Sustained Treatment-free Remission Research Articles

Treatment-free remission as a new goal in the management of chronic myeloid leukemia: Clinical and biological aspects.

The therapeutic armamentarium of chronic myeloid leukemia (CML) has dramatically improved after small molecule tyrosine kinase inhibitors (TKIs) targeting BCR::ABL1 became available, with a life expectancy now close to that of the general population. Although highly effective, these drugs also have a toxicity profile that is often mild to moderate, but sometimes severe. Indeed, long-term treatment with TKIs can lead to chronic adverse events that can negatively affect patients' quality of life and can promote significant morbidity and mortality, particularly in the case of second- or third-generation TKIs. Treatment discontinuation has therefore become an emerging goal for CML patients and numerous studies have evaluated in off-TKI subjects what requirements are appropriate for an attempt at treatment-free remission (TFR). TFR eligibility is currently limited to a small population of subjects with both deep and sustained molecular responses to TKIs. For those attempting TFR, average success rates are promising, with 25%-30% of patients experiencing prolonged TFR. In case of failure to maintain sustained TFR, safety results to date are reassuring, with almost all patients responding successfully to resumption of TKIs, and advanced-phase disease progression representing a very rare event. The purpose of this review is to discuss guidelines for TKI discontinuation, clinical advances from clinical trials and real-life experiences, and describe areas of research, particularly regarding the biological factors capable of predicting the success of TFR.

Successful rechallenge with azacytidine and venetoclax after sustained treatment-free remission in a relapsed acute myeloid leukemia patient: a case report.

Combined therapy with venetoclax and hypomethylating agents has significantly improved the outcome of unfit patients ineligible for intensive chemotherapy. A recently published exploratory analysis of the VIALE-A trial reported that up to 51% of patients achieving remission survived more than 2 years. These data along with those from reallife settings, lead to questioning how long it is appropriate to continue treatment in long-term survivors. Accordingly, recent retrospective studies suggested the feasibility of suspending therapy in selected patients while maintaining prolonged responses. Also, these studies showed that retreatment may induce a second remission in almost a third of patients. We report the case of a patient who received salvage therapy with venetoclax and azacytidine, that was discontinued few cycles after blasts clearance because of severe hematological toxicity. Despite suspension, he maintained a sustained response lasting almost one year and was successfully retreated with the same combination when a second relapse occurred.

Treatment-Free Remission in Chronic Myeloid Leukemia.

With the discovery of tyrosine kinase inhibitors (TKIs), overall survival in patients with chronic myeloid leukemia (CML) now approaches that of the general population. While these TKIs have proven to be lifesaving, remaining on them lifelong creates both physical and financial burdens for patients. Recently, multiple trials have begun looking into the efficacy of trialing patients off these TKIs to see if they can sustain treatment-free remission (TFR). TFR eligibility is currently limited to a small population of patients with both robust and sustained responses to TKIs. Currently, for those who attempt a trial of TFR, the average success rates are promising, with anywhere from 38 to 54% of patients experiencing sustained TFR. For those who fail to maintain sustained TFR, safety results to date are reassuring, with almost all patients successfully responding to the re-initiation of TKIs, with death and disease progression being very rare complications. Moving forward, research is being conducted to more accurately risk stratify patients at diagnosis and pair them with optimized upfront treatment regimens aimed at increasing candidacy for the trial of TFR.

International, Prospective Study Comparing Nilotinib Versus Imatinib with Early Switch to Nilotinib to Obtain Sustained Treatment-Free Remission in Patients with Chronic Myeloid Leukemia (SUSTRENIM trial): Analysis of the Eligibility to Treatment Discontinuation

Background. Treatment free remission (TFR) is one of the most important aims of CML treatment but, so far, the best treatment strategy to obtain a durable deep molecular response (DMR) and the overall rate of patients able to achieve a successful TKI discontinuation based on intention-to-treat principle from CML diagnosis are still debated. In November 2016 we launched an international, prospective, randomized, two arms study to evaluate both the depth of the molecular response and the rate of TFR in newly diagnosed CP-CML patients treated with a second generation TKI (Nilotinib, NIL) or with imatinib (IM) followed by switching to NIL in absence of optimal response (Clinical Trial number 02602314). Patients were randomized 1:1 between NIL and IM, stratifying on the Sokal score. All the patients achieving a MR4.0 or better by three years and maintaining this level of response up to the end of the fourth year of therapy were qualified for the discontinuation phase. We recently reported that patients enrolled in the NIL arm had a rate of MR4.5 at two years (primary co-endpoint of the study), significantly higher than those in the IM arm (32 vs 22%, p = 0.023 Pane F. et al, EHA 2022). The aim of the present analysis is to assess, in both arms of the trial, the percentage of patients achieving the eligibility to treatment discontinuation, defined as a MR4 maintained in 4 consecutive MRD analysis within the fourth year of therapy. Methods. In this pilot analysis, we first examined the rate of patients eligible to discontinuation and their baseline features (i.e. age, gender, ELTS and Sokal risk, BCR::ABL1 isoform) compared to patients without sustained MR4, using Fisher's exact test or Wilcoxon according to variable type. In patients discontinuing TKIs at 48 months, the successful TFR probability at 12 months after TKI withdrawal was computed with the Kaplan Meier method. Molecular relapse, defined as the loss of MMR or confirmed loss of MR3.0, progression, or death were considering as event in the event-free survival curve. Results. Of the 448 randomized patients, 289 had at least 48-month observation at the time of the present analysis and were evaluated for TFR eligibility, 141 in the IM arm and 148 in the NIL arm, respectively. Ninety-three patients (32%) showed a sustained MR4 in the fourth year and were deemed eligible for treatment discontinuation, 45 in the IM arm (32%) and 48 in the NIL arm (32%). Of the remaining 196 patients, 59 did not have the criteria to discontinue treatment and 137 previously went off study for failure, progression, toxicity, death, or other causes (66 in the IM arm and 71 in the NIL arm, respectively). We found that sustained MR4 achievement was significantly associated with low disease risk, according to both ELTS (81.7% vs 47.2% p<0.0001) and Sokal scores (50.5% vs 34.2%, p=0.008). There is a weak correlation to the age, being those eligible younger (median 52.5 vs 55 years, p=0.037), while no differences in gender and BCR::ABL1 isoform distributions were observed. Within the IM arm, patients who switched to NIL were 60/141 (43%), 44 within the first 12 months and 16 after the first year; those patients had a lower probability of starting the TFR phase compared to patients continuing IM (22% vs 40%, p=0.025). The median follow-up of the 93 patients who attempted treatment discontinuation at 48 months is 9.9 months (IQR: 5.3-12.1). The percentages of those patients in TFR were 82.9% (95% CI:74.8-91.8) at 6 months and 74.3% (95% CI:63.9-86.4) at 12 months. The analysis per random was considered premature given the short follow-up and the proportion of patients not yet evaluable for the discontinuation. Conclusions Although the results are still preliminary to draw definitive conclusions on the rate of sustained DMR and stable TFR , our data indicates that despite higher 24-month rates of MR4.5 in the NIL arm, the probability of reaching criteria for TFR attempt may be not different in the two study arms: one third of patients attempted discontinuation and the majority of them appear to be free of relapse after a median of 10 months from the therapy discontinuation. Among patients of the IM arm, patients switching to NIL due to absence of optimal response had a lower probability to attempt discontinuation. Noteworthy, as for the MR4.5 rate at 24 mo. of therapy, patients at low ELTS risk score are those with the highest probability to achieve sustained MR4 and being eligible for the treatment discontinuation.

Long-Term Follow-up of the AST Trial of Treatment-Free Remission in Chronic Myeloid Leukemia Patients

Background: Treatment-free remission (TFR) is a new goal for chronic myeloid leukemia (CML) patients who achieved a long deep molecular response (DMR) with better quality of life, reduced adverse events and high economic impact. The primary objective of the AST trial was to estimate molecular relapse rate at 24 month in CP-CML patients who discontinued TKI. Secondary objective to explore predictive markers for sustained TFR through clinical and immunological analysis ( innate inmune response). This update provides longer follow-up data and includes a new cohort of patients. Patients and Methods: AST-Argentina Stop Trial (NCT05926128) is a multicenter prospective study that included patients from 15 centers. Recruited patients ≥ 18 years, treated with TKI for at least 4 years, sustained MR 4.0 for ≥ 2 years and confirmed typical BCR-ABL1 b3a2 and/or b2a2 transcripts. Molecular studies were centralized in 2 internationally standardized laboratories and were performed monthly during the first 6 months, every 2 months until the first year, and every 3 months during the second year. TKI was restarted due to loss of major molecular response (MMR). Expression of multiple NK cell immunophenotypic markers(CD3-CD56+) was analyzed by flow cytometry at discontinuation time and 3 months later. The nonparametric Mann-Whitney test was used to compare the differences between relapsed and responding patients. Molecular relapse-free survival was estimated using the Kaplan-Meier method and optimal cut-off points were obtained using ROC curves. Comparisons between survival curves were made using the Log rank test method. The differences were considered statistically significant with p-values less than 0.05. Multivariate analysis was performed using the COX regression model. Results: A total of 81 patients divided into 2 cohorts were evaluated: 46 patients recruited between February 2018 and July 2020 (1st cohort) and 35 patients recruited between July 2022 and April 2023. Between these two periods, recruitment was stopped due to the COVID19 pandemic. This analysis focuses on the 1st cohort that has completed 24 months in the study. The median age was 57.5 years (24-86), median duration of treatment before discontinuation was 10.5 years (4.2-20). TKI treatment prior to discontinuation was as follows: Imatinib in 34 (73%) patients, Dasatinib 8 (17%), and Nilotinib 4 (9%). According to Sokal risk score: 22 (48%) were low risk, 14 (30%) intermediate, and 10 (22%) high risk. Seventeen patients (37%) lost MMR, leading to a 63% molecular relapse-free survival rate with a median follow-up of 47 months (41-52). All patients who lost MMR recovered it after restarting the same TKI, with a median time to response of 2.8 months (1-7). With a prolonged follow-up, 2 late relapses were observed (18 and 42 months) (Fig 1). For a univariate analysis, the continuous variables were dichotomized seeking to maximize the difference between the different cohorts. The differences were significant in the variables time in DMR (cut-off point: 51 months, p=0.0166)(HR=0.97 (0.94 - 0.99); p=0.013). Two of the NK cell markers showed significant differences between groups at month 3 after starting treatment, PD1 (Mann-Whitney p=0.035; Log-Rank test p=0.033) and NK-p44 (Mann-Whitney p=0.015; Log -Rank test p=0.020). Multivariate analysis using the Cox model that included variables as gender, age at diagnosis, time in DMR, time in TKI prior to discontinuation, Sokal score, and type of inhibitor, the clinical predictor of time in DMR was the only predictor, significantly associated with a higher rate of TFR, (HR = 0.97 (0.95 - 0.99); p=0.020). No patient experienced disease progression to advanced stages or death for any reason. Conclusion:This is the first multicenter study of TKI discontinuation in CML patients in Argentina showing that TKI can be safely discontinued in those who achieve and maintain a DMR before discontinuation. Molecular relapse-free survival rate was slightly higher than that reported in the international literature, and longer follow-up confirmed the sustained response. DMR before discontinuation showed to be a robust predictor of TFR. Although the sample size was increased, longer follow-up is needed to validate these findings in the second cohort. Potential advantages of TFR will not only impact in patients' quality of life but also show considerable reduction in the use of economic resources.

Acute Myeloid Leukemia Patients Who Stopped Venetoclax or/and Azacytidine for Other Reasons Than Progression Have a Prolonged Treatment Free Remission and Overall Survival. a Filo Study

Background Recent update of the VIALE-A study showed a long-term survival for approximately 30% of acute myeloid leukemia (AML) patients treated with venetoclax and azacitidine (VEN-AZA) for a newly-diagnosed AML (ND-AML) (Pratz K.W et al., ASH 2022). A recent report of a small cohort of responding patients who interrupted VEN-AZA displayed a sustained treatment-free remission (TFR) period suggesting that treatment interruptions might be considered (Chua CC. et al., Blood Adv. 2022). To evaluate the impact of VEN-AZA discontinuation on survival and time without treatment, we retrospectively analyzed the characteristics and outcomes of patients who stopped VEN and/or AZA for reasons other than progression (e.g. hematological or other toxicities). We presented the first 51 patients from our cohort last year at ASH meeting (Garciaz S. et al, ASH 2022). In this abstract, we analyzed separately ND-AML and relapsed/refractory (R/R) AML. Methods Eligible patients 1) have been treated with VEN-AZA for a ND or R/R AML, 2) have stopped AZA and/or VEN for more than 3 months, 3) are in remission (CR, CRi or Morphologic leukemia-free state, [MLFS]) at the time of treatment interruption, 4) are ≥ 18-year-old. Main endpoints were overall survival (OS) and treatment-free remission (TFR) calculated from the time between the last day of VEN to relapse, retreatment, or death. We measured the impact of prognostic factors on OS by a Cox regression taking disease status (ND vs R/R), the discontinued treatment (VEN vs VEN-AZA), the cytogenetics and NPM1 or IDH mutations. Results We included 83 patients from French Innovative Leukemia Organization (FILO) centers and Moffit Cancer Center (US) treated with VEN-AZA for a ND-AML or a R/R AML between 11/18 and 07/23. Regarding the ND-AML patients (n=60; 32 males and 28 females), the median age was 76 (range, 26-86.5), median platelet count, WBC, ANC and bone marrow blast involvement was 52 G/L (range, 9-296), 2.8 G/L (range, 0.6-200), 0.6 G/L (range, 0.02-31.6) and 40% (range, 10-99), respectively. Cytogenetics was intermediate (int.) in 48 cases (80%) and unfavorable (unfav.) in 12 patients (20%). Eleven AML (18.3%) had NPM1 mutations, and 19 (31.6%), IDH alterations including 7 IDH1, 8 IDH2R140 and 4 IDH2R172. Six (10%) and 5 (8.3%) patients had FLT3 or TP53 mutations, respectively. The median number of VEN-AZA cycle was 4 (1-17). The best response was CR (n=44, 73.3%), CRi (n=13, 18.3%) and MLFS (n=3, 5%). Twenty-one patients out of 25 (78%) reached MRD negativity assessed by molecular (n=11) or flow cytometry (n=10) techniques. Twenty-six patients (43.3%) stopped VEN-AZA and 34 (56.7%) stopped VEN and continued AZA monotherapy for a median number of 7 AZA cycles (1-41). Reasons for treatment discontinuation were prolonged cytopenia, non-hematological toxicities, patient choice or unknown in 35 (58%), 6 (10%), 8 (13.3%), and 11 (18.3%) patients, respectively. We registered 27 relapses and 24 deaths. Fourteen patients were retreated including 11 patients who were rechallenged with VEN-AZA. Second CR/CRi rate with VEN-AZA was 3/11 (27.7%). With a median follow of 23 months, median TFR was 15 months (ranges, 3-47) and median OS was 44 months (ranges, 7-50). We also analyzed a smaller cohort of 23 R/R responding patients who stopped AZA and/or VEN. The median age was 73, median number of previous lines was 1 (1-3). Twenty-one patients (91.3%) received prior intensive chemotherapy and 4 (17.4%) prior allogeneic hematopoietic transplantation. Cytogenetic risk was int. in 17 (73.9%) and unfav. in 5 patients (21.7%) and missing in one patient. NPM1 and IDH genes were mutated in 6 (26%) and 10 (43.4%) cases, respectively. Sixteen patients (69.6%) stopped VEN-AZA and 7 (30.4%) interrupted VEN only. Nine patients resumed a treatment including 6 patients rechallenged with VEN-AZA. Among them, 3/6 (50%) obtained a second CR/CRi. Median TFR and OS were 10 (ranges, 3-23) and 19 (ranges, 7-32), respectively. Factor impacting OS in multivariate analysis were R/R AML disease status (Hazard Ratio [HR] =0.47, ranges, 0.23-0.87), and IDH mutations (HR= 2.1, ranges, 1.05-4.34), but not unfav. cytogenetics, NPM1 mutations, or the discontinued treatment (VEN vs VEN-AZA). Conclusion: Discontinuation of VEN and/or AZA in responding patients was associated with sustained responses and long-term survival rates. Resuming treatment may induce a second remission in some patients.

Association of TIM-3 checkpoint receptor expression on T cells with treatment-free remission in chronic myeloid leukemia.

Dysregulation of immune-checkpoint receptors has been reported at diagnosis of chronic myeloid leukemia (CML), however, their role in the maintenance of remission after tyrosine kinase inhibitor (TKI) cessation is unclear. We assessed programmed cell death-1 (PD-1), T-cell immunoglobulin, and mucin-domain containing protein-3 (TIM-3), cytotoxic T-lymphocyte-associated protein-4 (CTLA-4), lymphocyte-activation gene-3 (LAG-3), andT-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domains (TIGIT) expression on T-cell subsets, regulatory T cells (T-regs), and natural killer (NK) cells at the time of TKI cessation in 44 patients (22 patients sustained treatment-free remission [TFR] and 22 experienced molecular relapse [MolR]). We confirmed our previous finding that absolute numbers of T-regs are increased in patients who experienced MolR compared with those who sustained TFR. The immune-checkpoint receptors PD-1, CTLA-4, LAG-3, and TIGIT on Tor NK cells were not differentially expressed between the MolR and TFR groups. However, TIM-3 was consistently upregulated on bulk T cells (CD3+) and T-cell subsets including, CD4+ T cells, CD8+ T cells, and T-regs, in patients who relapsed in comparison with those who maintained TFR after discontinuation. Furthermore, gene expression analysis from publicly available data sets showed increased TIM-3 expression on CML stem cells compared with normal hematopoietic stem cells. These findings suggest that among the targetable immune-checkpoint molecules, TIM-3 blockade may potentially improve effector immune response in patients with CML stopping TKI, while concomitantly targeting leukemic stem cells and could be a promising therapeutic strategy for preventing relapse after cessation of TKI in patients with CML.

Long-term outcomes of patients with type 1 or 2 autoimmune hepatitis presenting in childhood

In children with autoimmune hepatitis, uncertainties include outcomes associated with type 2 hepatitis, the possibility of and criteria for attempting withdrawal of treatment, and long-term outcomes. We report our experience on these issues. From 1973 to 2002, 117 children with type 1 (n= 65) or type 2 (n= 52) hepatitis, excluding fulminant hepatitis, were treated, primarily with prednisone and azathioprine. Median follow-up was 20 years in survivors. Normalisation of aminotransferases and prothrombin ratio were observed in 93% and 84% of children, respectively; sustained remission after treatment withdrawal was recorded in 24% of the entire population, with a median follow-up of 7 years. Sustained treatment-free remission was obtained in 11 of 24 children with follow-ups of 4-22 years based on durable normalisation of aminotransferases (without histological assessment). Gastrointestinal bleeding from varices and the emergence of extrahepatic autoimmune disorders occurred in 10 and 22 patients, respectively. Liver transplantation was performed in 23 patients at a median age of 21 years. The 30-year probabilities of overall and native liver survival were 81% and 61%, respectively. No differences were observed between type 1 and 2 hepatitis for any of the component parts of outcome. In the multivariate analysis, a persistent abnormal prothrombin ratio was associated with worse probabilities of overall and native liver survival. In terms of liver outcome, type 2 hepatitis is not different from type 1. Withdrawal of treatment is possible without prior liver histology. A persistent abnormal prothrombin ratio identifies patients who will require liver transplantation in adolescence or early adulthood. In children with autoimmune hepatitis, there are conflicting reports on the differences in outcome between type 1 and type 2 hepatitis, and on the possibility of treatment withdrawal, before which liver histology is required; data concerning >10-year overall and native liver survival rates are limited. In this study, we found no differences in outcomes between type 1 and 2 hepatitis; a durable treatment-free state was achieved in 19% of all patients throughout childhood and early adulthood, and in 45% of children for whom treatment withdrawal was attempted without prior liver histology; prothrombin was found to be predictive of 30-year overall and native liver survival. The results allow for a less-strict approach to treatment withdrawal in children, avoiding the risks of a liver biopsy, and they provide a tool to help anticipate the need for liver transplantation before complications occur.

Clonal Hematopoiesis Detected at the Time of Tyrosine Kinase Inhibitor Cessation Is Associated with Delayed Molecular Recurrence after Treatment-Free Remission in Patients with CML

Background Treatment-free remission (TFR) is a goal of therapy. However, ~50% of patients who attempt TFR will relapse, which mostly occurs by 6 months. The acquisition of somatic mutations in hematopoietic cells is common with age (clonal hematopoiesis, CH). Through next-generation sequencing studies we identified CH in patients in deep molecular remission. CH variants provide a selective growth advantage to cells, driving their clonal expansion. The clones also give rise to mutated immune effector cells with a proinflammatory profile that exacerbate diseases with a chronic inflammatory component, such as atherosclerosis. CH variants could potentially influence TFR, either by outcompeting an emerging residual CML clone or by altering immune function, which is known to play an important role in TFR. Aim To determine whether CH variants present at the time of therapy cessation could influence TFR. Methods An RNA-based hybridization capture sequencing method targeting 17 of the most frequently mutated CH genes was developed and applied to samples of 138 patients who attempted TFR. CH variants met strict criteria for pathogenicity based on their potential to confer growth and survival advantages. The CH status was confirmed by repeat testing of samples of 28 patients. The method reproducibly detected variants with a variant allele frequency (VAF) of ≥0.4%. Results The median follow-up for the 138 patients was 66 months from the TFR attempt. Molecular recurrence was defined as loss of major molecular response (MMR, BCR::ABL1 ≤0.1%). The probability of TFR was 64.5% at 6 months, 59.4% at 12 months and 51.0% at 84 months. CH variants were detected in 61/138 patients (44%): 107 variants in 12 genes. Multiple variants, range 2 - 7, were detected in 26 patients (19%). The median VAF was 0.9%, range 0.4 - 44%. Variants most frequently occurred in TET2 (44% of variants), DNMT3A (25%), PPM1D (7.4%) and ASXL1 (6.5%). The average age at cessation was 59.6 years, range 33 - 85. The average age of patients with CH was higher than those without CH: 64.7 versus 55.5 years, P < .0001. Only 3/13 patients (15%) aged ≤40 had CH compared with 6/7 patients (86%) ≥80. CH was significantly associated with TFR to 36 months after cessation. The optimal criteria for TFR prediction were at least one CH variant of VAF >2% or >2 variants (CH >2%/>2). Thirty-one of 138 patients (22%) had CH of VAF >2% (n = 24) or >2 variants (n = 7). The probability of TFR for these 31 patients was significantly higher than for the remaining patients when assessed at 6, 12, 24 and 36 months after cessation, Figure. The probability of TFR at 6 months was 90.3% for patients with CH >2%/>2 versus 57.0% for the remaining patients, P = .001. The probability of TFR at 36 months was 65.9% versus 51.2%, P = .049. A landmark analysis was performed at 12 months for the 74 patients who maintained TFR at 12 months. MMR was subsequently lost in 8/74 patients and the probability of TFR at 84 months was 86.9%. CH >2%/>2 occurred for 23/74 patients (31%). The probability of late molecular recurrence was higher among the patients with CH >2%/>2: 27.3% versus 5.5% for the remaining patients, P = .009. Overall, molecular recurrence occurred for 12/31 patients (39%) with CH >2%/>2 and 53/107 of remaining patients (50%). Time to molecular recurrence after cessation was longer for patients with CH >2%/>2 than the remaining patients: median 12.5 months versus 3.5 months, P < .0001. The longer time to molecular recurrence was linked to a different pattern of loss of MMR. The median time between first loss of MR4 (BCR::ABL1 ≤0.01%) and loss of MMR was 145 days for patients with CH >2%/>2 and 28 days for remaining patients, P = .0007. BCR::ABL1 values more frequently fluctuated before loss of MMR in patients with CH >2%/>2: 8/12 patients (67%, fluctuation over 120-1335 days) versus 6/53 (11%, fluctuation over 85-715 days) in the remaining patients, P =.016. Conclusion CH may improve the probability and duration of TFR, delaying the time to molecular recurrence, which has implications for patient selection and monitoring. Patients with CH who are eligible for therapy cessation have an excellent prospect of remaining drug-free for 1-2 years but their long term prospects of sustained TFR may be less certain compared to other patients, given the slower dynamics of relapse. Delayed relapse could be due to competition for clonal dominance between residual leukemic cells and larger CH clones, or modulation of the immune microenvironment. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Financial Impact of Imatinib Discontinuation in Brazil - a Real World Evidence Pharmacoeconomic Study in Chronic Myeloid Leukemia of a Private Institution

Introduction Recent studies showed that tyrosine kinase inhibitors (TKI) treatment could be safely discontinued in a selected group of chronic phase (CP) chronic myeloid leukemia (CML) patients that achieved deep molecular response (DMR), making treatment-free remission (TFR) a new goal of therapy. The discontinuation treatment in patients with sustained molecular response to MR4 or MR4.5, a practice that has been performed and consolidated since 2011 in other countries, is not feasible in Brazil outside clinical trials because of the lack of coverage for performing RQ-PCR as recommended by the international guidelines. For all these aspects, it seemed essential to us to analyze the financial impact of TKI discontinuation, following strict monitoring criteria, and perform a projection of economic costs in a population of CML patients treated in first-line with imatinib eligible for discontinuation. Aims: To demonstrate the feasibility of coverage of Q-PCR to perform discontinuation of imatinib treatment on eligible patients [ treatment free-response (TFR)] in Brazil based on the financial impact Material and Methods From 2020 -2021, 26 eligible patients from a single private institution in Brazil were invited to participate in a single-arm trial of Imatinib discontinuation (DIP). Inclusion criteria: age > 18 years, chronic phase, minimum of 04 years of Imatinib therapy, a deep molecular response sustained > or = 02 years (confirmed by 04 tests in the last two years, defined MR4.0 or MR 4.5 and a confirmatory exam at the moment of the screening). After discontinuation, patients were monitored by RT- PCR monthly in the first year, every two months in the second year, and every three months after the third year. Criteria for Imatinib re-initiation were the same of the Euro-Ski trial. Considering that US$ 1.00 are R$ 5.3 ( Brazilian currency- March /2022 ) for Branded Imatinib - 400 mg/d, the monthly cost has been estimated at R$ 16,933.90 or US$ 3,95.07 and the generic imatinib- 400mg/d monthly R$ 13,048.90 or US$ 2,462.05 ( CEMED- March/2022). The unitary value for the Q-PCR exam has been estimated, with a large price range at R$ 1,311.25 (R$790.00 to R$ 2,159.00) or US$ 247.40. Results Of 26 patients, 20 consent to discontinuation of imatinib. Six patients declined despite information because of their insecurity about TFR. Twelve patients (60%) presented MR4. The median age was 52.3, and 13 (65%) were female. Median time diagnosis to discontinuation of imatinib 8.5 (4.6-15.5) years. Twelve (60%) patients sustained TFR. . In this interim analysis, the median time of follow-up was 14.5 (2.7-18.8) months. During the follow-up, 244 RQ-PCR were performed. The cumulative time without treatment was 224.5 months. The costs with Q-PCR were R$ 319,945.00 or US$ 60,366.98 (244 exams during follow-up (median time 14,4 months). The average time of months without treatment was 224.5 months. The cost of treatment without discontinuation would be R$ 4,131,871.60 or US$ 779,598.41 (Branded Imatinib) or R$ 2,929,478.05 or US$ 552,731.70 (imatinib copies). The saving on median time of follow-up (14.4 months ) were R$ 3,811,926.60 or US$ 719,231.43 (Branded Imatinib) or R$ 2,609,533.05 or US$ 492,364.72 (imatinib copies). Discussion: Considering the methodology of Cost-Utility, the saving resulting from the discontinuation of treatment for 20 patients for 14.4 months despite the loss of MR of 40 % of patients were R$ 3,811,926.60 or US$ 719,231.43 (Branded Imatinib) or R$ 2,609,533.05 or US$ 492,364.72 (imatinib copies). The results show that if Q-PCR tests were available in clinical practice, within pre-established protocols, there would be equalization and adequacy with the international monitoring guidelines, and discontinuation protocols could be feasible in clinical practice. Conclusion: The possibility of discontinuation would have a huge financial impact on the Brazilian Health System, resulting in the economic viability of treating hundreds of patients and performing thousands of Q-PCR exams, creating a rational and balanced model of clinical efficacy coupled with basic sustainability premises of modern oncology.

FINANCIAL IMPACT OF IMATINIB DISCONTINUATION IN BRAZIL – A PHARMACOECONOMIC STUDY IN CHRONIC MYELOID LEUKEMIA OF A PRIVATE INSTITUTION

Recent studies showed that tyrosine kinase inhibitors (TKI) treatment could be safely discontinued in a selected group of chronic phase (CP) chronic myeloid leukemia (CML) patients that achieved deep molecular response (DMR), making treatment-free remission (TFR) a new goal of therapy. The discontinuation of treatment in patients with sustained molecular response to MR4 or MR4.5, a practice that has been performed in other countries is not feasible in Brazil outside clinical trials because of the lack of coverage for performing RQ-PCR as recommended by the international guidelines. For all these aspects, it seemed essential to us to analyze the financial impact of TKI discontinuation, following strict monitoring criteria, and perform a projection of economic costs in a population of CML patients treated in first-line with imatinib eligible for discontinuation. To demonstrate the feasibility of coverage of Q-PCR to perform discontinuation of imatinib treatment on eligible patients [ treatment free-response (TFR)] in Brazil based on the financial impact. From 2020 -2021, 20 eligible patients from a single private institution in Brazil were invited to participate in a single-arm trial of Imatinib discontinuation (DIP). After discontinuation, patients were monitored by RT- PCR monthly in the first year, every two months in the second year, and every three months after the third year. Criteria for Imatinib re-initiation were the same of the Euro-Ski trial. Considering that US$ 1.00 are R$ 5.3 (Brazilian currency- March /2022) for Branded Imatinib – 400 mg/d, the monthly cost has been estimated at R$ 16,933.90 or US$ 3,95.07 and the generic imatinib- 400mg/d monthly R$ 13,048.90 or US$ 2,462.05 (CEMED- March/2022). The unitary value for the Q-PCR exam has been estimated, with a large price range at R$ 1,311.25 (R$790.00 to R$ 2,159.00) or US$ 247.40. Of 26 patients, 20 consent to discontinuation of imatinib. Twelve patients (60%) presented MR4. Median time diagnosis to discontinuation of imatinib 8.5 (4.6-15.5) years. Twelve (60%) patients sustained TFR. During the follow-up, 244 RQ-PCR were performed. The cumulative time without treatment was 224.5 months. The costs with Q-PCR were R$ 319,945.00 or US$ 60,366.98 (244 exams during follow-up (median time 14,4 months). The average time of months without treatment was 224.5 months. The cost of treatment without discontinuation would be R$ 4,131,871.60 or US$ 779,598.41 (Branded Imatinib) or R$ 2,929,478.05 or US$ 552,731.70 (imatinib copies). The saving on median time of follow-up (14.4 months) were R$ 3,811,926.60 or US$ 719,231.43 (Branded Imatinib) or R$ 2,609,533.05 or US$ 492,364.72 (imatinib copies). Considering the methodology of Cost-Utility, the saving resulting from the discontinuation of treatment for 20 patients for 14.4 months despite the loss of MR of 40 % of patients were R$ 3,811,926.60 or US$ 719,231.43 (Branded Imatinib) or R$ 2,609,533.05 or US$ 492,364.72 (imatinib copies). The results show that if Q-PCR tests were available in clinical practice, within pre-established protocols, there would be equalization and adequacy with the international monitoring guidelines, and discontinuation protocols could be feasible in clinical practice. The possibility of discontinuation would have a huge financial impact on the Brazilian Health System, resulting in the economic viability of treating hundreds of patients and performing thousands of Q-PCR exams, creating a rational and balanced model of clinical efficacy coupled with basic sustainability premises of modern oncology.

Treatment-free remission after ceasing venetoclax-based therapy in patients with acute myeloid leukemia

AbstractThe clinical benefit of adding venetoclax (VEN) to hypomethylating agents or low-dose cytarabine in older and/or unfit patients with newly diagnosed acute myeloid leukemia (AML) has been confirmed in phase 3 studies. With the increased uptake of VEN-based therapies for patients with AML, a pertinent question is whether treatment can be safely ceased among patients who have achieved sustained remission. We hypothesized that a proportion of patients opting to cease therapy may benefit from a treatment-free remission (TFR) period without indefinite treatment. We report the retrospective outcomes of 29 patients in remission for a minimum of 12 months on VEN-based therapy, with 55% continuing therapy until disease progression and 45% electively ceasing treatment (STOP). With follow-up exceeding 5 years, we observed a median TFR lasting 45.8 months among the STOP cohort, with >50% of patients still in sustained remission at the data cutoff. The risk of relapse and duration of relapse-free and overall survival were similar between the 2 cohorts. Factors favoring sustained TFR within the cohort included NPM1 and/or IDH2 mutation at diagnosis, complete remission without measurable residual disease, and at least 12 months of VEN-based combination therapy prior to treatment cessation.

Subsequent attempt tyrosine kinase inhibitor discontinuation in patients with chronic myeloid leukemia; a single institute experience.

Discontinuation of tyrosine kinase inhibitors (TKIs) is now a feasible therapeutic goal for patients with chronic phase chronic myeloid leukemia (CML-CP). Whereas approximately half of patients experience molecular relapse, after resuming with any TKI; the majority re-achieve a deep molecular response (DMR). It is unclear whether such patients who re-achieve a durable DMR can discontinue TKI safely again. Here, we retrospectively assessed first, second, and third attempts to stop TKIs in patients with CML-CP. At the first attempt, 28 out of a total of 53 patients achieved sustained treatment-free remission (TFR; 53.4%; 95% confidence interval [CI], 39.0%-65.9%). Subsequently, 10 of 25 patients attempted a second TKI discontinuation, and in all cases, this was after receiving second-generation TKIs. Four of 10 patients successfully achieved TFR (37.5%; 95% CI, 9.9%-65.9%). All patients who relapsed at the second TKI discontinuation attempt were re-administered TKIs, and soon achieved at least a major molecular remission. All six second relapse patients had a loss of MR4.5 at 3 months after TKI discontinuation. These findings suggest that second and third attempts to successfully stop TKI treatment are feasible in patients with CML-CP.

Early BCR-ABL1 kinetics are predictive of subsequent achievement of treatment-free remission in chronic myeloid leukemia

With treatment-free remission (TFR) rapidly becoming the ultimate goal of therapy in chronic myeloid leukemia (CML), there is a need to develop strategies to maximize sustained TFR by improving our understanding of its key determinants. Chronic-phase CML patients attempting TFR were evaluated to identify the impact of multiple variables on the probability of sustained TFR. Early molecular response dynamics were included as a predictive variable, assessed by calculating the patient-specific halving time of BCR-ABL1 after commencing tyrosine kinase inhibitor (TKI) therapy. Overall, 115 patients attempted TFR and had ≥12 months of follow-up. The probability of sustained TFR, defined as remaining in major molecular response off TKI therapy for 12 months, was 55%. The time taken for the BCR-ABL1 value to halve was the strongest independent predictor of sustained TFR: 80% in patients with a halving time of <9.35 days (first quartile) compared with only 4% if the halving time was >21.85 days (last quartile) (P < .001). The e14a2 BCR-ABL1 transcript type and duration of TKI exposure before attempting TFR were also independent predictors of sustained TFR. However, the BCR-ABL1 value measured at 3 months of TKI was not an independent predictor of sustained TFR. A more rapid initial BCR-ABL1 decline after commencing TKI also correlated with an increased likelihood of achieving TFR eligibility. The association between sustained TFR and the time taken for BCR-ABL1 to halve after commencing TKI was validated using an independent dataset. These data support the critical importance of the initial kinetics of BCR-ABL1 decline for long-term outcomes.

Treatment-free remission and immunity in chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is caused by the reciprocal translocation t(9;22)(q34;q11), resulting in the BCR-ABL1 fusion gene. BCR-ABL1 tyrosine kinase inhibitors (TKIs) improve overall survival in patients with chronic phase CML (CML-CP). Approximately half of the patients who achieve a durable deep molecular response can achieve sustained treatment-free remission (TFR) after TKI discontinuation; thus TFR is now a therapeutic goal for most patients with CML-CP. Sensitive BCL-ABL1 transcript detection methods reveal that evidence of residual CML cells remains in patients who achieve sustained TFR, indicating that the host immune system protects against CML relapse. The human immune system is composed of innate and adaptive arms. Natural killer cells are major components of the innate immune system, while T cells are major components of the adaptive immune system. Myeloid-derived suppressor cells and regulatory T cells, both suppressors of the immune response, have important roles in the regulation of CML. Here, we review the current understanding of the immune response in CML, especially in TFR.

Chronic myeloid leukemia: aiming for treatment free remission

BCR-ABL tyrosine kinase inhibitors (TKIs) dramatically improve the chronic myeloid leukemia (CML) prognosis, and most CML patients in the chronic phase are now able to lead lives that are comparable to those of healthy individuals. However, the high cost and adverse effects associated with long-term treatment remain issues in the treatment of CML patients. At the setout, a clinical study involving the discontinuation of imatinib was conducted in France. Thereafter, several TKI stop studies of first-generation (imatinib) and second-generation TKIs (dasatinib, nilotinib) have shown an earlier response than that with imatinib. These studies revealed that almost 50% of CML patients who were treated with TKIs and achieved a certain period of sustained deep molecular response can stop TKIs safely and obtain sustained treatment-free remission (TFR). Adverse effects of TKI withdrawal and predicting factors for successful discontinuation including immunity are gradually becoming clear via these studies. For superior CML treatment, several promising agents, including ABL001, are being developed. I trust that these efforts will enable CML patients to maintain TFR in the near future.

Influence of major BCR-ABL1 transcript subtype on outcome in patients with chronic myeloid leukemia in chronic phase treated frontline with nilotinib.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of BCR-ABL1 transcript as a result of reciprocal translocation between chromosome 9 and 22. The most common transcripts subtypes are e13a2 (b2a2) and e14a2 (b3a2). The prognostic impact of the type of BCR-ABL1 transcript has been the subject of controversies over time. In the imatinib era, several studies have suggested a deeper and faster response in patients expressing e14a2. However, the impact on response after first line therapy with a second-generation tyrosine kinase inhibitor, nilotinib, is unknown.We retrospectively evaluated 118 patients newly diagnosed with chronic phase CML and treated frontline with nilotinib inside or outside clinical trial in five French centers. Only patients expressing e14a2 or e13a2 transcripts alone were analyzed.At baseline, 55.3% expressed e14a2, 44.7% expressed e13a2. The median age was 51 years and median follow-up was 49 months. Relative risks of CML at diagnosis were similar according to the ELTS score (p = .87). Complete hematological response and complete cytogenetic response rates were similar among groups. Patients expressing e14a2 transcripts compared to e13a2 transcripts had deeper and faster molecular responses, when considering MMR (100% vs 84.1%, p = .007) with a median time of 6.7 and 17.1 months or MR4.5 (100% vs 59.9%, p = .005) with a median time of 39.7 and 70.9 months, respectively. A sustained treatment free remission was observed in 10/10 patients with e14a2 versus 1/3 with e13a2 transcript (p = .04).In conclusion, even treated with nilotinib first line, patients with chronic phase CML expressing BCR-ABL1 e13a2 transcript have a lower rate of deep molecular responses.

Treatment-free remission after thrombopoietin receptor agonist discontinuation in patients with newly diagnosed immune thrombocytopenia: an observational retrospective analysis in real-world clinical practice.

Thrombopoietin receptor agonists (TPO-RAs) are used for treatment of chronic immune thrombocytopenia (ITP). Several studies have shown that TPO-RAs induce remission and sustained response, despite long-term discontinuation of therapy. Furthermore, TPO-RAs are effective in patients with newly diagnosed ITP. Here, we retrospectively assessed all patients with ITP who received TPO-RAs in our hospital, focusing on newly diagnosed, non-splenectomized patients who had discontinued TPO-RAs due to sustained complete response (CR, platelet count ≥ 100 × 109/L). Moreover, we explored predictive factors related to sustained treatment-free remission (TFR) without additional ITP treatment. Seventy-seven consecutive patients with ITP received TPO-RAs from 2011 to 2018. Twenty-seven newly diagnosed patients achieved CR and discontinued TPO-RAs. The overall response and discontinuation rates in all patients with ITP were 79.2% and 41.6%, respectively. In newly diagnosed patients who discontinued TPO-RAs, the 2-year TFR rate, cumulative incidence of loss of CR, and response (R) rate (platelet count ≥ 30 × 109/L) were 66.4%, 46.7%, and 34.0%, respectively. Patients who achieved R within 14days from the start of TPO-RA administration exhibited a higher 2-year TFR rate, compared with patients who did not (87.5% vs. 48.5%, p = 0.0106). In conclusion, patients with newly diagnosed ITP who achieve sustained response should consider discontinuation of TPO-RAs.

NKT-Like (CD3+CD56+) Cells in Chronic Myeloid Leukemia Patients Treated With Tyrosine Kinase Inhibitors.

Therapy with Tyrosine Kinase Inhibitors (TKI) aiming stable deep molecular response is the gold standard to treat Chronic Myeloid Leukemia (CML). NKT-like cells (CD3+CD56+) combine characteristics of T and NK cells. The physiopathological role of these cells remains unknown although the literature refers their association with inflammation, autoimmune diseases, and cancer. Since the information regarding the role of NKT-like cells in CML is rare, we aimed at the characterization of these cells in CML patients treated with TKIs. Peripheral blood NKT-like cells from 48 CML patients and 40 healthy donors were analyzed by multiparametric flow cytometry. Functional tests consisting of co-culture with leukemic target cells (K562 cell line) were used to measure degranulation and cytokine production. Our results revealed that NKT-like cells are decreased in treated CML patients, although they present increased expression of activation markers (CD69 and HLA-DR), increased degranulation (CD107a) and impaired IFN-γ production. Significantly alterations on the expression of tumor recognition (NCRs and NKp80), and immune regulation receptors (LAG-3, TIM-3, and CD137) by NKT-like cells were observed in CML patients. Second generation TKIs increased cell activation (CD69) and decreased expression of NKp44 and NKp80 by NKT-like cells from CML patients when compared to Imatinib. CML patients that achieved deep molecular response (MR4.5) presented downregulation of NKp44 and LAG-3. Further studies are needed to clarify the role of these cells as biomarkers of therapy response and also to evaluate their value for discrimination of better candidates for sustained treatment-free remission after TKI discontinuation.

PF408 DASFREE 2‐YEAR UPDATE: DASATINIB DISCONTINUATION IN PATIENTS (PTS) WITH CHRONIC MYELOID LEUKEMIA IN CHRONIC PHASE (CML‐CP) AND DEEP MOLECULAR RESPONSE (DMR)

Background:Treatment‐free remission (TFR) is a potential treatment goal for pts with CML‐CP. Sustained TFR has previously been reported for pts enrolled in the DASFREE trial (CA180406/NCT01850004), in which a 48% rate of relapse‐free survival was observed at 18 mo after dasatinib discontinuation (Shah Blood 2018). Here we report results for pts in DASFREE with a minimum of 2 y of follow‐up.Aims:To assess the durability of TFR at 2 y after discontinuing dasatinib treatment in pts with CML‐CP and dasatinib‐induced DMR.Methods:DASFREE is an open‐label, single‐arm phase 2 study in adult pts with CML‐CP on first‐line (1L) or subsequent‐line (≥2L) dasatinib for ≥2 y and with DMR (MR4.5; BCR‐ABL1 ≤0.0032% on the International Scale [IS]). MR4.5 was confirmed at a local lab for ≥1 y prior to enrollment and confirmed at a central lab twice within 3 mo prior to dasatinib discontinuation. BCR‐ABL1 was monitored centrally every mo after discontinuation in the 1st y and every 3 mo thereafter. If major molecular response (MMR; BCR‐ABL1 ≤0.1% IS) was lost, pts resumed dasatinib at their previous dose. The primary endpoint was the rate of MMR at 12 mo after discontinuation without restarting dasatinib. Key secondary endpoints include event‐free survival (EFS; survival with no loss of MMR), rate of transformation to accelerated phase/blast crisis (AP/BC), progression‐free survival (PFS; survival without progression to AP/BC), and overall survival. Key exploratory analyses include the frequency of adverse events (AEs) on and off treatment.Results:Pt characteristics were previously reported; briefly, 37 pts (44%) discontinued 1L dasatinib and 47 pts (56%) discontinued ≥2L dasatinib (Shah Blood 2018). To date, 11 pts (13%) have discontinued the study (2 off‐treatment; 9 after restarting dasatinib). In total, 46 pts lost MMR (1 pt lost MMR at mo 39 and had not restarted therapy at the time of this analysis) after a median of 4 mo (range 1–39) after discontinuation. Of the 46 pts who lost MMR, 45 (98%) restarted on dasatinib; 44 of 45 (98%) regained MMR after a median of 2 mo (range 1–4) and 43 (96%) regained MR4.5 after a median of 3 mo (range 2–18) (Figure). At 2 y, EFS was 46% (95% confidence interval [CI] 36, 57) in all pts, 51% (95% CI 35, 67) in 1L pts, and 42% (95% CI 28, 57) in ≥2L pts. PFS at 2 y was 99% (95% CI 96, 100) in all pts (there was 1 death unrelated to CML). No pts transformed to AP/BC. Time on prior treatment (regardless of line of dasatinib) was 65 mo for pts who lost MMR (n = 19) and 73 mo for pts who maintained MMR (n = 18). A univariate analysis revealed statistically significant associations between EFS and older age (hazard ratio [HR] 2.722; 95% CI 1.126, 6.578; P = 0.0261) and prior 1L therapy (HR 0.381; 95% CI 0.162, 0.893; P = 0.0265). All AEs observed thus far in DASFREE have been consistent with the known safety profile of dasatinib. There were 2 additional withdrawal events (in the same pts) at this follow‐up.Summary/Conclusion:Extended follow‐up results from DASFREE continue to support the feasibility of TFR in pts with CML‐CP who achieve stable DMR with dasatinib. The observed durability of TFR at 2 y (with 46% of all pts maintaining EFS) provides clinically relevant information for many pts considering TFR with dasatinib in the 1L and beyond. Lastly, no new pts experienced withdrawal events.image