After being a neglected and poorly-understood disorder for many years, there has been a recent explosion of data regarding the complex pathogenesis of myelodysplastic syndromes (MDS). On the therapeutic front, the approval of azacitidine, decitabine, and lenalidomide in the last decade was a major breakthrough. Nonetheless, the responses to these agents are limited and most patients progress within 2 years. Allogeneic stem cell transplantation remains the only potentially curative therapy, but it is associated with significant toxicity and limited efficacy. Lack or loss of response after standard therapies is associated with dismal outcomes. Many unanswered questions remain regarding the optimal use of current therapies including patient selection, response prediction, therapy sequencing and combinations, and management of resistance. It is hoped that the improved understanding of the underpinnings of the complex mechanisms of pathogenesis will be translated into novel therapeutic approaches and better prognostic/predictive tools that would facilitate accurate risk-adaptive therapy.

Wnt signaling is an evolutionarily conserved pathway that controls cell-to-cell interactions during embryogenesis. In adults, Wnt signaling plays a role in tissue homeostasis in almost every organ system. Aberrations within this pathway are implicated in a spectrum of human diseases. A variety of perturbations have been described in both solid and hematologic malignancies, lending way to Wnt signaling as a target for anti-cancer therapy. Of particular interest is the role of Wnt signaling in the development and maintenance of cancer stem cells, a rare population of cells that are able to maintain a tumor via self-renewal and thought to be more resistant to chemotherapy than bulk tumor cells. The ability to eradicate cancer stem cells may decrease the risk of cancer relapse and metastasis. A number of therapeutic agents specifically targeting the Wnt pathway have entered clinical trials, either as monotherapy or in combination with chemotherapy. We will provide an overview of agents that have been developed to target the Wnt pathways and a summary of pre-clinical and clinical trials.

Specific SREs are associated with worse outcomes, including increased pain, poorer QOL, morbidity, and survival. Treatment of SREs is associated with improved pain, although there remains a need for more effective treatment of SREs in prostate cancer patients.

Chronic GVHD (cGVHD) is an important problem after allotransplants. Some risk factors for cGVHD are similar to those of acute GVHD (aGVHD) but others are distinct indicating sometimes overlapping but unique pathogeneses. Precise incidence and prevalence data of cGVHD are lacking because of diverse diagnostic criteria but a 50% risk is a reasonable estimate. Incidence and prevalence of cGVHD are probably growing because of increased use of unrelated donors, blood rather than bone marrow (BM) grafts, decreased early transplant-related mortality (TRM) and increasing frequency of allotransplants. Pathophysiology of cGVHD is complex and poorly understood. Notably, no reliable surrogate end point to predict mechanism(s) of cGVHD has been identified. Therapy of cGVHD is unsatisfactory. Corticosteroids are effective but other drugs are controversial and few are rigorously tested in randomized trials. Highly variable response rates are reported because of small sample sizes and inconsistencies in eligibility, diagnostic and response criteria. We focus on the possible role of immunomodulatory drugs (IMiDs), thalidomide lenalidomide and pomalidomide, in preventing and treating cGVHD. The data suggest activity of thalidomide but at doses not clinically practical in many instances. There are few data with lenalidomide. Trials of pomalidomide, which has immune activities like thalidomide but with fewer adverse effects, are beginning. Because cGVHD is not recently reviewed in Bone Marrow Transplantation, we give a brief background and discuss challenges in diagnosing, understanding and treating cGVHD including the recently proposed National Institutes of Health consensus criteria for cGVHD. 1-3 It occurs in about 50% of persons surviving 41 year post transplant and causes substantial morbidity and mortality. There has been little progress over the past 30 years in preventing and/or treating cGVHD. Moreover, incidence and prevalence are increasing because of several factors including: (1) increased use of blood cell rather than BM grafts; (2) increasing use of incompletely HLA-matched related and unrelated donors; (3) increased use of donor-lymphocyte infusions, especially in the context of reduced-intensity allotransplants; (4) increased number of transplants done each year; and (5) increased proportion of transplants in older persons. [4][5][6] The focus of our review is on the use and potential of IMiD-class drugs to prevent and/or treat cGVHD. These drugs have unique, complex immune regulatory activities. As a prelude, we review some relevant definitional, laboratory and clinical features of cGVHD.

BackgroundBone marrow transplant-associated thrombotic microangiopathy (TA-TMA) is a relatively frequent but under-recognized and under-treated hematopoietic stem cell transplant (HSCT) complication that leads to significant post-transplant morbidity and mortality. Classic TMA-defining laboratory abnormalities appear at different times in the course of TA-TMA development, with schistocytes often appearing later in the disease course. In some severe TMA cases, schistocytes may be absent due to increased endothelial permeability. Unfortunately, many clinicians continue to perceive the presence of schistocytes as an absolute requirement for TA-TMA diagnosis, which leads to delayed recognition and treatment of this potentially fatal transplant complication.MethodsPatient chart review and PubMed literature search using the term, “transplant-associated thrombotic microangiopathy”.Case presentationA 54-year-old male IgG kappa multiple myeloma underwent a reduced intensity allogeneic HSCT from a 9/10 HLA-matched unrelated donor after conditioning with fludarabine and melphalan. On day + 27, the patient developed acute kidney injury followed by repeated episodes of diarrhea and gastrointestinal bleeding attributed to graft versus host disease (GVHD) and cytomegalovirus (CMV) colitis. Repeated colonic biopsies suggested CMV infection and GVHD. Despite appropriate treatment with antiviral therapy and immunosuppressants, the patient’s condition continued to deteriorate. He experienced concomitant anemia and thrombocytopenia as well as elevated lactate dehydrogenase and low haptoglobin levels, but a TA-TMA diagnosis was not made due to an absence of schistocytes on peripheral smear. The patient expired secondary to uncontrolled gastrointestinal bleeding. A post-mortem analysis of the resection specimen revealed extensive TMA involving numerous arteries and arterioles in the ileal and colonic submucosa as well as in the muscularis propria and deep lamina propria of the mucosa.ConclusionsTA-TMA can occur in the absence of peripheral blood schistocytes. Our experience underscores the importance of considering the diagnosis of intestinal TA-TMA in patients with refractory post-transplant diarrhea and GI bleeding, even if all classic features are not present.