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OBJECTIVE Basal insulin Fc (BIF) (insulin efsitora alfa; LY3209590), a fusion protein combining a novel single-chain insulin variant with a human IgG Fc domain, is designed for once-weekly basal insulin administration. This phase 2 study assessed the safety and efficacy of BIF versus degludec in insulin-naive patients with type 2 diabetes (T2D) previously treated with oral antihyperglycemic medications. RESEARCH DESIGN AND METHODS During this randomized, parallel, open-label study, 278 insulin-naive patients with T2D were randomly assigned (1:1) to receive BIF once weekly or degludec once daily over the 26-week treatment period. Both groups were titrated to fasting glucose of 80–100 mg/dL (4.4 to RESULTS After 26 weeks of treatment, BIF demonstrated a noninferior HbA1c change from baseline versus degludec, with a treatment difference of 0.06% (90% CI −0.11, 0.24; P = 0.56). Both BIF and degludec treatment led to significant reductions in FBG from baseline. At week 26, the between-treatment difference for BIF versus degludec was 4.7 mg/dL (90% CI 0.1, 9.3; P = 0.09). The rate of level 2 hypoglycemia was low and not significantly different between treatment groups (BIF 0.22 events/patient/year, degludec 0.15 events/patient/year; P = 0.64); there was no severe hypoglycemia. The occurrence of treatment-emergent adverse events was also similar between BIF and degludec. CONCLUSIONS Once-weekly BIF achieved excellent glycemic control similar to degludec, with no concerning hypoglycemia or other safety findings.

OBJECTIVE Basal Insulin Fc (BIF; insulin efsitora alfa; LY3209590), a fusion protein combining a novel single-chain insulin variant with a human IgG Fc domain, is designed for once-weekly basal insulin administration. This phase 2 study assessed safety and efficacy of BIF versus degludec in 265 patients with type 1 diabetes (T1D) using multiple daily injections. RESEARCH DESIGN AND METHODS During this randomized, parallel, open-label study, patients with T1D were randomized (1:1) to receive BIF once weekly or degludec once daily over the 26-week treatment period. Both groups were titrated to a fasting glucose level of 80–100 mg/dL. The primary end point was HbA1c change from baseline to week 26 (noninferiority margin, 0.4%). Secondary end points included percent time in range (TIR) (70–180 mg/dL), continuous glucose monitoring (CGM) fasting glucose (FG) level, and rate of hypoglycemia. RESULTS After 26 weeks, patients receiving BIF had noninferior HbA1c change from baseline versus those receiving degludec, with a statistically significant treatment difference of 0.17% (90% CI 0.01, 0.32; P = 0.07) favoring the comparator. Percent TIR was similar for patients in the BIF (56.1%) and degludec (58.9%; P = 0.112) groups at week 26. FG values were significantly higher for patients receiving BIF (158.8 mg/dL) versus degludec (143.2 mg/dL; P = 0.003). Rates of CGM-derived hypoglycemia were not statistically significantly different for BIF and degludec over 24 h for level 1 (P = 0.960) or level 2 (P = 0.517) hypoglycemia during the treatment period. Occurrence of serious adverse events was similar between the BIF and degludec groups. CONCLUSIONS Once-weekly BIF demonstrated noninferior glycemic control to once-daily degludec (treatment difference: 0.17% favoring degludec) and no difference in hypoglycemia or other safety findings in patients with T1D.

Objective Basal Insulin Fc (BIF; insulin efsitora alfa; LY3209590), a fusion protein combining a novel single-chain insulin variant with a human IgG Fc domain, is designed for once weekly basal insulin administration. This Phase 2 study assessed safety and efficacy of BIF versus degludec in insulin-naïve patients with type 2 diabetes (T2D) previously treated with oral antihyperglycemic medications. Research Design and Methods During this randomized, parallel, open-label study, 278 insulin-naïve patients with T2D were randomized (1:1) to receive BIF once weekly or degludec once daily over the 26-week treatment period. Both groups were titrated to fasting glucose of 80-100 mg/dL (4.4 to Results After 26 weeks of treatment, BIF demonstrated non-inferior HbA1c change from baseline versus degludec with a treatment difference of 0.06% (90% CI= -0.11, 0.24; p=0.56).. Both BIF and degludec treatment led to significant reductions in FBG from baseline; at Week 26 the between treatment difference for BIF versus degludec was 4.7 mg/dL [90% CI=0.1, 9.3]; p=0.09). The rate of Level 2 hypoglycemia was low and not significantly different between treatment groups (BIF=0.22; degludec=0.15 events/pt/yr; p=0.64); there was no severe hypoglycemia. The occurrence of treatment-emergent adverse events was also similar between BIF and degludec. Conclusions Once weekly BIF achieved excellent glycemic control similar to degludec with no concerning hypoglycemia or other safety findings.

Objective Basal Insulin Fc (BIF; insulin efsitora alfa; LY3209590), a fusion protein combining a novel single-chain insulin variant with a human IgG Fc domain, is designed for once weekly basal insulin administration. This Phase 2 study assessed safety and efficacy of BIF versus degludec in N=265 patients with type 1 diabetes (T1D) using multiple daily injections. Research Design and Methods During this randomized, parallel, open-label study, patients with T1D were randomized (1:1) to receive BIF once weekly or degludec once daily over the 26-week treatment period. Both groups were titrated to fasting glucose 80-100 mg/dL. Primary endpoint was HbA1c change from baseline to Week 26 (non-inferiority margin=0.4%). Secondary endpoints included percent time in range (TIR, 70-180 mg/dL), CGM fasting glucose (FG), and rate of hypoglycemia. Results After 26 weeks, BIF demonstrated non-inferior HbA1c change from baseline versus degludec with a statistically significant treatment difference of 0.17% (90% CI=0.01, 0.32; p=0.07) favoring the comparator. Percent TIR was similar for BIF (56.1%) and degludec (58.9%; p=0.112) at Week 26. FG values were significantly higher for BIF (158.8 mg/dL) versus degludec (143.2 mg/dL; p=0.003). Rates of CGM-derived hypoglycemia were not statistically significantly different for BIF and degludec over 24 hours for Level 1 (p=0.960) or Level 2 (p=0.517) during the treatment period. Occurrence of serious adverse events was similar between BIF and degludec. Conclusions Once weekly BIF demonstrated non-inferior glycemic control to once daily degludec (treatment difference: 0.17% favoring degludec) and no difference in hypoglycemia or other safety findings in patients with T1D.

Neutralizing monoclonal antibodies (mAb), novel therapeutics for the treatment of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), have been urgently researched from the start of the pandemic. The selection of the optimal mAb candidate and therapeutic dose were expedited using open-access in silico models. The maximally effective therapeutic mAb dose was determined through two approaches; both expanded on innovative, open-science initiatives. A physiologically-based pharmacokinetic (PBPK) model, incorporating physicochemical properties predictive of mAb clearance and tissue distribution, was used to estimate mAb exposure that maintained concentrations above 90% inhibitory concentration of in vitro neutralization in lung tissue for up to 4 weeks in 90% of patients. To achieve fastest viral clearance following onset of symptoms, a longitudinal SARS-CoV-2 viral dynamic model was applied to estimate viral clearance as a function of drug concentration and dose. The PBPK model-based approach suggested that a clinical dose between 175 and 500 mg of bamlanivimab would maintain target mAb concentrations in the lung tissue over 28 days in 90% of patients. The viral dynamic model suggested a 700 mg dose would achieve maximum viral elimination. Taken together, the first-in-human trial (NCT04411628) conservatively proceeded with a starting therapeutic dose of 700 mg and escalated to higher doses to evaluate the upper limit of safety and tolerability. Availability of open-access codes and application of novel in silico model-based approaches supported the selection of bamlanivimab and identified the lowest dose evaluated in this study that was expected to result in the maximum therapeutic effect before the first-in-human clinical trial.

Therapeutics for patients hospitalized with coronavirus disease 2019 (COVID-19) are urgently needed during the pandemic. Bamlanivimab is a potent neutralizing monoclonal antibody that blocks severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) attachment and entry into human cells, which could potentially lead to therapeutic benefit. J2W-MC-PYAA was a randomized, double-blind, sponsor unblinded, placebo-controlled, single ascending dose first-in-human trial (NCT04411628) in hospitalized patients with COVID-19. A total of 24 patients received either placebo or a single dose of bamlanivimab (700 mg, 2,800 mg, or 7,000 mg). The primary objective was assessment of safety and tolerability, including adverse events and serious adverse events, with secondary objectives of pharmacokinetic (PK) and pharmacodynamic analyses. Treatment-emergent adverse event (TEAE) rates were identical in the placebo and pooled bamlanivimab groups (66.7%). There were no apparent dose-related increases in the number or severity of TEAEs. There were no serious adverse events or deaths during the study, and no discontinuations due to adverse events. PKs of bamlanivimab is linear and exposure increased proportionally with dose following single i.v. administration. The half-life was ~ 17 days. These results demonstrate the favorable safety profile of bamlanivimab, and provided the initial critical evaluation of safety, tolerability, and PKs in support of the development of bamlanivimab in several ongoing clinical trials.

Basal Insulin Fc (BIF; LY3209590) , a fusion protein combining a novel single-chain insulin variant with a human IgG Fc domain, is designed for QW administration. This randomized, parallel, open-label Ph2 study assessed safety and efficacy of BIF vs. DEG in insulin-naïve patients with T2D previously treated with oral antihyperglycemic medication. BIF was injected QW, and DEG was injected QD. Both groups were titrated to fasting blood glucose (FBG) ≤100 mg/dL. The primary endpoint was HbA1c change from baseline (CFBL) to Wk 26 (non-inferiority margin=0.4%) . Patients randomized to BIF (N=129) and DEG (N=135) had a mean age of 58.4 yrs and baseline HbA1c of 8.0%. After 26 wks, BIF showed non-inferiority vs. DEG for HbA1c CFBL with a treatment difference of 0.06% (90% CI = -0.11, 0.24; p = .56) , and both groups had >75% time in range (70-180 mg/dL) on average at Wk 26 (Figure) . BIF and DEG significantly reduced FBG from baseline (treatment difference BIF vs. DEG = 4.7 mg/dL [90% CI = 0.1, 9.3]; p = .09) . Rate of Level 2 hypoglycemia was low and not significantly different (BIF = 0.22; DEG = 0.15 events/pt/yr; p = 0.64) . Occurrence of treatment-emergent adverse events was similar between BIF and DEG. QW BIF achieved excellent glycemic control similar to DEG with no concerning hypoglycemia or other safety findings, supporting continued development of BIF in Ph3. Disclosure J.M. Bue-Valleskey: None. C.M. Kazda: Employee; Eli Lilly and Company. Stock/Shareholder; Eli Lilly and Company. C. Ma: None. J. Chien: Employee; Eli Lilly and Company. Q. Zhang: Employee; Eli Lilly and Company. Stock/Shareholder; Eli Lilly and Company. E. Chigutsa: Employee; Eli Lilly and Company. W. Landschulz: Employee; Eli Lilly and Company. J. Swan: Employee; Eli Lilly and Company. A. Haupt: Employee; Lilly. Stock/Shareholder; Lilly. J. Frias: Advisory Panel; Altimmune, Becton, Dickinson and Company, Eli Lilly and Company, Gilead Sciences, Inc., Intercept Pharmaceuticals, Inc., Merck & Co., Inc., Sanofi. Consultant; 89bio, Inc., Akero Therapeutics, Inc., Altimmune, Becton, Dickinson and Company, Carmot Therapeutics, Inc., Eli Lilly and Company, Novo Nordisk, Pfizer Inc., Sanofi. Research Support; Afimmune Limited, Akero Therapeutics, Inc., AstraZeneca, Boehringer Ingelheim International GmbH, Bristol-Myers Squibb Company, Carmot Therapeutics, Inc., Eli Lilly and Company, Intercept Pharmaceuticals, Inc., Ionis Pharmaceuticals, Janssen Pharmaceuticals, Inc., Madrigal Pharmaceuticals, Inc., Merck & Co., Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk, Pfizer Inc., Poxel SA, Sanofi. Speaker's Bureau; Eli Lilly and Company, Merck & Co., Inc., Novo Nordisk, Sanofi. Funding Funded by Eli Lilly and Company.

BACKGROUNDBebtelovimab is a potent, fully human IgG1 monoclonal antibody (mAb) targeting the S-protein of SARS-CoV-2, with broad neutralizing activity to all currently known SARS-CoV-2 variants of concern, including omicron variant lineages. Specialized developmental approaches accelerated the initiation of a clinical trial designed to evaluate the efficacy and safety of bebtelovimab alone (BEB) or together with bamlanivimab (BAM) and etesevimab (ETE) delivered via slow intravenous push for the treatment of mild-to-moderate COVID-19.METHODSThis portion of the phase 2, BLAZE-4 trial (J2X-MC-PYAH; NCT04634409) enrolled 714 patients (between May and July 2021) with mild-to-moderate COVID-19 within 3 days (≤3 days) of laboratory diagnosis of SARS-CoV-2 infection. Patients at low risk for severe COVID-19 were randomized 1:1:1 (double-blinded) to placebo, BEB 175 mg, or BEB 175 mg+BAM 700 mg+ETE 1400 mg (BEB+BAM+ETE). Patients at high risk for progression to severe COVID-19 were randomized 2:1 (open-label) to BEB or BEB+BAM+ETE, and a subsequent treatment arm enrolled patients to BEB+BAM+ETE using Centers for Disease Control and Prevention (CDC) updated criteria for High-risk. All treatments were administered intravenously over ≥30 seconds (open-label BEB) or ≥6.5 minutes (all other treatment arms). For the placebo-controlled patients (termed Low-risk), the primary endpoint was the proportion of patients with persistently high viral load (PHVL) (log viral load >5.27) on Day 7. For the open-label patients (termed High-risk), the primary endpoint was safety. In nonclinical studies, SARS-CoV-2 isolates were tested using an endpoint neutralization assay to measure BEB’s inhibitory concentration greater than 99% (IC99).RESULTSBaseline viral sequencing data were available from 611 patients; 90.2% (n=551) aligned with a variant of interest or concern (WHO designation), with the majority infected with delta (49.8%) or alpha (28.6%) variants. Among the Low-risk patients, PHVL occurred in 19.8% of patients treated with placebo, as compared to 12.7% (p=0.132) of patients treated with BEB+BAM+ETE and 12.0% (p=0.097) of patients treated with BEB, a 36% and 40% relative risk reduction, respectively. Viral load-area under the curve analysis from baseline to Day 11 showed statistically signficant reductions for patients treated with BEB (p=0.006) and BEB+BAM+ETE (p=0.043) compared to patients who received placebo. Time to sustained symptom resolution was reduced by a median of 2 days for patients treated with BEB (6 days; p=0.003) and 1 day for patients treated with BEB+BAM+ETE (7 days; p=0.289) compared to placebo (8 days). The incidence of COVID-19-related hospitalization or all-cause deaths by day 29 were similar across treatment arms, as expected given the patients’ risk status (the Low risk cohorts had a Low risk of hospitalization, and High risk cohorts received only active therapy without placebo). Overall, safety results were consistent with previous studies investigating mAbs targeting SARS-CoV-2. The proportion of patients with treatment emergent adverse events (AEs) were 9.7% in Low-risk (n=37/380) and 14.7% in High-risk (n=48/326) patients treated with BEB or BEB+BAM+ETE; majority of AEs were considered mild or moderate in severity. Serious AEs were reported in 2.1% of High-risk patients (n=7/326), including one death (a cerebrovascular accident); 1 serious AE was reported among Low-risk patients. In an in vitro neutralization assay, BEB neutralized the omicron isolate (BA.1) with 99.CONCLUSIONSIn patients with mild-to-moderate COVID-19, treatment with BEB or BEB+BAM+ETE was associated with greater viral clearance, a reduction in time to sustained symptom resolution, and safety results consistent with mAbs that target SARS-CoV-2. Integration of clinical findings with in vitro neutralization of emerging viral variants offered a pragmatic framework for investigating the efficacy of a new antiviral mAb agent, as demonstrated by bebtelovimab.

Abemaciclib is an oral anticancer drug that inhibits cyclin dependent kinases 4 and 6 and is metabolized by cytochrome P450 3A in the intestines and liver to active metabolites. The objectives were (1) to develop a mechanistic model to characterize the pharmacokinetics (PK) of the active moieties and investigate the effect of patient factors and (2) apply the model to dat from two phase III breast cancer trials of abemaciclib in combination with endocrine therapy. To develop the model, data from seven phase I studies and two phase II studies including 421 patients with cancer and 65 healthy individuals were pooled for nonlinear mixed effects modeling. The PK was similar between patients and healthy subjects, and the effects of diarrhea, formulation, race, and patient covariates on exposure were negligible. Application of the model confirmed its predictive performance and that abemaciclib PK did not change when coadministered with endocrine therapy.

Basal insulin Fc (BIF; LY3209590) is a novel, once-weekly, long-acting IgG Fc-fusion protein assessed for the treatment of diabetes mellitus. A 32-week study evaluating the safety and efficacy of BIF vs. degludec in persons with T2DM previously treated with a basal insulin showed HbA1c non-inferiority of BIF vs. degludec with significantly fewer hypoglycemic events (≤70 mg/dL). Here we present CGM data derived by Dexcom G6, allowing a more detailed assessment of glycemic control of BIF vs. degludec. The study included 2 dosing algorithms for BIF with different fasting glucose (FG) targets: ≤140 mg/dL (BIF-A1) and ≤120 mg/dL (BIF-A2). Degludec was titrated to FG ≤100 mg/dL. Subjects were randomized to 1 of the 3 arms. Subject (N=399) mean age was 60.2 yrs and baseline HbA1c was 8.1%. For the entire 32 weeks, the percent of 24 hrs in range, hyperglycemia and hypoglycemia was similar for the 3 arms (Figure). At Week 32, total duration of hypoglycemia was similar across 7 days post-injection for BIF-A1 and A2, showing that duration of hypoglycemia is independent of day post-injection. CGM data confirm that BIF showed similar glycemic control vs. degludec despite higher FG targets and numerically lower time in hypoglycemia. The flat pharmacokinetic profile enables near peakless insulin concentrations without an increase in hypoglycemia risk at highest exposure. Disclosure C. M. Kazda: Employee; Self; Eli Lilly and Company. J. Chien: Stock/Shareholder; Self; Eli Lilly and Company. Q. Zhang: Employee; Self; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company. E. Chigutsa: Employee; Self; Eli Lilly and Company. W. Landschulz: Employee; Self; Lilly Diabetes, Employee; Spouse/Partner; Covance Inc., Stock/Shareholder; Self; Lilly Diabetes. P. Wullenweber: None. A. Haupt: Employee; Self; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company. J. P. Frias: Consultant; Self; 89bio, Inc., Altimmune, Axcella Health Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Gilead Sciences, Inc., Intercept Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk, Pfizer Inc., Sanofi, Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Bristol-Myers Squibb Company, CymaBay Therapeutics, Eli Lilly and Company, Intercept Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Madrigal Pharmaceuticals, Inc., Merck & Co., Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk, Pfizer Inc., Sanofi, Speaker’s Bureau; Self; Merck & Co., Inc., Sanofi. Funding Eli Lilly and Company

BACKGROUND: A major challenge in medicine is translation of preclinical model findings to humans, especially therapy duration. One major example is recent shorter-duration therapy regimen failures in tuberculosis. METHODS: We used set theory mapping to develop a computational/modeling framework to map the time it takes to extinguish the Mycobacterium tuberculosis population on chemotherapy from multiple hollow fiber system model of tuberculosis (HFS-TB) experiments to that observed in patients. The predictive accuracy of the derived translation transformations was then tested using data from 108 HFS-TB Rapid Evaluation of Moxifloxacin in Tuberculosis (REMoxTB) units, including 756 colony-forming units (CFU)/mL. Derived transformations, and Latin hypercube sampling–guided simulations were used to predict cure and relapse after 4 and 6 months of therapy. Outcomes were compared to observations, in 1932 patients in the REMoxTB clinical trial. RESULTS: HFS-TB serial bacillary burden and serial sputum data in the derivation dataset formed a structure-preserving map. Bactericidal effect was mapped with a single step transformation, while the sterilizing effect was mapped with a 3-step transformation function. Using the HFS-TB REMoxTB data, we accurately predicted the proportion of patients cured in the 4-month REMoxTB clinical trial. Model-predicted vs clinical trial observations were (i) the ethambutol arm (77.0% [95% confidence interval {CI}, 74.4%–79.6%] vs 77.7% [95% CI, 74.3%–80.9%]) and (ii) the isoniazid arm (76.4% [95% CI, 73.9%–79.0%] vs 79.5% [95% CI, 76.1%–82.5%]). CONCLUSIONS: We developed a method to translate duration of therapy outcomes from preclinical models to tuberculosis patients.

Basal insulin Fc (BIF; LY3209590) is a novel, once-weekly, long-acting IgG Fc-fusion protein that is being assessed for the treatment of diabetes mellitus. The presented study evaluated the safety and efficacy of BIF compared to insulin degludec over 32 weeks in patients with T2DM previously treated with oral antidiabetic drugs and a basal insulin. The study design included 2 different dosing algorithms for BIF (BIF-A1 and BIF-A2) with two different fasting glucose (FG) targets of ≤140 mg/dL (BIF-A1) and ≤120 mg/dL (BIF-A2). Insulin degludec was titrated to a FG target of ≤100mg/dL using a modified Riddle treat-to-target algorithm. Study participants (N=399) were randomized in a 1:1:1 ratio to 1 of 3 parallel treatment groups. The average age of participants was 60.2 years, baseline HbA1c was 8.1% and duration of diabetes 14.7 years. There were no statistically significant differences in demographics or baseline characteristics across the 3 treatment groups. Both BIF groups achieved non-inferiority (non-inferiority margin = 0.4%) for the primary endpoint of HbA1c change from baseline to Week 32 with a mean±SE reduction for BIF-A1, BIF-A2 and insulin degludec of 0.6±0.1%, 0.6±0.1% and 0.7±0.1%, respectively. In line with the different fasting serum glucose (FSG) targets, insulin degludec achieved greater FSG lowering from baseline as compared to the BIF arms. Similarly, both BIF dosing groups showed significantly fewer hypoglycemic events compared to insulin degludec (all documented events as well as nocturnal events) when assessing events ≤70 mg/dL (3.9 mmol/L). Hypoglycemic events

Prasugrel, a P2Y12 adenosine diphosphate (ADP) receptor antagonist, inhibits ADP-mediated platelet activation and aggregation in patients with sickle cell anemia (SCA). We developed a population pharmacokinetic (popPK) model in pediatric patients from 2 to

Necitumumab is a second-generation, recombinant, human immunoglobulin G1, epidermal growth factor (EGFR) receptor antibody that specifically blocks the ligand binding site of EGFR. Necitumumab potentially acts by blocking ligand epidermal growth factor (EGF) binding-mediated activation of the EGFR signaling pathway, inhibiting tumor growth, angiogenesis, and anti-apoptotic mechanisms. Necitumumab inhibited the interaction of EGF and EGFR with a concentration that inhibits binding by 50 % of approximately 0.9 nM (0.13 mg/L) and demonstrated antitumor activity during in vivo experiments associated with trough plasma concentrations of approximately 40 mg/L. This work describes the population pharmacokinetics of necitumumab in cancer patients when administered with or without concomitant chemotherapy and evaluates patient characteristics that may guide dosing. Nonlinear mixed-effects modeling of serum concentration data across five clinical studies (phases I–III) indicated that necitumumab exhibited target-mediated drug disposition, commonly observed with monoclonal antibodies, and that pharmacokinetics were expected to be linear in the studied dose ranges when administered as repeated infusions. No age, sex, race, or concomitant medication factors were found influential, while weight was a statistically significant factor for both distribution and elimination. Simulations from the final model indicated that only a limited reduction in patient drug exposure variability would be achieved by weight- or body surface area-based dosing. Necitumumab effective half-life was estimated to approximately 2 weeks, and steady state was achieved within three to four cycles of treatment. The phase III dosing schedule of 800 mg dosed on days 1 and 8 of a 21-day schedule resulted in serum concentrations that exceeded the 40-mg/L threshold indicated by preclinical experiments.

Ixekizumab, a high-affinity monoclonal antibody, selectively targets interleukin-17A and has been shown to be efficacious in the treatment of moderate to severe psoriasis. The objective was to describe the relationship between ixekizumab concentrations and efficacy response (static Physician Global Assessment [sPGA] and the Psoriasis Activity and Severity Index [PASI) scores] after 12 weeks of ixekizumab treatment in psoriasis patients from 3 phase 3 studies. Data from 2888 psoriasis patients randomized to receive placebo or 80 mg ixekizumab every 2 weeks or every 4 weeks were analyzed. Separate logistic regression models describing the relationship between ixekizumab concentrations and sPGA or PASI scores at week 12 were used to determine the probability of patients achieving a response and to investigate the impact of various patient factors other than drug concentrations on response rates. Both dosing regimens were efficacious, with higher rates of response achieved with the higher range of observed ixekizumab concentrations after every-2-week dosing. Although higher bodyweight, palmoplantar involvement, lower baseline disease state, or high baseline C-reactive protein were associated with slightly lower response rates, the magnitude of effect of these factors on sPGA(0,1) response was small, with all subgroups able to achieve high levels of response. Other factors tested had no effect including age, sex, and antidrug antibody status. Logistic regression modeling of ixekizumab concentration and efficacy data accurately identified the proportion of responders using sPGA or PASI end points. The higher concentration ranges achieved with 80 mg every 2 weeks versus every 4 weeks were associated with higher response levels.

The relationships between antituberculosis drug exposure and treatment effects on humans receiving multidrug therapy are complex and nonlinear. In patients on treatment, an analysis of the rate of decline in the sputum bacillary burden reveals two slopes. The first is the α-slope, which is thought to reflect bactericidal effect, followed by a β-slope, which is thought to reflect sterilizing activity. We sought to characterize the effects of standard first-line treatment on sterilizing activity. Fifty-four patients receiving combination therapy for pulmonary tuberculosis in a clinical trial had drug concentrations measured and Mycobacterium tuberculosis isolates available for MIC identification. Sputum sample cultures were performed at baseline and weekly for 8 weeks. A time-to-event model based on the days to positivity in the liquid cultures was used to estimate the β-slope. The pharmacokinetic parameters of rifampin, isoniazid, ethambutol, and pyrazinamide were determined for each patient. Multivariate adaptive regression splines analyses, which simultaneously perform linear and nonlinear analyses, were used to identify the relationships between the predictors and the β-slope. The potential predictors examined included HIV status, lung cavitation, 24-h area under the concentration-time curve (AUC), peak drug concentration ( C max ), AUC/MIC ratio, C max /MIC ratio, and the time that that concentration persisted above MIC. A rifampin C max of >8.2 mg/liter and a pyrazinamide AUC/MIC of >11.3 were key predictors of the β-slope and interacted positively to increase the β-slope. In patients with a rifampin AUC of C max /MIC increased the β-slope, while increasing isoniazid C max decreased it, suggesting isoniazid antagonism. Antibiotic concentrations and MICs interact in a nonlinear fashion as the main drivers of a sterilizing effect. The results suggest that faster speeds of sterilizing effect might be achieved by omitting isoniazid and by increasing rifampin, pyrazinamide, and ethambutol exposures. However, isoniazid and ethambutol exposures may only be of importance when rifampin exposure is low. These findings need confirmation in larger studies. (This study has been registered at controlled-trials.com under registration no. ISRCTN80852505.)

Objectives To identify the pyrazinamide MIC above which standard combination therapy fails. Methods MICs of pyrazinamide were determined for Mycobacterium tuberculosis isolates, cultured from 58 patients in a previous randomized clinical trial in Cape Town, South Africa. The MICs were determined using BACTEC MGIT 960 for isolates that were collected before standard treatment with isoniazid, rifampicin, pyrazinamide and ethambutol commenced. Weekly sputum collections were subsequently made for 8 weeks in order to culture M. tuberculosis in Middlebrook broth medium. Classification and regression tree (CART) analysis was utilized to identify the pyrazinamide MIC predictive of sputum culture results at the end of pyrazinamide therapy. The machine learning-derived susceptibility breakpoints were then confirmed using standard association statistics that took into account confounders of 2 month sputum conversion. Results The pyrazinamide MIC range was 12.5 to >100 mg/L for the isolates prior to therapy. The epidemiological 95% cut-off value was >100 mg/L. The 2 month sputum conversion rate in liquid cultures was 26% by stringent criteria and 48% by less stringent criteria. CART analysis identified an MIC breakpoint of 50 mg/L, above which patients had poor sputum conversion rates. The relative risk of poor sputum conversion was 1.5 (95% CI: 1.2–1.8) for an MIC >50 mg/L compared with an MIC ≤50 mg/L. Conclusions We propose a pyrazinamide susceptibility breakpoint of 50 mg/L for clinical decision making and for development of rapid susceptibility assays. This breakpoint is identical to that identified using computer-aided simulations of hollow fibre system output.

Pharmacokinetic exposure and the MIC of fluoroquinolones are important determinants of their efficacy against Mycobacterium tuberculosis . Population modeling was used to describe the steady-state plasma pharmacokinetics of moxifloxacin in 241 tuberculosis (TB) patients in southern Africa. Monte Carlo simulations were applied to obtain the area under the unbound concentration-time curve from 0 to 24 h ( f AUC 0–24 ) after daily doses of 400 mg or 800 mg moxifloxacin and 800 mg ofloxacin. The MIC distributions of ofloxacin and moxifloxacin were determined for 197 drug-resistant clinical isolates of Mycobacterium tuberculosis . For a specific MIC, the probability of target attainment (PTA) was determined for target f AUC 0–24 /MIC ratios of ≥53 and ≥100. The PTAs were combined with the MIC distributions to calculate the cumulative fraction of response (CFR) for multidrug-resistant (MDR) Mycobacterium tuberculosis strains. Even with the less stringent target ratio of ≥53, moxifloxacin at 400 mg and ofloxacin at 800 mg achieved CFRs of only 84% and 58% for multidrug-resistant isolates with resistance to an injectable drug, while the 800-mg moxifloxacin dose achieved a CFR of 98%. Using a target ratio of ≥100 for multidrug-resistant strains (without resistance to injectable agents or fluoroquinolones), the CFR was 88% for moxifloxacin and only 43% for ofloxacin, and the higher dose of 800 mg moxifloxacin was needed to achieve a CFR target of >90%. Our results indicate that moxifloxacin is more efficacious than ofloxacin in the treatment of MDR-TB. Further studies should determine the optimal pharmacodynamic target for moxifloxacin in a multidrug regimen and clarify safety issues when it is administered at higher doses.

Days to positivity in automated liquid mycobacterial culture have been shown to correlate with mycobacterial load and have been proposed as a useful biomarker for treatment responses in tuberculosis. However, there is currently no quantitative method or model to analyze the change in days to positivity with time on treatment. The objectives of this study were to describe the decline in numbers of mycobacteria in sputum collected once weekly for 8 weeks from patients on treatment for tuberculosis using days to positivity in liquid culture. One hundred forty-four patients with smear-positive pulmonary tuberculosis were recruited from a tuberculosis clinic in Cape Town, South Africa. A nonlinear mixed-effects repeated-time-to-event modeling approach was used to analyze the time-to-positivity data. A biexponential model described the decline in the estimated number of bacteria in patients' sputum samples, while a logistic model with a lag time described the growth of the bacteria in liquid culture. At baseline, the estimated number of rapidly killed bacteria is typically 41 times higher than that of those that are killed slowly. The time to kill half of the rapidly killed bacteria was about 1.8 days, while it was 39 days for slowly killed bacteria. Patients with lung cavitation had higher bacterial loads than patients without lung cavitation. The model successfully described the increase in days to positivity as treatment progressed, differentiating between bacteria that are killed rapidly and those that are killed slowly. Our model can be used to analyze similar data from studies testing new drug regimens.

Despite the important role of fluoroquinolones and the predominant use of ofloxacin for treating multidrug-resistant tuberculosis in South Africa, there are limited data on ofloxacin pharmacokinetics in patients with multidrug-resistant tuberculosis, no ofloxacin pharmacokinetic data from South African patients, and no direct assessment of the relationship between ofloxacin pharmacokinetics and the MIC of ofloxacin of patient isolates. Our objectives are to describe ofloxacin pharmacokinetics in South African patients being treated for multidrug-resistant tuberculosis and assess the adequacy of ofloxacin drug exposure with respect to the probability of pharmacodynamic target attainment (area under the time curve/MIC ratio of at least 100). Sixty-five patients with multidrug-resistant tuberculosis were recruited from 2 hospitals in South Africa. We determined the ofloxacin MICs for the Mycobacterium tuberculosis isolates from baseline sputum specimens. Patients received daily doses of 800 mg ofloxacin, in addition to other antitubercular drugs. Patients underwent pharmacokinetic sampling at steady state. NONMEM was used for data analysis. The population pharmacokinetics of ofloxacin in this study has been adequately described. The probability of target attainment expectation in the study population was 0.45. Doubling the dose to 1,600 mg could increase this to only 0.77. The currently recommended ofloxacin dose appeared inadequate for the majority of this study population. Studies to assess the tolerability of higher doses are warranted. Alternatively, ofloxacin should be replaced with more potent fluoroquinolones.

Among patients with tuberculosis, rifampin plasma concentrations and sputum conversion rates have been reported to be lower in Africans. Rifampin is a substrate of P-glycoprotein (coded for by the ABCB1 gene) and organic anion-transporting polypeptide 1B1 (coded for by SLCO1B1 ). The objectives were to identify genetic polymorphisms of drug transporters and the transcriptional regulators pregnane X receptor (PXR) and constitutive androstane receptor (CAR) with an impact on rifampin pharmacokinetics in South Africans. Fifty-seven patients with tuberculosis from Cape Town underwent pharmacokinetic sampling during treatment with rifampin, pyrazinamide, isoniazid, and ethambutol. DNA was genotyped for ABCB1 , SLCO1B1 , PXR , and CAR polymorphisms by using real-time PCR. NONMEM was used for data analysis. The allele frequency of the SLCO1B1 rs4149032 polymorphism was 0.70. Patients heterozygous and homozygous for this polymorphism had reductions in the bioavailability (and, thus, the area under the curve [AUC]) of rifampin of 18% and 28%, respectively. Simulations showed that increasing the daily rifampin dose by 150 mg in patients with the polymorphism would result in plasma concentrations similar to those of wild-type individuals and reduce the percentage of patients with peak plasma concentrations ( C max ) below 8 mg/liter from 63% to 31%. ABCB1 , PXR , and CAR polymorphisms were not associated with differences in rifampin pharmacokinetics. SLCO1B1 rs4149032 was present in most patients and was associated with substantially reduced rifampin exposure. These data suggest that the standard recommended dose of rifampin should be reconsidered for South Africans.

Exposure to lower-than-therapeutic levels of anti-tuberculosis drugs is likely to cause selection of resistant strains of Mycobacterium tuberculosis and treatment failure. The first-line anti-tuberculosis (TB) regimen consists of rifampicin, isoniazid, pyrazinamide, and ethambutol, and correct management reduces risk of TB relapse and development of drug resistance. In this study we aimed to investigate the effect of standard of care plus nutritional supplementation versus standard care on the pharmacokinetics of isoniazid, pyrazinamide and ethambutol among sputum smear positive TB patients with and without HIV. In a clinical trial in 100 Tanzanian TB patients, with or without HIV infection, drug concentrations were determined at 1 week and 2 months post initiation of anti-TB medication. Data was analysed using population pharmacokinetic modelling. The effect of body size was described using allometric scaling, and the effects of nutritional supplementation, HIV, age, sex, CD4+ count, weight-adjusted dose, NAT2 genotype, and time on TB treatment were investigated. The kinetics of all drugs was well characterised using first-order elimination and transit compartment absorption, with isoniazid and ethambutol described by two-compartment disposition models, and pyrazinamide by a one-compartment model. Patients with a slow NAT2 genotype had higher isoniazid exposure and a lower estimate of oral clearance (15.5 L/h) than rapid/intermediate NAT2 genotype (26.1 L/h). Pyrazinamide clearance had an estimated typical value of 3.32 L/h, and it was found to increase with time on treatment, with a 16.3% increase after the first 2 months of anti-TB treatment. The typical clearance of ethambutol was estimated to be 40.7 L/h, and was found to decrease with age, at a rate of 1.41% per year. Neither HIV status nor nutritional supplementations were found to affect the pharmacokinetics of these drugs in our cohort of patients.

Nutritional supplementation to tuberculosis (TB) patients has been associated with increased weight and reduced mortality, but its effect on the pharmacokinetics of first-line anti-TB drugs is unknown. A cohort of 100 TB patients (58 men; median age, 35 [interquartile range {IQR}, 29 to 40] years, and median body mass index [BMI], 18.8 [17.3 to 19.9] kg/m 2 ) were randomized to receive nutritional supplementation during the intensive phase of TB treatment. Rifampin plasma concentrations were determined after 1 week and 2 months of treatment. The effects of nutritional supplementation, HIV, time on treatment, body weight, and SLCO1B1 rs4149032 genotype were examined using a population pharmacokinetic model. The model adjusted for body size via allometric scaling, accounted for clearance autoinduction, and detected an increase in bioavailability (+14%) for the patients in the continuation phase. HIV coinfection in patients not receiving the supplementation was found to decrease bioavailability by 21.8%, with a median maximum concentration of drug in serum ( C max ) and area under the concentration-time curve from 0 to 24 h (AUC 0–24 ) of 5.6 μg/ml and 28.6 μg · h/ml, respectively. HIV-coinfected patients on nutritional supplementation achieved higher C max and AUC 0–24 values of 6.4 μg/ml and 31.6 μg · h/ml, respectively, and only 13.3% bioavailability reduction. No effect of the SLCO1B1 rs4149032 genotype was observed. In conclusion, nutritional supplementation during the first 2 months of TB treatment reduces the decrease in rifampin exposure observed in HIV-coinfected patients but does not affect exposure in HIV-uninfected patients. If confirmed in other studies, the use of defined nutritional supplementation in HIV-coinfected TB patients should be considered in TB control programs. (This study has the controlled trial registration number ISRCTN 16552219.)

The study sought to investigate the relationship between efavirenz exposure and the CYP2B6 516G→T(*6) genotype in HIV/AIDS outpatients, using pharmacokinetic modelling and simulation. Blood samples where obtained from 74 outpatients treated with a combination regimen including 600 mg efavirenz daily for a duration of at least 3 weeks at clinics in Harare, Zimbabwe. The subjects were genotyped for the major CYP2B6 variant, CYP2B6*6, associated with reduced enzyme activity, using a PCR-RFLP method. Efavirenz plasma concentrations were determined by HPLC-UV. Population pharmacokinetic modelling and simulation of the data were performed in NONMEM VI. A high allele frequency of the CYP2B6*6 allele of 49% was observed. Efavirenz plasma concentrations were above 4 mg/L in 50% of the patients. Genotype and sex were identified as predictive covariates of efavirenz disposition. Pharmacokinetic parameter estimates indicate that a dose reduction to 400 mg efavirenz per day is possible in patients homozygous for the CYP2B6*6 genotype without compromising therapeutic efficacy. The CYP2B6*6 allele occurs at a high frequency in people of African origin and is associated with high efavirenz concentrations. Simulations indicate that an a priori 35% dose reduction in homozygous CYP2B6*6 patients would maintain drug exposure within the therapeutic range in this group of patients. Our preliminary results suggest the conduct of a prospective clinical dose optimization study to evaluate the utility of genotype-driven dose adjustment in this population.

Pharmacometricians are virtually nonexistent in Africa and the developing world. The unrelenting burden of infectious diseases, which are often treated using medicines with narrow effectiveness and safety dose ranges, and the growing prevalence and recognition of non-communicable diseases represent significant threats for the patients, although affording an opportunity for advancing science. This article outlines the case for pharmacometricians to redirect their expertise to focus on the disease burden affecting the developing world. CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e69; doi:10.1038/psp.2013.45; published online 28 August 2013