Population Pharmacokinetics and Pharmacodynamics of Carfilzomib in Combination with Rituximab, Ifosfamide, Carboplatin, and Etoposide in Adult Patients with Relapsed/Refractory Diffuse Large B Cell Lymphoma

BACKGROUND

In patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), salvage chemotherapy regimens (e.g., rituximab, ifosfamide, carboplatin, and etoposide, R-ICE) yield poor outcomes. Carfilzomib, an irreversible proteasome inhibitor, can overcome acquired rituximab-chemotherapy resistance and, when combined with R-ICE, improves outcomes in patients with R/R DLBCL.

OBJECTIVE

This analysis aimed to develop a population pharmacokinetic/pharmacodynamic (PK/PD) model for carfilzomib in R/R DLBCL patients.

PATIENTS AND METHODS

In a single-center, open-label, prospective phase 1 study, patients received carfilzomib (10, 15, or 20 mg/m2) on days 1, 2, 8, and 9, and standard doses of R-ICE on days 3-6 every 21 days (maximum of three cycles). Carfilzomib plasma concentrations up to 24 h postinfusion were measured by liquid chromatography coupled with tandem mass spectrometry. Proteasome activity (PD biomarker) in peripheral blood mononuclear cells was assessed on days 1-2 with sparse sampling. PK/PD models were developed using NONMEM v7.4.1 interfaced with Finch Studio v1.1.0 and PsN v4.7.0. Model selection was guided by objective function value, goodness-of-fit, and visual predictive checks. Stepwise covariate modeling was used for covariate selection.

RESULTS

Twenty-eight patients were enrolled in the PK/PD analysis, from whom 217 PK samples and 127 PD samples were included. Carfilzomib PK was best described by a two-compartment model with linear disposition (typical total clearance of 133 L/h). Proteasome activity was best characterized using a turnover model with irreversible inactivation. All parameters were estimated with good precision. No statistically significant covariates were identified.

CONCLUSIONS

A validated population-based PK/PD model of carfilzomib was developed successfully. Further research is needed to identify sources of variability in response to treatment with carfilzomib in combination with R-ICE.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier number NCT01959698.

Human Papillomavirus Infection: The Role of Vaccination in Pediatric Patients

Human papillomavirus (HPV) infection is the most common sexually transmitted infection among adolescents and adults in the United States. Given the prevalence of this infection and its relationship with the development of cervical cancer, HPV vaccine development has been a major public health initiative in the last decade. Despite extensive research in the development of these vaccines, there remain many unanswered questions in academic and public arenas regarding their administration and role in adolescent medicine.

Evaluation of corn distillers grains and ruminally protected lysine and methionine for lactating dairy cows

Twelve multiparous Holstein cows averaging 57 d (36 to 77 d) postpartum at the start of the experiment were utilized in a replicated 4 x 4 Latin square design. Dietary protein supplements were 1) soybean meal, 2) soybean meal plus ruminally protected Lys and Met, 3) corn distillers grains, and 4) corn distillers grains plus ruminally protected Lys and Met. Dry matter intakes were lower for cows fed diets containing soybean meal than for cows fed diets containing corn distillers grains. Milk yield increased with the corn distillers grains (34.3, 34.0, 35.3, and 36.7 kg/d for cows fed diets 1 through 4, respectively), especially when supplemented with ruminally protected Lys and Met. Milk protein yield and percentage were increased by amino acid supplementation. Milk fat yield and percentage were unaffected by diet. The only milk protein fraction affected was nonprotein N, which was lower in the milk of cows fed corn distillers grains. Lysine, Met, and Phe were indicated as the most limiting amino acids for all diets when using amino acid extraction efficiency and transfer efficiency to indicate limiting amino acids. When corn distillers grains were supplemented with ruminally protected Lys and Met, milk yield and milk protein yield and percentage increased because the diet containing corn distillers grains was probably deficient in Lys.

Comparison of the inhibitory effect of ouabain and dihydroouabain on the Na(+)-K+ ATPase from frog skin

1. The effects of ouabain and dihydroouabain (DHO) on Na(+)-K+ ATPase from frog skin were investigated. 2. Ouabain seemed to be a more effective inhibitor, reaching near maximum inhibition at 10(-5) M while DHO reached near maximum at 10(-3) M. 3. Both inhibitors acted within the first few minutes, but ouabain inhibited more strongly over virtually the whole 2 hr considered. 4. Pre-incubation of the enzyme with ATP or Na+ reduced the level of inhibition due to subsequent ouabain or DHO, but preincubation with K+ did not.

Cardiac actions of bovine parathyroid hormone (1-34), isoproterenol, and propranolol in turtles

1. In isolated turtle hearts bovine parathyroid hormone (b-PTH) (1-34) stimulated both force of contraction and rate (beats/min) apparently stimulating beats/min to a larger extent. 2. Isoproterenol stimulated both rate and force, perhaps affecting contractile force more. 3. Propranolol alone clearly decreased contractile force and beats/min. 4. Pre-treatment with propranolol removed stimulatory effects of both bPTH (1-34) and isoproterenol. Propranolol's effect on isoproterenol was expected. Its effect on bPTH (1-34) may be related to beta-stimulation by PTH or to some other non-specific inhibitory effect of propranolol.

Interrelationships among epidermal Na-K ATPase, developmental stage and length of Rana catesbeiana tadpoles

Sodium and potassium activated adenosine triphosphatase (Na-K ATPase) was extracted from the skin of Rana catesbeiana tadpoles and adults. Using carefully staged tadpoles, it was noted that the enzyme level increases two or three stages before there is a perceptible potential difference generated across the skin. The level of non-ouabain-inhibitable ATPase remains constant throughout the life cycle. It was also concluded that Rana catesbeiana tadpoles cannot be reliably staged using length as a key trait.

Nicarbazin complex yields dinitrocarbanilide as ultrafine crystals with improved anticoccidial activity

Nicarbazin, a drug used to control the protozoal disease coccidiosis in poultry, is a complex of the highly insoluble drug 4,4'-dinitrocarbanilide with 2-hydroxy-4,6-dimethylpyrimidine. The structures of this and other 4,4'-dinitrocarbanilide complexes have not been determined, but an analogous 2:1 complex of 4,4'-dinitrodiphenylamine with 1,4-diacetylpiperazine has been prepared in which the only possible bonds are hydrogen bonds between the amide carbonyls and amino hydrogens. Scanning electron microscopy revealed that micron-size crystals of nicarbazin disintegrate in water to form much smaller dinitrocarbanilide crystals. Similar complex dissolution in the gut of poultry may account for the greater effectiveness of dinitrocarbanilide when administered as complexed rather than uncomplexed drug. Particle size problems associated with other highly insoluble drugs and pesticides may be resolved by the use of nicarbazin-like complexes.

Role of adrenals on development of pressure-induced myocardial hypertrophy

The effect of coarctation of the abdominal aorta (AC) and of sham operation (SO) on the development of myocardial hypertrophy was studied in three groups of male rats, i.e., a group without treatment prior to AC or SO (untreated), a group with bilateral adrenalectomy (ADX) 5-7 days before AC or SO, and a group in which the adrenal medulla was removed (MDX) 5-7 days before AC or SO. MDX resulted in functional elimination of the adrenal medulla without apparent effect on cortical function. The animals were killed 7-10 days after AC or SO. AC produced carotid blood pressure (CBP) increases of 33, 31, and 25 mmHg in the untreated, ADX, and MDX groups, respectively. Ventricular weight (HW), ventricular RNA concentration, and RNA-to-DNA ratio increased significantly after AC only in the untreated and MDX groups. In the ADX group, hypertension was followed by an increase in HW that could be detected only after normalization for body weight. It is concluded that absence of the adrenal gland significantly reduces the development of pressure-induced myocardial hypertrophy. Apparently, this is due to the absence of the adrenal cortex and not absence of the adrenal medulla.

Addiction liability of albino rats: breeding for quantitive differences in morphine drinking

Selective breeding produced two strains of rats that differ in their susceptibility to morphine addiction. Inbreeding the more susceptible rats in an unselected population produced susceptible offspring; inbreeding resistant rats produced resistant offspring. Further selection and inbreeding increased the strain difference in the F(2) and F(3) generations. The F(3) generation also differed in their susceptibility to alcohol addiction.