Positive Minimal Residual Disease Research Articles

B-227 Customized molecular tests for minimal residual disease: a tool for therapeutic decisions in follicular lymphoma patients

Abstract Background Monitoring of minimal residual disease (MRD) is based on accurate laboratory tests which can recognize a small fraction of malignant cells that survived the course of treatment. Several studies of the B-non-Hodgkin lymphoma group have been presented that MRD positivity at the end of treatment is a negative prognostic index. Follicular lymphoma (FL) is a chronic indolent malignancy, which response highly to immuno-chemotherapy followed by prolonged remissions but with inevitable relapse in most patients. The GALLIUM study showed that immuno-chemotherapy combinations, 6 cycles of bendamustine-obinutuzumab (BO), is the most efficacious treatment, but with severe side effects .In addition, 90% of patients achieved negative MRD from peripheral blood (PB) or bone marrow (BM) after only 3 BO cycles. These findings raise the possibility for MRD based treatment approach, where the duration of chemotherapy could be decided according to MRD status at mid-induction (MI). Identification of a marker in the PB and/or BM of each FL patient which will be use to the design of a sensitive RQ-PCR test for MRD detection for follow-up. Methods Qualitative PCR for translocation 14:18 and for the VDJ rearrangement sequence of the immunoglobulin heavy chain was used for marker identification. MRD monitoring was done by RQ-PCR. MRD monitoring for VDJ was designed specifically to each patients based on his VDJ sequence. MRD was assessed on PB and BM at MI. Results Marker for monitoring was identified at 11/21 patients in this study. After 3 combined therapy cycles, 7 patients were found to have MRD negativity by RQ-PCR therefore continue with immuno-therapy only. MRD positivity was assessed in BM of 3 patients (0.11%, 0.022%, and 0.133%). These 3 patients continued with the combined therapy. RQ-PCR sensitivity was 10-4-10-5. Conclusions This study will reveal the ability to use sensitive and specific MRD that has to be designed for each patient according to his marker and enable the establishment of a treatment with a high safety profile for FL patients. Correlation between MRD status and clinical and safety parameters will be assessed at the end of the study, 30 months after the first treatment, taking into account MRD status from different time point of the follow-up period.

Allogeneic Hematopoietic Cell Transplantation With Reduced Toxicity Conditioning for Pediatric B Lymphoid Malignancy.

Conventional conditioning regimens for children with lymphoid malignancy undergoing allogeneic hematopoietic cell transplantation (HCT) are myeloablative and involve high-dose total body irradiation (TBI). Such regimens are associated with significant late complications. Here, we used a reduced-toxicity conditioning regimen comprising fludarabine, cytarabine, melphalan, and low-dose TBI (FLAMEL) to treat 5 patients with lymphoid malignancy before HCT. Four patients maintained complete remission (range, 18 to 63mo), whereas the remaining patient who had positive minimal residual disease (MRD) before HCT relapsed. FLAMEL might be a suitable conditioning regimen for children with lymphoid malignancy if pre-HCT MRD is negative.

Haploidentical versus Cord Blood Transplantation in Pediatric AML. A Retrospective Outcome Analysis on Behalf of the Pediatric Subcommittee of GETH (Grupo Español de Trasplante Hematopoyético)

Haploidentical stem cell transplantation (Haplo-SCT) and cord blood transplantation (CBT) are both effective alternative treatments in patients suffering from acute myeloid leukemia (AML) and lacking a matched HLA donor. In the last years, many centers have abandoned CBT procedures mostly due to concern about poorer immune recovery compared with Haplo-SCT. We conducted a retrospective multicenter study comparing the outcomes using both alternative approaches in AML. A total of 122 transplants (86 Haplo-SCTs and 36 CBTs) from 12 Spanish centers were collected from 2007 to 2021. Median age at hematopoietic stem cell transplantation (HSCT) was 7 years (0.4-20). Thirty-nine patients (31.9%) showed positive minimal residual disease (MRD) at HSCT and a previous HSCT was performed in 37 patients (30.3%). The median infused cellularity was 14.4 × 106/kg CD34+ cells (6.0-22.07) for Haplo-SCT and 4.74 × 105/kg CD34+ cells (0.8-9.4) for CBT. Median time to neutrophil engraftment was 14 days (7-44) for Haplo-SCT and 17 days (8-29) for CBT (P = .03). The median time to platelet engraftment was 14 days (6-70) for Haplo-SCT and 43 days (10-151) for CBT (P < .001). Graft rejection was observed in 13 Haplo-SCTs (15%) and in 6 CBTs (16%). The cumulative incidence of acute graft versus host disease (GvHD) grades II-IV was 54% and 51% for Haplo-SCT and CBT, respectively (P = .50). The cumulative incidence of severe acute GvHD (grades III-IV) was 22% for Haplo-SCT and 25% for CBT (P = .90). There was a tendency to a higher risk of chronic GvHD in the Haplo-SCT group being the cumulative incidence of 30% for Haplo-SCT and 12% for CBT (P = .09). The cumulative incidence of relapse was 28% and 20% for Haplo-SCT and CBT, respectively (P = .60). We did not observe statistically significant differences in outcome measures between Haplo-SCT and CBT procedures: 5-year overall survival (OS) was 64% versus 57% (P = .50), 5-year disease-free survival (DFS) 58% versus 57% (P = .80), GvHD-free and relapse-free survival (GFRFS) 41% versus 54% (P = .30), and cumulative incidence of transplant-related mortality (TRM) 14% versus 15% (P = .80), respectively. In the multivariate analysis, MRD positivity and a disease status >CR1 at the time of HSCT were significantly associated with poorer outcomes (P < .05). In conclusion, our study supports that both haploidentical and cord blood transplantation show comparable outcomes in pediatric AML patients. We obtained comparable survival rates, although CBT showed a trend to lower rates of chronic GvHD and higher GFRFS, demonstrating that it should still be considered a valuable option, particularly for pediatric patients.

Risk factors for recurrence of childhood acute lymphoblastic leukemia after treatment with the Chinese Children's Cancer Group ALL-2015 protocol

To investigate the cumulative incidence of recurrence (CIR) in children with acute lymphoblastic leukemia (ALL) after treatment with the Chinese Children's Cancer Group ALL-2015 (CCCG-ALL-2015) protocol and the risk factors for recurrence. A retrospective analysis was conducted on the clinical data of 852 children who were treated with the CCCG-ALL-2015 protocol from January 2015 to December 2019. CIR was calculated, and the risk factors for the recurrence of B-lineage acute lymphoblastic leukemia (B-ALL) were analyzed. Among the 852 children with ALL, 146 (17.1%) experienced recurrence, with an 8-year CIR of 19.8%±1.6%. There was no significant difference in 8-year CIR between the B-ALL group and the acute T lymphocyte leukemia group (P>0.05). For the 146 children with recurrence, recurrence was mainly observed in the very early stage (n=62, 42.5%) and the early stage (n=46, 31.5%), and there were 42 children with bone marrow recurrence alone (28.8%) in the very early stage and 27 children with bone marrow recurrence alone (18.5%) in the early stage. The Cox proportional-hazards regression model analysis showed that positive MLLr fusion gene (HR=4.177, 95%CI: 2.086-8.364, P<0.001) and minimal residual disease≥0.01% on day 46 (HR=2.013, 95%CI: 1.163-3.483, P=0.012) were independent risk factors for recurrence in children with B-ALL after treatment with the CCCG-ALL-2015 protocol. There is still a relatively high recurrence rate in children with ALL after treatment with the CCCG-ALL-2015 protocol, mainly bone marrow recurrence alone in the very early stage and the early stage, and minimal residual disease≥0.01% on day 46 and positive MLLr fusion gene are closely associated with the recurrence of B-ALL.

Prognostic significance of ctDNA mutation analysis in patients with HER2-positive breast cancer undergoing neoadjuvant chemotherapy.

e12654 Background: Neoadjuvant chemotherapy (NACT) combined with dual anti-HER2 agents followed by surgical resection is the standard treatment for stage II-III HER2- positive breast cancer (BC). Despite the availability of effective therapies such as ado-trastuzumab emtansine (T-DM1) and neratinib, identifying patients at high risk of disease recurrence remains challenging. To evaluate whether circulating tumor DNA (ctDNA) can be used as a biomarker to assess treatment response in patients with HER2-positive EBC treated with neoadjuvant anti-HER2 therapy. ctDNA burden can serve as a useful determinant for escalating or de-escalating (neo)adjuvant strategy in EBC patients. This study aimed to assess the role of ctDNA mutation analysis using low-pass whole-genome sequencing (lpWGS) and whole exome sequencing (WES) in evaluating blood copy-number burden (bCNB), genomic alterations, mutational signatures, blood tumor mutational burden (bTMB), and minimal residual disease (MRD) monitoring. Methods: A total of 46 HER2-positive BC patients who underwent NACT combined with dual anti-HER2 agents and surgical resection were enrolled, including 28 clinical stage II and 17 III patients. Plasma samples were collected at four time points: before NACT, after 3 cycles, at the completion of NACT, and after surgery. lpWGS was utilized to assess bCNB, while WES was performed to evaluate genomic alterations, mutational signatures, and bTMB. Mutations selected from the baseline sample were monitored for MRD. In cases where lpWGS yielded negative results, targeted NGS sequencing was conducted. Somatic mutations are identified by whole exome sequencing across 20,000 genes (with boosted sequencing coverage for 600 cancer-related genes). Between 4-50 personalized somatic mutations or fusions are selected for each patient. This personalized panel together with a fixed MRD core panel is utilized for MRD detection and monitoring. Results: Among the enrolled patients, nodal metastasis was observed in 29 patients and 29 were hormone receptor-positive, and 36 achieved pCR (78.2%). Positive ctDNA was detected 58.8% of patients. Higher nodal stage was associated with ctDNA positivity at baseline. MRD positivity after chemotherapy was observed in 4 patients and 2 patients achieved pCR TP53 was the most frequently altered gene, followed by PIK3CA, MAP3K1, REV3L, MYC, MAP2K4, ERBB3, ATRX, ATM and ALK. This pattern is comparable to that observed in previous studies on BC. Non-PCR patients commonly exhibit MAP3K1 and MAP2K4 alteration is their ctDNA. Conclusions: The identification of MRD, regardless of pCR status, can be valuable for risk stratification and personalized treatment decision-making. Further studies are warranted to validate these findings and explore the clinical implications of ctDNA mutation analysis in HER2-positive BC management.

Correlation of circulating tumor DNA and recurrence in patients with metastatic colorectal cancer with no evidence of disease: An open-label, prospective, phase II study.

3549 Background: Patients with metastatic colorectal cancer (mCRC) can achieve no evidence of disease (NED) after curative treatment. However, how to precisely guide the treatment after NED remained to be explored. Minimal residual disease (MRD) detection using circulating tumor DNA (ctDNA) analysis has shown to help identify patients’ risk of relapse in early-stage CRC. Thus we aimed to explore the feasibility of ctDNA by a tumor-informed personalized approach to predict recurrence and guide chemotherapy in mCRC with NED. Methods: We enrolled mCRC patients who achieved NED after local curative treatment from June 2022 to December 2023. Surgical or puncture tissues were collected. Blood samples were collected prior to curative treatment, at 1 month after curative treatment, and subsequently every 2–3 months until disease progression or completion of a 2-year follow-up period. Tumor-derived variants were identified by whole-exon sequencing of the tissue samples. Up to 50 highly ranked variants were selected for the personalized panel design, which was used to assess the MRD status of blood samples. Patients with negative MRD post curative treatment were followed, while those with positive MRD were subjected to investigator-determined adjuvant chemotherapy (ACT). Results: A total of 106 mCRC patients with NED after curative treatment were enrolled. The ctDNA was detected in 62 patients (92.5%, 62/67) pre curative treatment and in 55 patients (51.9%, 55/106) post curative treatment. At a median follow-up period of 252 days, 42 patients experienced recurrence and 33 patients (78.6%) had positive ctDNA post curative treatment. Patients with positive ctDNA post curative treatment demonstrated an inferior recurrence-free survival (RFS) than those with negative ctDNA (HR: 4.58, 95% CI: 2.18–9.64; P&lt;0.001), which was not observed by CEA (HR: 1.87, 95% CI: 0.84–4.15; P=0.12). In patients with negative ctDNA after curative treatment, there was no difference in RFS between those treated with ACT or not (HR: 2.51, 95% CI: 0.48–13.04; P=0.25). During the dynamic longitudinal monitoring of ctDNA, the median RFS was 5.6 months, 15.5 months, 10.2 months and unreached in patients with persistently positive ctDNA, converted negative ctDNA, converted positive ctDNA, and persistently negative ctDNA, respectively (log-rank P for trend &lt;0.001). All recurrent patients had at least one positive ctDNA detection before imaging confirmed recurrence, and the median lead time interval of ctDNA positivity to radiographic recurrence was 112 days (range, 3–441 days). Conclusions: Our results demonstrated that patients with ctDNA negative post curative treatment had superior RFS compared with those with positive ctDNA. Post curative treatment and dynamic ctDNA had the potential to guide ACT in mCRC patients with NED. The follow-up is still on-going. Clinical trial information: NCT05635630 .

Evolution of tisagenlecleucel use for the treatment of pediatric and young adult relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL): Center for International Blood &amp; Marrow Transplant Research (CIBMTR) registry results.

10016 Background: Tisagenlecleucel is an autologous CD19-directed chimeric antigen receptor (CAR) T-cell immunotherapy indicated for patients (pts) up to 25 y of age with B-ALL that is refractory or in second or later relapse. Since the pivotal ELIANA trial, pt characteristics now include pts &lt; 3 y, pts with isolated central nervous system relapse, and pts with leukemia burden &lt; 5%. Here we examine the impact of tisagenlecleucel on the pt treatment journey since FDA approval in 2017. Methods: Data were collected as a part of a noninterventional, prospective, longitudinal study using the CIBMTR registry. Pts were treated in the United States, Canada, Korea, or Taiwan. Results: As of May 4, 2023, 974 pts received tisagenlecleucel. Primary disease history has evolved since 2017. Notably, disease burden prior to infusion has decreased (≥50% blasts: 18% in 2018, 4% in 2022) and a higher proportion of pts received tisagenlecleucel while in morphological complete remission (34% in 2018, 51% in 2022). Between 2018 and 2022, the proportion of pts who were in third or greater relapse decreased (14% vs 2%, respectively). Pts ≥18 y had more prior exposure to blinatumomab and inotuzumab compared with pts &lt; 18 y: 27% vs 16% and 17% vs 7%, respectively. The proportion of pts undergoing ≥1 hematopoietic stem cell transplantation (HSCT) before tisagenlecleucel infusion decreased (37% in 2018, 15% in 2022), coinciding with the use of tisagenlecleucel in earlier lines of therapy. Reporting of B-cell recovery was suboptimal. In total, 34.5% (314/911) of pts received postinfusion HSCT (reasons for HSCT were not captured for most pts); 8.5% (77/911) of pts received postinfusion HSCT to treat relapse, persistent/progressive disease, or positive minimal residual disease. Although the overall rate of postinfusion HSCT did not change, pts with high-risk cytogenetics showed a decrease in HSCT frequency. Previously, most pts &lt; 3 y with KMT2A rearrangement received a HSCT. Since 2017, only 16% (12/75) of pts &lt; 3 y received a prior HSCT despite 72% (54/75) having a KMT2A rearrangement. Furthermore, of the pts with rearrangement, only 43% (23/53) received a HSCT postinfusion. With censoring for HSCT, median RFS improved: 18 mo in 2018, 27 mo in 2020, and not estimable in 2021. OS was not substantially affected by HSCT censoring; 36-mo probabilities (95% CI) with and without censoring were 66 (61-71) and 62 (57-66), respectively. Conclusions: Pediatric and young adult pts with r/r B-ALL are receiving tisagenlecleucel earlier in the course of their disease treatment, reducing the use of HSCT for r/r disease, and prolonging RFS. As both real-world and clinical trial data supporting the curative potential of tisagenlecleucel grow, the use of HSCT in pts with remission after CAR-T should be carefully evaluated.

Personalized circulating tumor (ct)DNA for monitoring disease status in HPV-negative head and neck squamous cell carcinoma.

6056 Background: Highly sensitive minimal residual disease (MRD) assays using circulating tumor (ct)DNA have broad clinical potential and are impacting cancer care. Circulating human papillomavirus (HPV) DNA has emerged as a biomarker of occult MRD among patients (pts) with HPV+ oropharyngeal cancers, but most head and neck squamous cell carcinomas (HNSCC) are not virally driven. Despite multimodality therapy, nearly half of pts with locoregionally advanced HPV-negative HNSCC relapse. As ctDNA has the potential to identify MRD, predict outcomes, and guide treatment for these pts, we performed a retrospective cohort study to evaluate the performance of a custom-built, clinically and commercially available ctDNA assay for this population. Methods: Pts with newly diagnosed HPV-negative HNSCC (all mucosal sites) treated at a single academic institution with pre-treatment ctDNA testing (Signatera, Natera) performed during clinical care were identified. Signatera utilizes up to 16-plex PCR from matched tumor and blood to develop a personalized ctDNA assay. A subset of patients had additional ctDNA testing during follow-up. Study objectives were to understand baseline ctDNA detection in relation to disease characteristics, and to correlate ctDNA changes on- and post-treatment with disease status and survival. Results: Testing was performed in 92 of 115 (80%) pts with HPV-negative HNSCC (median age: 66, 69% male, 64% smokers); ctDNA testing could not be performed in 23 (20%) pts due to insufficient tumor tissue. Oral cavity (43%) and larynx (22%) were the most common subsites; with most having clinical T2-3 (54%) and N1-2 (51%) disease (AJCC 2017 8th edition) treated with definitive surgery (46, 40%) and/or chemoradiation (59, 51%). Pre-treatment, 69/92 (75%) pts had detectable ctDNA (range: 0.03-4049.69 mean tumor molecules/mL). No baseline independent clinical features predicted pre-treatment ctDNA detectability or levels (multiple logistic/linear regression modeling), but levels varied by T and N stage in univariate analysis (both p&lt;0.05; Kruskal-Wallis test). At a median follow-up of 5.2 months (range: 0.2-15.1), 47 pts (51%) had &gt;1 test result (range: 1-7; 170 total samples). Of 47 pts, 17 (36%) had ctDNA detected after treatment. Disease-free survival was significantly worse for pts who were ctDNA positive vs. negative after treatment (HR 4.35, 95%CI: 1.68-11.21, p&lt;0.01); 1-year overall survival was 83.7% vs. 100% for pts who were ctDNA positive vs. negative. Conclusions: Tumor-informed, personalized ctDNA testing is feasible among pts with non-virally mediated HNSCC. ctDNA positivity as an early indicator of MRD positivity post-treatment was associated with inferior survival, identifying a high-risk subgroup. Further research is warranted to understand whether ctDNA may be leveraged to guide therapy and improve outcomes for HNSCC.

Preliminary efficacy and safety of total neoadjuvant therapy combined with PD-L1 blockade in pMMR/MSS locally advanced rectal cancer (ESTIMATE): A prospective, single-arm, phase II trial.

e15602 Background: Patients with locally advanced rectal cancer (LARC) experience benefits from total neoadjuvant therapy (TNT). This study aims to explore the efficacy and safety of combining TNT with immunotherapy for pMMR/MSS LARC patients. Methods: ESTIMATE is a prospective, single-center, phase II study (ChiCTR2400079718) enrolling pMMR/MSS LARC patients with tumors located 10cm away from the anal margin. Treatment involved induction chemotherapy with immunotherapy ([mFOLFOX6, days 1-2 + Envafolimab 200mg, ih, day 1]; q2w; 2 cycles), long-course concurrent chemoradiotherapy (LCRT) with immunotherapy ([IMRT, 50Gy/25f, 2Gy + Cape 825mg/m2, bid]; 5w + Envafolimab 200mg, ih, day 1; q2w; 3 cycles), consolidation chemotherapy with immunotherapy ([mFOLFOX6 + Envafolimab; 2 cycles), and then total mesorectal excision (TME) 3 weeks later or watch and wait (W&amp;W). The primary endpoint is the pathological complete response (pCR) rate. Results: Until Nov. 16th, 2023, 35 patients were enrolled, with 28 completing the TNT regimen. The efficacy analysis revealed that out of 28 patients, 12 (42.9%) achieved clinical complete response (cCR), with 7 individuals choosing the W&amp;W strategy. 21 patients underwent TME, yielding 8 with a tumor regression grade (TRG) of 0, 7 with TRG of 1, and 6 with TRG of 2. The rates of pCR, major pathological response (MPR), and complete response (CR) were 38.1% (8/21), 71.4% (15/21), and 53.6% (15/28), respectively. 25 (89.3%) patients experienced treatment-related adverse events (AEs) of any grade. Non-hematological AEs included decreased appetite, fatigue, nausea, and vomiting, while hematological AEs mainly comprised thrombocytopenia, anemia, and leukopenia or neutrophilia. Grade III AEs were primarily leukopenia or neutrophilia (2/28, 7.1%). Additionally, circulating tumor DNA (ctDNA) levels were measured in 7 patients who chose the W&amp;W strategy after achieving cCR. Of these, 6 tested negative for minimal residual disease (MRD), while 1 had a positive MRD result (ctDNA: 0.56 MTM/ml). As of Jan. 26th, 2024, with a median follow-up of 5 months (range: 3-6), no recurrence was observed in any of the patients. Conclusions: The TNT approach, integrating LCRT with mFOLFOX6 and PD-L1 blockade, demonstrated a favorable CR rate and acceptable tolerability, offering a potential avenue for organ preservation in low rectal cancer patients with pMMR/MSS. Long-term benefits need validation through further follow-up. Clinical trial information: ChiCTR2400079718. [Table: see text]

Adjuvant chemotherapy with mFOLFOXIRI versus mFOLFOX6 in MRD-positive stage II-III colorectal cancer.

TPS3642 Background: About 25% to 30% of resectable high-risk stage II and stage III colon cancers might relapse after radical resection and adjuvant chemotherapy with FOLFOX regimen. Recent studies have underscored the significance of circulating tumor DNA (ctDNA)-based minimal residual disease (MRD), representing a residual presence of cancer cells, as a prognostic factor for postoperative recurrence in CRC. Patients exhibiting positive MRD predicted a considerable high risk of recurrence and metastasis, even after adjuvant chemotherapy. In the realm of postoperative adjuvant chemotherapy, Comparing with FOLFOX, whether the early introduction of intensified chemotherapy, mFOLFOXIRI, could further eradicate MRD and improve the long-term prognosis remains unclear. Methods: This multicenter phase III study (NCT05427669) plans to enroll 340 colorectal cancer patients with MRD positive after curative-intent R0 surgical resection, age 18 to 70 years, ECOG performance status 0-1. Patients were randomized (1:1) to receive mFOLFOXIRI (oxaliplatin 85 mg/m², leucovorin 400 mg/m², irinotecan 150 mg/m², and 5-FU 2.4 g/m²over 46 h) or mFOLFOX6 (oxaliplatin 85 mg/m², leucovorin 400 mg/m², 5-FU bolus 400 mg/m2 then 2.4 g/m² over 46 h) every two weeks for 24 weeks (12 cycles). Patients will be followed for 5 years after the end of adjuvant chemotherapy. The primary endpoint was 3-year DFS. A gain of 14% in 3-yr DFS is expected (74% in the experimental arm vs. 60% in the control arm; α, 5% [two-sided log-rank test]; 1-β, 80%). Secondary endpoints included overall survival, 3-year distant metastasis-free survival, QoL and toxicity. Clinical trial information: NCT05427669 .

Ponatinib as a Prophylactic or Pre-Emptive Strategy to Prevent Cytological Relapse after Allogeneic Stem Cell Transplantation in Patients with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia Transplanted in Complete Cytological Remission.

The administration of TKIs after Allo-SCT in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) remains controversial, and the TKI approach (prophylactic, pre-emptive or salvage) is still heterogeneous in transplant centers. In this context, very little is known about the feasibility and safety of third-generation TKIs. In this paper, we analyze the efficacy and safety of ponatinib (PONA) administered after Allo-SCT to prevent cytologic relapse of Ph + ALL. This is a multicenter observational study including 48 patients (pts) with Ph + ALL (median age 49 years) who received PONA after Allo-SCT while in complete cytological remission (cCR); 26 (54%) had positive minimal residual disease (MRD pos) before Allo-SCT. PONA was administered after Allo-SCT prophylactically (starting with MRD neg) in 26 pts or pre-emptively (starting with MRD pos post-SCT and without hematological relapse) in 22 pts. Patients treated prophylactically with PONA started treatment earlier, at a median of 4.3 months (range 1.5-6) after Allo-SCT, than those treated pre-emptively, who started PONA at a median of 7.4 months (range 2-63) after Allo-SCT (p = 0.01). The median starting dose of PONA was 30 mg/day (range 15-45). A dose reduction was required in 10/48 (21%) of cases, but a permanent discontinuation of PONA, due to toxicity, was required in only 5/48 pts (10.5%). No deaths due to PONA-related adverse events (AEs) were reported. The median follow-up time after Allo-SCT was 34 months (range 7.7-118). At the last follow-up, the median duration of PONA therapy was 22 months (range 2-100). The 5-year OS and RFS after Allo-SCT were 92% and 71%, respectively. The 5-year RFS after Allo-SCT of pts who received PONA prophylaxis was 95%, and it was 57% for those who received PONA pre-emptively (log-rank p = 0.02). In conclusion, this multicenter analysis of 48 patients with Ph + ALL undergoing Allo-SCT while in CcR, although with the caution of the retrospective data, supports the feasibility of PONA maintenance strategy after Allo-SCT with a low rate of discontinuations (10.5%) due to PONA-related AE.

Survival after allogeneic transplantation according to pretransplant minimal residual disease and conditioning intensity in patients with acute myeloid leukemia.

The measurement of minimal residual disease (MRD) by multiparametric flow cytometry (MFC) before hematopoietic stem cell transplantation (HSCT) in patients with acute myeloid leukemia (AML) is a powerful prognostic factor. The interaction of pretransplant MRD and the conditioning intensity has not yet been clarified. The aim of this study is to analyze the transplant outcomes of patients with AML who underwent HSCT in complete remission (CR), comparing patients with positive MRD (MRD+) and negative MRD (MRD-) before HSCT, and the interaction between conditioning intensity and pre-HSCT MRD. We retrospectively analyzed the transplant outcomes of 118 patients with AML who underwent HSCT in CR in a single institution, comparing patients with MRD+ and MRD- before HSCT using a cutoff of 0.1% on MFC, and the interaction between conditioning intensity and pre-HSCT MRD. Patients with MRD+ before HSCT had a significantly worse 2-year (2y) event-free survival (EFS) (56.5% vs. 32.0%, p = 0.018) than MRD- patients, due to a higher cumulative incidence of relapse (CIR) at 2 years (49.0% vs. 18.0%, p = 0.002), with no differences in transplant-related mortality (TRM) (2y-TRM, 19.0% and 25.0%, respectively, p = 0.588). In the analysis stratified by conditioning intensity, in patients who received MAC, those with MRD- before HSCT had better EFS (p = 0.009) and overall survival (OS) (p = 0.070) due to lower CIR (p = 0.004) than MRD+ patients. On the other hand, the survival was similar in reduced intensity conditioning (RIC) patients regardless of the MRD status. Patients with MRD+ before HSCT have worse outcomes than MRD- patients. In patients who received MAC, MRD- patients have better EFS and OS due to lower CIR than MRD+ patients, probably because they represent a more chemo-sensitive group. However, among RIC patients, results were similar regardless of the MRD status.

MIR4435-2HG as a possible novel predictive biomarker of chemotherapy response and death in pediatric B-cell ALL.

Introduction: Although B-cell acute lymphoblastic leukemia (B-cell ALL) survival rates have improved in recent years, Hispanic children continue to have poorer survival rates. There are few tools available to identify at the time of diagnosis whether the patient will respond to induction therapy. Our goal was to identify predictive biomarkers of treatment response, which could also serve as prognostic biomarkers of death, by identifying methylated and differentially expressed genes between patients with positive minimal residual disease (MRD+) and negative minimal residual disease (MRD-). Methods: DNA and RNA were extracted from tumor blasts separated by immunomagnetic columns. Illumina MethlationEPIC and mRNA sequencing assays were performed on 13 bone marrows from Hispanic children with B-cell ALL. Partek Flow was used for transcript mapping and quantification, followed by differential expression analysis using DEseq2. DNA methylation analyses were performed with Partek Genomic Suite and Genome Studio. Gene expression and differential methylation were compared between patients with MRD-/- and MRD+/+ at the end of induction chemotherapy. Overexpressed and hypomethylated genes were selected and validated by RT-qPCR in samples of an independent validation cohort. The predictive ability of the genes was assessed by logistic regression. Survival and Cox regression analyses were performed to determine the association of genes with death. Results: DAPK1, BOC, CNKSR3, MIR4435-2HG, CTHRC1, NPDC1, SLC45A3, ITGA6, and ASCL2 were overexpressed and hypomethylated in MRD+/+ patients. Overexpression was also validated by RT-qPCR. DAPK1, BOC, ASCL2, and CNKSR3 can predict refractoriness, but MIR4435-2HG is the best predictor. Additionally, higher expression of MIR4435-2HG increases the probability of non-response, death, and the risk of death. Finally, MIR4435-2HG overexpression, together with MRD+, are associated with poorer survival, and together with overexpression of DAPK1 and ASCL2, it could improve the risk classification of patients with normal karyotype. Conclusion: MIR4435-2HG is a potential predictive biomarker of treatment response and death in children with B-cell ALL.

Real-world advantage and challenge of post-autologous stem cell transplantation MRD negativity in high-risk patients with double-hit multiple myeloma

BackgroundAutologous stem-cell transplantation (ASCT) remains a beneficial approach for patients with newly diagnosed multiple myeloma (NDMM) in the age of novel therapeutic agents. Nevertheless, limited real-world data is available to establish criteria for identifying high-risk ASCT patients.MethodsWe analyzed outcomes for 168 NDMM patients who underwent ASCT at our center from December 2015 to December 2022. We investigated the impact of the number of high-risk cytogenetics (HRCA), defined as t(4;14), t(14;16), 1q21 gain/amplification, and del(17p), as well as the post-ASCT minimal residual disease (MRD) status as prognostic indicators. We assessed progression-free survival (PFS) and overall survival (OS), and focused on identifying risk factors.ResultsThe cohort included 42% of patients (n = 71) with 0 HRCA, 42% (n = 71) with 1 HRCA, and 16% (n = 26) with ≥ 2 HRCA. After a median follow-up of 31 months, the median PFS was 53 months (95% CI, 37–69), and OS was not reached for the entire cohort. Despite similar rates of MRD-negativity post-ASCT, patients with ≥ 2 HRCA, termed “double hit” (DH), had a significantly higher risk of progression/mortality than those with 0 or 1 HRCA. Multivariate analysis highlighted DH (HR 4.103, 95% CI, 2.046–8.231) and MRD positivity post-ASCT (HR 6.557, 95% CI, 3.217–13.366) as adverse prognostic factors for PFS, with DH also linked to inferior OS. As anticipated, DH patients with post-ASCT MRD positivity displayed the poorest prognosis, with a median PFS of 7 months post-ASCT. Meanwhile, DH patients with MRD negativity post-ASCT showed improved prognosis, akin to MRD-negative non-DH patients. It is noteworthy to exercise caution, as DH patients who initially achieved MRD negativity experienced a 41% cumulative loss of that status within one year.ConclusionsThis study strongly advocates integrating DH genetic assessments for eligible ASCT patients and emphasizes the importance of ongoing MRD monitoring, as well as considering MRD-based treatment adaptation for those patients in real-world settings.

Investigation of the immune profile of multiple myeloma patients achieving long-term survival after autologous stem cell transplantation

Objective: To identify the characteristics of the bone marrow immune microenvironment associated with long-term survival in multiple myeloma (MM) patients. Methods: In the follow-up cohort of patients with newly diagnosed MM and who received "novel agent induction therapy and subsequent autologous stem cell transplantation and immunomodulator maintenance therapy" in the First Affiliated Hospital of Sun Yat-sen University, a cross-sectional study was carried out between August 2019 and May 2020. Using NanoString technology, the RNA expression of 770 bone marrow immune-related markers was compared between 16 patients who had progression-free survival ≥5 years and 5 patients with progressive disease. Among the 16 patients who achieved long-term survival, 9 achieved persistent minimal residual disease (MRD) negative while the other 7 had persistent positive MRD. The functional scores of each kind of immune cells were calculated based on the expression level of characteristic genes, so as to indirectly obtained the proportion of each immune cell subset. The Mann-Whitney U test and the Kruskal Wallis test were used for statistical analysis. Results: The proportion of neutrophils was significantly higher in long-surviving MM patients than in patients with progressive disease [functional scores, 13.61 (13.33, 14.25) vs. 12.93 (12.58, 13.38); Z=2.31, P=0.021]. Among long-surviving patients, those who were MRD-positive had a significantly greater number of mast cells compared with those who were MRD-negative [functional scores, 7.09 (6.49, 8.57) vs. 6.03 (5.18, 6.69); H=2.18, P=0.029]. Compared with patients with progressive disease, four genes (CTSG, IFIT2, S100B, and CHIT1) were significantly downregulated and six (C4B, TNFRSF17, CD70, IRF4, C2, and GAGE1) were upregulated in long-surviving patients. Among long-surviving patients, only gene CMA1 was significantly upgraded, 10 genes (ISG15, OAS3, MX1, IFIT2, DDX58, SIGLEC1, CXCL10, IL1RN, SERPING and TNFSF10) were significantly downregulated in the MRD-positive group compared with that in the MRD-negative group, the first 5 of which are related to the interferon response pathway. Conclusions: The increased neutrophil and mast cell numbers may be related to long-term survival in MM. Interferon signaling activation may be a key bone marrow immune profiling feature for MRD-negative, long-surviving patients with MM.

Abstract 5189: The potential of minimal residual disease (MRD) in guiding adjuvant therapy (AT) decisions in non-small cell lung cancer (NSCLC)

Abstract Background: Circulating tumor DNA (ctDNA)-based minimal residual disease (MRD) detection has become a strong prognostic stratification factor in post-operation non-small cell lung cancer (NSCLC). Here we sought to investigate the guiding potential of MRD in informing adjuvant therapy (AT) decisions. Methods: Patients with stage IA-IIIB NSCLC who had undergone confirmed R0 resection were enrolled. Blood samples were collected prospectively one month after surgery before initiation of AT (landmark) and longitudinally every 3-6 months since surgery. Postoperative AT was conducted according to the guideline recommendations and regular radiographical examinations were recommended for relapse surveillance. MRD detection was conducted via the MinerVa platform (Genecast Biotechnology Co., Ltd) using a tumor-informed strategy based on a fixed next-generation sequencing (NGS) panel spanning 769 cancer-related genes. Results: 168 patients were included in this study, with 11 (6.5%) experiencing confirmed relapse. Positive MRD was detected in 10.2% (16/157) of patients at landmark and was associated with a significantly higher risk of shorter disease-free survival (DFS)(HR: 26.2[6.7-102.7], P&amp;lt;0.001), irrespective of disease stage or gene alteration. Dynamic changes in ctDNA status further stratified patients into three subgroups with different prognosis. Consistent negative MRD detected at the landmark and all longitudinal timepoints represented the group with the best prognosis, while positive MRD detected at either the landmark or one subsequent timepoint showed a worse prognosis (Neg-Pos vs. Neg-Neg, HR: 37[3.2-438], P=0.004; Pos-Neg vs. Neg-Neg, HR: 14[1.2-172], P=0.035). The group with the worst prognosis occurred with consistent positive MRD (Pos-Pos vs. Neg-Neg, HR: 50[5.3-473], P&amp;lt;0.001). For patients with negative landmark MRD, there was no significant difference between the DFS of patients who received AT and those who didn’t(P=0.241), and the result was replicated in a highly controversial subgroup: stage I patients with high-risk factors (P=0.130). Besides, whether chemotherapy was applied before targeted therapy in the EGFR-mutant subgroup showed no influence on DFS provided that landmark MRD was negative (P=0.197). In multivariate analysis considering pathological high-risk factors, poor differentiation was identified as an independent risk factor for landmark MRD positivity (HR: 10.6[1.96-168.01], P=0.030). Conclusions: MRD is a strong and steady prognostic factor in post-operative NSCLC. AT may be waved for stage I patients with high-risk factors given that they had negative landmark MRD, same as the adjuvant chemotherapy before targeted therapy for patients with sensitive EGFR mutation. More attention should be paid to poorly differentiated tumors, indicative of a high-risk subgroup with potential residual diseases. Citation Format: Siyu Lei, Haiyan Xu, Yaning Yang, Linyan Tian, Ting Ma, Yan Wang. The potential of minimal residual disease (MRD) in guiding adjuvant therapy (AT) decisions in non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5189.

The value of minimal residual disease and IKZF1 deletion for predicting prognosis in adult patients with B-cell acute lymphoblastic leukemia

Objective: To reassess the prognostic value of minimal residual disease (MRD) and IKZF1 gene deletions in adults with B-cell acute lymphoblastic leukemia (B-ALL) who received pediatric-specific chemotherapy regimens during the Nanfang Hospital PDT-ALL-2016 trial. Methods: We retrospectively analyzed the prognosis of 149 adult patients with B-ALL who were admitted to Nanfang Hospital from January 2016 to September 2020. Prognostic factors were identified using Cox regression models. Results: The complete remission rate was 93.2% in 149 patients, with a 5-year overall survival (OS) rate of (54.3±5.0) % and a cumulative incidence of relapse (CIR) of (47.5±5.2) %. The Cox regression analysis revealed that MRD positivity at day 45 (MRD(3)) after induction therapy was independently associated with relapse risk (HR=2.535, 95%CI 1.122-5.728, P=0.025). Deletion of IKZF1 gene was independently associated with mortality risk (HR=1.869, 95%CI 1.034-3.379, P=0.039). Based on MRD(3) and IKZF1 gene status, we categorized adult patients with B-ALL into the low-risk (MRD(3)-negative and IKZF1 gene deletion-negative) and high-risk (MRD(3)-positive and/or IKZF1 gene wild type) groups. The 5-year OS and CIR rates were (45.5±6.0) % vs (69.4±8.6) % (P<0.001) and (61.6±8.3) % vs (25.5±6.5) % (P<0.001), respectively, in the high-risk and low-risk groups, respectively. The multivariate analysis showed that the high-risk group was an independent risk factor for OS (HR=3.937, 95%CI 1.975-7.850, P<0.001) and CIR (HR=4.037, 95%CI 2.095-7.778, P<0.001) . Conclusion: The combined use of MRD and IKZF1 gene in prognostic stratification can improve clinical outcome prediction in adult patients with B-ALL, helping to guide their treatment.

Outcomes and prognosis of haploidentical haematopoietic stem cell transplantation in children with FLT3-ITD mutated acute myeloid leukaemia.

The presence of internal tandem duplication mutations in the FMS-like tyrosine kinase 3 receptor (FLT3-ITD) is a poor prognostic predictor in paediatric patients with acute myeloid leukaemia (AML). We evaluated the treatment outcomes and prognostic factors of 45 paediatric patients with FLT3-ITD AML who achieved complete remission before haploidentical haematopoietic stem cell transplantation (haplo-HSCT) at our institution from 2012 to 2021. Among the 45 patients, the overall survival (OS), event‑free survival (EFS), and cumulative incidence of relapse (CIR) rates were 74.9% ± 6.6%, 64.1% ± 7.2%, and 31.4% ± 7.1%, respectively, with 48.8 months of median follow-up. Univariate and multivariate analyses associated positive minimal residual disease (MRD) at pre-HSCT and non-remission (NR) after introduce 1 with inferior long-term survival. The 100-day cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 35.6% ± 5.2%, and that of grade III-IV aGVHD was 15.6% ± 3.0% The overall 4-year cumulative incidence of chronic graft-versus-host disease after transplantation was 35.7% ± 9.8%, respectively. In conclusion, haplo-HSCT may be a feasible strategy for paediatric patients with FLT3-ITD AML, and pre-HSCT MRD status and NR after introduce 1 significantly affected the outcomes.

Ixazomib, Lenalidomide, and Dexamethasone (IRD) Treatment with Cytogenetic Risk-Based Maintenance in Transplant-Eligible Myeloma: A Phase 2 Multicenter Study by the Nordic Myeloma Study Group.

Scarce data exist on double maintenance in transplant-eligible high-risk (HR) newly diagnosed multiple myeloma (NDMM) patients. This prospective phase 2 study enrolled 120 transplant-eligible NDMM patients. The treatment consisted of four cycles of ixazomib-lenalidomide-dexamethasone (IRD) induction plus autologous stem cell transplantation followed by IRD consolidation and cytogenetic risk-based maintenance therapy with lenalidomide + ixazomib (IR) for HR patients and lenalidomide (R) alone for NHR patients. The main endpoint of the study was undetectable minimal residual disease (MRD) with sensitivity of <10-5 by flow cytometry at any time, and other endpoints were progression-free survival (PFS) and overall survival (OS). We present the preplanned analysis after the last patient has been two years on maintenance. At any time during protocol treatment, 28% (34/120) had MRD < 10-5 at least once. At two years on maintenance, 66% of the patients in the HR group and 76% in the NHR group were progression-free (p = 0.395) and 36% (43/120) were CR or better, of which 42% (18/43) had undetectable flow MRD <10-5. Altogether 95% of the patients with sustained MRD <10-5, 82% of the patients who turned MRD-positive, and 61% of those with positive MRD had no disease progression at two years on maintenance (p < 0.001). To conclude, prolonged maintenance with all-oral ixazomib plus lenalidomide might improve PFS in HR patients.

Real-world prognostic significance of attaining minimal residual disease negativity in newly diagnosed multiple myeloma

The aim of the study was to evaluate the prognostic impact of minimal residual disease (MRD) in the real-world setting and the interaction between MRD and molecular risk, clinical response and autologous stem-cell transplant (ASCT). A retrospective analysis of 275 newly diagnosed multiple myeloma (NDMM) patients who achieved very good partial remission (VGPR) or better before maintenance were involved. We examined MRD status by multiparameter flow cytometry (MFC). At a median follow-up of 37 months (4–88 months), In patients who achieved ≥ VGPR, those with MRD negativity had significantly longer PFS (51 vs. 26 months; P < 0.001) and OS (Not reached: NR vs. 62 months, P < 0.001) than those with MRD positivity. MRD positivity was the independent prognostic factor for PFS with hazard ratios of 2.650 (95% CI 1.755–4.033, P < 0.001) and OS with hazard ratios of 2.122 (95% CI 1.155–3.899, P = 0.015). Achieving MRD negativity was able to ameliorate a poor prognosis associated with genetic high risk. MRD negativity was associated with better PFS regardless of ASCT treatment. MRD status was more predictable for clinical outcome than conventional clinical responses. Moreover, Sustained MRD negativity ≥ 12 or ≥ 24 months improved both PFS and OS. Patients with NDMM who achieved MRD-negative status or sustained MRD negativity had deep remission and improved clinical outcomes regardless of high-risk cytogenetics, ASCT and clinical responses in a real-world setting.