Pharmacokinetics, Pharmacodynamics, and Safety of Etrolizumab in Children With Moderately to Severely Active Ulcerative Colitis or Crohn's Disease: Results from a Phase 1 Randomized Trial

BACKGROUND

Etrolizumab, a humanized anti-β7 antibody, has not been studied in children. Here, we evaluate the pharmacokinetics, pharmacodynamics, and safety of etrolizumab in children with inflammatory bowel disease.

METHODS

Patients age 4 to 17 years with moderately to severely active ulcerative colitis or Crohn's disease were randomized 1:1 to receive 1.5mg/kg of etrolizumab subcutaneously every 4 weeks (q4w) or 3.0mg/kg every 8 weeks (q8w) for 16 weeks in this open-label phase 1 trial. Pharmacokinetics, pharmacodynamics, safety, and efficacy were assessed.

RESULTS

Of the 24 patients treated, 21 completed the study. In the groups of 1.5mg/kg q4w and 3.0mg/kg q8w, respectively, mean (SD) maximum concentration (Cmax) was 9.8 (4.86) µg/mL and 18.1 (6.25) µg/mL; and mean (SD) area under the curve within a dosing interval (AUCtau) was 167 (86.9) and 521 (306) μg·day/mL after the last dose. The Cmax increased dose proportionally. The AUC over an 8-week period was slightly higher in the 3.0mg/kg q8w dose group. Median half-life was similar for both dosing regimens. Median numbers of free β7high gut-homing T and B cell subsets declined below 10% of baseline, confirming β7 target engagement and complete/near-complete receptor occupancy. Adverse events were consistent with the safety profile in adults. Approximately 60% of patients achieved a clinical response.

CONCLUSIONS

Etrolizumab showed a dose-proportional increase in Cmax and a slightly greater than dose-proportional increase in AUCtau. Both regimens achieved complete/near-complete β7 receptor occupancy, with a similar relationship to concentration as adults. Etrolizumab was well tolerated and demonstrated clinical activity in children.

Phase 1 and Scintigraphy Studies to Evaluate Safety, Tolerability, Pharmacokinetics, and Lung Deposition of Inhaled GDC-0214 in Healthy Volunteers

Several inflammatory cytokines that promote inflammation and pathogenesis in asthma signal through the Janus kinase 1 (JAK1) pathway. This phase I, randomized, placebo‐controlled trial assessed the pharmacokinetics and safety of single and multiple ascending doses up to 15 mg twice daily for 14 days of a JAK1 inhibitor, GDC‐0214, in healthy volunteers (HVs; n = 66). Doses were administered with a dry powder, capsule‐based inhaler. An accompanying open‐label gamma scintigraphy study in HVs examined the lung deposition of a single dose of inhaled Technetium‐99m (^99mTc)‐radiolabeled GDC‐0214. GDC‐0214 plasma concentrations were linear and approximately dose‐proportional after both single and multiple doses. Peak plasma concentrations occurred at 15–30 min after dosing. The mean apparent elimination half‐life ranged from 32 to 56 h across all single and multiple dose cohorts. After single and multiple doses, all adverse events were mild or moderate, and none led to treatment withdrawal. There was no clear evidence of systemic toxicity due to JAK1 inhibition, and systemic exposure was low, with plasma concentrations at least 15‐fold less than the plasma protein binding‐corrected IC50 of JAK1 at the highest dose. Scintigraphy showed that approximately 50% of the emitted dose of radiolabeled GDC‐0214 was deposited in the lungs and was distributed well to the peripheral airways. ^99mTc‐radiolabeled GDC‐0214 (1 mg) exhibited a mean plasma C_max similar to that observed in phase I at the same dose level. Overall, inhaled GDC‐0214 exhibited pharmacokinetic properties favorable for inhaled administration.

Pharmacokinetics and exposure-efficacy relationships of omalizumab in patients with nasal polyps

The anti-immunoglobulin E (IgE) antibody, omalizumab (Xolair), is approved in the United States for the treatment of allergic asthma and chronic spontaneous urticaria, and has recently been studied for the treatment of nasal polyposis following completion of the two replicate phase 3 studies (POLYP 1 and POLYP 2). The dosing of omalizumab used in the phase 3 studies is based on a combination of patients' pre-treatment IgE level and body weight, similar to the approach used in allergic asthma. The objectives of the current analyses were to evaluate whether the pharmacokinetics (PK) of omalizumab and its pharmacodynamic (PD) effect on free and total IgE level in chronic rhinosinusitis with nasal polyps (CRSwNP) are consistent with those in allergic asthma via population PK/PD modeling and simulation, and to graphically explore exposure-response relationships and free IgE-response relationships in CRSwNP. Omalizumab PK and PD effect of total and free IgE in CRSwNP are generally consistent with those in asthma. Observed post-treatment free IgE suppressions were generally within the target range of the baseline IgE- and body weight-based omalizumab dosing table, with 74.2% and 93.0% of patients achieving a serum free IgE level below 25 ng/mL and 50 ng/mL, respectively at Week 24. Exposure-response analyses indicated that there was no clear correlation between omalizumab or free IgE concentration and key efficacy endpoints within the POLYP studies. Overall, these results indicate that the body weight and IgE-based dosing regimen of omalizumab was appropriate for use in CRSwNP patients.

Pharmacokinetics of the Monoclonal Antibody MHAA4549A Administered in Combination With Oseltamivir in Patients Hospitalized With Severe Influenza A Infection

MHAA4549A is a human anti‐influenza A monoclonal antibody developed to treat influenza A. We report MHAA4549A serum, nasopharyngeal, and tracheal aspirate pharmacokinetics from a phase 2b study in hospitalized patients with severe influenza A. Patients were randomized 1:1:1 into 3 groups receiving single intravenous doses of 3600 mg (n = 55) or 8400 mg (n = 47) MHAA4549A or placebo (n = 56). Patients also received oral oseltamivir twice daily for ≥5 days. Serum, nasopharyngeal, and tracheal aspirate pharmacokinetic samples were collected on days 1‐60 from MHAA4549A‐treated groups. Day 5 plasma samples from all groups were collected for assessing the pharmacokinetics of oseltamivir and its active metabolite, oseltamivir carboxylate. Noncompartmental pharmacokinetic analysis was performed using Phoenix WinNonlin. Data were collected during a preplanned interim analysis that became final when the trial terminated because of a lack of efficacy. Serum MHAA4549A concentrations were dose‐proportional and biphasic. Mean MHAA4549A clearance was 288‐350 mL/day, and mean half‐life was 17.8‐19.0 days. Nasopharyngeal MHAA4549A concentrations were non‐dose‐proportional. We detected MHAA4549A in tracheal aspirate samples, but intersubject variability was high. MHAA4549A serum and nasopharyngeal exposures were confirmed in all MHAA4549A‐treated patients. Serum MHAA4549A had faster clearance and a shorter half‐life in influenza A‐infected patients compared with healthy subjects. MHAA4549A detection in tracheal aspirate samples indicated exposure in the lower respiratory tract. Oseltamivir and oseltamivir carboxylate exposures were similar between MHAA4549A‐treated and placebo groups, suggesting a lack of MHAA4549A interference with oseltamivir pharmacokinetics.

Paragonimiasis: treatment with praziquantel in 40 human cases and in 1 cat

40 patients infected with P. westermani were divided into 3 groups and treated with praziquantel (2-cyclohexylcarbonyl-1,2,3,6,7,11b-hexahydro-4H-pyrazino[2,1-a]++ +isoquinolin- 4-one) by 3 different dosages. Parasitological cure was achieved in 27/40 patients, i.e. 67.5%. Details are given in this short communication.