CDK4/6 Inhibition Sensitizes Intracranial Tumors to PD-1 Blockade in Preclinical Models of Brain Metastasis

PURPOSE

Brain metastases are associated with high morbidity and are often resistant to immune checkpoint inhibitors. We evaluated whether CDK4/6 inhibitor (CDKi) abemaciclib can sensitize intracranial tumors to programmed cell death protein 1 (PD-1) inhibition in mouse models of melanoma and breast cancer brain metastasis.

EXPERIMENTAL DESIGN

Treatment response was evaluated in vivo using immunocompetent mouse models of brain metastasis bearing concurrent intracranial and extracranial tumors. Treatment effect on intracranial and extracranial tumor-immune microenvironments (TIME) was evaluated using immunofluorescence, multiplex immunoassays, high-parameter flow cytometry, and T-cell receptor profiling. Mice with humanized immune systems were evaluated using flow cytometry to study the effect of CDKi on human T-cell development.

RESULTS

We found that combining abemaciclib with PD-1 inhibition reduced tumor burden and improved overall survival in mice. The TIME, which differed on the basis of anatomic location of tumors, was altered with CDKi and PD-1 inhibition in an organ-specific manner. Combination abemaciclib and anti-PD-1 treatment increased recruitment and expansion of CD8+ effector T-cell subsets, depleted CD4+ regulatory T (Treg) cells, and reduced levels of immunosuppressive cytokines in intracranial tumors. In immunodeficient mice engrafted with human immune systems, abemaciclib treatment supported development and maintenance of CD8+ T cells and depleted Treg cells.

CONCLUSIONS

Our results highlight the distinct properties of intracranial and extracranial tumors and support clinical investigation of combination CDK4/6 and PD-1 inhibition in patients with brain metastases. See related commentary by Margolin, p. 257.

Galectin inhibitory disaccharides promote tumour immunity in a breast cancer model

High level galectin-1 expression results in cancer cell evasion of the immune response, increased tumour survival and aggressive metastases. Using a galectin-1 polyclonal antibody, high levels of galectin-1 protein were shown to be expressed by breast cancer cells established from FVB/N MMTV-c-neu mice as well as by the B16F10 melanoma cell line. In mixed lymphocyte cultures using tumour cells as antigenic stimulators, addition of recombinant galectin-1 dose-dependently inhibited lymphocyte production. Disaccharides were identified that inhibited galectin-1 function and increased growth and activation of CD8(+) CTL's killing cancer cells. X-ray crystallographic structures of human galectin-1 in complex with inhibitory disaccharides revealed their mode of binding. Combining galectin-blocking carbohydrates as adjuvants with vaccine immunotherapy in vivo to promote immune responses significantly decreased tumour progression and improved the outcomes for tumour challenged mice. This is the first report showing that suitably selected galectin-1 blocking disaccharides will act as adjuvants promoting vaccine stimulated immune responses against tumours in vivo.

Patterns of Disease-Modifying Antirheumatic Drug Use, Medical Resource Consumption, and Cost Among Rheumatoid Arthritis Patients

We compared medical resource use and costs among rheumatoid arthritis (RA) patients receiving alternative disease-modifying antirheumatic drugs (DMARDs). The cohort study used data from a managed care organization. Health plan members who were prescribed DMARD therapy for at least 2 consecutive months, were age 18 years or older, had at least 6 months of DMARD-free enrollment prior to the first DMARD, and had a diagnosis of RA before or during the first month of DMARD were eligible. Median duration of initial DMARD therapy was 10 months overall: 11 months for hydroxychloroquine (n = 252), 15 months for methotrexate (n = 185), 5 months for sulfasalazine (n = 49), and 5 months for other mono/combination therapy (n = 85) (p < 0.0001). The average monthly cost of care was $853, of which $294 (34%) was for RA-coded medical services. In multivariate analyses, monthly RA-coded costs varied significantly by initial DMARD. RA costs and duration of initial therapy varied significantly by initial DMARD.

Cost effectiveness of microwave thermotherapy in patients with benign prostatic hyperplasia: part I-methods

OBJECTIVES

To present the method used to evaluate the cost effectiveness, from the societal perspective, of transurethral microwave thermotherapy relative to medical therapy (alpha-blocking agents) and transurethral resection of the prostate (TURP) for a hypothetical cohort of 65-year-old men with moderate-to-severe benign prostatic hyperplasia (BPH) symptoms.

METHODS

We constructed a decision-analytic Markov model with 25 health states describing the 3 treatments, 5 short-term clinical events, and 17 possible long-term outcomes. Each health state had an associated cost and utility. Utility weights, reflecting an individual's preference for a specific health outcome, range from 0, indicating death, to 100, indicating perfect health. Utility estimates were obtained by interviewing 13 men with moderate-to-severe BPH symptoms using the standard gamble preference measurement technique. On the basis of their risk attitudes, the patients were classified as risk averse or non-risk averse. The rates of remission, temporary and permanent adverse events, retreatment, and mortality were obtained from the Targis System (Urologix) randomized clinical trial, published reports, and a consensus panel. The costs during the 5 years after treatment initiation were estimated using national Medicare reimbursement schedules. The costs are reported in 1999 U.S. dollars.

RESULTS

Eliciting utility values from patients with BPH was feasible and generated internally consistent and externally valid measures. In the non-risk-averse group, the utility value for significant remission, moderate remission, no remission, and worsening BPH symptoms without an adverse event was 99.1, 97.1, 94.4, and 87.3, respectively. As expected, the risk-averse individuals (n = 6) exhibited higher utility values than those in the non-risk-averse group (n = 7). In the non-risk-averse group, thermotherapy was the preferred treatment, and in the risk-averse group, medical therapy was preferred. In both groups, TURP was the least preferred therapy. The initial thermotherapy procedure costs without complications were estimated at $2629, and the initial TURP procedure costs without complications were estimated at $4597. Time-dependent probabilities were developed to reflect treatment durability.

CONCLUSIONS

The resulting model parameters appear to be suitable for evaluating the cost effectiveness of thermotherapy relative to medical therapy and TURP in 65-year-old men with moderate-to-severe BPH symptoms.

Cost effectiveness of microwave thermotherapy in patients with benign prostatic hyperplasia: part II--results

OBJECTIVES

To evaluate the cost effectiveness of transurethral microwave thermotherapy relative to medical therapy (alpha-blocking agents) and transurethral resection of the prostate (TURP) for patients with moderate-to-severe benign prostatic hyperplasia (BPH) symptoms.

METHODS

A cost-effectiveness analysis was performed from the societal perspective for a hypothetical cohort of 65-year-old men with moderate-to-severe BPH symptoms. We calculated the incremental cost effectiveness of thermotherapy relative to medical therapy and TURP during 5 years after treatment initiation. Event probabilities were obtained from published reports, a consensus panel, and the Targis System (Urologix) randomized clinical trial. Costs were estimated using the national Medicare reimbursement schedules. Costs are reported in 1999 U.S. dollars. Total thermotherapy procedure costs were estimated at $2629. Quality-of-life and utility estimates were obtained by interviewing 13 patients with moderate-to-severe BPH symptoms. On the basis of their risk attitudes, patients were classified into risk-averse or non-risk-averse groups. The costs and health effects were discounted at 3% annually.

RESULTS

In a hypothetical cohort of 10,000 non-risk-averse patients who were candidates for all three modalities, the 5-year costs were highest for patients undergoing TURP and lowest for those receiving medical therapy ($7334 and $6294, respectively). The thermotherapy group exhibited the highest 5-year utility value (53.52 quality-adjusted life-months). Compared with medical therapy, thermotherapy resulted in an additional 0.23 quality-adjusted life-months, with an incremental cost of $741. This yielded an incremental cost per quality-adjusted life-year gained of $38,664 for thermotherapy compared with medical therapy. Thermotherapy had a higher utility (difference of 1.71 quality-adjusted life-months) and lower cost (difference of $299) compared with TURP and thus was dominant over TURP. The results were similar for a hypothetical cohort of 10,000 risk-averse patients.

CONCLUSIONS

From a societal perspective, thermotherapy appears to be a reasonable and cost-effective alternative to both medical and surgical treatment. However, the actual treatment decision should be based on multiple factors, only one of which is cost effectiveness.

Medical resource use and costs among rheumatoid arthritis patients receiving disease-modifying antirheumatic drug therapy

OBJECTIVE

To identify costs among rheumatoid arthritis (RA) patients receiving alternative disease-modifying antirheumatic drug (DMARD) therapies.

METHODS

Using managed care organization data, we identified members who (a) were prescribed any DMARD therapy for two consecutive months between July 1993 and February 1998, (b) were aged > or = 18 years, (c) had > or = 6 months of DMARD-free enrollment prior to the first DMARD, and (d) had a diagnosis of RA.

RESULTS

The average age of the cohort (n = 571) was 51 years, and 70% were women. Mean duration of enrollment following initiation of DMARD therapy (observation period) was 19.5 months; 28.8% of patients switched DMARD regimens. The average monthly cost of care was $853, of which $294 (34%) was for RA-coded medical services. Monthly RA-coded costs varied by DMARD: hydroxychloroquine $227 (n = 252), methotrexate $340 (n = 185); sulfasalazine $233 (n = 49), and other mono/combination therapy $425 (n = 85) (P = 0.001).

CONCLUSION

Costs of RA-coded care in patients receiving DMARDs are low and vary by DMARD.

One-year costs of second-line therapies for depression

BACKGROUND

We compared patterns of medical resource utilization and costs among patients receiving a serotonin-norepinephrine reuptake inhibitor (venlafaxine), one of the selective serotonin reuptake inhibitors (SSRIs), one of the tricyclic agents (TCAs), or 1 of 3 other second-line therapies for depression.

METHOD

Using claims data from a national managed care organization, we identified patients diagnosed with depression (ICD-9-CM criteria) who received second-line antidepressant therapy between 1993 and 1997. Second-line therapy was defined as a switch from the first class of antidepressant therapy observed in the data set within 1 year of a diagnosis of depression to a different class of antidepressant therapy. Patients with psychiatric comorbidities were excluded.

RESULTS

Of 981 patients included in the study, 21% (N = 208) received venlafaxine, 34% (N = 332) received an SSRI, 19% (N = 191) received a TCA, and 25% (N = 250) received other second-line antidepressant therapy. Mean age was 43 years, and 72% of patients were women. Age, prescriber of second-line therapy, and prior 6-month expenditures all differed significantly among the 4 therapy groups. Total, depression-coded, and non-depression-coded 1-year expenditures were, respectively, $6945, $2064, and $4881 for venlafaxine; $7237, $1682, and $5555 for SSRIs; $7925, $1335, and $6590 for TCAs; and $7371, $2222, and $5149 for other antidepressants. In bivariate analyses, compared with TCA-treated patients, venlafaxine- and SSRI-treated patients had significantly higher depression-coded but significantly lower non-depression-coded expenditures. Venlafaxine was associated with significantly higher depression-coded expenditures than SSRIs. However, after adjustment for potential confounding covariables in multivariate analyses, only the difference in depression-coded expenditures between SSRI and TCA therapy remained significant.

CONCLUSION

After adjustment for confounding patient characteristics, 1-year medical expenditures were generally similar among patients receiving venlafaxine, SSRIs, TCAs, and other second-line therapies for depression. Observed differences in patient characteristics and unadjusted expenditures raise questions as to how different types of patients are selected to receive alternative second-line therapies for depression.

The epidemiology of rubella and congenital rubella in Australia, 1992 to 1997

Selective rubella vaccination of schoolgirls commenced in 1971 and was followed by a significant reduction in congenital rubella. Infant vaccination with MMR was introduced in 1989 to interrupt circulation of the virus in young children, and in 1994/95 the adolescent school based rubella vaccination program was changed to MMR for both boys and girls. This report reviews the epidemiology of rubella and congenital rubella between 1992 and 1997 using reports to the National Notifiable Diseases Surveillance System (NNDSS) and the Australian Paediatric Surveillance Unit (APSU). Notification rates for rubella exceeded 20 per 100,000 in 1992, 1993 and 1995 and declined to 7.2 per 100,000 in 1997. Sixty-one per cent of notifications occurred between September and December and 68% occurred in males. The incidence rate in males aged 15-22 years peaked at 152.6 per 100,000 in 1995 reflecting the lack of immunisation in this cohort. From 1993 to 1997, 19 children were reported with congenital rubella syndrome, representing 1 in 67,000 live births. Of these, 17 had multiple defects (4 died) and 2 had deafness only. There were also 5 infants with congenital rubella infection but no defects. Australia's rate of congenital rubella syndrome exceeded that of the United Kingdom and the United States of America but this may be partly attributable to differences in reporting practices. The impact of changing the second dose of MMR vaccine to 4 years of age in 1998 will require careful monitoring.

GBF1: A novel Golgi-associated BFA-resistant guanine nucleotide exchange factor that displays specificity for ADP-ribosylation factor 5

Expression cloning from a cDNA library prepared from a mutant CHO cell line with Golgi-specific resistance to Brefeldin A (BFA) identified a novel 206-kD protein with a Sec7 domain termed GBF1 for Golgi BFA resistance factor 1. Overexpression of GBF1 allowed transfected cells to maintain normal Golgi morphology and grow in the presence of BFA. Golgi- enriched membrane fractions from such transfected cells displayed normal levels of ADP ribosylation factors (ARFs) activation and coat protein recruitment that were, however, BFA resistant. Hexahistidine-tagged-GBF1 exhibited BFA-resistant guanine nucleotide exchange activity that appears specific towards ARF5 at physiological Mg2+concentration. Characterization of cDNAs recovered from the mutant and wild-type parental lines established that transcripts in these cells had identical sequence and, therefore, that GBF1 was naturally BFA resistant. GBF1 was primarily cytosolic but a significant pool colocalized to a perinuclear structure with the beta-subunit of COPI. Immunogold labeling showed highest density of GBF1 over Golgi cisternae and significant labeling over pleiomorphic smooth vesiculotubular structures. The BFA-resistant nature of GBF1 suggests involvement in retrograde traffic.

Medical resource use and cost of venlafaxine or tricyclic antidepressant therapy. Following selective serotonin reuptake inhibitor therapy for depression

OBJECTIVE

An analysis of administrative and claims data was performed to compare the resource use and costs to a managed-care organisation of venlafaxine, a serotonin and norepinephrine reuptake inhibitor (SNRI), versus tricyclic antidepressant (TCA) therapy, after switching from a selective serotonin reuptake inhibitor (SSRI).

DESIGN

One-year costs and frequencies of all medical services, and of services coded for depression, were compared between patients who received venlafaxine and TCA therapy as second-line therapy using bivariate and multivariate statistical analyses.

SETTING

Data were obtained from 9 individual health plans with more than 1.1 million covered lives affiliated with a national managed-care organisation.

PATIENTS AND PARTICIPANTS

Health plan members were included if they had a diagnosis of depression between July 1993 and February 1997. They also had to have at least 2 months of prescriptions for SSRI therapy followed by at least 2 months of venlafaxine or TCA therapy, and continuous enrollment in the plan from at least 6 months prior to 12 months following initiation of venlafaxine or TCA therapy. 188 patients who received venlafaxine and 172 patients who received TCAs met the inclusion criteria.

MAIN OUTCOME MEASURES AND RESULTS

Patients who received TCAs were slightly but significantly older (43 vs 40 years) than venlafaxine recipients and, during 6 months prior to initiating therapy, had significantly higher mean costs coded for depression ($US451 vs $US311) and costs not coded for depression ($US4500 vs $US2090). Psychiatrists prescribed a significantly higher proportion of venlafaxine than TCA prescriptions (46.3 vs 25.0%). Prior to adjusting for confounding characteristics, during 12 months following initiation of therapy, mean depression-coded costs were significantly higher for venlafaxine than TCA recipients ($US1948 vs $US1396) and mean costs not coded for depression were significantly lower ($US4595 vs $US6677). Overall costs were not significantly different ($US6543 for venlafaxine vs $US8073 for TCA). Significant cost differences were observed with primary care physicians as initial prescribers of second-line therapy but not with psychiatrists. However, costs between the 2 groups were similar after adjusting for confounding variables, including prior 6-month costs and initial prescriber of second-line therapy.

CONCLUSIONS

Payer costs are similar among patients receiving venlafaxine and TCA therapy following SSRI therapy. Higher costs of venlafaxine pharmacotherapy relative to TCA therapy may be offset by lower costs of other medical services. Differences in prescribing patterns and costs between primary care physicians and psychiatrists warrant further investigation.

Cost effectiveness of recombinant human insulin-like growth factor I therapy in patients with ALS

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a fatal, degenerative neuromuscular disease characterised by a progressive loss of voluntary motor activity. Recombinant human insulin-like growth factor I (rhIGF-I) has been shown to be useful in treating ALS. The purpose of this study was to examine the cost effectiveness of rhIGF-I therapy in patients who have ALS.

DESIGN

We performed a cost-effectiveness analysis from the societal perspective on 177 patients who received treatment with rhIGF-I or placebo in a North American randomised clinical trial. We estimated the incremental cost-effectiveness ratio of rhIGF-I using resource utilisation and functional status measurements from the clinical trial. Costs were estimated from 1996 US Medicare reimbursement schedules. Utility weights were elicited from ALS healthcare providers using the standard gamble technique.

MAIN OUTCOME MEASURES AND RESULTS

The overall cost per quality-adjusted life-year (QALY) gained for rhIGF-I therapy compared with placebo was $US67,440. For the subgroups of patients who were progressing rapidly or were in earlier stages of disease at enrolment, rhIGF-I cost $US52,823 and $US43,197 per QALY gained, respectively.

CONCLUSIONS

Treatment with rhIGF-I is most cost effective in ALS patients who are either in earlier stages of the disease or progressing rapidly. The cost effectiveness of rhIGF-I therapy compares favourably with treatments for other chronic progressive diseases.

Assessment of the frequency and costs of posttransplantation hospitalizations in patients receiving tacrolimus versus cyclosporine

We assessed the frequency and costs of hospitalizations in patients receiving tacrolimus (FK506) compared with patients receiving cyclosporine A for immunosuppression during 1 year after kidney transplantation. Four hundred twelve cadaveric kidney transplant recipients were randomized onto a phase III, prospective, multicenter, clinical trial. Hospital billing data were collected for 1 year posttransplantation. Total inpatient costs were calculated from billed charges and standardized to 1995 US dollars. Medical resource utilization rates and inpatient costs were compared between treatment groups using unpaired Student's t-tests. Complete billing data (transplantation and all posttransplantation hospitalizations) were available for 65% (268 of 412) of the study patients. Among tacrolimus and cyclosporine patients with complete billing data, the rates of allograft rejection were 32% and 47%, respectively (P=0.009), and the rates of rehospitalization during the year after transplantation were 53% and 63%, respectively (P=0.080). The mean per-episode rehospitalization costs were significantly lower among tacrolimus-treated patients compared with cyclosporine-treated patients ($7,495 v $11,497; P=0.031), and the mean total rehospitalization costs were significantly lower in the tacrolimus group compared with the cyclosporine group ($8,550 v $14,869; P=0.029). In addition, the total 1-year hospitalization costs (including transplantation and posttransplantation hospitalizations) were significantly lower in the tacrolimus group compared with the cyclosporine group ($53,435 v $61,191; P=0.046). Compared with cyclosporine-based immunosuppression, tacrolimus-based immunosuppression for kidney transplant recipients was associated with a significantly lower rate of rejection, which was associated with significantly lower per-episode rehospitalization costs, lower total 1-year rehospitalization costs, and lower total 1-year hospitalization costs.

Profiling assisted reproductive technology: outcomes and quality of infertility management

OBJECTIVE

To critically appraise the content of the American Society for Reproductive Medicine (ASRM)/Society for Reproductive Technology (SART) Registry.

DESIGN

English-language literature review.

PATIENT(S)

Women undergoing treatment with assisted reproductive technology (ART).

INTERVENTION(S)

Current ART treatments, including IVF, GIFT, zygote intrafollopian transfer (ZIFT), oocyte micromanipulation, and cryopreserved embryo transfers.

MAIN OUTCOME MEASURE(S)

Compliance with clinical practice guidelines, and casemix-adjusted rates of live delivery, clinical pregnancy, ectopic pregnancy, miscarriage, birth defects, implantation, fertilization, and retrieval.

RESULT(S)

Outcomes should be adjusted for variation in patient characteristics known to affect prognosis, including maternal age, the duration of infertility, the presumed cause(s) of infertility, the patient's prior history of treatment for infertility, and diethylstilbestrol exposure. Outcome rates should be reported using the patient as the denominator, as well as cycle, retrieval, and transfer. The statistical significance of observed differences in events rates should be indicated. Because widely accepted clinical practice guidelines related to performance of ART procedures are not available, compliance with practice guidelines cannot currently be assessed.

CONCLUSION(S)

Reports based on ASRM/SART Registry data can be enhanced by refined casemix adjustment, assessing outcome rates per patient, as well as per component of ART procedure, and by providing an indication of the statistical significance of observed differences in event rates. In addition, a critical appraisal of available evidence related to particular aspects of infertility management would help clarify the areas in which there is an evidentiary basis for formulation of practice guidelines, as well as topics requiring additional clinical research.

Nurse practitioners & reimbursement

Nursing's Agenda for Health Care Reform (1991) embraces primary health care as the focus of a restructured health care system. As part of this reformed system, consumers would access the most cost-effective providers in community-based settings. Removal of financial and regulatory barriers that limit consumer access to providers, such as lack of direct reimbursement by Medicare for nurse practitioners, should be eliminated according to this plan. Senate bills S2103 and S2104 have been recently introduced to the U.S. Senate mandating reimbursement for services provided by nurse practitioners, clinical nurse specialists, nurse midwives, and physician assistants at 97% of physician payment. The aim of this global legislation is to eliminate the current piecemeal mechanisms for nurse practitioner reimbursement and remove financial disincentives. Case examples presented in this article illustrate how obstacles to reimbursement limit access to care for consumers. Quality of care, opportunities for autonomous practice, and control of nursing practice issues have been highlighted as well by the case format. It is intended that these cases would be useful to support changes in patterns of nurse practitioner reimbursement.