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Purpose: Clinical trials are critical to informing cancer care but often are hampered by slow accrual and lack of generalizability because of poor geographic accessibility. We tested the feasibility of replacing onsite study visits with telemedicine visits in a prospective clinical trial., Methods: Castration-naïve patients with prostate cancer and a rising serum prostate-specific antigen after definitive local therapy were eligible. Patients were required to have a single onsite visit for enrollment. Study treatment consisted of oral metformin 850 mg daily for 1 month followed by 850 mg twice daily for 5 months. Telehealth video visits (televisits) were conducted monthly by using a Health Insurance Portability and Accountability Act-compliant smartphone application. The primary objective was to determine the feasibility of telemedicine-enabled study visits. Secondary objectives were defining safety, anticancer activity, quality of life, and patient satisfaction., Results: Fifteen patients with a median age of 68 years (range, 57 to 83 years) and median one-way driving time to the study center of 71 minutes (range, 12 to 147 minutes) were enrolled. The patients completed 84 eligible televisits (completion rate, 100%; 95% CI, 0.80 to 1). Diarrhea was the most common adverse event but was limited to grade 1 in severity; a single patient experienced grade ≥ 3 adverse events. Seven patients (46.7%; 95% CI, 24.8% to 69.9%) had a ≤ 20% increase in prostate-specific antigen relative to baseline. Patients agreed or strongly agreed that they would participate in a telemedicine-enabled clinical trial in the future., Conclusion: To our knowledge, this interventional oncology clinical trial is the first to be conducted through telemedicine. Telemedicine-enabled trials are feasible and may overcome geographic barriers to trial participation. Metformin was generally well tolerated but associated with modest anticancer activity.

In an Essay, Matthew Todd and colleagues discuss an open source approach to drug development.

Patient and physician awareness and acceptance of trials and patient ineligibility are major cancer clinical trial accrual barriers. Yet, trials are typically conceived and designed by small teams of researchers with limited patient input. We hypothesized that through crowdsourcing, the intellectual and creative capacity of a large number of researchers, clinicians, and patients could be harnessed to improve the clinical trial design process. In this study, we evaluated the feasibility and utility of using an internet-based crowdsourcing platform to inform the design of a clinical trial exploring an antidiabetic drug, metformin, in prostate cancer. Over a six-week period, crowd-sourced input was collected from 60 physicians/researchers and 42 patients/advocates leading to several major (eg, eligibility) and minor modifications to the clinical trial protocol as originally designed. Crowdsourcing clinical trial design is feasible, adds value to the protocol development process, and may ultimately improve the efficiency of trial conduct., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Donor/recipient MHC class II matching permits survival of experimental allografts without permanent immunosuppression, but is not clinically applicable due to the extensive polymorphism of this locus. As an alternative, we have tested a gene therapy approach in a preclinical animal model to determine whether expression of allogeneic class II transgenes (Tg's) in recipient bone marrow cells would allow survival of subsequent Tg-matched renal allografts. Somatic matching between donor kidney class II and the recipient Tg's, in combination with a short treatment of cyclosporine A, prolonged graft survival with DR and promoted tolerance with DQ. Class II Tg expression in the lymphoid lineage and the graft itself were sequentially implicated in this tolerance induction. These results demonstrate the potential of MHC class II gene transfer to permit tolerance to solid organ allografts.

The major cause of xenograft loss beyond hyperacute rejection is a form of injury, traditionally termed delayed xenograft rejection (DXR), whose pathogenesis is unknown. Here we analyze the immunologic and morphologic features of DXR that develops in pig kidney xenografts transplanted into nonhuman primates. Kidneys from miniature swine were transplanted into cynomolgus monkeys (n = 14) or baboons (n = 11) that received regimens aimed to induce mixed chimerism and tolerance. No kidney was rejected hyperacutely. Morphologic and immunohistochemical studies were performed on serial biopsies, and an effort was made to quantify the pathologic features seen. The early phase of DXR (Days 0-12) was characterized by focal deposition of IgM, IgG, C3, and scanty neutrophil and macrophage infiltrates. The first abnormality recognized was glomerular and peritubular capillary endothelial cell death as defined by in situ DNA nick-end labeling (TUNEL). Damaged endothelial cells underwent apoptosis and, later, frank necrosis. The progressive phase developed around Day 6 and was characterized by progressive deposition of IgM, IgG, C3, and prominent infiltration of cytotoxic T cells and macrophages, with a small number of NK cells. Thrombotic microangiopathy developed in the glomeruli and peritubular capillaries with TUNEL+ endothelial cells, platelet aggregation, and destruction of the capillary network. Only rare damaged arterial endothelial cells and tubular epithelial cells were observed, with rare endothelialitis and tubulitis. In the advanced phase of DXR, interstitial hemorrhage and infarction occurred. During the development of DXR, the number of TUNEL+ cells increased, and this correlated with progressive deposition of antibody. The degree of platelet aggregation correlated with the number of TUNEL+ damaged endothelial cells. We conclude that peritubular and glomerular capillary endothelia are the primary targets of renal DXR rather than tubular epithelial cells or arterial endothelium and that the earliest detectable change is endothelial cell death. DXR was characterized by progressive destruction of the microvasculature (glomeruli and peritubular capillaries) and formation of fibrin-platelet thrombi. Both cytotoxic cells and antibodies potentially mediate the endothelial damage in DXR; however, in this model, DXR is largely humorally mediated and is better termed "acute humoral xenograft rejection."

Background: Mixed allogeneic hematopoietic chimerism has previously been reliably achieved and shown to induce tolerance to fully MHC-mismatched allografts in mice and monkeys. However, the establishment of hematopoietic chimerism has been difficult to achieve in the discordant pig-to-primate xenogeneic model., Methods: To address this issue, two cynomolgus monkeys were conditioned by whole body irradiation (total dose 300 cGy) 6 and 5 days before the infusion of pig bone marrow (BM). Monkey anti-pig natural antibodies were immunoadsorbed by extracorporeal perfusion of monkey blood through a pig liver, immediately before the intravenous infusion of porcine BM (day 0). Cyclosporine was administered for 4 weeks and 15-deoxyspergualin for 2 weeks. One monkey received recombinant pig cytokines (stem cell factor and interleukin 3) for 2 weeks, whereas the other received only saline as a control., Results: Both monkeys recovered from pancytopenia within 4 weeks of whole body irradiation. Anti-pig IgM and IgG antibodies were successfully depleted by the liver perfusion but returned to pretreatment levels within 12-14 days. Methylcellulose colony assays at days 180 and 300 revealed that about 2% of the myeloid progenitors in the BM of the cytokine-treated recipient were of pig origin, whereas no chimerism was detected in the BM of the untreated control monkey at similar times. The chimeric animal was less responsive by mixed lymphocyte reaction to pig-specific stimulators than the control monkey and significantly hyporesponsive when compared with a monkey that had rejected a porcine kidney transplant., Conclusion: To our knowledge, this is the first report of long-term survival of discordant xenogeneic BM in a primate recipient.

Background: Transfer of MHC class II genes, through allogeneic bone marrow (BM) transplantation, induced long-lasting acceptance of renal allografts in miniature swine. To adapt this approach to the clinic, we have now examined whether somatic transfer of allogeneic class II DR genes, into otherwise autologous bone marrow cells (BMC), can provide the matching required for inducing immune tolerance., Methods: Autologous BMC were transduced ex vivo with recombinant retroviruses for allogeneic DRB followed by BM transplantation. The recipients were then challenged with kidney allografts solely matched to the DRB transgene., Results: Five miniature swine received autologous BMC conditioned with growth factors and transduced with recombinant retrovirus vectors containing allogeneic (n=4) or syngeneic (n=1) class II DRB genes and a drug-resistance marker. Expression of retrovirus-derived products in BM-derived cells was demonstrated by the detection of drug-resistant colony-forming progenitors and the presence of DRB retrovirus transcripts in peripheral cells. Analysis of selective mixed lymphocyte reaction responses to DR or DQ antigens indicated decreased reactivity toward the transduced DR gene product. Among all of the animals receiving fully mismatched kidney allografts, but with DRB matched to the transduced DRB, the one with the highest gene transduction rate showed stable allograft function and essentially normal renal histology for 2.5 years. A control animal, which received a syngeneic DRB gene, rejected its kidney allograft in 120 days after an earlier rejection crisis., Conclusions: These studies demonstrate that allogeneic MHC gene transfer into BM provides a new strategy for inducing tolerance across MHC barriers.

Two monoclonal antibodies (mAb) with specificities for mature T-cell subsets in miniature swine have been characterized previously. Antibody 74-12-4 recognizes the porcine CD4 accessory molecule and 76-2-11 is specific for the CD8 molecule. We have now examined the effects of in vivo administration of 74-12-4 and 76-2-11 on several parameters of transplantation immunity. No prolongation of class I disparate skin or kidney graft survival was observed in animals treated with either mAb alone or with a combination of both. In addition, in vivo treatment with these mAbs, in combination with subtherapeutic total body irradiation, failed to permit engraftment of allogenic bone marrow. These therapeutic failures were thought likely to be a consequence of the fact that 74-12-4 coats, but does not deplete, CD4 cells in vivo. Because there are numerous anti-human mAbs that likewise fail to deplete in vivo, we have used 74-12-4 as a prototype to further manipulations aimed at achieving depletion. We attempted to eliminate 74-12-4-coated cells in two animals by subsequent administration of a hyperimmune pig anti-mouse Ig serum. In both such treated animals, administration of this serum produced surprisingly rapid clearance of 74-12-4 from the circulation and caused uncoating of CD4 cells, but no significant cell elimination was detected by flow cytometry. We have also prepared an anti-porcine-CD4 immunotoxin by conjugating 74-12-4 to the ribosome inhibitory plant toxin, pokeweed antiviral protein. This immunotoxin led to significant but not complete CD4 cell depletion from the peripheral blood in four of four treated animals. Further manipulations and possibly development of new anti-porcine CD4 mAbs may therefore be required to achieve complete depletion and successful mAb-mediated modification of transplantation responses.

Bone marrow transplantation has been shown to induce donor-specific tolerance in rodent models. This approach could potentially be applied to xenotransplantation across discordant species barriers. To evaluate host factors resisting hematopoietic cell engraftment, we have developed two model systems utilizing the combination of swine into severe combined immunodeficient (SCID) mice. SCID mice lack functional B and T lymphocytes, and can therefore be used to evaluate nonimmune factors resisting marrow engraftment, and for adoptive transfer studies to test the role of immune cells and antibodies. First we transplanted swine bone marrow cells into SCID mice conditioned with whole-body irradiation (4 Gy). For nine weeks following the intravenous administration of 10(8) swine bone marrow cells, up to 3.8% of peripheral blood leukocytes were of swine origin, as determined by flow cytometry (FCM). These cells were all of the myeloid lineage. Swine IgG was also detectable in the serum for up to 14 weeks. The bone marrow of the reconstituted mice contained low percentages of swine myeloid cells, and swine myeloid progenitors could be detected for up to 20 weeks after bone marrow transplantation. In a second model, we grafted thymus and liver tissue from 45-69-day-old swine fetuses under the kidney capsule of 4 Gy-irradiated SCID mice. A suspension containing 10(8) swine fetal liver cells (FLC) was also administered i.p. Long-term repopulation with swine T cells was observed, with up to 1.5% swine T cells detected in the WBC, peritoneum, and spleen for at least 5.5 months postgrafting. These T cells expressed either CD4 or CD8, whereas up to 17.6% of cells in the thymic grafts expressed both CD4 and CD8. The i.p. FLC suspension was required for optimal long-term graft maintenance. Our studies show that (1) low level myeloid and B lymphocyte reconstitution can be achieved by transferring adult swine BMC to irradiated SCID recipients; (2) swine myeloid progenitors were detectable long-term in BMC of these mice, suggesting that stem cell engraftment was achieved; and (3) T cell reconstitution of SCID mice by swine progenitors requires cotransplantation of a swine stromal environment, as is provided by fetal swine thymus/liver grafts. We conclude that nonimmune factors such as those provided by species-specific stromal environments are important for reconstitution of some lineages by discordant hematopoietic stem cells.

Recombinant retroviral vectors, engineered to express the beta-chain gene of swine major histocompatibility complex class II DR, were developed for the genetic modification of swine hematopoietic stem cells (HSC). The expression of these vectors in swine bone marrow has been studied both in culture and after bone marrow transplantation. In addition, myeloid progenitor colony assays were performed on swine umbilical cord blood as part of a study to identify alternative sources of HSC for somatic gene transfer, revealing the presence of both granulocyte macrophage colony forming-units (CFU-GM) and CFU-Mix at frequencies comparable to those found in juvenile swine bone marrow.

(LEW x BN)F1 cardiac allografts are rejected within 36 hr in LEW rats presensitized with BN skin grafts 7 days earlier (acute rejection occurs within 8 days). We have previously described the effects of individual CD4 (BWH-4), CD25 (IL-2R, ART-18) mAbs, and CsA therapeutic regimens upon cardiac allograft survival in sensitized hosts. The present studies were designed to probe an adjunctive use of ART-18 or CsA upon BWH-4-mediated suppression of accelerated graft injury. Sequential therapy with BWH-4 and ART-18 in the sensitization phase (days -7 to -1) and effector phase (from day 0, the day of cardiac transplant), respectively, prolonged graft survival additively to c. 22 days. Treatment with BWH-4 markedly diminished host humoral response against ART-18 preparation. BWH-4 given in concert with subtherapeutic dose of CsA produced graft survival comparable to that induced by mAb alone (c. 13 days) with concomitant decreased host anti-BWH-4 response. None of the combined regimens affected the frequency of circulating CD4+ cells, as compared with that exerted by BWH-4 monotherapy. Thus this study defines principles and some mechanistic aspects of optimal immunosuppressive strategies potentiating the effects of CD4-targeted therapy.

CD4 monoclonal antibody therapy prolongs allograft survival in a variety of experimental models and is currently undergoing clinical trials, though surprisingly little is known about the effects of CD4 mAb therapy on intragraft effector mechanisms that mediate rejection. We previously reported the significantly improved survival of (LEWxBN)F1 cardiac allografts in LEW rats treated for 10 days with the new CD4 mAb, BWH-4, at a dose of 700 micrograms/day, i.v., starting at the time of engraftment. Thus, CD4-treated rats showed prolongation of allograft survival to a median of 37 days (range 22 to greater than 100 days) post-Tx, compared with rejection at 7 days in untreated controls. We now report the results of detailed immunohistologic studies of allografts collected from these rats. Comparison of acutely rejecting allografts in untreated rats with well-functioning allografts collected at day 7 post-Tx from CD4-treated rats showed that CD4 mAb: (1) significantly reduced mononuclear cell infiltration, interstitial edema, hemorrhage formation and vascular and extravascular thrombosis; (2) inhibited mononuclear cell induction of receptors for IL-2 and transferrin, and upregulation of class II antigens and ICAM-1 on leukocytes and endothelial cells; (3) suppressed intragraft mononuclear cell and/or endothelial production of the cytokines IL-1, IL-2, IL-6, IFN-gamma, and TNF; and (4) blocked upregulation of endothelial tissue factor and downregulation of thrombomodulin, and consequently inhibited fibrin deposition. Studies of allografts from CD4-treated rats collected at day 30 post-Tx, prior to clinical rejection, showed a resurgence of CD4+ cells within allografts and a dense cellular immune response. We conclude that short-term CD4 mAb therapy has potent and extensive inhibitory effects on cytokine-related mononuclear cell and endothelial activation in vivo, blocking multiple afferent and efferent steps of the alloresponse.

Unlabelled: LBNF1 cardiac allografts (Tx) are rejected within 36 hr in LEW rats sensitized with BN skin Tx 7 days earlier, compared to 8-day rejection in unmodified hosts. Treatment with cyclosporine or ART-18, an anti-interleukin 2 receptor (IL-2[R]) mAb monoclonal antibody, abrogates accelerated rejection and prolongs mean Tx survival to 42 days and 16 days, respectively. ART-18 given in concert with subtherapeutic dose of CsA extends survival to 25 days. These studies were designed to dissect the early mechanisms leading to ART-18 and/or CsA-mediated abrogation of accelerated Tx injury. No effect of concomitant mAb administration upon CsA through levels was noted in Tx recipients conditioned with both modalities. The beneficial effect of ART-18+CsA treatment was also unrelated to CsA-induced diminished host responses to mAb, as shown by ELISA. In the biodistribution studies 125I-labeled ART-18 accumulated preferentially into host lymphoid tissues and Tx itself and away from the blood. In animals that were concomitantly given "cold" CsA, the clearance of labeled ART-18 from the blood increased further, as did mAb sequestration into the Tx. The sensitized hosts developed high titers of complement-dependent cytotoxic (CDC) antibodies, which peaked at the time of actual Tx loss. ART-18 or CsA alone inhibited CDC, whereas combined therapy decreased further the humoral effects of sensitization. The cell-mediated lymphocytotoxicity assay revealed a similar pattern. CsA, ART-18, and combination therapy each modulated the deposition of IgG, IgM, and C3 in Tx, as shown by immunohistology. However, only CsA or ART-18+CsA therapy abolished or markedly decreased elaboration of IL-2, interferon gamma, and tissue necrosis factor alpha., In Conclusion: (1) the adjunctive low dose of CsA potentiates the inhibitory effects of ART-18 upon humoral and cellular responses, leading to accelerated rejection of cardiac Tx in presensitized rats; (2) the synergistic interaction between both modalities that results in the inhibition of lymphokine production is critical and correlates with long-term Tx survival; (3) the biodistribution patterns of mAb are important--an increased blood level of mAb does not necessarily translate into its higher therapeutic efficacy.

We studied the effects and mechanism of action of BWH-4, an IgG2a mouse antirat CD4 monoclonal antibody that recognizes a distinct epitope on the CD4 molecule, in LEW recipients of (LEW x BN)F1 vascularized heterotopic cardiac allografts. Ten animals received daily injections of 700 micrograms BWH-4 for ten days after engraftment. Median actuarial allograft survival was 37 days for the treated animals compared with 7.5 days for controls (n = 6). There was depletion of peripheral blood CD4+ lymphocytes to 4 +/- 1% one week posttransplant (normal = 48 +/- 4%, n = 6). Six additional animals were treated with a lower dose (100 micrograms) of BWH-4 daily for ten days. Median actuarial allograft survival was 10 days and the circulating CD4+ cells decreased to 30 +/- 6% at one week posttransplant. All six low-dose-treated animals mounted an anti-BN alloantibody response by 3 weeks, while only one of the ten high-dose-treated animals had positive alloantibodies two weeks posttransplant. Lymphocyte-mediated cytotoxicity against donor lymphoblasts was completely abolished in the high-dose-treated animals when compared with acutely rejecting controls. We also used low-dose (100 micrograms) BWH-4 to pretreat eleven experimental animals for 7 days prior to engraftment. The circulating CD4+ cells decreased to only 12 +/- 2% on the day of transplantation and 26 +/- 9% one week posttransplant. However, six (55%) pretreated animals survived more than 55 days. There was a 66% decrease in lymphocyte-mediated cytotoxicity against donor lymphoblasts when compared with acutely rejecting controls. We conclude that the anti-CD4 mAb, BWH-4, prevents acute rejection of vascularized heterotopic rat cardiac allografts; this effect is mediated by depletion of the CD4+ T cell subset, suppression of alloantibody production, and inhibition of lymphocyte-mediated cytotoxicity.

Although CD4-targeted therapy markedly prolongs survival of organ allografts in naive rodents, its effects in primed hosts have not been studied. In our model of accelerated rejection (ACCR) of cardiac Tx in rats, treatment with BWH-4, a CD4 mAb (IgG2a), in the sensitization (between skin and heart Tx) but not in the effector (after cardiac Tx) phase, abrogated fulminant less than 36 hr rejection response and prolonged Tx survival to ca. 11 days. This effect correlated with decreased frequency of circulating CD4+ cells, but it did not depend upon their total depletion. It was also related to BWH-4 mAb-mediated elimination/depression of strong anti-donor humoral responses and cellular responses as determined by lymphocyte-mediated cytotoxicity and mixed lymphocyte reaction and mounted otherwise at the time of engraftment by untreated sensitized hosts. Immunoperoxidase studies of cardiac Tx from BWH-4-conditioned recipients revealed reduced T and B cell activities, reflected in abolition/reduction in deposition of humoral mediators, infiltrating cells, intra-Tx elaboration of interleukin-2 and interferon-gamma, and cell activation. This first report of the successful use of CD4 mAb in sensitized recipients of vascularized organ Tx, stresses the role of CD4+ cells as potential targets for immunosuppression in the sensitization phase of accelerated Tx injury. The beneficial therapeutic effect, probably due to both depletion and functional inhibition of CD4+ T cells, has been achieved by using relatively low doses of BWH-4 mAb.