In relapsed or refractory diffuse large B-cell lymphoma, CD19 expression by immunohistochemistry alone is not a predictor of response to loncastuximab tesirine

CD19-targeting treatments have shown promise in relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). Loncastuximab tesirine (loncastuximab tesirine-lpyl [Lonca]) is a CD19-targeting antibody-drug conjugate indicated for R/R DLBCL after at least two systemic treatments. CD19 expression was evaluated in patients receiving Lonca in the LOTIS-2 clinical trial with available tissue samples obtained after last systemic therapy/before Lonca treatment. Lonca cytotoxicity was evaluated in a panel of six lymphoma cell lines with various CD19 expression levels. Quantitative systems pharmacology (QSP) modelling was used to predict Lonca responses. Lonca responses were seen in patients across all CD19 expression levels, including patients with low/no detectable CD19 expression and H-scores at baseline. Similarly, Lonca induced cytotoxicity in cell lines with different levels of CD19 expression, including one with very low expression. QSP modelling predicted that CD19 expression by immunohistochemistry alone does not predict Lonca response, whereas inclusion of CD19 surface density improved response prediction. Virtual patients responded to Lonca with estimated CD19 as low as 1000 molecules/cell of CD19, normally below the immunohistochemistry detection level. We found Lonca is an effective treatment for R/R DLBCL regardless of CD19 expression by immunohistochemistry. These results provide the basis for future studies addressing CD19-targeted agent sequencing.

Abstract 4151: Effect of camidanlumab tesirine (Cami) as monotherapy and in combination with pembrolizumab (PEM) on the immune cell profile in patients with selected advanced solid tumors

Background: Cami, an investigational anti-CD25, pyrrolobenzodiazepine-based antibody drug conjugate, imparts cytotoxicity on CD25+ regulatory T cells (Tregs), leading to immunomodulatory effects (eg, modifying effector T cell [Teff]:Treg intratumoral balance).

Objective: Describe the pharmacokinetics (PK) and circulating immune cell profile of Cami monotherapy and in combination with PEM in patients with advanced solid tumors.

Methods: In the dose-escalation phase 1b trial of Cami (NCT03621982) in patients with advanced solid tumors after failure of recommended therapies, we investigated Cami monotherapy (n=44; doses: 20, 30, 45, 60, 80, 100, 125, and 150 µg/kg every 3 weeks [Q3W]) and Cami combination therapy (n=12; doses: 30, 45, and 60 µg/kg with PEM 200 mg Q3W). Serum conjugated antibody (cAb) and total antibody (tAb) were quantified by a validated chemoimmunoluminescence assay. Soluble CD25 was quantified by a qualified enzyme-linked immunoassay. Circulating immune cell absolute counts were assessed by flow cytometry for Tregs (FoxP3+CD25+CD127low) as a fraction of absolute CD4+ cells, Teff (CD8+), and Teff:Treg. Statistical analyses were performed using a linear mixed-effects model (maximum likelihood) for the biomarker effects model with cAb area under the curve (AUC) during cycle 1, therapy (monotherapy vs combination), and treatment cycle as fixed effects and log AUC slope with intercept by subject or visit day as random effects.

Results: PK analysis found Cmax and AUC of cAb and tAb increased during cycles 1 and 2 with Cami monotherapy and combination therapy across the range of doses. Variability of AUCinf for cAb in cycle 1 appeared modest to marked across discrete dose groups (CV=14.7-98.1%). The clearance of cAb ranged from 1.34 to 3.52 L/day in cycle 1 with no apparent differences between monotherapy and combination therapy. Biomarker modeling demonstrated that cAb AUC and cycle were associated with a significant Tregs depletion and a significant positive effect on Teff:Treg ratio but with no relevant effect on Teff. Within cycle, treatment-related modulation of Teff and Tregs was observed for all doses and conditions. Soluble CD25 appears to be significantly positively affected by cycle 2 treatment.

Conclusions: PK exposure of Cami was dose-related with varying degrees of interpatient variability. Circulating Tregs were significantly decreased and Teff:Treg was significantly increased by Cami exposure, demonstrating the intended immunomodulatory effect of Cami in circulation and suggesting that a combination approach with Cami could address an immune-resistance mechanism. Future analyses will consider discrete PEM effect, correlates to tumor biopsy expression and response, and combined Cami+PEM effect in tumor biopsies. Funding: ADC Therapeutics; medical writing: CiTRUS Health Group.

Citation Format: Igor Puzanov, Christopher T. Chen, Patricia LoRusso, Kyriakos P. Papadopoulos, Shivaani Kummar, Erika Hamilton, Yvan LeBruchec, Karin Havenith, Serafino Pantano, Marie Toukam, Jens Wuerthner, Joseph Boni. Effect of camidanlumab tesirine (Cami) as monotherapy and in combination with pembrolizumab (PEM) on the immune cell profile in patients with selected advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4151.

Efficacy and Safety Exposure-Response Analysis of Loncastuximab Tesirine in Patients with B cell non-Hodgkin Lymphoma

We developed an integrated population pharmacokinetic model to investigate loncastuximab tesirine pharmacokinetics (PK) and exposure-response relationships for relapsed/refractory B cell non-Hodgkin lymphoma, including diffuse large B cell lymphoma (DLBCL). The model, based on the recommended dosing schedule (150 µg/kg every 3 weeks [Q3W] for 2 cycles; 75 µg/kg Q3W thereafter) and drug concentrations in phase 1 and 2 studies (DLBCL [n = 284], non-DLBCL [n = 44]), was used to characterize loncastuximab tesirine PK and evaluate exposure covariates. Relationships between exposure (pyrrolobenzodiazepine-conjugated antibody [cAb] cycle 1 average concentration) and (1) efficacy (including overall response rate [ORR; primary endpoint] and overall survival [OS]) and (2) grade ≥ 2 treatment-emergent adverse events were explored. Statistical analyses included univariate and multivariate logistic regression, Kaplan-Meier analysis, and Cox proportional hazard regression. cAb and total Ab were best described by a two-compartment linear model with time-dependent clearance. The cAb steady-state half-life increased to 20.6 days by ~ 15 weeks. cAb exposure was lower for low albumin, mild/moderate hepatic impairment, non-DLBCL subtypes, and Eastern Cooperative Oncology Group scores > 1. Significant positive associations were reported between exposure and ORR (p = 3.21E-6), OS (p = 0.0016), grade ≥ 2 increased gamma-glutamyltransferase, liver function test abnormalities, pain, and skin/nail reactions (p < 0.05). Low albumin, bulky disease, and mild/moderate hepatic impairment had a significant negative effect on OS (p < 0.01). Modeling supports the recommended loncastuximab tesirine dosing schedule. Although reduced exposure and efficacy were predicted for specific covariates (e.g., low albumin, mild/moderate hepatic impairment), dose increases are not recommended. Trial registration: NCT02669017 and NCT03589469.

Abstract 1366: Integrated population modeling of loncastuximab tesirine (Lonca) exposure in B-cell non-Hodgkin lymphoma (B-NHL)

Lonca is an antibody (Ab) drug conjugate comprising a humanized monoclonal Ab directed against B-cell antigen CD19, conjugated with a potent pyrrolobenzodiazepine (PBD) dimer toxin. In a Phase 1 (NCT02669017) study in relapsed or refractory (R/R) B-NHL, a recommended Phase 2 dosing regimen for Lonca of 150 µg/kg once every 3 weeks (Q3W) for two doses, followed by 75 µg/kg Q3W was identified then evaluated in a Phase 2 (NCT03589469) study in R/R diffuse large B-cell lymphoma (DLBCL). A population pharmacokinetic (PPK) model was developed to characterize the pharmacokinetics (PK) of the Lonca dosing regimen and evaluate exposure covariates.

The integrated PPK model was used to describe drug concentrations for Lonca PBD-conjugated Ab (5,301 samples), total Ab (5,241 samples), and unconjugated warhead SG3199 (239 samples) in serum from 328 patients. Samples were taken pre-dose, at end of infusion and at pre-determined timepoints post-infusion throughout the trials. Analysis was performed using non-linear mixed-effects modeling (NONMEM, v7.4 [ICON Solutions]). Subgroup analyses were conducted on model-predicted exposure metrics derived from simulation of Lonca PK profiles based on empirical Bayesian estimates of individual PK parameters.

Concentration-time data of Lonca PBD-conjugated Ab and total Ab were best characterized by a two-compartment model with parallel linear clearance (0.218 L/day), and a time-dependent clearance component which approached zero by ~15 weeks. The estimated volume of distribution of central compartment was 3.86 L and the estimated typical half-life at steady state of Lonca is ~3 weeks. The effect of body weight, age, sex, race, renal impairment, drug formulation, anti-drug Ab, ECOG, and concomitant P-gp inhibitors did not show clinically important influence on exposure (&lt; ±30% change relative to reference). Based on model-predicted Cycle 1 average concentration (Cavg) patients with low albumin (&lt;35 g/L, n=49) had 52% lower Cavg than patients with normal albumin levels (≥35 g/L, n=279). Patients with non-DLBCL (n=44) had 61% lower Cavg than patients with DLBCL (n=284). Trends of lower exposures with baseline mild/moderate hepatic impairment and ECOG status &gt;1 were noted but did not appear to be of clinical relevance.

In conclusion, Lonca exposure was well described by a two-compartment model with linear and time-dependent clearance; the latter is thought to reflect reduction of tumor cells. Lonca exposure was lower in non-DLBCL patients, and lower in patients with hypoalbuminemia secondary to enhanced protein clearance in patients with critical illness. Overall, modeling demonstrates rapid attainment of steady-state exposure for Lonca given 150 µg/kg Q3W for two doses, and a sustaining profile for Lonca given 75 µg/kg Q3W thereafter for patients with DLBCL.

Citation Format: Melhem Solh, Juan Pablo Alderuccio, Anastasios Stathis, David Ungar, Sam Liao, Lisa Khouri, Xiaoyan Zhang, Joseph Boni. Integrated population modeling of loncastuximab tesirine (Lonca) exposure in B-cell non-Hodgkin lymphoma (B-NHL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1366.

Camidanlumab tesirine in patients with relapsed or refractory lymphoma: a phase 1, open-label, multicentre, dose-escalation, dose-expansion study

BACKGROUND

Novel approaches are required to improve outcomes in relapsed or refractory classical Hodgkin lymphoma and non-Hodgkin lymphoma. We aimed to evaluate camidanlumab tesirine, an anti-CD25 antibody-drug conjugate, in this patient population.

METHODS

This was a phase 1, dose-escalation (part 1), dose-expansion (part 2), multicentre trial done in 12 hospital sites (seven in the USA and five in the UK). Adults (≥18 years old) with pathologically confirmed relapsed or refractory classical Hodgkin lymphoma or non-Hodgkin lymphoma, an Eastern Cooperative Oncology Group performance status 0-2, who had no therapies available to them with established clinical benefit for their disease stage were enrolled. Camidanlumab tesirine was administered intravenously (3-150 μg/kg) once every 3 weeks. Primary objectives were to assess dose-limiting toxicity, determine maximum tolerated dose and recommended expansion dose(s), and assess safety of camidanlumab tesirine. Safety was assessed in all treated patients; antitumour activity was assessed in patients with one or more valid baseline and post-baseline disease assessment and in those who had disease progression or died after first study-drug dose. This trial was registered with ClinicalTrials.gov, NCT02432235.

FINDINGS

Between Oct 5, 2015, and Jun 30, 2019, 133 patients were enrolled (77 [58%] had classical Hodgkin lymphoma and 56 (42%) had non-Hodgkin lymphoma). Median follow-up was 9·2 months (IQR 4·2-14·3). Eight dose-limiting toxicities were reported in five (6%) of 86 patients who were evaluable; the maximum tolerated dose was not reached. The recommended doses for expansion were 30 μg/kg and 45 μg/kg for patients with classical Hodgkin lymphoma and 80 μg/kg for patients with T-cell non-Hodgkin lymphomas. No recommended doses for expansion were defined for B-cell non-Hodgkin lymphomas. Grade 3 or worse treatment-emergent adverse events (reported by ≥10% of the 133 patients) included increased γ-glutamyltransferase (20 [15%] patients), maculopapular rash (16 [12%]), and anaemia (15 [11%]); 74 (56%) patients had serious treatment-emergent adverse events, most commonly pyrexia (16 [12%]). One (1%) fatal treatment-emergent adverse event and two (2%) deaths outside the reporting period were considered at least possibly study-drug related. Antitumoural activity was seen in classical Hodgkin and non-Hodgkin lymphomas; notably in all patients with classical Hodgkin lymphoma, the overall response was 71% (95% CI 60-81).

INTERPRETATION

These results warrant evaluation of camidanlumab tesirine as a potential treatment option for relapsed or refractory lymphoma, particularly in patients with classical Hodgkin lymphoma.

FUNDING

ADC Therapeutics.

A phase 1b, open-label, dose-escalation study to evaluate camidanlumab tesirine (Cami) as monotherapy in patients (pts) with advanced solid tumors

2556

Background: Depletion of tumor-infiltrating CD25+ regulatory T cells (Tregs), which inhibit tumor-specific immune responses, could contribute to tumor eradication. Cami (ADCT-301), an anti-CD25, pyrrolobenzodiazepine-based antibody-drug conjugate, targets CD25+ Tregs. A mouse surrogate has shown potent antitumor activity in solid tumor models. Here we report preliminary data from the monotherapy arm of a phase 1b trial of Cami in pts with selected advanced solid tumors. Methods: The monotherapy dose-escalation part of this open-label study enrolled pts (aged ≥18 years) with selected advanced solid tumors and no suitable existing therapy. The primary objective was to characterize safety and tolerability, and to identify the recommended phase 2 dose of Cami monotherapy. Secondary and exploratory objectives included evaluation of preliminary antitumor activity, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity. Pts received Cami every 3 weeks (1 cycle) with dose escalation per a 3+3 design. Disease control rate (DCR) was assessed (complete and partial responses [CR, PR] and stable disease). Results: At data cut-off (Dec 17, 2020), 44 pts were enrolled, with primary tumor types (stage IVA/B: 27 pts; 61.4%) of colorectal (15 pts; 34.1%), pancreatic (14 pts; 31.8%), head and neck, ovarian/fallopian tube, and renal cell carcinoma (all 3 pts; 6.8%), non-small cell lung cancer (2 pts; 4.5%), gastric, esophageal/GEJ, melanoma, and triple-negative breast cancer (each 1 pt; 2.3%). Median (range) age was 60.5 (33–82) years; median (range) number of prior systemic therapies was 4 (1–9). Pts received a median (range) of 2 (1–6) Cami cycles at doses of 20–150 µg/kg. Median (range) treatment duration was 22 (1–178) days. No dose-limiting toxicities were reported. The maximum tolerated dose (MTD) was not reached. All-grade treatment-emergent adverse events (TEAEs) in ≥20% pts were nausea (18 pts; 40.9%), decreased appetite and fatigue (each 16 pts; 36.4%), constipation (13 pts; 29.5%), abdominal pain (11 pts; 25%), and rash (10 pts; 22.7%). The only Grade ≥3 TEAE in ≥10% pts was anemia (5 pts; 11.4%). Grade 3 autoimmune AEs (colitis, immune-mediated AE, systemic inflammatory response syndrome) and neurologic AEs (dysphagia and asthenia, but not GBS) were reported in 3 (6.8%) and 2 (4.5%) pts, respectively. 1 (2.3%) Cami-related TEAE led to treatment withdrawal; no Cami-related TEAEs were fatal. DCR was 25% (95% CI: 11.1, 34.7); 11/44 pts attained stable disease. No pts had CR or PR. Conclusions: Dose escalation of Cami monotherapy is complete. The safety profile is encouraging and MTD was not reached. PK/PD data will be presented. 150 µg/kg is the highest dose investigated for single-agent Cami and the highest to be investigated combined with pembrolizumab in selected advanced solid tumors in the current protocol. Funding: ADC Therapeutics SA NCT03621982. Clinical trial information: NCT03621982.

Phase 1 study of inotuzumab ozogamicin combined with R-GDP for the treatment of patients with relapsed/refractory CD22+ B-cell non-Hodgkin lymphoma

Objective: To evaluate safety, tolerability, and preliminary activity of inotuzumab ozogamicin (InO) plus rituximab, gemcitabine, dexamethasone, and cisplatin (R-GDP) in patients with relapsed/refractory CD22+ B-cell non-Hodgkin lymphoma (NHL). Methods: Patients received InO plus R-GDP (21-day cycle; six-cycle maximum) using up-and-down dose-escalation schema for gemcitabine and cisplatin to define the highest dosage regimen(s) with acceptable toxicity (Part 1; n = 27). Part 2 (n = 10) confirmed safety and tolerability; Part 3 (n = 18) evaluated preliminary efficacy. Results: Among 55 patients enrolled, 42% were refractory at baseline (median 2 [range, 1-6] prior therapies); 38% had diffuse large B-cell lymphoma (DLBCL). The highest dosage regimen with acceptable toxicity was InO 0.8 mg/m², rituximab 375 mg/m², cisplatin 50 mg/m², gemcitabine 500 mg/m² (day 1 only) and dexamethasone 40 mg (days 1-4); this was confirmed in Part 2, in which three patients had dose-limiting toxicities (grade 4 thrombocytopenia [n = 2], febrile neutropenia [n = 2]). Most frequent treatment-related adverse events were thrombocytopenia (any grade, 85%; grade ≥3, 75%) and neutropenia (69%; 62%). Overall (objective) response rate (ORR) was 53% (11 complete, 18 partial responses); ORR was 71%, 33%, and 62% in patients with follicular lymphoma (n = 14), DLBCL (n = 21), and mantle cell lymphoma (n = 13), respectively. Conclusions: InO 0.8 mg/m² plus R-GDP was associated with manageable toxicity, although gemcitabine and cisplatin doses were lower than in the standard R-GDP regimen due to hematologic toxicity. Evidence of antitumor activity was observed; however, these exploratory data should be interpreted with caution due to the small sample size and short follow-up duration (Clinicaltrials.gov number: NCT01055496).

Comparison of two doses of intravenous temsirolimus in patients with relapsed/refractory mantle cell lymphoma

Temsirolimus 175 mg once-weekly for 3 weeks, followed by 75 mg once-weekly intravenously dosed (175/75 mg) is approved in the European Union for treatment of relapsed/refractory mantle cell lymphoma (MCL). A phase IV study explored whether similar efficacy, but improved safety could be achieved with 75 mg without 175 mg loading doses (ClinicaTrials.gov: NCT01180049). Patients with relapsed/refractory MCL were randomized to once-weekly temsirolimus 175/75 mg (n = 47) or 75 mg (n = 42). Treatment continued until objective disease progression. Primary endpoint: progression-free survival (PFS). Secondary endpoints included overall survival (OS) and adverse events (AEs). Median PFS was 4.3 versus 4.5 months (hazard ratio [HR] 0.731; 80% confidence interval [CI], 0.520-1.027), and median OS 18.7 versus 11.0 months (HR 0.681; 80% CI, 0.472-0.982) with 175/75 mg versus 75 mg. There were fewer patients with serious AEs, dose reduction, or death with 175/75 mg (57.4%, 48.9%, and 48.9%) versus 75 mg (73.8%, 64.3%, and 65.1%). Temsirolimus 175/75 mg remains the preferred dosing regimen for relapsed/refractory MCL.

Stem cell-like transcriptional reprogramming mediates metastatic resistance to mTOR inhibition

Inhibitors of the mechanistic target of rapamycin (mTOR) are currently used to treat advanced metastatic breast cancer. However, whether an aggressive phenotype is sustained through adaptation or resistance to mTOR inhibition remains unknown. Here, complementary studies in human tumors, cancer models and cell lines reveal transcriptional reprogramming that supports metastasis in response to mTOR inhibition. This cancer feature is driven by EVI1 and SOX9. EVI1 functionally cooperates with and positively regulates SOX9, and promotes the transcriptional upregulation of key mTOR pathway components (REHB and RAPTOR) and of lung metastasis mediators (FSCN1 and SPARC). The expression of EVI1 and SOX9 is associated with stem cell-like and metastasis signatures, and their depletion impairs the metastatic potential of breast cancer cells. These results establish the mechanistic link between resistance to mTOR inhibition and cancer metastatic potential, thus enhancing our understanding of mTOR targeting failure.

Preclinical to Clinical Translation of Antibody-Drug Conjugates Using PK/PD Modeling: a Retrospective Analysis of Inotuzumab Ozogamicin

A mechanism-based pharmacokinetic/pharmacodynamic (PK/PD) model was used for preclinical to clinical translation of inotuzumab ozogamicin, a CD22-targeting antibody-drug conjugate (ADC) for B cell malignancies including non-Hodgkin's lymphoma (NHL) and acute lymphocytic leukemia (ALL). Preclinical data was integrated in a PK/PD model which included (1) a plasma PK model characterizing disposition and clearance of inotuzumab ozogamicin and its released payload N-Ac-γ-calicheamicin DMH, (2) a tumor disposition model describing ADC diffusion into the tumor extracellular environment, (3) a cellular model describing inotuzumab ozogamicin binding to CD22, internalization, intracellular N-Ac-γ-calicheamicin DMH release, binding to DNA, or efflux from the tumor cell, and (4) tumor growth and inhibition in mouse xenograft models. The preclinical model was translated to the clinic by incorporating human PK for inotuzumab ozogamicin and clinically relevant tumor volumes, tumor growth rates, and values for CD22 expression in the relevant patient populations. The resulting stochastic models predicted progression-free survival (PFS) rates for inotuzumab ozogamicin in patients comparable to the observed clinical results. The model suggested that a fractionated dosing regimen is superior to a conventional dosing regimen for ALL but not for NHL. Simulations indicated that tumor growth is a highly sensitive parameter and predictive of successful outcome. Inotuzumab ozogamicin PK and N-Ac-γ-calicheamicin DMH efflux are also sensitive parameters and would be considered more useful predictors of outcome than CD22 receptor expression. In summary, a multiscale, mechanism-based model has been developed for inotuzumab ozogamicin, which can integrate preclinical biomeasures and PK/PD data to predict clinical response.

Effect of rifampin on the pharmacokinetics of bosutinib, a dual Src/Abl tyrosine kinase inhibitor, when administered concomitantly to healthy subjects

BACKGROUND

Bosutinib is an orally bioavailable dual Src/Abl tyrosine kinase inhibitor and a CYP3A4 enzyme substrate. This study assessed the safety, tolerability, and pharmacokinetics of bosutinib when coadministered with the CYP3A4 inducer rifampin in 24 healthy men.

METHODS

Subjects received single oral doses of bosutinib 500 mg (Days 1 and 14) and once-daily oral doses of rifampin 600 mg (Days 8-17); serial blood samples were analyzed.

RESULTS

Bosutinib exposures were reduced following concomitant administration of rifampin vs. bosutinib alone, measured by peak plasma concentration (C(max); 112 vs. 16.0 ng/mL; 86% reduction), total area under the concentration-time curve (AUC; 2740 vs. 207 ng·h/mL; 92% reduction), and AUC to the last measurable concentration at time T (2440 vs. 158 ng·h/mL; 94% reduction). Median time to C(max) and mean half-life were shorter for bosutinib plus rifampin vs. single-agent bosutinib. Oral clearance increased approximately 13-fold; the volume of distribution increased from 9560 to 72,900 L. Treatment-emergent adverse events appeared less frequently with bosutinib plus rifampin (59%) vs. single-agent bosutinib (79%); diarrhea was reported in 11 (46%) vs. 4 (18%) subjects, respectively.

CONCLUSIONS

Concomitant use of potent or moderate CYP3A inducers with bosutinib should be avoided because of the effects of drug-drug interaction observed between bosutinib and rifampin.

Abstract 4518: Model-based integration of pharmacokinetics, efficacy and safety data for optimizing therapy of inotuzumab ozogamicin in subjects with indolent non-Hodgkin's lymphoma

Purpose

This study aimed to develop a quantitative method for optimizing the dose and regimen of inotuzumab ozogamicin (InO) in patients with indolent non-Hodgkin lymphoma (NHL) by simultaneously balancing the safety and efficacy outcome measures

Design

Analysis was based on data from a multi-center, single arm, open-label study of intravenous InO administered at a dose of 1.8 mg/m2, every 4 weeks (Q4W) for at least 4 cycles.

Patients and Methods

Pharmacokinetics (PK), safety, and efficacy data from a phase 2 trial of InO in 81 patients were evaluated by modeling and simulation. PK disposition was described by a 2-compartment model linked to: 1) an exponential tumor growth model of time-dependent tumor size change (efficacy determinant expressed as objective response rate); 2) a precursor-dependent platelet inhibition model to describe time-dependent platelet count change (safety determinant expressed as thrombocytopenia grades). Modeling and simulation was performed using NONMEM version 7.2 (ICON Development Solutions, Ellicott City, MD) and internally validated using study data and safety and efficacy response surfaces generated based on virtual trial simulations, from which a clinical utility index (CUI) contour was constructed and optimal InO dosage regimens were selected.

Results

The model-predicted rate of grade 3 or 4 thrombocytopenia for the studied dose of 1.8 mg/m2 Q4W was 44.2% versus observed of 45.8%. The efficacy-response surface indicated that InO, at the dosage regimen studied in the trial (1.8 mg/m2 Q4W), exhibited near-optimal efficacy, with little improvement gained from alternative dosage regimens. The predicted effective objective response rate was 53.1% versus observed of 55.8%. The safety-response surface indicated that modifying the dosage regimen (without compromising efficacy) modestly improved the safety profile. The CUI contour identified a dosage regimen of 2 mg/m2 administered every 10 to 12 weeks as an optimal InO dosage regimen to consider for patients with indolent NHL.

Conclusion

A novel approach to InO treatment optimization in patients with indolent NHL was developed by simultaneously balancing safety and efficacy outcome measures without technical or subjective bias to one or the other. For patients with indolent NHL, increasing the InO dosage interval may improve the tolerability profile, albeit modestly, without substantially compromising efficacy. This approach has broad utility for oncology because it allows objective identification of an optimal dose and regimen for confirmatory trials based on early clinical trial information.

Citation Format: Kenneth Luu, Joseph Boni. Model-based integration of pharmacokinetics, efficacy and safety data for optimizing therapy of inotuzumab ozogamicin in subjects with indolent non-Hodgkin's lymphoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4518. doi:10.1158/1538-7445.AM2015-4518

Safety and clinical activity of a combination therapy comprising two antibody-based targeting agents for the treatment of non-Hodgkin lymphoma: results of a phase I/II study evaluating the immunoconjugate inotuzumab ozogamicin with rituximab

PURPOSE

Inotuzumab ozogamicin (INO) is an antibody-targeted chemotherapy agent composed of a humanized anti-CD22 antibody conjugated to calicheamicin, a potent cytotoxic agent. We performed a phase I/II study to determine the maximum-tolerated dose (MTD), safety, efficacy, and pharmacokinetics of INO plus rituximab (R-INO) for treatment of relapsed/refractory CD20(+)/CD22(+) B-cell non-Hodgkin lymphoma (NHL).

PATIENTS AND METHODS

A dose-escalation phase to determine the MTD of R-INO was followed by an expanded cohort to further evaluate the efficacy and safety at the MTD. Patients with relapsed follicular lymphoma (FL), relapsed diffuse large B-cell lymphoma (DLBCL), or refractory aggressive NHL received R-INO every 4 weeks for up to eight cycles.

RESULTS

In all, 118 patients received one or more cycles of R-INO (median, four cycles). Most common grade 3 to 4 adverse events were thrombocytopenia (31%) and neutropenia (22%). Common low-grade toxicities included hyperbilirubinemia (25%) and increased AST (36%). The MTD of INO in combination with rituximab (375 mg/m(2)) was confirmed to be the same as that for single-agent INO (1.8 mg/m(2)). Treatment at the MTD yielded objective response rates of 87%, 74%, and 20% for relapsed FL (n = 39), relapsed DLBCL (n = 42), and refractory aggressive NHL (n = 30), respectively. The 2-year progression-free survival (PFS) rate was 68% (median, not reached) for FL and 42% (median, 17.1 months) for relapsed DLBCL.

CONCLUSION

R-INO demonstrated high response rates and long PFS in patients with relapsed FL or DLBCL. This and the manageable toxicity profile suggest that R-INO may be a promising option for CD20(+)/CD22(+) B-cell NHL.

Abstract 3767: Use of pharmacokinetic-pharmacodynamic modeling to characterize platelet response following inotuzumab ozogamicin treatment in patients with follicular or diffuse large B-cell non-Hodgkin's lymphoma

Background: Inotuzumab ozogamicin (CMC-544) is an immunoconjugate chemotherapy agent composed of a CD22-directed IgG4 antibody linked to calicheamicin, a potent cytotoxic anti-tumor antibiotic. Thrombocytopenia was the most frequent adverse event observed in phase 1/2 studies. This integrated population pharmacokinetic-pharmacodynamic (PK/PD) analysis was undertaken to a) elucidate the relationship between exposure of inotuzumab or total calicheamicin (tCali) and the decrease in platelet count; b) identify the covariates that influence the PK of inotuzumab and platelet response; and c) optimize the dosing schedule. Methods: Serum concentrations of inotuzumab, tCali (sum of conjugated and unconjugated forms), and platelet count were available from 5 phase 1/2 studies with follicular or diffuse large B-cell non-Hodgkin's lymphoma (NHL) who received inotuzumab alone or in combination with rituximab. Most patients received 1.8 mg/m2 of inotuzumab infused over 1 hour every 3 to 4 weeks (dose range, 0.4-2.4 mg/m2). The sequential PK/PD analysis was performed by nonlinear regression using NONMEM, version 7, level 1.2 (Icon Development Solutions, Hanover, MD). Covariates (factors for demography, hematology measures, renal and hepatic function, and baseline tumor size) were evaluated using graphical analysis, a general additive model (GAM), and a stepwise covariate model by forward addition and backward elimination process (SCM). Results and Conclusion: A 2-compartment model with linear elimination adequately described the PK of inotuzumab and tCali. The time course of platelet response was modeled using a semi-mechanistic transit compartment model model with drug effect as a sigmoidal Emax function. Significant covariate effects identified for PK estimates of inotuzumab included baseline body surface area (BSA) on clearance (CL) and central volume (V1), and baseline creatinine clearance on inter-compartment clearance (Q). For tCali, significant covariate effects included baseline BSA on CL and V1, treatment occasion (cycle) on CL and V1, and gender on peripheral volume (V2). The CL of tCali decreased from 0.73 L/h in Cycle 1 to 0.3 L/h in Cycles 2 and 3, suggesting a nonlinear disposition process. For the platelet model, the EC50 estimates for effect of inotuzumab and tCali on production of platelets were 219 and 50.2 ng/mL, respectively. Baseline platelet count was identified as a significant covariate. Integrated modeling of drug concentration and platelet count provides a means to quantify the magnitude of platelet suppression and to identify dosing schedules that mitigate the incidence of thrombocytopenia.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3767. doi:1538-7445.AM2012-3767

Phase I study of temsirolimus in combination with EKB-569 in patients with advanced solid tumors

Purpose Activation of EGFR can stimulate proliferative and survival signaling through mTOR. Preclinical data demonstrates synergistic activity of combined EGFR and mTOR inhibition. We undertook a phase I trial of temsirolimus (T, an mTOR inhibitor) and EKB-569 (E, an EGFR inhibitor) to determine the safety and tolerability. Methods The primary aim was to determine the maximally tolerated dose (MTD) of this combination in adults with solid tumors. Following the dose-escalation phase, (Cohort A), two subsequent cohorts were used to assess any pharmacokinetic (PK) interaction between the agents. Results Forty eight patients were enrolled. The MTD of this combination was E, 35 mg daily and T, 30 mg on days 1-3 and 15-17 using a 28-day cycle. The most common toxicities were nausea, diarrhea, fatigue, anorexia, stomatitis, rash, anemia, neutropenia, thrombocytopenia, and hypertriglyceridemia. Sixteen patients (36%) had at least one grade 3 toxicity. The most frequent grade 3/4 toxicities were diarrhea, dehydration, and nausea and vomiting (19% each). No grade 5 events were seen. Four patients had a partial response and 15 had stable disease. Clinical benefit was seen across a range of tumor types and in all cohorts. PK analysis revealed no significant interaction between E and T. Conclusions This combination of agents is associated with tolerable toxicities at doses that induced responses. PK studies revealed no interaction between the drugs. Further investigations of this targeting strategy may be attractive in renal cell carcinoma, non-small cell lung cancer, alveolar sarcoma, and carcinoid tumor.

Safety, pharmacokinetics, and preliminary clinical activity of inotuzumab ozogamicin, a novel immunoconjugate for the treatment of B-cell non-Hodgkin's lymphoma: results of a phase I study

PURPOSE Inotuzumab ozogamicin (CMC-544) is an antibody-targeted chemotherapy agent composed of a humanized anti-CD22 antibody conjugated to calicheamicin, a potent cytotoxic agent. This was a phase I study to determine the maximum-tolerated dose (MTD), safety, and preliminary efficacy of inotuzumab ozogamicin in an expanded MTD cohort of patients with relapsed or refractory CD22(+) B-cell non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS Inotuzumab ozogamicin was administered intravenously as a single agent once every 3 or 4 weeks at doses ranging from 0.4 to 2.4 mg/m(2). Outcomes included MTD, safety, pharmacokinetics, response, progression-free survival (PFS), and overall survival. Results Seventy-nine patients were enrolled. The MTD was determined to be 1.8 mg/m(2). Common adverse events at the MTD were thrombocytopenia (90%), asthenia (67%), and nausea and neutropenia (51% each). The objective response rate at the end of treatment was 39% for the 79 enrolled patients, 68% for all patients with follicular NHL treated at the MTD, and 15% for all patients with diffuse large B-cell lymphoma treated at the MTD. Median PFS was 317 days (approximately 10.4 months) and 49 days for patients with follicular NHL and diffuse large B-cell lymphoma, respectively. CONCLUSION Inotuzumab ozogamicin has demonstrated efficacy against CD22(+) B-cell NHL, with reversible thrombocytopenia as the main toxicity.

Analysis of PTEN and HIF-1alpha and correlation with efficacy in patients with advanced renal cell carcinoma treated with temsirolimus versus interferon-alpha

BACKGROUND

Exploratory subgroup analyses from the phase 3 global advanced renal cell carcinoma (ARCC) trial were conducted to determine if baseline levels of the tumor molecular markers PTEN and HIF1 alpha correlated with efficacy in patients treated with temsirolimus (Torisel) versus interferon-alpha (IFN).

METHODS

Patients in the IFN group received 3 million U (MU) subcutaneously 3x weekly, escalating to 18 MU. Patients in the temsirolimus group received 25 mg intravenously weekly. PTEN and HIF1 alpha baseline levels were measured in archived tumor specimens by immunohistochemistry.

RESULTS

There was no correlation between baseline PTEN and HIF1 alpha levels and treatment effect with respect to overall survival (OS), progression-free survival, or objective response rate (ORR) in patients with advanced renal cell carcinoma with poor-risk prognostic factors.

CONCLUSIONS

The baseline status of the molecular markers PTEN and HIF1 alpha did not correlate with efficacy in renal cell carcinoma patients treated with temsirolimus versus IFN. Patients demonstrated OS and progression-free survival benefit when treated with temsirolimus regardless of PTEN and HIF1 alpha status. Thus, baseline PTEN and HIF-1 levels may not predict response to temsirolimus. Alternatively, the lack of correlation may be due to the variability in tumor specimens that occurred because of the global nature of the clinical trial. Other markers in the phosphoinositide 3-kinase (PI3K)/Akt pathway may be of utility as predictors of response to temsirolimus in patients with advanced renal cell carcinoma.

Population pharmacokinetic modeling for intravenous temsirolimus and sirolimus metabolite in subjects with various solid tumors

2522

Background: Temsirolimus (TEMSR) is an mTOR inhibitor approved for treatment of patients with advanced renal cell carcinoma, and under development for relapsed/refractory mantle cell lymphoma (MCL). In MCL, TEMSR showed a dose-related increase in median progression-free survival [4.8 vs. 3.4 mo] and objective response rate [22% vs 6%] for 175 mg x 3 wks then 75 or 25 mg weekly regimens (175/75-mg and 175/25-mg), respectively. We aim to characterize the population pharmacokinetic exposure, covariate influence, and differences afforded by these regimens. Methods: Nonlinear mixed-effects models of TEMSR and sirolimus (SIR; major active metabolite) blood concentrations were defined in healthy subjects and patients. Modeling for TEMSR employed a 4-compartment model with saturable distribution to red cells and peripheral tissue, and modeling for SIR utilized a linear 2- compartment model with factor for dose. Covariates included demographic factors, clinical labs, and disease condition. Following validation, simulations with variability were used to evaluate effects of covariates on exposure. Results: Final datasets comprised 1342 observations from 150 subjects (TEMSR) and 1648 observations from 279 subjects (SIR). In a typical patient (56-year-old male weighing 76.5 kg), disease affected TEMSR clearance (62.4 L/h in MCL, 92.1 L/h in breast cancer vs. 112 L/h for other subjects). Dose, single vs. multiple, and body weight affected SIR apparent clearance. Simulations for the 175/75-mg regimen indicate that significant covariates yield only modest differences on blood exposures. For MCL (175/75-mg regimen), TEMSR Cmax (week 3) was 2574 ng/mL and SIR Ctrough (week 6) was 10.7 ng/mL. AUC for the 75-mg maintenance arm was ∼2.3-fold (TEMSR) and ∼3.5-fold higher (SIR) than respective values of the 25-mg arm. Correlation of average AUC to clinical response was not apparent. Conclusions: No significant differential effects were observed for age, gender, race, or hepatic and renal laboratory measures. Covariates of disease, while significant, have only modest effects on the exposure profile. Higher clinical responses observed with the 175/75-mg regimen as compared with the 175/25-mg regimen may critically derive from differences in exposure.

[Table: see text]

A single-dose, placebo- and moxifloxacin-controlled 3-period study of the effects of temsirolimus on cardiac repolarization in healthy subjects

2551

Background: Temsirolimus (CCI-779) is a novel selective inhibitor of the mammalian target of rapamycin (mTOR) approved by the US FDA for the treatment of patients with advanced renal cell carcinoma. This study was designed to assess the effect of a single dose of 25 mg IV temsirolimus on the corrected QT interval (QTc) in healthy subjects. Methods: Fifty-eight (58) healthy subjects were enrolled in this 3-period crossover study. In periods 1 and 2, subjects were administered IV placebo either alone or with open-label oral moxifloxacin. In period 3, subjects were administered 25 mg IV temsirolimus. Serial ECGs were digitally captured in triplicate and manually over read by a central vendor. The primary statistical objective was to estimate the effect of temsirolimus compared with placebo on change from time-matched baseline QTc at the end of infusion (0.5 hour time point). Secondary endpoints and objectives included estimates of effect at 12 additional time points, population PKPD analyses, and categorical summaries of interval data. Assay sensitivity was evaluated by the effect of moxifloxacin on change from time-matched baseline QTc as compared with placebo. Results: Temsirolimus had no effect on the QTc interval in the primary analysis. At 11 of 12 secondary time points, the upper bound for the temsirolimus QTc 90% CIs for the time-matched change from baseline difference from placebo was less than 10 msec without evidence of QTc trends or relationship to temsirolimus or sirolimus whole blood concentrations. Mean concentrations were comparable to those observed in patients with renal cell carcinoma following administration of 25 mg IV temsirolimus. Moxifloxacin produced a statistically significant increase in the QTc interval as compared with placebo. No relevant PKPD relationship was seen using linear or Emax models. No subject in this study had a QTc interval exceeding 450 msec and no subjects had a change from baseline >30 msec. Conclusions: We conclude that therapeutic exposures of temsirolimus are not associated with changes in QTc interval that reach the level of regulatory significance, according to ICH E14 guidance. The findings are consistent with the lack of QTc interval prolongation observed in studies of cancer patients.

[Table: see text]

A phase I study of EKB-569 in combination with capecitabine in patients with advanced colorectal cancer

PURPOSE

To determine the maximum tolerated dose (MTD), characterize the principal toxicities, and assess the pharmacokinetics of EKB-569, an oral selective irreversible inhibitor of the epidermal growth factor receptor tyrosine kinase, in combination with capecitabine in patients with advanced colorectal cancer.

EXPERIMENTAL DESIGN

Patients were treated with EKB-569 daily for 21 days and capecitabine twice daily for 14 days of a 21-day cycle. The dose levels of EKB-569 (mg/day) and capecitabine (mg/m(2) twice daily) assessed were 25/750, 50/750, 50/1,000 and 75/1,000. An expanded cohort was enrolled at the MTD to better study toxicity and efficacy. Samples of plasma were collected to characterize the pharmacokinetics of the agents. Treatment efficacy was assessed every other cycle.

RESULTS

A total of 37 patients, the majority of whom had prior chemotherapy, received a total of 163 cycles of treatment. Twenty patients were treated at the MTD, 50 mg EKB-569, daily and 1,000 mg/m(2) capecitabine twice daily. Dose-limiting toxicities were diarrhea and rash. No patients had complete or partial responses but 48% had stable disease. The conversion of capecitabine to 5-fluorouracil was higher for the combination of EKB-569 and capecitabine (321+/-151 ng*h/mL) than for capecitabine alone (176+/-62 ng*hours/mL; P=0.0037).

CONCLUSION

In advanced colorectal cancer, 50 mg EKB-569 daily can be safely combined with 1,000 mg/m(2) capecitabine twice a day. A statistically significant increase in plasma levels of 5-fluorouracil for the combination of EKB-569 and capecitabine may be due to the single-dose versus multiple-dose exposure difference, variability in exposure or a potential drug interaction.

Pharmacokinetic profile of temsirolimus with concomitant administration of cytochrome p450-inducing medications

Temsirolimus is a novel inhibitor of the mammalian target of rapamycin, with antitumor activity in advanced tumors. Because temsirolimus and its metabolite, sirolimus, are cytochrome P450 (CYP) 3A4/5 substrates, the potential exists for interaction with drugs that induce CYP3A activity, including enzyme inducers and rifampin. Cancer patients received once-weekly intravenous (IV) 220 mg/m(2) temsirolimus with or without enzyme inducers. Coadministration with enzyme inducers decreased temsirolimus maximum plasma concentration (C(max)) by 36% and increased volume of distribution by 99%. Sirolimus C(max) and area under the concentration-time curve (AUC) were decreased by 67% and 43%, respectively. In healthy adult subjects, coadministration of 25-mg intravenous temsirolimus with rifampin had no significant effect on temsirolimus C(max) and AUC but decreased sirolimus C(max) and AUC by 65% and 56%, respectively. Rifampin decreased AUC(sum) by 41%. Temsirolimus was well tolerated in both studies. If concomitant agents with CYP3A induction potential are used, higher temsirolimus doses may be needed to achieve adequate tumor tissue drug levels.

Phase II trial of temsirolimus (CCI-779) in recurrent glioblastoma multiforme: a North Central Cancer Treatment Group Study

BACKGROUND

Temsirolimus (CCI-779) is a small-molecule inhibitor of the mammalian target of rapamycin (mTOR) and represents a rational therapeutic target against glioblastoma multiforme (GBM).

METHODS

Recurrent GBM patients with < or = 1 chemotherapy regimen for progressive disease were eligible. Temsirolimus was administered in a 250-mg intravenous dose weekly.

RESULTS

Sixty-five patients were treated. The incidence of grade 3 or higher nonhematologic toxicity was 51%, and consisted mostly of hypercholesterolemia (11%), hypertriglyceridemia (8%), and hyperglycemia (8%). Grade 3 hematologic toxicity was observed in 11% of patients. Temsirolimus peak concentration (Cmax), and sirolimus Cmax and area under the concentration-time curve were decreased in patients receiving p450 enzyme-inducing anticonvulsants (EIACs) by 73%, 47%, and 50%, respectively, but were still within the therapeutic range of preclinical models. Twenty patients (36%) had evidence of improvement in neuroimaging, consisting of decrease in T2 signal abnormality +/- decrease in T1 gadolinium enhancement, on stable or reduced steroid doses. Progression-free survival at 6 months was 7.8% and median overall survival was 4.4 months. Median time to progression (TTP) for all patients was 2.3 months and was significantly longer for responders (5.4 months) versus nonresponders (1.9 months). Development of grade 2 or higher hyperlipidemia in the first two treatment cycles was associated with a higher percentage of radiographic response (71% v 31%; P = .04). Significant correlation was observed between radiographic improvement and high levels of phosphorylated p70s6 kinase in baseline tumor samples (P = .04).

CONCLUSION

Temsirolimus is well tolerated in recurrent GBM patients. Despite the effect of EIACs on temsirolimus metabolism, therapeutic levels were achieved. Radiographic improvement was observed in 36% of temsirolimus-treated patients, and was associated with significantly longer TTP. High levels of phosphorylated p70s6 kinase in baseline tumor samples appear to predict a patient population more likely to derive benefit from treatment. These findings should be validated in other studies of mTOR inhibitors.

Phase II study of temsirolimus (CCI-779), a novel inhibitor of mTOR, in heavily pretreated patients with locally advanced or metastatic breast cancer

PURPOSE

In this study, two doses of temsirolimus (CCI-779), a novel inhibitor of the mammalian target of rapamycin, were evaluated for efficacy, safety, and pharmacokinetics in patients with locally advanced or metastatic breast cancer who had been heavily pretreated.

PATIENTS AND METHODS

Patients (n = 109) were randomly assigned to receive 75 or 250 mg of temsirolimus weekly as a 30-minute intravenous infusion. Patients were evaluated for tumor response, time to tumor progression, adverse events, and pharmacokinetics of temsirolimus.

RESULTS

Temsirolimus produced an objective response rate of 9.2% (10 partial responses) in the intent-to-treat population. Median time to tumor progression was 12.0 weeks. Efficacy was similar for both dose levels but toxicity was more common with the higher dose level, especially grade 3 or 4 depression (10% of patients at the 250-mg dose level, 0% at the 75-mg dose level). The most common temsirolimus-related adverse events of all grades were mucositis (70%), maculopapular rash (51%), and nausea (43%). The most common, clinically important grade 3 or 4 adverse events were mucositis (9%), leukopenia (7%), hyperglycemia (7%), somnolence (6%), thrombocytopenia (5%), and depression (5%).

CONCLUSION

In heavily pretreated patients with locally advanced or metastatic breast cancer, 75 and 250 mg temsirolimus showed antitumor activity and 75 mg temsirolimus showed a generally tolerable safety profile.

Safety and pharmacokinetics of escalated doses of weekly intravenous infusion of CCI-779, a novel mTOR inhibitor, in patients with cancer

PURPOSE

To establish the safety, tolerability, and pharmacokinetic parameters of CCI-779, a selective inhibitor of the mammalian target of rapamycin, in patients with advanced cancer.

PATIENTS AND METHODS

Using a modified continuous reassessment method, we performed a phase I with pharmacokinetic study of CCI-779 given as a weekly 30 minutes intravenous (I.V.) infusion.

RESULTS

Twenty-four patients received CCI-779 at doses ranging 7.5 to 220 mg/m(2). No immunosuppressive effect was reported. Dose-limiting thrombocytopenia occurred in two patients at 34 or 45 mg/m(2). At 220 mg/m(2), dose-limiting toxicities consisted of manic-depressive syndrome, stomatitis, and asthenia in two of nine patients, preventing further dose escalation. The most frequent drug-related toxicities were acne-like, maculopapular rashes and mucositis or stomatitis. All toxicities were reversible on treatment discontinuation. Maximum concentration and area under the concentration-time curve increase sub-proportionally with dose. Mean steady-state volume of distribution ranged from 127 to 385L. Sirolimus was a major metabolite (metabolite-to-parent ratio range, 2.5 to 3.5). Whole blood clearance was nonlinear, ranging from 19 to 51 L/h (34 to 220 mg/m(2)). Variability predicted with flat doses appears comparable with data based on body-surface area-normalized treatment. Partial responses were observed in one patient with renal clear-cell carcinoma and in one patient with breast adenocarcinoma.

CONCLUSION

CCI-779 displayed no immunosuppressive effects with manageable and reversible adverse events at doses up to 220 mg/m(2), the highest dose tested. Based on our results, weekly doses of 25, 75, and 250 mg CCI-779 not based on classical definitions of maximum-tolerated dose are being tested in phase II trials in patients with breast and renal cancer.

Population-based pharmacokinetics of the soluble TNFr etanercept: a clinical study in 43 patients with ankylosing spondylitis compared with post hoc data from patients with rheumatoid arthritis

OBJECTIVE

The purpose of this study was to evaluate the pharmacokinetics of etanercept in patients with ankylosing spondylitis (AS) in a phase 3 study.

METHODS

Serum etanercept concentrations were analyzed from samples obtained at weeks 4 and 12 from 43 patients with AS (median age: 45 years; median body weight: 75 kg; white/non-white: 40/3; male/female: 34/9) receiving 25 mg subcutaneously twice weekly for 12 weeks. A population pharmacokinetics analysis using NONMEM was conducted to estimate individual etanercept pharmacokinetic parameters. Initially, appropriate base and covariate population pharmacokinetic models were built based on data from 10 prior clinical studies of etanercept administered subcutaneously or intravenously to healthy subjects (n = 53) and to patients with rheumatoid arthritis (RA) (n = 212). The influence of demographic characteristics on the pharmacokinetics of etanercept was thoroughly evaluated. The stability of the final model was evaluated using both internal (bootstrapping) and external (data splitting) validation approaches. Finally, the selected final population covariate model was used to estimate the Bayesian pharmacokinetic parameters for the patients with AS.

RESULTS

The data from the 10 prior clinical studies were optimally fitted to a 2-compartment linear population covariate model. Both age (< 17 years) and body weight (< 60 kg) were found to be important covariates on clearance. Both bootstrapping and data splitting validated the population model. The mean Bayesian-predicted etanercept clearance and steady-state trough concentration were 0.072 l/h and 2,004 ng/ml, respectively. The pharmacokinetic parameters of etanercept in the patients with AS were similar to those observed in the patients with RA.

CONCLUSIONS

The pharmacokinetics of etanercept in patients with AS were similar to those in patients with RA. The AS disease state does not appear to alter the disposition of etanercept.

Phase I and pharmacokinetic study of CCI-779, a novel cytostatic cell-cycle inhibitor, in combination with 5-fluorouracil and leucovorin in patients with advanced solid tumors

BACKGROUND

CCI-779 is a novel ester of the immunosuppressive agent sirolimus that exerts cytostatic effects by the inhibition of the translation of cell-cycle regulatory proteins. We investigated the maximum tolerated dose (MTD) and pharmacokinetics (PK) of CCI-779 in combination with leucovorin (LV) and 5-fluorouracil (5-FU) in patients with advanced solid tumors.

PATIENTS AND METHODS

Patients were treated with LV at 200 mg/m(2) as a 1-h i.v. infusion directly followed by continuous 24-h i.v. infusion of 5-FU, in the first patient at 2000 mg/m(2) and in subsequent patients at 2600 mg/m(2). CCI-779 was administered directly prior to LV as a 30-min i.v. infusion at a starting dose of 15 mg/m(2) beginning at day 8 and escalated in subsequent cohorts of patients. One cycle consisted of six weekly administrations followed by 1 week of rest. Blood samples were drawn to assess PK of CCI-779 as well as its effect on steady-state 5-FU exposures.

RESULTS

Twenty-eight patients entered the study, the majority having tumor types for which 5-FU is used as a treatment. CCI-779 doses of 15, 25, 45 and 75 mg/m(2) were investigated. Skin toxicity (rash) was prominent at all dose levels examined. Stomatitis was the dose-limiting toxicity (DLT) for 75 mg/m(2) doses of CCI-779. Subsequently the cohort at 45 mg/m(2) was expanded to a total of 15 patients, and at this dose level two treatment-related deaths occurred due to mucositis with bowel perforation. Based on the toxicities observed, it was decided to discontinue the study. Partial responses were observed in three patients with gastrointestinal tumors. No pharmacokinetic interaction between CCI-779 and 5-FU was observed.

CONCLUSIONS

The safety profiles of CCI-779 and 5-FU/LV suggest an overlap of drug-related toxicities, and the administration of these drugs at these doses and schedule resulted in unacceptable toxicity and therefore cannot be recommended. If CCI-779 is to be used in combination with 5-FU/LV, other doses or schedules of administration will need to be explored.

Pharmacokinetic and pharmacodynamic action of etodolac in patients after oral surgery

The objective of this double-blind, randomized, parallel-group study was to evaluate the pharmacokinetics of etodolac and the pharmacodynamic response of pain in patients following oral surgery who had received 200 or 400 mg of etodolac immediate release (IR), 400 or 1200 mg of etodolac extended release (ER), or a placebo. Etodolac concentrations in 441 plasma samples from 187 patients were analyzed for population pharmacokinetics using the NONMEM program. A one-compartment pharmacokinetic model with first-order absorption described the observed data. For etodolac IR, the population mean (%CV) estimates were 3.01 L/h (5.3%) for clearance, 13.6 L (6.8%) for volume of distribution, and 2.31 h-1 (33%) for ka. Respective values for etodolac ER were 3.68 L/h (11%) for clearance, 24.3 L (22%) for volume of distribution, and 0.172 h-1 (24%) for ka. These values generally agreed with previously reported values in healthy adults. Pharmacodynamic assessments included collection of a four-level categorical rating of pain intensity for up to 24 hours after treatment. Pain intensity difference scores were temporally related to etodolac concentrations and were described using an indirect response model. Mean (%CV) pharmacodynamic parameters were IC50 of 14.0 mg/L (9.5%), kout of 1.62 h-1 (13%), FR of 0.56 (8.2%), and Hill coefficients that ranged from 1.26 to 3.34 units. A single 1200 mg dose of etodolac ER given once daily was shown to provide substantial efficacy for 13 hours after dose, modest effect through 24 hours, and a more sustained duration of action than the IR dosage form.

Steady-state pharmacokinetics of idebenone in healthy volunteers

An open study was conducted with 12 healthy male Caucasian volunteers to determine the single dose and steady-state pharmacokinetics in plasma after a total daily dose of 90 mg of idebenone administered as 45 mg twice daily for 10 consecutive days. In the dose regimen investigated, multiple daily doses of 90 mg of idebenone were well tolerated by healthy male volunteers and were not associated with any clinically relevant changes in ECG or clinical laboratory parameters. The results of the physical examinations after study termination revealed normal findings in all volunteers. To evaluate the single dose and steady-state pharmacokinetic profile, blood samples were collected at predetermined time points during the study. In those subjects examined, generally good systemic exposure with rapid absorption of idebenone was obtained throughout the entire dosing period. Exposures to idebenone and its metabolites after both single and repeated oral doses of idebenone were comparable in magnitude. Further, the exposures attained were generally consistent with those observed in a previous study after 30 mg three times daily. All pharmacokinetic assessments were associated with a low to moderate degree of inter-subject variability.

T cell hybridomas define the class II MHC-restricted response to vesicular stomatitis virus infection

T cell hybridomas with specificity for VSV (vesicular stomatitis virus)-infected cells were generated in an attempt to better define the la-restricted helper T cell response to VSV. The hybridomas were created by fusing BALB/c (H-2d) anti-VSV immune spleen cells to the murine thymoma BW 5147. These hybridomas produce IL-2 when stimulated with VSV-infected spleen cells. They were found to recognize viral antigens in association with I-Ad and, in addition, could also be stimulated by VSV-infected A20 cells (an Ia-positive B cell lymphoma of H-2d origin). The purified viral membrane glycoprotein, G protein, and Gs (secreted G protein that lacks the hydrophobic and intracytoplasmic domains) both stimulated IL-2 production when added to cultures of A20 and the hybridomas. These hybridomas therefore recognize a viral antigenic determinant on G protein. Since chemically-fixed antigen-presenting cells fail to stimulate the hybridomas after exogenous addition of purified G protein we can conclude that these T cell hybridomas recognize a processed form of the G protein. Stimulator cells created by expression in A20 of a transfected cDNA encoding G protein were also recognized. Recognition in this case was I-Ad-restricted, as anti-I-Ad monoclonal antibodies blocked stimulation, and an Ia-negative cell (P815) expressing a transfected G protein gene failed to stimulate the hybridomas. Even after paraformaldehyde fixation, G gene-transfected, Ia-positive cells could stimulate the hybridomas, suggesting that processing of this endogenously-synthesized antigen has occurred.

Contamination of illicit phencyclidine with 1-piperidinocyclohexanecarbonitrile

A retrospective study of illicit phencyclidine (PCP), which consisted of 94 different cases or 213 individual samples, has shown that one third of both the powder/tablets and green plant material contained the synthetic contaminant 1-piperidinocyclohexanecarbonitrile (PCC). The mole % PCC/PCP ranged from 1 to 68%. The method of analysis was gas chromatography (3% OV-7, 205 degrees C) and in preparation for analysis the sample was dissolved directly in chloroform or extracted from a strongly acidic solution (0.1 N HCl). Using these extraction conditions PCC was found not to undergo measurable decomposition.