Evaluation of serological response to anti-SARS-CoV-2 mRNA vaccination in hematological patients.

Introduction: In immunocompromised patients, SARS-CoV-2 mRNA vaccine has been used in Italy from the beginning of the vaccination campaign, but several studies have shown that the serological response of onco-hematological patients was reduced compared to healthy subjects, due to the state of immunosuppression because of both underlying disease and administered therapy. Methods: We evaluated the association of anti-SARS-CoV-2 spike IgG titers in 215 hematological patients with clinical and demographic variables to verify if it was possible to identify predictive parameters of serological response, as well as using a control group, consisting of healthy health workers of San Carlo Hospital in Potenza. Anti-SARS-CoV2 IgG titers were evaluated after 30-45 days post second dose vaccine using chemiluminescent microparticle immunoassay technology. Results: Patients with hematological malignancies, compared with the control arm, had both a mean concentration of anti-SARS-CoV-2 IgG significantly lower and a seroconversion rate numerically lower. All chronic lymphatic leukemia patients showed levels of antibody titer below the mean concentration, also in only clinical surveillance patients. Comparing serological response in hematological malignancies, only acute leukemia patients who were off therapy had the highest seroconversion rate among the patients' cohorts and a mean antibody concentration greater than the control arm. Patients treated with steroids and rituximab showed a lower level of anti-SARS-CoV-2 spike IgG. Differences in anti-spike IgG levels among chronic myeloid leukemia patients stratified according to tyrosine kinase inhibitor therapy and molecular response were observed, and they could have interesting implications on the evaluation of the effects of these drugs on the immune system, but having not reached statistical significance at the moment. The cohort of patients who received a stem cell transplant was very heterogeneous because it included different hematological malignancies and different types of transplant; however, a mean concentration of anti-SARS-CoV2 IgG greater than the control arm was reported. Indeed, among patients who performed a transplant for over 6 months only one had a spike IgG concentration below the cutoff. Conclusions: Our data confirm reduced serological response in hematological patients after anti-SARS-CoV-2 vaccination. However, we found a great diversity of SARS-CoV-2 antibody response according to types of pathologies and therapies.

Prospective assessment of NGS-detectable mutations in CML patients with nonoptimal response: the NEXT-in-CML study.

In chronic myeloid leukemia (CML) patients, tyrosine kinase inhibitors (TKIs) may select for drug-resistant BCR-ABL1 kinase domain (KD) mutants. Although Sanger sequencing (SS) is considered the gold standard for BCR-ABL1 KD mutation screening, next-generation sequencing (NGS) has recently been assessed in retrospective studies. We conducted a prospective, multicenter study (NEXT-in-CML) to assess the frequency and clinical relevance of low-level mutations and the feasibility, cost, and turnaround times of NGS-based BCR-ABL1 mutation screening in a routine setting. A series of 236 consecutive CML patients with failure (n = 124) or warning (n = 112) response to TKI therapy were analyzed in parallel by SS and NGS in 1 of 4 reference laboratories. Fifty-one patients (22 failure, 29 warning) who were negative for mutations by SS had low-level mutations detectable by NGS. Moreover, 29 (27 failure, 2 warning) of 60 patients who were positive for mutations by SS showed additional low-level mutations. Thus, mutations undetectable by SS were identified in 80 out of 236 patients (34%), of whom 42 (18% of the total) had low-level mutations somehow relevant for clinical decision making. Prospective monitoring of mutation kinetics demonstrated that TKI-resistant low-level mutations are invariably selected if the patients are not switched to another TKI or if they are switched to a inappropriate TKI or TKI dose. The NEXT-in-CML study provides for the first time robust demonstration of the clinical relevance of low-level mutations, supporting the incorporation of NGS-based BCR-ABL1 KD mutation screening results in the clinical decision algorithms.

Long-term outcome and prospective validation of NIH response criteria in 39 patients receiving imatinib for steroid-refractory chronic GVHD.

Forty adults aged 28 to 73 years were entered into a prospective trial of imatinib for the treatment of steroid-refractory chronic graft-versus-host disease (SR-cGVHD). After 6 months, intention-to-treat (ITT) analysis of 39 patients who received the drug, regardless of the duration of treatment, revealed 14 partial responses (PR), 4 minor responses (MR) with relevant steroid sparing (46%) according to Couriel criteria, and 20 ≥ PR (51.3%), as per the National Institutes of Health (NIH) criteria and NIH severity score changes. The best responses were seen in the lungs, gut, and skin (35%, 50%, and 32%, respectively). After a median follow-up of 40 months, 28 patients were alive, with a 3-year overall survival (OS) and event-free survival of 72% and 46%, respectively. The 3-year OS was 94% for patients responding at 6 months and 58% for nonresponders according to NIH response, suggesting that these criteria represent a reliable tool for predicting OS after second-line treatment. Monitoring of anti-platelet-derived growth factor receptor (PDGF-R) antibodies showed a significant decrease in PDGF-R stimulatory activity in 7 responders, whereas it remained high in 4 nonresponders. This study confirms the efficacy of imatinib against SR-cGVHD and suggests that the response at 6 months significantly predicts long-term survival.

Plerixafor added to chemotherapy plus G-CSF is safe and allows adequate PBSC collection in predicted poor mobilizer patients with multiple myeloma or lymphoma.

We evaluated the safety and efficacy of plerixafor, subsequent to disease-specific chemotherapy followed by granulocyte-colony stimulating factor (G-CSF), in 37 multiple myeloma (MM) or lymphoma patients, who were candidates for autologous stem cell transplantation (ASCT) predicted as poor mobilizers (PMs). Patients were identified as predicted PMs according to the history of a previously failed mobilization attempt or the presence of ≥1 factors predicting an unsuccessful harvest, such as advanced disease, prior extensive radiotherapy, or prolonged treatment, with stem cell poisons, advanced age, or extensive bone marrow involvement. Plerixafor (0.24 mg/kg) was administered subcutaneously for up to 3 consecutive days while continuing G-CSF for 9 to 11 hours before the planned apheresis. Plerixafor administration was safe and no significant adverse events were recorded. We observed a median 4-fold increase (range: 1.4-32) in the number of circulating CD34(+) cells following plerixafor compared with baseline CD34(+) cell concentration (from a median of 5 cells/µL, range: 1-32, to a median of 32 cells/µL, range: 6-201). Twenty-seven of the 37 patients (14 of 17 with MM and 13 of 20 with lymphoma) had ≥2×10(6) CD34(+) cells/kg collected in 1-3 apheretic procedures. Of the 27 patients rescued with plerixafor, 24 (13 MM, 11 lymphoma) have been transplanted with plerixafor-mobilized peripheral blood stem cells, showing a rapid and durable hematologic recovery. Our results suggest that the addition of plerixafor to G-CSF after disease-oriented chemotherapy is safe and allows for a satisfactory harvest in order to perform a safe ASCT, in a relevant proportion of lymphoma and MM patients considered to be PMs.

Tirosin kinase inhibitors in chronic graft versus host disease: from bench to bedside.

Chronic Graft Versus Host Disease (cGVHD) is a major complication of allogeneic stem-cell transplantation (SCT). In many inflammatory fibrotic diseases, such as Systemic Scleroderma (SSc) and cGVHD with fibrotic features, an abnormal activation of transforming growth factor (TGFß) and platelet-derived growth factor receptor (PDGF-R) pathways have been observed. Tyrosin Kinase Inhibitors (TKIs), which are currently used for treatment of patients with Chronic Myeloid Leukemia (CML), share potent antifibrotic and antiinflammatory properties, being powerful dual inhibitors of both PDGF-R and TGFß pathways. Moreover accumulating in vitro data confirm that TKIs, interacting with the TCR and other signalling molecules, carry potent immunomodulatory effects, being involved in both T-cell and B-cell response. Translation to the clinical setting revealed that treatment with Imatinib can achieve encouraging responses in patients with autoimmune diseases and steroid-refractory cGVHD, showing a favourable toxicity profile. While the exact mechanisms leading to such efficacy are still under investigation, use of TKIs in the context of clinical trials should be promoted, aiming to evaluate the biological changes induced in vivo by TKIs and to assess the long term outcome of these patients. Second-generation TKIs, with more favourable toxicity profile are under evaluation in the same setting.

The tyrosine kinase inhibitor ZD6474 blocks proliferation of RET mutant medullary thyroid carcinoma cells.

Oncogenic conversion of the RET tyrosine kinase is a frequent feature of medullary thyroid carcinoma (MTC). ZD6474 (vandetanib) is an ATP-competitive inhibitor of RET, epidermal growth factor receptor (EGFR), and vascular endothelial growth factor receptors kinases. In this study, we have studied ZD6474 mechanism of action in TT and MZ-CRC-1 human MTC cell lines, carrying cysteine 634 to tryptophan (C634W) and methionine 918 to threonine (M918T) RET mutation respectively. ZD6474 blunted MTC cell proliferation and RET, Shc and p44/p42 mitogen-activated protein kinase (MAPK) phosphorylation. Single receptor knockdown by RNA interference showed that MTC cells depended on RET for proliferation. Adoptive expression of the ZD6474-resistant V804M RET mutant rescued proliferation of TT cells under ZD6474 treatment, showing that RET is a key ZD6474 target in these MTC cells. Upon RET inhibition, adoptive stimulation of EGFR partially rescued TT cell proliferation, MAPK signaling, and expression of cell-cycle-related genes. This suggests that simultaneous inhibition of RET and EGFR by ZD6474 may overcome the risk of MTC cells to escape from RET blockade through compensatory over-activation of EGFR.