients yielded highly significant relation between kx(o) and DeltaP(cath) (kx(o) = m(1)DeltaP(cath) + b(1), where m(1) = 40.7 +/- 8.0 dyne/mm Hg, b(1) = 1540 +/- 116 dyne, r(2) = 0.97, P <.001). Regression analysis showed no significant correlation between 4V(2) and DeltaP(cath) (4V(2) = m(2)DeltaP(cath) + b(2), where m(2) = 0.01 +/- 0.03, m(2)/s(2)/mm Hg and b(2) = 2.07 +/- 0.44 m(2)/s(2), P = nonsignificant). We conclude that E-wave analysis by parametrized diastolic filling predicts peak atrioventricular gradients reliably and more accurately than 4V(2).

Potent immune activation in chronic hepatitis C patients upon administration of an oral inducer of endogenous interferons that acts via Toll-like receptor 7.

BACKGROUND: ANA773, an oral prodrug of a small-molecule Toll-like receptor (TLR)7 agonist, induces a dose-related decrease in serum HCV RNA levels in chronic hepatitis C patients. METHODS: The prodrug ANA773 was administered to healthy individuals and chronic hepatitis C patients. At different time points during the course of treatment, modulation of the phenotype and function of peripheral leukocytes were evaluated to determine the role of distinct immune cells on the clinical outcome of therapy. RESULTS: Early after administration of the TLR7 agonist, a mild transient reduction of the number of lymphocytes was observed in both healthy individuals and chronic hepatitis C patients. Moreover, repeated administration of ANA773 resulted in transiently reduced numbers of myeloid and plasmacytoid dendritic cells (DC) in blood. Interestingly, reduced plasmacytoid DC numbers as well as increased serum interferon (IFN)-α and IFN-γ inducible protein (IP)-10 levels were observed only in virological responders (≥1 log(10) IU/ml reduction of HCV RNA levels upon ANA773 treatment), but were absent in virological non-responders. In vitro stimulation of peripheral blood mononuclear cells from virological responders showed a high frequency of IFN-α-producing plasmacytoid DC upon stimulation in vitro with ANA773, whereas no IFN-α was induced in non-responders. CONCLUSIONS: These findings indicate that the viral load decline in chronic hepatitis C patients treated with the TLR7 agonist ANA773 is likely due to intrinsic differences in the induction of endogenous IFNs and IFN-stimulated gene products (IFN-α and IP-10) upon TLR7 ligation.

Isatoribine, an agonist of TLR7, reduces plasma virus concentration in chronic hepatitis C infection.

Immune-based therapy is the mainstay treatment for chronic hepatitis C virus (HCV) infection but causes multiple side effects and achieves durable viral clearance in only approximately 50% of patients. Most new investigational anti-HCV compounds are direct-acting antivirals for which durability of response and risk of viral mutations and resistance are not yet known. Therefore, continuing discovery and development of new immune-based treatments is desirable. Toll-like receptors (TLRs) are pathogen recognition receptors that initiate the innate immune response. The responsiveness of HCV or other ongoing chronic systemic infections to treatment with a selective TLR agonist has not been reported. Isatoribine is a selective agonist of TLR7. In a proof-of-concept study, we found that once-daily 7-day treatment with intravenous isatoribine 800 mg caused a significant (P = .001) reduction of plasma HCV RNA (mean, -0.76; range, -2.85 to +0.21 log(10) units) in otherwise untreated patients (n = 12) who were chronically infected with HCV. Viral load reduction occurred in patients infected with genotype 1 as well as non-genotype 1 HCV. The reduction of viral load was correlated with induction of markers of a heightened immune antiviral state, including 2'-, 5'- oligoadenylate synthetase levels in whole blood. This treatment was well tolerated, with a low frequency of mild to moderate adverse events. In conclusion, systemic administration of the selective TLR7 agonist isatoribine resulted in dose-dependent changes in immunologic biomarkers and a statistically significant antiviral effect with relatively few and mild side effects.