Daratumumab for the treatment of multiple myeloma.

Since its initial approval in 2015, daratumumab has had a tremendous impact on the treatment of multiple myeloma. It is a monoclonal antibody that targets CD38, an antigen with high surface expression on multiple myeloma cells. While it initially received approval as a monotherapy for multiply relapsed multiple myeloma, its favorable toxicity profile allowed for combinations with other novel myeloma therapies leading to numerous indications as a component of triplet and quadruplet regimens. These indications now span relapsed/refractory populations and both transplant-eligible and transplant-ineligible patients with newly diagnosed myeloma. Further investigations are underway to continue to expand the reach of daratumumab, including large phase III collaborative trials to assess the efficacy of daratumumab as part of post-transplant maintenance and its impact on smoldering myeloma. The recent introduction of a subcutaneous formulation of daratumumab with proven noninferiority will improve the convenience and accessibility of the drug. In this review, we examine the preclinical development of daratumumab, its pharmacology and clinical investigations that demonstrated its safety and efficacy. Furthermore, we discuss the outstanding questions related to daratumumab and ongoing clinical trials seeking to answer them.

Glasdegib for the treatment of adult patients with newly diagnosed acute myeloid leukemia or high-grade myelodysplastic syndrome who are elderly or otherwise unfit for standard induction chemotherapy.

On November 21, 2018, the U.S. Food and Drug Administration (FDA) approved glasdegib in combination with low-dose cytarabine (LDAC), for the treatment of newly diagnosed acute myeloid leukemia (AML) in patients > 75 years old or who have comorbidities that would be prohibitive of intensive induction chemotherapy. Glasdegib is a small-molecule inhibitor of a component of the hedgehog (HH) pathway, an upregulated pathway in leukemia and leukemia stem cells that is associated with relapse, drug resistance and poor survival. Preclinical studies suggested that glasdegib could sensitize AML cells to chemotherapy. FDA approval was based on a randomized, placebo-controlled, phase II trial in elderly or infirmed adults with new AML, unable to receive intensive induction chemotherapy, in whom the addition of glasdegib to LDAC nearly doubled the median overall survival compared with LDAC alone. In this report, we examine the preclinical development of glasdegib, its pharmacology and the clinical investigation that demonstrated its safety and efficacy, resulting in its approval. Additionally, we highlight ongoing investigation and future applications of this therapy.

Donor-lymphocyte infusion following haploidentical hematopoietic cell transplantation with peripheral blood stem cell grafts and PTCy.

Donor-lymphocyte infusion (DLI) for relapse following haploidentical hematopoietic cell transplantation (haploHCT) with post-transplant cyclophosphamide (PTCy) has been described in recipients of bone marrow grafts, but not recipients of G-CSF mobilized peripheral blood (PB) grafts. We retrospectively identified patients who underwent DLI following PB-haploHCT with PTCy for relapse, or loss of chimerism (LOC). Twelve patients (57%) received DLI for hematologic relapse/persistent disease, seven (33%) for extramedullary relapse and two (10%) for LOC. Sixteen (76%) received chemotherapy prior to DLI, which did not correlate with response. The most common first dose was 1 × 106 CD3+ cells/kg. Two patients developed grade I aGvHD post DLI, one had grade II and two had grade III. One developed mild skin cGvHD 1361 days post DLI. Pre-DLI aGvHD predicted post-DLI aGvHD (P=0.025). Six patients achieved CR after DLI for overt relapse, one achieved full donor chimerism after LOC. Patients with LOC or EM relapse had superior relapse-free survival following DLI (P=0.029). DLI following PB-haploHCT with PTCy is a viable salvage therapy for overt relapse or LOC without a substantial increase in GvHD, and donor lymphocytes may be collected simultaneously with graft collection to facilitate availability in patients at high risk of relapse.

Oncolytic measles virus strains have significant antitumor activity against glioma stem cells.

Glioblastoma (GBM) is the most common primary brain tumor in adults and has a dismal prognosis despite multimodality treatment. Given the resistance of glioma stem cells (GSC) to chemotherapy and radiation therapy, their eradication could prevent tumor recurrence. We sought to evaluate the antitumor activity of measles virus (MV) derivatives against GSC. We generated neurosphere cultures from patient-derived primary tumor GBM xenografts, and we characterized them for the GSC markers CD133, SOX2, Nestin, ATF5 and OLIG2. Using the MV-strains MV-GFP, MV-CEA and MV-NIS we demonstrated infection, viral replication and significant cytopathic effect in vitro against GSC lines. In tumorigenicity experiments, GBM44 GSC were infected with MV in vitro and subsequently implanted into the right caudate nucleus of nude mice: significant prolongation of survival in mice implanted with infected GSC was observed, compared with mock-infected controls (P=0.0483). In therapy experiments in GBM6 and GBM12 GSC xenograft models, there was significant prolongation of survival in MV-GFP-treated animals compared with inactivated virus-treated controls (GBM6 P=0.0021, GBM12 P=0.0416). Abundant syncytia and viral replication was demonstrated in tumors of MV-treated mice. Measles virus derivatives have significant antitumor activity against glioma-derived stem cells in vitro and in vivo.

Impaired p53 function leads to centrosome amplification, acquired ERalpha phenotypic heterogeneity and distant metastases in breast cancer MCF-7 xenografts.

In this study, we establish an MCF-7 xenograft model that mimics the progression of human breast carcinomas typified by loss of p53 integrity, development of centrosome amplification, acquired estrogen receptor (ERalpha) heterogeneity, overexpression of Mdm2 and metastatic spread from the primary tumor to distant organs. MCF-7 cells with abrogated p53 function (vMCF-7(Dnp53)) maintained nuclear ERalpha expression and normal centrosome characteristics in vitro. However, following mitogen stimulation, they developed centrosome amplification and a higher frequency of aberrant mitotic spindles. Centrosome amplification was dependent on cdk2/cyclin activity since treatment with the small molecule inhibitor SU9516 suppressed centriole reduplication. In contrast to the parental MCF-7 cells, when introduced into nude mice as xenografts, tumors derived from the vMCF-7(DNp53) cell line developed a strikingly altered phenotype characterized by increased tumor growth, higher tumor histopathology grade, centrosome amplification, loss of nuclear ERalpha expression, increased expression of Mdm-2 oncoprotein and resistance to the antiestrogen tamoxifen. Importantly, while MCF-7 xenografts did not develop distant metastases, primary tumors derived from vMCF-7(DNp53) cells gave rise to lung metastases. Taken together, these observations indicate that abrogation of p53 function and consequent deregulation of the G1/S cell cycle transition leads to centrosome amplification responsible for breast cancer progression.

Recency, range expansion, and unsorted lineages: implications for interpreting neutral genetic variation in the sharp-tailed grouse (Tympanuchus phasianellus).

Both current and historical patterns of variation are relevant to understanding and managing ecological diversity. Recently derived species present a challenge to the reconstruction of historical patterns because neutral molecular data for these taxa are more likely to exhibit effects of recent and ongoing demographic processes. We studied geographical patterns of neutral molecular variation in a species thought to be of relatively recent origin, Tympanuchus phasianellus (sharp-tailed grouse), using mitochondrial control region sequences (CR-I), amplified fragment length polymorphisms (AFLP), and microsatellites. For historical context, we also analysed CR-I in all species of Tympanuchus. Within T. phasianellus, we found evidence for restricted gene flow between eastern and western portions of the species range, generally corresponding with the range boundary of T. p. columbianus and T. p. jamesi. The mismatch distribution and molecular clock estimates from the CR-I data suggested that all Tympanuchus underwent a range expansion prior to sorting of mitotypes among the species, and that sorting may have been delayed as a result of mutation-drift disequilibrium. This study illustrates the challenge of using genetic data to detect historical divergence in groups that are of relatively recent origin, or that have a history dominated by nonequilibrium conditions. We suggest that in such cases, morphological, ecological, and behavioural data may be particularly important adjuncts to molecular data for the recognition of historically or adaptively divergent groups.

Mechanical properties of alveolar epithelial cells in culture.

With the use of magnetic twisting cytometry, we characterized the mechanical properties of rat type II alveolar epithelial (ATII) cells in primary culture and examined whether the cells' state of differentiation and the application of deforming stresses influence their resistance to shape change. Cells were harvested from rat lungs as previously described (Dobbs LG. Am J Physiol Lung Cell Mol Physiol 258: L134-L147, 1990) and plated at a density of 1 x 10(6) cells/cm(2) in fibronectin-coated 96 Remova wells, and their mechanical properties were measured 2-9 days later. We show 1) that ATII cells form much stronger bonds with RGD-coated beads than they do with albumin- or acetylated low-density lipoprotein-coated beads, 2) that RGD-mediated bonds seemingly "mature" during the first 60 min of bead contact, 3) that the apparent stiffness of ATII cells increases with days in culture, 4) that stiffness falls when the RGD-coated beads are intermittently oscillated at 0.3 Hz, and 5) that this fall cannot be attributed to exocytosis-related remodeling of the subcortical cytoskeleton. Although the mechanisms of force transfer between basement membrane, cytoskeleton, and plasma membrane of ATII cells remain to be resolved, such analyses undoubtedly require definition of the cell's mechanical properties. To our knowledge, the results presented here provide the first data on this topic.

Validation of a new live cell strain system: characterization of plasma membrane stress failure.

Motivated by our interest in lung deformation injury, we report on the validation of a new live cell strain system. We showed that the system maintains a cell culture environment equivalent to that provided by conventional incubators and that its strain ouput was uniform and reproducible. With this system, we defined cell deformation dose (i.e., membrane strain amplitude)-cell injury response relationships in alveolar epithelial cultures and studied the effects of temperature on them. Deformation injury occurred in the form of reversible, nonlethal plasma membrane stress failure events and was quantified as the fraction of cells with uptake and retention of fluorescein-labeled dextran (FITC-Dx). The undeformed control population showed virtually no FITC-Dx uptake at any temperature, which was also true for cells strained by 3%. However, when the membrane strain was increased to 18%, ~5% of cells experienced deformation injury at a temperature of 37 degrees C. Moreover, at that strain, a reduction in temperature to 4 degrees C resulted in a threefold increase in the number of cells with plasma membrane breaks (from 4.8 to 15.9%; P < 0.05). Cooling of cells to 4 degrees C also lowered the strain threshold at which deformation injury was first seen. That is, at a 9% substratum strain, cooling to 4 degrees C resulted in a 10-fold increase in the number of cells with FITC-Dx staining (0.7 vs. 7.5%, P < 0.05). At that temperature, A549 cells offered a 50% higher resistance to shape change (magnetic twisting cytometry measurements) than at 37 degrees C. We conclude that the strain-injury threshold of A549 cells is reduced at low temperatures, and we consider temperature effects on plasma-membrane fluidity, cytoskeletal stiffness, and lipid trafficking as responsible mechanisms.

Deformation-induced lipid trafficking in alveolar epithelial cells.

Mechanical ventilation with a high tidal volume results in lung injury that is characterized by blebbing and breaks both between and through alveolar epithelial cells. We developed an in vitro model to simulate ventilator-induced deformation of the alveolar basement membrane and to investigate, in a direct manner, epithelial cell responses to deforming forces. Taking advantage of the novel fluorescent properties of BODIPY lipids and the fluorescent dye FM1-43, we have shown that mechanical deformation of alveolar epithelial cells results in lipid transport to the plasma membrane. Deformation-induced lipid trafficking (DILT) was a vesicular process, rapid in onset, and was associated with a large increase in cell surface area. DILT could be demonstrated in all cells; however, only a small percentage of cells developed plasma membrane breaks that were reversible and nonlethal. Therefore, DILT was not only involved in site-directed wound repair but might also have served as a cytoprotective mechanism against plasma membrane stress failure. This study suggests that DILT is a regulatory mechanism for membrane trafficking in alveolar epithelia and provides a novel biological framework within which to consider alveolar deformation injury and repair.

A clinical pathway for congestive heart failure.

This study has shown improved outcomes with the use of a clinical pathway. However, under PPS additional ways for coordination among healthcare providers and patients need to be developed to ensure improved care beyond those focusing on the use of the pathway. One recommendation is the use of telehealth.

Predictors of hospital readmission among the elderly with congestive heart failure.

This study compared elderly patients with congestive heart failure discharged from home healthcare to the home vs. those rehospitalized. The rate of rehospitalization in this sample of 117 was 27%. Significant predictors of rehospitalization included number of home healthcare days, number of previous hospitalizations, and the services of a home health aide. Implications include the timing and nature of home health visits.

Stretch induces cytokine release by alveolar epithelial cells in vitro.

Mechanical ventilation can injure the lung, causing edema and alveolar inflammation. Interleukin-8 (IL-8) plays an important role in this inflammatory response. We postulated that cyclic cell stretch upregulates the production and release of IL-8 by human alveolar epithelium in the absence of structural cell damage or paracrine stimulation. To test this hypothesis, alveolar epithelial cells (A549 cells) were cultured on a deformable silicoelastic membrane. When stretched by 30% for up to 48 h, the cells released 49 +/- 34% more IL-8 (P < 0.001) than static controls. Smaller deformations (20% stretch) produced no consistent increase in IL-8. Stretch of 4 h duration increased IL-8 gene transcription fourfold above baseline. Stretch had no effect on cell proliferation, cell viability as assessed by (51)Cr release assay, or the release of granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha. We conclude that deformation per se can trigger inflammatory signaling and that alveolar epithelial cells may be active participants in the alveolitis associated with ventilator-induced lung injury.

Experimental emphysema.

This animal model of emphysema exhibits the same abnormalities in respiratory mechanics as those seen in human emphysema. The histologic and radiographic findings also closely resemble changes of panacinar disease. Moreover, the progressive hypoxemia preceding hypercarbia also parallels the clinical course seen in human disease. Drawbacks of this model include the long time period required to develop significant changes and the cost of maintaining the animals for such a time period. Large cystic areas were not noted in our animals and one would have to turn to another model to address the problem of giant bullous emphysema. There is no ideal animal model of pulmonary emphysema, and the usefulness of an experimental model should be judged on how well it answers the specific questions. Significant information has been obtained using various animal models of emphysema in lung transplantation, diaphragmatic function, pulmonary hemodynamics, and in several other areas. The dog appears to be a suitable model for thoracic surgical research on emphysema.

Regional adaptations of rabbit diaphragm muscle fibers to unilateral denervation.

We hypothesized that adaptations of the rabbit diaphragm (Dia) after unilateral denervation (DNV) result from removal of a neural influence rather than from passive stress. Length changes of midcostal and sternal Dia regions were measured before and after DNV by using sonomicrometry. Midcostal fibers passively lengthened after DNV, whereas sternal fibers shortened. In both regions, these length changes were associated with minimal stress, as estimated from passive force-length relationships. Morphological and contractile adaptions of midcostal and sternal Dia regions were examined after 1 and 4 wk of DNV. In both Dia regions, type I fibers progressively hypertrophied, whereas type IIb fibers atrophied. After DNV, changes in isometric contraction were similar in both Dia regions. Twitch contraction and half-relaxation times increased, force-frequency relationships shifted leftward, and maximum tetanic force decreased. We conclude that passive length changes and mechanical stress are not the main determinants of the morphological and contractile adaptations of the Dia after unilateral DNV but that these adaptations result from DNV itself.