The direct and legacy effects of drying-rewetting cycles on active and relatively resistant soil carbon decomposition

Global climate change is expected to increase the frequency of drought and heavy precipitation, which could create more frequent drying-rewetting cycles (DWC) in the soils. Although DWC effects on SOC decomposition has been widely studied, the effect of DWC and the subsequent legacy effect on the decomposition of different SOC pools is still unclear. We conducted a 128-d laboratory incubation to investigate the DWC effects by using soils from old-field for 15 years (OF, representing active SOC), bare-fallow for 15 years (BF), and bare-fallow for 23 years plus extra 815-d incubation (BF+, representing relatively resistant SOC). The experiment included nine 10-d DWC of three treatments: 1) constant-moisture at 60% WHC, 2) mild DWC with 10-d drying to 40% WHC and rewetting to 80% WHC, and 3) strong DWC with 10-d drying to 20% WHC and rewetting to 100% WHC. Following DWC period, there was a 10-d stabilization period (adjusting all treatments to 60% WHC), and then a 28-d extended incubation. During DWC period, the strong DWC had strong effect on CO2 release compared with the constant-moisture control, reducing the SOC decomposition from OF by 8% and BF by 10%, while increasing the SOC decomposition of BF+ by 16%. During extended period, both mild and strong DWC significantly increased SOC mineralization of OF, but decreased that of BF and BF+. This legacy effect compensated the changes in CO2 release during DWC period, resulting in the minor response of SOC decomposition of OF and BF+ to the DWC during the entire incubation.

Azacitidine (AZA) for Patients with Vexas and Myelodysplastic Syndrome (MDS): Data from the French Vexas Registry

Background MDS are associated in 10% to 25% of the cases with systemic inflammatory or auto-immune diseases (SIAD). The management of SIADs in this context includes glucocorticoids and biologics with variable response rates, but we and others found that hypomethylating agents, especially azacytidine (AZA), can have some efficacy in SIADs associated with lower risk MDS (Fraison, J.-B. et al. Leuk. Res. 43, 13-17 (2016).). The recently described VEXAS syndrome (Vacuoles, E1 Enzyme, X-linked, Autoinflammatory, Somatic syndrome) (Beck et al, NEJM 2020) an autoinflammatory disease characterized by somatic mutation of the UBA1 gene, is often associated with hematological disorders, especially MDS, and its treatment is often unsuccessful Based on a French nationwide registry of patients with VEXAS syndrome, we described the efficacy and safety of AZA in VEXAS syndrome patients with concomitant MDS. Patients A French nationwide registry of 116 patients with VEXAS syndrome was established in Jan 2021. We collected in this registry patient cases with concomitant MDS (according to WHO 2016) who received at least 1 full cycle of AZA (5 to 7 days). Major response of autoinflammatory disease to AZA was defined by at least 50% steroids dose reduction to less than 10 mg/day during at least one month, and minor response by at least 50% steroid dose reduction but to > 10 mg/day, during at least one month. Results Of the 58 patients with concomitant MDS included in the French VEXAS registry, 11 had received at least 1 cycle of AZA. All patients were males and median age was 64 (range 54-73), WHO : MDS MLD (n=6) , MDS SLD (n=1), MDS EB1 (n=4) ) ,R-IPSS low (n=7), intermediate (n=3) high (n=1). Median time from MDS diagnosis to AZA onset was 8 (range 0-88) months. VEXAS phenotype mostly included skin lesions (100%), fever (91%) and constitutional symptoms (91%). All patients, except one, were steroid dependent at AZA onset. In addition to steroids, patients had received a median of 1 immunosuppressive treatment (IST) (range 0-6). The median number of AZA cycles was 11 (range 2-35). Median follow up from AZA onset was 32 months (range 12-75). Five (46%) patients discontinued AZA before the end of follow-up, after 2 to 10 cycles due to failure (n=4) and persistent response after 6 cycles (n=1). Response of autoinflammatory disease to AZA was achieved in 5 patients (45%) including major response in 2 patients, and minor response in 3, while 6 patients had no response. Best response was observed after 4 cycles (n=4) and after 6 cycles (n=1). In responders, prednisone could be discontinued in 1 patient. Duration of response was 6, 8+, 12, 21, 27+ months (Median 16.5). Three of the 5 responders subsequently received another IST. Of 10 anemic and 5 thrombocytopenic patients,3 obtained erythroid and 2 obtained platelet response, respectively (IWG 2006 criteria). Two patients experienced serious adverse events during AZA treatment, including pneumocystis pneumonia (n=1), severe colitis and bacterial pneumonia (n=1). Conclusions Our results, in a limited patient number, suggest that AZA can improve auto inflammatory symptoms in 45% of patients with VEXAS syndrome and underlying MDS, allowing decrease or even discontinuation of steroids, during a median time > 1 year, with concomitant hematological response in about 50% of the cases and limited side effects. A prospective study with more patients will be needed to confirm those results. Disclosures Comont: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees; Takeda: Speakers Bureau. Riviere: Octapharma: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees. Terriou: Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Terrier: LFB: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Membership on an entity's Board of Directors or advisory committees. Georgin-Lavialle: Novartis: Membership on an entity's Board of Directors or advisory committees; Soby: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Fenaux: Syros Pharmaceuticals: Honoraria; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding.

CTNI-06. TRAM-01: A PHASE 2 STUDY OF TRAMETINIB FOR PATIENTS WITH PEDIATRIC GLIOMA WITH ACTIVATION OF THE MAPK/ERK PATHWAY

BACKGROUND Pediatric low-grade gliomas (PLGG) are the most frequent brain tumors in children. It is known that the majority of PLGG have activation of the MAPK/ERK pathway. METHODS This ongoing multicenter phase II trial includes three progressing/refractory PLGG groups: NF1 patients, KIAA1549-BRAF fusion patients and patients with other activation of the MAPK/ERK pathway (excluding V600E). The primary objective was to evaluate the overall response rate based on RANO criteria after daily oral trametinib administration for 18 cycles, lasting 28 days each. Secondary objectives include the assessment of progression-free survival, tolerability of trametinib, serum levels of trametinib and quality of life evaluation during treatment. RESULTS As of February 12 2021, 50 patients have been enrolled (NF1: n=10; KIAA1549-BRAF fusion: n=31; other: n=9 including 5 patients with FGFR1 alterations). Median age is 8.8 years (range 2.4-25.5). Median follow-up is 17.5 months (range 4.7-28.5). Forty-three patients are evaluable. The overall response includes: 4 partial response (PR) (9%), 18 minor response (MR) (42%), 17 stable disease (40%), 4 progressive disease (9%). Median time to response is 5.5 months (range 2.4-13.8). Median duration of response is 6.1 months (range 0.6-26.5). Progression free survival at 12 months is 79.9% (95% CI 68.5-93.6%) and median progression free survival has not yet been reached. Treatment was discontinued for 30 patients: 16 after completing 18 cycles as planned, 5 for progressive disease, 5 for adverse events, 4 for other reasons. A total of 8 patients progressed after discontinuation of treatment including 6 patients (37.5%) that completed 18 cycles. Five of these patients had achieved minor response prior to discontinuation. CONCLUSION Trametinib is a potentially effective targeted therapy for patients with recurrent/refractory PLGG. Treatment was overall well tolerated. This ongoing trial will continue to gather data on response rate, duration of response and safety of trametinib for PLGG.

A Simple Fluorescent Aptasensing Platform Based on Graphene Oxide for Dopamine Determination

Dopamine (DA) is a catecholamine neurotransmitter playing an important role in different biological functions including central nervous, renal, cardiovascular, and hormonal systems. The sensitive and selective detection of this neurotransmitter plays a key role in the early diagnosis of various diseases related to abnormal levels of dopamine. Therefore, it is of great importance to explore rapid, simple, and accurate methods for detection of dopamine with high sensitivity and specificity. We propose in this work, a fluorescent aptasensor based on graphene oxide (GO) as a quencher, for the rapid determination of dopamine. The principle of this aptasensor is based on fluorescence resonance energy transfer (FRET), where GO was used as energy donor, and a carboxyfluorescein (FAM)-labeled aptamer as acceptor. In the absence of DA, FAM-aptamer was adsorbed on the surface of GO through π-π stacking interactions between nucleotide bases and the carbon network, leading to a weak FRET and a quenching of the FAM fluorescence. However, by adding the target, the aptamer undergoes a conformational change to bind to DA with high affinity, resulting in a fluorescence recovery. Under the optimal experimental conditions, the fluorescence recovery was linearly proportional to the concentration of DA in the range of 3-1680 nM, with a limit of detection of 0.031 nM. Moreover, the developed assay exhibited minor response in the presence of various interferents and it revealed a satisfactory applicability in human serum samples.

SYST-04. TRAM-01: A PHASE 2 STUDY OF TRAMETINIB FOR PATIENTS WITH PEDIATRIC GLIOMA WITH ACTIVATION OF THE MAPK/ERK PATHWAY

BACKGROUND Pediatric low-grade gliomas (PLGG) are the most frequent brain tumors in children. It is known that the majority of PLGG have activation of the MAPK/ERK pathway. METHODS This ongoing multicenter phase II trial includes three progressing/refractory PLGG groups: NF1 patients, KIAA1549-BRAF fusion patients and patients with other activation of the MAPK/ERK pathway (excluding V600E). The primary objective was to evaluate the overall response rate based on RANO criteria after daily oral trametinib administration for 18 cycles, lasting 28 days each. Secondary objectives include the assessment of progression-free survival, tolerability of trametinib, serum levels of trametinib and quality of life evaluation during treatment. RESULTS As of February 12 2021, 50 patients have been enrolled (NF1: n=10; KIAA1549-BRAF fusion: n=31; other: n=9 including 5 patients with FGFR1 alterations). Median age is 8.8 years (range 2.4-25.5). Median follow-up is 17.5 months (range 4.7-28.5). Forty-three patients are evaluable. The overall response includes: 4 partial response (PR) (9%), 18 minor response (MR) (42%), 17 stable disease (40%), 4 progressive disease (9%). Median time to response is 5.5 months (range 2.4-13.8). Median duration of response is 6.1 months (range 0.6-26.5). Progression free survival at 12 months is 79.9% (95% CI 68.5-93.6%) and median progression free survival has not yet been reached. Treatment was discontinued for 30 patients: 16 after completing 18 cycles as planned, 5 for progressive disease, 5 for adverse events, 4 for other reasons. A total of 8 patients progressed after discontinuation of treatment including 6 patients (37.5%) that completed 18 cycles. Five of these patients had achieved minor response prior to discontinuation. CONCLUSION Trametinib is a potentially effective targeted therapy for patients with recurrent/refractory PLGG. Treatment was overall well tolerated. This ongoing trial will continue to gather data on response rate, duration of response and safety of trametinib for PLGG.

Long-term follow-up of ibrutinib monotherapy in treatment-naive patients with Waldenstrom macroglobulinemia

Herein, we present the final report of a single-center, prospective phase II study evaluating ibrutinib 420 mg once daily in 30 treatment-naive patients with Waldenstrom macroglobulinemia (WM). The present study is registered with ClinicalTrials.Gov (NCT02604511). With a median follow-up of 50 months, the overall, major, and VGPR response rates were 100%, 87%, and 30%. The VGPR rate was numerically but not significantly lower in patients with than without CXCR4 mutations (14% vs. 44%; p = 0.09). The median time to a minor response was 0.9 months, and to a major response was 1.9 months, though were longer in those with mutated CXCR4 at 1.7 months (p = 0.07) and 7.3 months (p = 0.01). Six patients had disease progression. The median progression-free survival (PFS) was not reached, and the 4-year PFS rate was 76%. There was also a non-significant lower 4-year PFS rate in patients with than without CXCR4 mutations (59% vs. 92%; p = 0.06). The most common treatment-related adverse events were fatigue, upper respiratory infection, and hematoma. Atrial fibrillation occurred in 20% of patients. Ibrutinib monotherapy induced durable responses in treatment-naive patients with WM. CXCR4 mutations impacted VGPR attainment, time to major response, and 4-year PFS rate.

Sensitivity of Photosynthesis to Warming in Two Similar Species of the Aquatic Angiosperm Ruppia from Tropical and Temperate Habitats

Climate change-related events, such as marine heatwaves, are increasing seawater temperatures, thereby putting pressure on marine biota. The cosmopolitan distribution and significant contribution to marine primary production by the genus Ruppia makes them interesting organisms to study thermal tolerance and local adaptation. In this study, we investigated the photosynthetic responses in Ruppia to the predicted future warming in two contrasting bioregions, temperate Sweden and tropical Thailand. Through DNA barcoding, specimens were determined to Ruppia cirrhosa for Sweden and Ruppia maritima for Thailand. Photosynthetic responses were assessed using pulse amplitude-modulated fluorometry, firstly in short time incubations at 18, 23, 28, and 33 °C in the Swedish set-up and 28, 33, 38, and 43 °C in the Thai set-up. Subsequent experiments were conducted to compare the short time effects to longer, five-day incubations in 28 °C for Swedish plants and 40 °C for Thai plants. Swedish R. cirrhosa displayed minor response, while Thai R. maritima was more sensitive to both direct and prolonged temperature stress with a drastic decrease in the photosynthetic parameters leading to mortality. The results indicate that in predicted warming scenarios, Swedish R. cirrhosa may sustain an efficient photosynthesis and potentially outcompete more heat-sensitive species. However, populations of the similar R. maritima in tropical environments may suffer a decline as their productivity will be highly reduced.

Combining Ixazomib With Subcutaneous Rituximab and Dexamethasone in Relapsed or Refractory Waldenström's Macroglobulinemia: Final Analysis of the Phase I/II HOVON124/ECWM-R2 Study

PURPOSE Proteasome inhibitors are effective in Waldenström's macroglobulinemia (WM) but require parenteral administration and are associated with polyneuropathy. We investigated efficacy and toxicity of the less neurotoxic oral proteasome inhibitor ixazomib combined with rituximab, in patients with relapsed WM. METHODS We conducted a multicenter phase I/II trial with ixazomib, rituximab, and dexamethasone (IRD). Induction consisted of eight cycles IRD wherein rituximab was started in cycle 3, followed by rituximab maintenance. Phase I showed feasibility of 4 mg ixazomib. Primary end point for phase II was overall response rate (ORR [≥ minimal response]) after induction. RESULTS A total of 59 patients were enrolled (median age, 69 years; range, 46-91 years). Median number of prior treatments was 2 (range 1-7); 70% had an intermediate or high WM-IPSS (International Prognostic Scoring System for WM) score. After eight cycles, ORR was 71% (42 out of 59) (14% very good partial response [PR], 37% PR, and 20% minor response). Depth of response improved until month 12 (best ORR 85% [50 out of 59]: 15% very good PR, 46% PR, and 24% minor response). Median duration of response was 36 months. The average hematocrit level increased significantly (0.33-0.38 L/L) after induction ( P < .001). After two cycles of ixazomib and dexamethasone, immunoglobulin M levels decreased significantly (median 3,700-2,700 mg/dL, P < .0001). Median time to first response was 4 months. Median progression-free survival and overall survival were not reached. After median follow-up of 24 months (range, 7.4-54.3 months), progression-free survival and overall survival were 56% and 88%, respectively. Toxicity included mostly grade 2 or 3 cytopenias, grade 1 or 2 neurotoxicity, and grade 2 or 3 infections. No infusion-related reactions or immunoglobulin M flare occurred with use of subcutaneous rituximab. Quality of life improved significantly after induction. In total, 48 patients (81%) completed at least six cycles of IRD. CONCLUSION Combination of IRD shows promising efficacy with manageable toxicity in patients with relapsed or refractory WM.

Single-Agent Oral Vinorelbine in the Treatment of Pediatric Progressive Optic Pathway Glioma: A Single Institutional Experience

Purpose: The vinca alkaloids’ activity against pediatric low-grade glioma (PLGG) is well established. The goal of the present study is to describe our experience with oral vinorelbine in patients with progressive optic pathway glioma (OPG), not only regarding the clinical response, but also the cost benefit using an oral medication. Methods: Patients under 21 years of age with unresectable and/or progressive OPG were eligible. Oral vinorelbine was administered at a dose of 90mg/m2 daily on days 0, 8 and 22, in a scheme of 4 weekly cycles for a total of 18 cycles (54 doses). Results: From 2013 to 2018, sixteen patients were enrolled onto the study, with a median age of 9,1 years (range 4,6-17,8y). The most common histology was pilocytic astrocytoma (88,8%). Best response to chemotherapy was reviewed with a response rate (complete, partial, or minor response) of 30% for the patients treated exclusively with the oral drug. Five-year event-free survival (EFS) rate was 43.4%. Six patients had to change to intravenous vinorelbine due to gastrointestinal toxicity, vomiting grade III. None of the patients showed neurotoxicity. The total cost including drug acquisition, administration and toxicity management was lower with the oral formulation comparing to IV one. Conclusion: Single-agent oral vinorelbine seems to have some clinical activity in the management of recurrent or refractory pediatric OPG, being an interesting and cost-effective option, minding that gastrointestinal toxicity may be limiting and a combination of antiemetics should be considered in this treatment regimen.

Randomized Phase II Trial of MIBG Versus MIBG, Vincristine, and Irinotecan Versus MIBG and Vorinostat for Patients With Relapsed or Refractory Neuroblastoma: A Report From NANT Consortium

PURPOSE 131I-metaiodobenzylguanidine (MIBG) is an active radiotherapeutic for neuroblastoma. The primary aim of this trial was to identify which of three MIBG regimens was likely associated with the highest true response rate. PATIENTS AND METHODS Patients 1-30 years were eligible if they had relapsed or refractory neuroblastoma, at least one MIBG-avid site, and adequate autologous stem cells. Patients received MIBG 18 mCi/kg on day 1 and autologous stem cell on day 15. Patients randomly assigned to arm A received only MIBG; patients randomly assigned to arm B received intravenous vincristine on day 0 and irinotecan daily on days 0-4; patients randomly assigned to arm C received vorinostat (180 mg/m2/dose) orally once daily on days 1 to 12. The primary end point was response after one course by New Approaches to Neuroblastoma Therapy criteria. The trial was designed with 105 patients to ensure an 80% chance that the arm with highest response rate was selected. RESULTS One hundred fourteen patients were enrolled, with three ineligible and six unevaluable, leaving 105 eligible and evaluable patients (36 in arm A, 35 in arm B, and 34 in arm C; 55 boys; and median age 6.5 years). After one course, the response rates (partial response or better) on arms A, B, and C were 14% (95% CI, 5 to 30), 14% (5 to 31), and 32% (18 to 51). An additional five, five, and four patients met New Approaches to Neuroblastoma Therapy Minor Response criteria on arms A, B, and C, respectively. On arms A, B, and C, rates of any grade 3+ nonhematologic toxicity after first course were 19%, 49%, and 35%. CONCLUSION Vorinostat and MIBG is likely the arm with the highest true response rate, with manageable toxicity. Vincristine and irinotecan do not appear to improve the response rate to MIBG and are associated with increased toxicity.