Azacitidine, lenalidomide and donor lymphocyte infusions for relapse of myelodysplastic syndrome, acute myeloid leukemia and chronic myelomonocytic leukemia after allogeneic transplant: the Azalena-Trial

Azacitidine (Aza) combined with donor lymphocyte infusions (DLI) is an established treatment for relapse of myeloid malignancies after allogeneic transplantation. Based on its immunomodulatory and anti-leukemic properties we considered Lenalidomide (Lena) to act synergistically with Aza/DLI to improve outcome. We, therefore, prospectively investigated tolerability and efficacy of this combination as first salvage therapy for adults with post-transplant relapse of acute myeloid leukemia, myelodysplastic syndromes and chronic myelomonocytic leukemia. Patients were scheduled for eight cycles Aza (75 mg/m2 day 1-7), Lena (2.5 or 5 mg, days 1-21) and up to three DLI with increasing T-cell dosages (0.5×106-1.5×107 cells/kg). Primary endpoint was safety, while secondary endpoints included response, graft-versus-host disease (GvHD) and overall survival (OS). Fifty patients with molecular (52%) or hematological (48%) relapse of myelodysplastic syndromes (n=24), acute myeloid leukemia (n=23) or chronic myelomonocytic leukemia (n=3) received a median of seven (range, 1-8) cycles including 14 patients with 2.5 mg and 36 with 5 mg Lena daily dosage. Concomitantly, 34 patients (68%) received at least one DLI. Overall response rate was 56% and 25 patients (50%) achieved complete remission being durable in 80%. Median OS was 21 months and 1-year OS rate 65% with no impact of type of or time to relapse and Lena dosages. Treatment was well tolerated indicated by febrile neutropenia being the only grade ≥3 non-hematologic adverse event in >10% of patients and modest acute (grade 2-4 24%) and chronic (moderate/severe 28%) GvHD incidences. In summary, Lena can be safely added to Aza/DLI without excess of GvHD and toxicity. Its significant anti-leukemic activity suggests that this combination is a novel salvage option for post-transplant relapse (clinicaltrials gov. Identifier: NCT02472691)

SS18-SSX-Dependent YAP/TAZ Signaling in Synovial Sarcoma

PURPOSE: Synovial sarcoma is a soft tissue malignancy characterized by a reciprocal t(X;18) translocation. The chimeric SS18-SSX fusion protein acts as a transcriptional dysregulator representing the major driver of the disease; however, the signaling pathways activated by SS18-SSX remain to be elucidated to define innovative therapeutic strategies. EXPERIMENTAL DESIGN: Immunohistochemical evaluation of the Hippo signaling pathway effectors YAP/TAZ was performed in a large cohort of synovial sarcoma tissue specimens. SS18-SSX dependency and biological function of the YAP/TAZ Hippo signaling cascade were analyzed in five synovial sarcoma cell lines and a mesenchymal stem cell model in vitro. YAP/TAZ-TEAD-mediated transcriptional activity was modulated by RNAi-mediated knockdown and the small-molecule inhibitor verteporfin. The effects of verteporfin were finally tested in vivo in synovial sarcoma cell line-based avian chorioallantoic membrane and murine xenograft models as well as a patient-derived xenograft. RESULTS: A significant subset of synovial sarcoma showed nuclear positivity for YAP/TAZ and their transcriptional targets FOXM1 and PLK1. In synovial sarcoma cells, RNAi-mediated knockdown of SS18-SSX led to significant reduction of YAP/TAZ-TEAD transcriptional activity. Conversely, SS18-SSX overexpression in SCP-1 cells induced aberrant YAP/TAZ-dependent signals, mechanistically mediated by an IGF-II/IGF-IR signaling loop leading to dysregulation of the Hippo effectors LATS1 and MOB1. Modulation of YAP/TAZ-TEAD-mediated transcriptional activity by RNAi or verteporfin treatment resulted in significant growth inhibitory effects in vitro and in vivo. CONCLUSIONS: Our preclinical study identifies an elementary role of SS18-SSX-driven YAP/TAZ signals, highlights the complex network of oncogenic signaling pathways in synovial sarcoma pathogenesis, and provides evidence for innovative therapeutic approaches.status: publishe