Targeted Rho-associated kinase 2 inhibition suppresses murine and human chronic GVHD through a Stat3-dependent mechanism.

Chronic graft-versus-host disease (cGVHD) remains a major complication following allogeneic bone marrow transplantation (BMT). The discovery of novel therapeutics is dependent on assessment in preclinical murine models of cGVHD. Rho-associated kinase 2 (ROCK2) recently was shown to be implicated in regulation of interleukin-21 (IL-21) and IL-17 secretion in mice and humans. Here, we report that the selective ROCK2 inhibitor KD025 effectively ameliorates cGVHD in multiple models: a full major histocompatibility complex (MHC) mismatch model of multiorgan system cGVHD with bronchiolitis obliterans syndrome and a minor MHC mismatch model of sclerodermatous GVHD. Treatment with KD025 resulted in normalization of pathogenic pulmonary function, which correlates with a marked reduction of antibody and collagen deposition in the lungs of treated mice to levels comparable to non-cGVHD controls. Spleens of mice treated with KD025 had decreased frequency of T follicular helper cells and increased frequency of T follicular regulatory cells, accompanied by a reduction in signal transducer and activator of transcription 3 (STAT3) and concurrent increase in STAT5 phosphorylation. The critical role of STAT3 in this cGVHD model was confirmed by data showing that mice transplanted with inducible STAT3-deficient T cells had pulmonary function comparable to the healthy negative controls. The therapeutic potential of targeted ROCK2 inhibition in the clinic was solidified further by human data demonstrating the KD025 inhibits the secretion of IL-21, IL-17, and interferon γ along with decreasing phosphorylated STAT3 and reduced protein expression of interferon regulatory factor 4 and B-cell lymphoma 6 (BCL6) in human peripheral blood mononuclear cells purified from active cGVHD patients. Together these data highlight the potential of targeted ROCK2 inhibition for clinical cGVHD therapy.

Feasibility of frequent patient-reported outcome surveillance in patients undergoing hematopoietic cell transplantation.

Patient-reported outcomes (PROs), including symptoms and health-related quality of life (HRQOL), provide a patient-centered description of hematopoietic cell transplantation (HCT)-related toxicity. These data characterize the patient experience after HCT and may have prognostic usefulness for long-term outcomes after HCT. We conducted a study of 32 patients after HCT (10 autologous HCT recipients, 11 full-intensity conditioning allogeneic HCT recipients, and 11 reduced-intensity conditioning allogeneic HCT recipients) to determine the feasibility of weekly electronic PRO collection from HCT until day (D) +100. We used questions from the PRO version of the Common Terminology Criteria for Adverse Events to capture symptoms, and the Patient-Reported Outcomes Measurement Information System Global Health scale to measure physical and mental HRQOL. The vast majority (94%) of patients used the electronic PRO system, with only 6% opting for paper-and-pencil only. The median weekly percentage of participants who completed the surveys was 100% in all cohorts through hospital discharge, and remained 100% for the autologous HCT and reduced-intensity allogeneic HCT cohorts through D+100. Patients were satisfied with the electronic system, giving high marks for readability, comfort, and questionnaire length. Symptom severity varied by absolute level and type of symptom across the 3 cohorts, with the full-intensity allogeneic HCT cohort exhibiting the greatest median overall symptom severity, peaking at D+7. Median physical health HRQOL scores decreased with time in the 3 cohorts, and HRQOL was generally correlated with overall symptom severity. Our results demonstrate the feasibility of frequent electronic PROs in the early post-HCT period. Future studies in larger populations to explore predictive models using frequent PRO data for outcomes, including long-term HRQOL and survival, are warranted.

A novel system for simultaneous in vivo tracking and biological assessment of leukemia cells and ex vivo generated leukemia-reactive cytotoxic T cells.

To determine the mechanisms by which adoptive immunotherapy could reduce lethality to acute myelogenous leukemia (AML), a novel technique was developed to track both leukemic blasts and adoptively transferred cytotoxic T cells (CTLs) independently and simultaneously in mice. To follow the fate of ex vivo generated anti-AML-reactive CTLs, splenocytes obtained from enhanced green fluorescent protein transgenic mice were cocultured with AML lysate-pulsed dendritic cells, which subsequently were expanded by exposure to anti-CD3/CD28 monoclonal antibody-coated magnetic microspheres. To track AML cells, stable transfectants of C1498 expressing DsRed2, a red fluorescent protein, were generated. Three factors related to CTLs correlated with disease-free survival: (a). CTL L-selectin expression. L-Selectin high fractions resulted in 70% disease-free survival, whereas L-selectin low-expressing CTLs resulted in only 30% disease-free survival. (b). Duration of ex vivo expansion (9 versus 16 days). Short-term expanded CTLs could be found at high frequency in lymphoid organs for longer than 4 weeks after transfer, whereas long-term expanded CTLs were cleared from the system after 2 weeks. Duration of expansion correlated inversely with L-selectin expression. (c). CTL dose. A higher dose (40 versus 5 x 10(6)) resulted in superior disease-free survival. This survival advantage was achieved with short-term expanded CTLs only. The site of treatment failure was mainly the central nervous system where no CTLs could be identified at AML sites.