Identifying and Assessing Putative Allosteric Sites and Modulators for CXCR4 Predicted through Network Modeling and Site Identification by Ligand Competitive Saturation.

The chemokine receptor CXCR4 is a critical target for the treatment of several cancer types and HIV-1 infections. While orthosteric and allosteric modulators have been developed targeting its extracellular or transmembrane regions, the intramembrane region of CXCR4 may also include allosteric binding sites suitable for the development of allosteric drugs. To investigate this, we apply the Gaussian Network Model (GNM) to the monomeric and dimeric forms of CXCR4 to identify residues essential for its local and global motions located in the hinge regions of the protein. Residue interaction network (RIN) analysis suggests hub residues that participate in allosteric communication throughout the receptor. Mutual residues from the network models reside in regions with a high capacity to alter receptor dynamics upon ligand binding. We then investigate the druggability of these potential allosteric regions using the site identification by ligand competitive saturation (SILCS) approach, revealing two putative allosteric sites on the monomer and three on the homodimer. Two screening campaigns with Glide and SILCS-Monte Carlo docking using FDA-approved drugs suggest 20 putative hit compounds including antifungal drugs, anticancer agents, HIV protease inhibitors, and antimalarial drugs. In vitro assays considering mAB 12G5 and CXCL12 demonstrate both positive and negative allosteric activities of these compounds, supporting our computational approach. However, in vivo functional assays based on the recruitment of ß-arrestin to CXCR4 do not show significant agonism and antagonism at a single compound concentration. The present computational pipeline brings a new perspective to computer-aided drug design by combining conformational dynamics based on network analysis and cosolvent analysis based on the SILCS technology to identify putative allosteric binding sites using CXCR4 as a showcase.

Plerixafor con factor estimulante de colonias de granulocitos (G-CSF) en pacientes con linfoma o mieloma múltiple candidatos a trasplante autólogo con difícil movilización de células progenitoras hematopoyéticas / Plerixafor with granulocyte colony-stimulating factor (G-CSF) in patients with lymphoma or multiple myeloma candidates for autologous transplantation with difficult mobilization of hematopoietic progenitor cells

INTRODUCCIÓN: Como parte de las funciones de la UFETS, se ha elaborado el presente informe sobre el uso de plerixafor en combinación con factor estimulante de colonias de granulocitos en pacientes con linfomas o mieloma múltiple de tumores sólidos sensibles a quimioterapia candidatos a trasplante autólogo con difícil movilización de células progenitoras hematopoyéticas. - En Perú, solo en el Instituto Nacional de Enfermedades Neoplásica se registran más de 500 casos de LNH anualmente y de MM se registran más de 90 casos anualmente La población a esperada en el INEN es de 12 pacientes al año, según reportes de la oficina de epidemiología. - El plerixafor induce la movilización de células madre al torrente sanguíneo desde la médula ósea, y está aprobado por la FDA y EMA para el tratamiento de la LCV. METODOLOGÍA: La estrategia de búsqueda sistemática de información científica para el desarrollo del presente informe se realizó siguiendo las recomendaciones de la Pirámide jerárquica de la evidencia propuesta por Haynes y se consideró los siguientes estudios: Sumarios y guías de práctica clínica. Revisiones sistemáticas y/o meta-análisis. Ensayos Controlados Aleatorizados (ECA). Estudios Observacionales (cohortes, caso y control, descriptivos) No hubo limitaciones acerca de la fecha de publicación o el idioma para ningún estudio. RESULTADOS: Se realizó una búsqueda sistemática encontrando 1 RS-MS que respondía la pregunta PICO. - El metanálisis no encontró diferencias entre el grupo plerixafor y el placebo con respecto a la mortalidad a los 12 meses (RR: 1,00, IC 95 %: 0,59 a 1,69; p=1,00) ni eventos adversos (RR: 1,02, IC 95 %: 0,99 a 1,06; p = 0,19. Con respecto al resultado de la recolección exitosa de células madre, se evidenció ventaja en el grupo plerixafor (RR: 2,42; IC 95 %: 1,98 a 2,96; p<0,001. La evidencia encontrada es de calidad moderada, se incluyó estudios clínicos aleatorizados, doble ciegos, con comparador, financiados por el productor de plerixafor. CONCLUSIONES: La presente evaluación evaluó el uso de plerixafor con filgastrin para movilización de células progenitoras para trasplante autólogo. Se hizo una búsqueda sistemática, encontrando 1 RS-MS que respondía la pregunta PICO. El MA encontró que respecto al resultado de la recolección exitosa de células madre, se evidenció ventaja en el grupo plerixafor con un RR de 2.42. La evidencia encontrada es de calidad moderada, se incluyó estudios clínicos aleatorizados, doble ciegos, con comparador, financiados por el productor de plerixafor

Informe de evaluación científica basada en la evidencia disponible: mieloma múltiple / Scientific evaluation report based on available evidence: multiple myeloma

INTRODUCCIÓN: El mieloma múltiple (MM) se caracteriza por la proliferación neoplásica de células plasmáticas que producen una inmunoglobulina monoclonal, estas células plasmáticas proliferan en la médula ósea y, frecuentemente, dan como resultado una extensa destrucción esquelética con lesiones osteolíticas, osteopenia y / o fracturas patológicas. La sospecha diagnóstica se inicia, generalmente debido a la presencia de dolor óseo con lesiones líticas, aumento de la concentración sérica total de proteínas o presencia de una proteína monoclonal en orina o suero, signos o síntomas sistémicos sugestivos de malignidad como anemia inexplicada, hipercalcemia, insuficiencia renal aguda con un urinálisis suave o raramente el síndrome nefrótico debido a la amiloidosis de cadena ligera de inmunoglobulina concurrente, pudiendo presentarse de forma copulativa. Es importante distinguir MM tanto de otras causas de las presentaciones clínicas anteriores, como de otras discrasias de células plasmáticas, para fines de pronóstico y tratamento. TECNOLOGÍAS ANALIZADAS: Bortezomib / Daratumumab / Plerixafor / Lenalidomida / Bendamustina. EFICACIA DE LOS TRATAMIENTOS: -Bortezomib: La adición de bortezomib al tratamiento del mieloma múltiple disminuye la mortalidad. En cuanto a los efectos adversos, la adición de bortezomib aumenta el riesgo de éstos. ­ Daratumumab: La adición de daratumumab al tratamiento del mieloma múltiple podría disminuir la mortalidad, pero la certeza de la evidencia es baja. En cuanto a los efectos adversos, estos no son reportados. ­ Plerixafor: La adición de perixafor al tratamiento del mieloma múltiple podría tener poco o nulo efecto sobre la mortalidad, pero la certeza de la evidencia es baja. En cuanto a los efectos adversos la adición de plerixafor probablemente no se asocia a efectos adversos, o estos son mínimos. ­Lenalidomida: La adición de lenalidomida al tratamiento del mieloma múltiple probablemente no disminuye la mortalidad. En cuanto a los efectos adversos la adición de lenalidomida aumenta los estos efectos grado 3 y 4. ­Bendamustina: No se encontró evidencia sobre la eficacia de la adición de bendamustina al tratamiento del mieloma múltiple. En cuanto a los efectos adversos, tampoco se encontraron estudios que evaluaran la seguridad de la adición de bendamustina. ANÁLISIS ECONÓMICO: Para Bortezomib se consideran los pacientes que logran una remisión completa de células cancerígenas, estimada aproximadamente en un 40%, junto con los que padecen mieloma múltiple y no logran remisión completa de la enfermedad, estimada aproximadamente en un 60% (2). Por lo que el impacto presupuestario proyectado para el año 2018 para pacientes que logran remisión y los que no remiten es de $MM 1.491 y $MM 4.473 respectivamente. Para Bendamustina se considera la cantidad de pacientes que logran una remisión completa de células cancerígenas, estimada aproximadamente en un 40%, junto con la población que padece mieloma múltiple y que son refractarios o tiene una recaída, estimada aproximadamente en un 60% (2). Esto traducido en cantidad de personas aproximadas es 163 y 245, respectivamente, por lo que se proyecta un impacto presupuestario para el año 2018 de $MM 971 para pacientes con remisión completa y de $MM 2.185 para pacientes refractarios al tratamiento. Para Daratumumab no se encuentra evidencia de evaluaciones económicas de este tratamiento para pacientes con mieloma múltiple. El impacto presupuestario proyectado para el año 2018 es de $MM 44.775. Para Lenalidomida se considera la cantidad de pacientes que con anterioridad cuenten con un tratamiento previo a tratarse con lenalidomida, para esto se considera al 60% de la población que desarrolla la enfermedad pero que con un primer diagnóstico no ha sido posible la remisión completa de su cuerpo. El número de personas correspondientes a este 60% es 245 (2). El impacto presupuestario proyectado para el año 2018 es de $MM 3.232. Para el tratamiento con Plerixafor, el impacto presupuestario proyectado para el año 2018 es de $MM 556. CONCLUSIÓN: Se hace presente que la oferta recibida en este Ministerio de Salud, contempla mecanismo de riesgo compartido, por lo que se sugiere que la CENABAST en una eventual compra, considere dicha modalidad contractual. Asimismo, cabe indicar que la determinaicón del Precio Máximo Industrial se ha ajustado a derecho. Por último y sin perjuicio de lo antes señalado, es dable agregar que, conforme al análisis efectuado al presente informe, éste se ajusta a derecho.

Plerixafor for stem cell mobilization: the current status.

PURPOSE OF REVIEW: Nowadays, plerixafor is approved for patients who fail to mobilize sufficient CD34⁺ cells for an autologous stem cell transplantation. Plerixafor is effective in the majority of these patients, who otherwise could not be treated adequately. We discussed in this review the current status of the optimal use of plerixafor in different clinical diagnoses and settings. RECENT FINDINGS: Plerixafor seems to be more effective in patients with multiple myeloma than in lymphoma. Even patients who had very low circulating CD34⁺ cells before administration of plerixafor have an important benefit. Several strategies in different clinical settings showed an effective response after administration of plerixafor, without the superiority of one strategy. Plerixafor is well tolerated with acceptable toxicity; however, it is an expensive drug. SUMMARY: Plerixafor is an effective drug in patients who fail to mobilize with conventional strategy. No strategy seems superior for the optimal use of plerixafor. More studies focusing on the kinetics and cost-effectiveness are needed.

A nationwide survey of the use of plerixafor in patients with lymphoid malignancies who mobilize poorly demonstrates the predominant use of the "on-demand" scheme of administration at French autologous hematopoietic stem cell transplant programs.

BACKGROUND: High-dose chemotherapy supported with autologous stem cell transplantation is a standard therapeutic option for a subset of patients with lymphoid malignancies. Cell procurement is nowadays done almost exclusively through cytapheresis, after mobilization of hematopoietic stem and progenitor cells (HSPCs) from the marrow to peripheral blood (PB). The egress of HSPCs out of hematopoietic niches occurs in various physiologic or nonhomeostatic situations; pharmacologic approaches include the administration of acutely myelosuppressive agents or hematopoietic growth factors such as recombinant human granulocyte-colony-stimulating factor (rHuG-CSF). The introduction of plerixafor, a first-of-its-class molecule that reversibly inhibits the interaction between the chemokine CXCL-12 (also known as SDF-1) and its receptor CXCR-4, has offered new opportunities for the so-called "poor mobilizers" who achieve insufficient mobilization and/or collection with conventional approaches. STUDY DESIGN AND METHODS: Because of the lack of consensus on a definition for poor mobilizers and the relatively high cost of plerixafor, French competent authorities have mandated a postmarketing survey on its use in routine practice. RESULTS AND CONCLUSION: We report here the results of this nationwide survey that confirms the clinical efficacy of plerixafor, even in the subset of patients who barely increased PB CD34+ cell count in response to rHuG-CSF-containing mobilization regimen. Furthermore, analysis of this registry showed that despite heterogeneity in medical practices, the early-"on-demand" or "preemptive"-introduction of plerixafor was widely used and did not result in an excess of prescriptions, beyond its expected use at the time when marketing authorization was granted.

An algorithm for utilizing peripheral blood CD34 count as a predictor of the need for plerixafor in autologous stem cell mobilization--cost-effectiveness analysis.

Certain patients who receive granulocyte colony-stimulating factor (GCSF) for autologous hematopoietic stem cell (AHSC) collection fail to mobilize well enough to proceed with transplant. When plerixafor is used with GCSF, the likelihood of achieving the CD34⁺ stem cell target in fewer collections is higher; plerixafor use in all patients is unlikely to be cost-effective. This study retrospectively evaluated the effectiveness of utilizing a peripheral blood CD34⁺ stem cell count (PBCD34) ≤8/µL on day 4 of GCSF-based AHSC mobilization as a threshold for plerixafor administration, and compared the efficacy of collection and cost analysis using historical controls. All patients in the study cohort reached their CD34⁺ targets in ≤3 collections. Significantly more patients who received plerixafor + GCSF versus GCSF alone reached their CD34⁺ target in one collection (P = 0.045); however, there were no significant differences in the number of collections or in cumulative product yields. The historical cohort had 10.3% mobilization failures; the number of collections per patient needed to reach the target was significantly higher in the historical cohort versus study cohort (P = 0.001) as was the number of patients requiring more than one collection to reach their target (P = 0.023). However, the average cost per patient was also significantly higher in the study cohort (P = 0.025). Further refinement of the algorithm may reduce the difference in cost between the two mobilization strategies.

Effectiveness and cost analysis of "just-in-time" salvage plerixafor administration in autologous transplant patients with poor stem cell mobilization kinetics.

BACKGROUND: Plerixafor is a recently Food and Drug Administration (FDA)-approved CXCR4 antagonist, which is combined with granulocyte-colony-stimulating factor (G-CSF) to facilitate stem cell mobilization of lymphoma and myeloma patients. STUDY DESIGN AND METHODS: To evaluate the effectiveness and the related costs of a "just-in-time" strategy of plerixafor administration, we performed a retrospective cohort study comparing 148 consecutive lymphoma and myeloma patients in whom mobilization was attempted during 2008 before the Food and Drug Administration (FDA) approval of plerixafor with 188 consecutive patients mobilized during 2009 after FDA approval. RESULTS: Plerixafor was administered to 64 of 188 patients considered to be at risk for mobilization failure due to either their medical history ("high risk," n = 23) or the occurrence of peripheral blood CD34+ count of fewer than 15 × 10(6) cells/L with a white blood cell count of greater than 10 × 10(9) cells/L after at least 5 days of G-CSF administration (just-in-time, n = 41). The success rates of collecting a minimum transplant CD34+ cell dose (≥2 × 10(6) cells/kg) or target cell dose (≥5 × 10(6) lymphoma or ≥10 × 10(6) CD34+ cells/kg myeloma) in the just-in-time patients compared favorably with the 36 poor mobilizers collected with G-CSF alone: 93% versus 72% and 42% versus 22%, respectively. CONCLUSIONS: The use of plerixafor in selected high-risk patients and poor mobilizers did not increase the total charges associated with stem cell collection when compared with poor mobilizers treated with G-CSF alone. The targeted use of plerixafor increased the overall success rate of mobilizing a minimum number of CD34+ cells from 93% to 98% in patients with hematologic malignancies scheduled for autotransplant and increased the overall charges associated with stem cell collection in all patients by an average of 17%.

Plerixafor mobilization leads to a lower ratio of CD34+ cells to total nucleated cells which results in greater storage costs.

BACKGROUND: Plerixafor (Mozobil, AMD3100) with granulocyte-colony stimulating factor (G-CSF) mobilizes more CD34+ cells/kg compared to G-CSF alone. Given that plerixafor enhances mobilization of multiple white blood cell lineages, we determined if more storage space is required for products collected from patients mobilized with plerixafor. METHODS: A review of the medical records of 15 patients mobilized with chemotherapy and G-CSF (control) and 14 patients mobilized with plerixafor plus G-CSF (plerixafor) was performed. Data on demographics, baseline characteristics, CD34+ cells/kg, total nucleated cells, total mononuclear cells, total apheresis sessions, and total bags for storage were collected. Mean values were determined and compared using Student's t-test. RESULTS: We found that the proportion of CD34+ cells among total nucleated cells was less in the plerixafor group compared to the control group (P = 0.0427). More nucleated cells (10.7 x 10(10) vs. 7.1 x 10(10), P =0.0452) and mononuclear cells (9.7 x 10(10) vs. 5.9 x 10(10), P = 0.0059) were mobilized with plerixafor plus G-CSF. However, there was no significant difference in CD34+ cells/kg, total CD34+ cells or the proportion of mononuclear cells among total nucleated cells between the two groups. More storage bags were required for the plerixafor group compared to the control group (15 vs. 9, P = 0.0299). CONCLUSION: Mobilization with plerixafor plus G-CSF resulted in a smaller proportion of CD34+ cells collected and a greater number of storage bags. An increase in the number of bags required for stem cell storage may be logistically problematic and will also lead to increased costs for storage of stem cells.

Plerixafor: A chemokine receptor-4 antagonist for mobilization of hematopoietic stem cells for transplantation after high-dose chemotherapy for non-Hodgkin's lymphoma or multiple myeloma.

BACKGROUND: Autologous hematopoietic stem cell (HSC) transplantation is used to facilitate hematopoietic recovery after administration of high-dose chemotherapy in patients with Hodgkin's disease, non-Hodgkin's lymphoma (NHL), multiple myeloma (MM), leukemias, and some solid tumors. There are limitations to the existing methods of mobilizing CD34+ HSC with chemotherapy and/or granulocyte colony-stimulating factor (G-CSF). Plerixafor, a bicyclam molecule that acts as a pure antagonist of chemokine receptor-4, is approved by the US Food and Drug Administration for use in combination with G-CSF for mobilization of CD34+ HSC in patients with NHL or MM. OBJECTIVE: This review presents information on plerixafor, including its mechanism of action in mobilizing stem cells, pharmacokinetics, clinical efficacy, adverse effects, and pharmacoeconomic considerations. METHODS: MEDLINE, EMBASE (1996-June 2009), and International Pharmaceutical Abstracts (1970-June 2009) were searched on July 9, 2009, using the key words plerixafor and AMD3100 for reports relating to HSC mobilization. The search was updated on September 20, 2009, and again on January 30, 2010. The reference lists of identified articles were examined for additional abstracts and other sources of information. The journal Blood was searched online to identify abstracts presented at Annual Meetings of the American Society of Hematology. RESULTS: After administration of plerixafor, HSC migrate from the bone marrow into the peripheral blood, permitting collection by apheresis. Clinical trials in humans have found that the combination of G-CSF + plerixafor facilitates mobilization of HSC. In patients with MM without extensive previous treatment who were undergoing a first mobilization, the use of G-CSF + plerixafor was reported to double counts of circulating peripheral CD34+ HSC and thus double the number of CD34+ HSC collected in half as many apheresis procedures, although rates of engraftment, graft durability, transplantation, and survival outcomes were not significantly improved. In patients with Hodgkin's disease or NHL, in whom limited success in mobilization is expected, G-CSF + plerixafor also facilitated or improved mobilization with improved apheresis yields, again without significant improvement in outcomes. Common (> or = 20%) adverse events of plerixafor used in combination with G-CSF include diarrhea (37%), nausea (34%), injection-site reactions (34%), fatigue (27%), and headache (22%). Plerixafor 0.24 mg/kg SC is administered on the evening of the fourth day of G-CSF dosing, approximately 11 hours before the first apheresis session. Daily doses of plerixafor can be repeated up to 3 times on consecutive days to achieve adequate HSC collection. The average wholesale price of a 24-mg vial of plerixafor is $7500. CONCLUSIONS: Plerixafor is an effective agent for mobilizing CD34+ HSC. Long-term treatment outcomes are being studied in patients undergoing autologous transplantation of HSC mobilized with G-CSF + plerixafor.

Ampelopsin, a small molecule inhibitor of HIV-1 infection targeting HIV entry.

OBJECTIVE: To investigate the anti-HIV effects of ampelopsin and its interaction with HIV-1 coreceptor CXCR4. METHODS: Through anti-virus experiments in vitro, the inhibitory effect of ampelopsin on HIV-1 infection was verified. Chemotaxis assay was performed to show the ability to induce PBMCs migration by ampelopsin, RANTES and SDF-1alpha. Fluorescence labelling monoclonal antibody was utilized to observe the interaction of ampelopsin and CXCR4. Mice immunosuppressant model was also established to detail the role ampelopsin played in regulating cellular immunological functions. RESULTS: Ampelopsin could protect sensitive cells against HIV-1 infection and dramatically reduce HIV-1 antigen P24 expression. HIV-1SF33 attaching to MT-4 cells was interfered by ampelopsin, and the EC50 was 0.175 mg/mL for cellular protection and 0.024 mg/mL for P24 inhibition. At co-cultivating phase, EC50 was 0.229 mg/mL and 0.197 mg/mL respectively. Furthermore, the EC50 was 0.179 mg/mL and 0.348 mg/mL in acute infection. Human PBMCs migration was induced after being challenged with ampelopsin or chemokines, and synergistic action was observed during co-treatment. Ampelopsin alone resulted in maximal chemotaxis at 1 mg/mL. HIV-1 co-receptor CXCR4 on the surface of PBMCs was decreased by internalization, which indicated the effect of ampelopsin on CXCR4. About 70% CXCR4 was reduced by ampelopsin at 1 mg/mL. Ampelopsin also augmented cellular immunological functions in immunosuppressive mice. CONCLUSION: Ampelopsin displays a strong inhibitive role during HIV-1 absorption, incubation and acute infection. These results are coincident with its immune enhancement.