Managing chronic myeloid leukaemia in the elderly with intermittent imatinib treatment

The Italian Multicentric Randomized OPTkIMA Trial on Fixed vs Progressive Intermittent TKI Therapy in CML Elderly Patients: 3-Years of Molecular Response and Quality of Life Monitoring After Completing the Treatment Plan

BACKGROUND

Intermittent treatment with tyrosine kinase inhibitors (TKIs) is an option for elderly chronic myeloid leukemia (CML) patients who are often candidates for life-long treatment.

MATERIALS AND METHODS

The Italian phase III multicentric randomized Optimize TKIs Multiple Approaches (OPTkIMA) study aimed to evaluate if a progressive de-escalation of TKIs is able to maintain the molecular remission (MR)3.0 and to improve Health-Related Quality of Life (HRQoL) in CML elderly patients.

RESULTS

A total of 215 patients in stable MR3.0/MR4.0 were randomized to receive an intermittent TKI schedule 1 month ON-1 month OFF for 3 years (FIXED arm; n = 111) vs. a progressive de-escalation TKI dose up to one-third of the starting dose at the 3rd year (PROGRESSIVE arm; n = 104). Two hundred three patients completed the 3rd year of OPTkIMA study. At the last follow-up, MR3.0 loss was 27% vs. 46% (P = .005) in the FIXED vs PROGRESSIVE arm, respectively. None of these patients experienced disease progression. The 3-year probability of maintaining the MR3.0 was 59% vs. 53%, respectively (P = .13). HRQoL globally improved from the baseline to the 3rd year, without any significant difference between the 2 arms. After the 3rd year, the proportion of patients who was address to TKI discontinuation in the 2 arms was 36% (FIXED) vs. 58% (PROGRESSIVE) (P = .03).

CONCLUSIONS

The intensification of intermittent TKI therapy is associated with a higher incidence of MR3.0 loss, but those patients who maintain the MR3.0 molecular response at the end of the study have been frequently considered eligible for TFR. The HRQoL generally improved during the de-escalation therapy in both randomization arms.

Artificial Intelligence-Based Management of Adult Chronic Myeloid Leukemia: Where Are We and Where Are We Going?

Artificial intelligence (AI) is emerging as a discipline capable of providing significant added value in Medicine, in particular in radiomic, imaging analysis, big dataset analysis, and also for generating virtual cohort of patients. However, in coping with chronic myeloid leukemia (CML), considered an easily managed malignancy after the introduction of TKIs which strongly improved the life expectancy of patients, AI is still in its infancy. Noteworthy, the findings of initial trials are intriguing and encouraging, both in terms of performance and adaptability to different contexts in which AI can be applied. Indeed, the improvement of diagnosis and prognosis by leveraging biochemical, biomolecular, imaging, and clinical data can be crucial for the implementation of the personalized medicine paradigm or the streamlining of procedures and services. In this review, we present the state of the art of AI applications in the field of CML, describing the techniques and objectives, and with a general focus that goes beyond Machine Learning (ML), but instead embraces the wider AI field. The present scooping review spans on publications reported in Pubmed from 2003 to 2023, and resulting by searching "chronic myeloid leukemia" and "artificial intelligence". The time frame reflects the real literature production and was not restricted. We also take the opportunity for discussing the main pitfalls and key points to which AI must respond, especially considering the critical role of the 'human' factor, which remains key in this domain.

Twenty years of evolution of CML therapy: how the treatment goal is moving from disease to patient

The introduction of imatinib in 2000 opened the era of tyrosine kinase inhibitors (TKIs) for CML therapy and has revolutionized the life expectancy of CML patients, which is now quite like the one of the healthy aged population. Over the last 20 years, both the TKI therapy itself and the objectives have undergone evolutions highlighted and discussed in this review. The main objective of the CML therapy in the first 10 years after TKI introduction was to abolish the disease progression from the chronic to the blastic phase and guarantee the long-term survival of the great majority of patients. In the second 10 years (from 2010 to the present), the main objective of CML therapy moved from survival, considered achieved as a goal, to treatment-free remission (TFR). Two phenomena emerged: no more than 50-60% of CML patients could be candidates for discontinuation and over 50% of them molecularly relapse. The increased cumulative incidence of specific TKI off-target side effects was such relevant to compel to discontinue or reduce the TKI administration in a significant proportion of patients and to avoid a specific TKI in particular settings of patients. Therefore, the treatment strategy must be adapted to each category of patients. What about the patients who do not get or fail the TFR? Should they be compelled to continue the TKIs at the maximum tolerated dose? Alternative strategies based on the principle of minimal effective dose have been tested with success and they are now re-evaluated with more attention, since they guarantee survival and probably a better quality of life, too. Moving from treating the disease to treating the patient is an important change of paradigm. We can say that we are entering a personalized CML therapy, which considers the patients' age, their comorbidities, tolerability, and specific objectives. In this scenario, the new techniques supporting the monitoring of the patients, such as the digital PCR, must be considered. In the present review, we present in deep this evolution and comment on the future perspectives of CML therapy.

Successful treatment discontinuation in CML patients with full-dose and low-dose TKI: Results from real-world practice

Background: In clinical studies, some patients who achieve deep molecular response (DMR) can successfully discontinue tyrosine kinase inhibitor (TKI). TKI dose reduction is also an important aspect of alleviating adverse effects and improving quality of life. This study aimed to explore the outcome after drug withdrawal in Chinese CML patients. Methods: We conducted a retrospective analysis of the outcome of 190 patients who stopped TKI. 27 patients experienced dose reduction before TKI discontinuation. The median duration of TKI treatment and MR4 before discontinuation was 82 months and 61 months. Results: With median follow-up after stopping TKI treatment of 17 months, the estimated TFR (Treatment Free Remission) were 76.9% (95%CI, 70.2%-82.4%), 68.8% (95%CI, 61.3%-75.2%), and 65.5% (95%CI, 57.4%-72.5%) at 6, 12 and 24 months. For full-dose and low-dose TKI groups, the TFR at 24 months was 66.7% and 55.8% (p = 0.320, log-rank). Most patients (56/57) quickly achieved MMR after restarting TKI treatment. Multivariable analysis showed that patients with TKI resistance had a higher risk of molecular relapse than patients without TKI resistance (p < 0.001). Conclusion: TFR rates were not impaired in patients experiencing dose reduction before TKI discontinuation compared to patients with full-dose TKI. Our data on Chinese population may provide a basis for the safety and feasibility of TKI discontinuation, including discontinuation after dose reduction, in clinical practice.

Digital PCR as a New Method for Minimal Residual Disease Monitoring and Treatment Free Remission Management in Chronic Myeloid Leukemia Patients: Is It Reliable?

The effective and sensitive monitoring of Minimal Residual Disease or Measurable Residual Disease (MRD) is a very important aspect in the management of patients affected by hematologic malignancies. The recent availability of new technologies has opened to the improvement of MRD monitoring. It is particularly relevant in patients affected by Chronic Myeloid Leukemia (CML). MRD monitoring is key in the management of CML patients thanks to the efficacy of TKIs therapy. Moreover, the policies of TKIs discontinuation aimed at treatment free remission are strongly based on the good selection of patients eligible for stopping TKIs therapy. The recently described application of digital PCR in CML patients monitoring seems to improve the accuracy and precision in the identification of optimal responders. The present review reports an overview on the application of digital PCR in the monitoring of MRD in CML and its impact on TKIs discontinuation trials and, consequently, on TFR success.

Treatment-Free Remission in Chronic Myeloid Leukemia Patients Treated With Low-Dose TKIs: A Feasible Option Also in the Real-Life. A Campus CML Study

Treatment-free remission (TFR) has become a primary therapeutic goal in CML and is also considered feasible by international guidelines. TKIs dose reduction is often used in real-life practice to reduce adverse events, although its impact on TFR is still a matter of debate. This study aimed to explore the attitude of Italian hematologists towards prescribing TKIs at reduced doses and its impact on TFR. In September 2020, a questionnaire was sent to 54 hematology centers in Italy participating to the Campus CML network. For each patient, data on the main disease characteristics were collected. Most of the hematologists involved (64.4%) believed that low-dose TKIs should not influence TFR. Indeed, this approach was offered to 194 patients. At the time of TFR, all but 3 patients had already achieved a DMR, with a median duration of 61.0 months. After a median follow-up of 29.2 months, 138 (71.1%) patients were still in TFR. Interestingly, TFR outcome was not impaired by any of the variables examined, including sex, risk scores, BCR-ABL1 transcript types, previous interferon, type and number of TKIs used before treatment cessation, degree of DMR or median duration of TKIs therapy. On the contrary, TFR was significantly better after dose reduction due to AEs; furthermore, patients with a longer DMR duration showed a trend towards prolonged TFR. This survey indicates that low-dose TKI treatment is an important reality. While one third of Italian hematologists still had some uncertainties on TFR feasibility after using reduced doses of TKIs outside of clinical trials, TFR has often been considered a safe option even in patients treated with low-dose TKIs in the real-life setting. It should be noted that only 28.9% of our cases had a molecular recurrence, less than reported during standard dose treatment. Consequently, TFR is not impaired using low-dose TKIs.

Development of BCR-ABL1 Transgenic Zebrafish Model Reproducing Chronic Myeloid Leukemia (CML) Like-Disease and Providing a New Insight into CML Mechanisms

Zebrafish has proven to be a versatile and reliable experimental in vivo tool to study human hematopoiesis and model hematological malignancies. Transgenic technologies enable the generation of specific leukemia types by the expression of human oncogenes under specific promoters. Using this technology, a variety of myeloid and lymphoid malignancies zebrafish models have been described. Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasia characterized by the BCR-ABL1 fusion gene, derived from the t (9;22) translocation causing the Philadelphia Chromosome (Ph). The BCR-ABL1 protein is a constitutively activated tyrosine kinas inducing the leukemogenesis and resulting in an accumulation of immature leukemic cells into bone marrow and peripheral blood. To model Ph+ CML, a transgenic zebrafish line expressing the human BCR-ABL1 was generated by the Gal4/UAS system, and then crossed with the hsp70-Gal4 transgenic line. The new line named (BCR-ABL1pUAS:CFP/hsp70-Gal4), presented altered expression of hematopoietic markers during embryonic development compared to controls and transgenic larvae showed proliferating hematopoietic cells in the caudal hematopoietic tissue (CHT). The present transgenic zebrafish would be a robust CML model and a high-throughput drug screening tool.

Molecular response and quality of life in chronic myeloid leukemia patients treated with intermittent TKIs: First interim analysis of OPTkIMA study

Background

Intermittent treatment with TKIs is an option for the great majority (70%–80%) of CML patients who do not achieve a stable deep molecular response and are not eligible for treatment discontinuation. For these patients, the only alternative is to assume TKI continuously, lifelong.

Methods

The Italian phase III multicentric randomized OPTkIMA study started in 2015, with the aim to evaluate if a progressive de‐escalation of TKIs (imatinib, nilotinib, and dasatinib) is able to maintain the molecular response (MR^3.0) and to improve Health Related Quality of Life (HRQoL).

Results

Up to December 2018, 166/185 (90%) elderly CML patients in stable MR^3.0/MR^4.0 completed the first year of any TKI intermittent schedule 1 month ON and 1 month OFF. The first year probability of maintaining the MR^3.0 was 81% and 23.5% of the patients who lost the molecular response regained the MR^3.0 after resuming TKI continuously. Patients’ HRQoL at baseline was better than that of matched peers from healthy population. Women was the only factor independently associated with worse baseline HRQoL (p > 0.0001). Overall, global HRQoL worsened at 6 (p < 0.001) but returned to the baseline value at 12 months and it was statistically significantly worse in women (p = 0.001).

Conclusions

De‐escalation of any TKI by 1 month ON/OFF schedule maintains the MR^3.0/MR^4.0 in 81% of the patients during the first 12–24 months. No patients progressed to accelerated/blastic phase, all the patients (23.5%) losing MR^3.0 regained the MR^3.0 and none suffered from TKI withdrawn syndrome. The study firstly report on HRQoL in elderly CML patients moving from a continuous daily therapy to a de‐escalated intermittent treatment.

Exosomes and Extracellular Vesicles in Myeloid Neoplasia: The Multiple and Complex Roles Played by These "Magic Bullets"

Simple Summary

Extracellular vesicles (EVs) are released by the majority of cell types and can be isolated from both cell cultures and body fluids. They are involved in cell-to-cell communication and may shuttle different messages (RNA, DNA, and proteins). These messages are known to influence the microenvironment of cells and their behavior. In recent years, some evidence about the involvement of EVs and exosomes, an EV subgroup, in immunomodulation, the transfer of disease markers, and the treatment of myeloid malignancies have been reported. Little is known about these vesicles in this particular setting of hematologic neoplasia; here, we summarize and critically review the available results, aiming to encourage further investigations.

Abstract

Extracellular vesicles (exosomes, in particular) are essential in multicellular organisms because they mediate cell-to-cell communication via the transfer of secreted molecules. They are able to shuttle different cargo, from nucleic acids to proteins. The role of exosomes has been widely investigated in solid tumors, which gave us surprising results about their potential involvement in pathogenesis and created an opening for liquid biopsies. Less is known about exosomes in oncohematology, particularly concerning the malignancies deriving from myeloid lineage. In this review, we aim to present an overview of immunomodulation and the microenvironment alteration mediated by exosomes released by malicious myeloid cells. Afterwards, we review the studies reporting the use of exosomes as disease biomarkers and their influence in response to treatment, together with the recent experiences that have focused on the use of exosomes as therapeutic tools. The further development of new technologies and the increased knowledge of biological (exosomes) and clinical (myeloid neoplasia) aspects are expected to change the future approaches to these malignancies.

Dose Optimization of Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia: A New Therapeutic Challenge

The chronic myeloid leukemia (CML) therapeutic landscape has dramatically changed with tyrosine kinase inhibitor (TKI) development, which allows a near-normal life expectancy. However, long-term TKI exposure has been associated with persistent adverse events (AEs) which negatively impact on quality of life (QoL) and have the potential to cause significant morbidity and mortality. In clinical practice, TKI dose reduction is usually considered to reduce AEs and improve QoL, but dose optimization could have also another aim, i.e., the achievement and maintenance of cytogenetic and molecular responses. While therapy cessation appeared as a safe option for about half of the patients achieving an optimal response, no systematic assessment of long-term TKI dose de-escalation has been made. The present review is focused on the most recent evidences for TKIs dose modifications in CML clinical studies and in the real-life setting. It will consider TKI dose modifications in newly diagnosed patients, dose reduction for AEs, or in deep molecular response, either as a prelude to treatment-free remission (TFR) or as continuous maintenance therapy in those patients not wishing to attempt TFR. In addition, it will focus on patients not achieving a molecular response deep enough to go to TFR, and for whom dose reduction could be an option to avoid AEs.

Molecular Testing in CML between Old and New Methods: Are We at a Turning Point?

Molecular monitoring of minimal residual disease (MRD) and BCR-ABL1 kinase domain (KD) mutation testing have a well consolidated role in the routine management of chronic myeloid leukemia (CML) patients, as they provide precious information for therapeutic decision-making. Molecular response levels are used to define whether a patient has an "optimal", "warning", or "failure" response to tyrosine kinase inhibitor (TKI) therapy. Mutation status may be useful to decide whether TKI therapy should be changed and which alternative TKI (or TKIs) are most likely to be effective. Real-time quantitative polymerase chain reaction (RQ-qPCR) and Sanger sequencing are currently the gold standard for molecular response monitoring and mutation testing, respectively. However, in recent years, novel technologies such as digital PCR (dPCR) and next-generation sequencing (NGS) have been evaluated. Here, we critically describe the main features of these old and novel technologies, provide an overview of the recently published studies assessing the potential clinical value of dPCR and NGS, and discuss how the state of the art might evolve in the next years.

RT-qPCR versus Digital PCR: How Do They Impact Differently on Clinical Management of Chronic Myeloid Leukemia Patients?

Real-time quantitative PCR (RT-qPCR) is the gold standard to quantify the BCR-ABL1 transcript for molecular response monitoring in chronic myeloid leukemia (CML) patients, and it plays a pivotal role in clinical decision-making process, even if it presents technical limits. Increasing data suggest that digital PCR (dPCR) is more accurate and reliable than RT-qPCR in CML minimal residual disease monitoring and in patients' selection for treatment discontinuation. But what about the identification of treatment discontinuation failures? We present the case of a CML patient enrolled both in a study aiming to comparatively assess molecular response by RT-qPCR and dPCR and in the progressive arm of the OPTkIMA trial. This is a phase III trial including CML patients randomized to receive a fixed versus a progressive intermittent tyrosine kinase inhibitor regimen. At 24 months, because of two consecutive detections of MR^2.0 by RT-qPCR, the patient resumed daily treatment. Conversely, dPCR revealed a stability of molecular response and even a slight decreasing of transcript over time. An additional specimen was sampled one month after the first MR^2.0 detection because of clinical decision: RT-qPCR resulted MR^3.0 and dPCR confirmed the transcript's stability. Nowadays, the resumption of therapy is RT-qPCR-driven despite its limits in detection and robustness. In this case, according to dPCR, the patient could have continued intermittent treatment and the stability of response was then confirmed by RT-qPCR. So, dPCR could be able to better identify peculiar clinical response to therapy.

On the road to treatment-free remission in chronic myeloid leukemia: what about 'the others'?

INTRODUCTION

The treatment of chronic myeloid leukemia (CML) has been drastically changed by the approval of tyrosine kinase inhibitors (TKIs). CML is now managed as a chronic disease requiring both long-term treatment and close molecular monitoring in the majority of patients.

AREAS COVERED

Evidence suggests that in a substantial number of patients who have achieved a stable deep molecular response (DMR), TKI treatment can be safely discontinued without loss of response. Therefore, treatment-free remission (TFR), through the achievement of a DMR, is increasingly regarded as a feasible treatment goal in about 20% to 40% CML patients. Nevertheless, a proportion of patients with chronic-phase CML treated with TKIs remain in stable MMR and do not achieve a DMR.

EXPERT OPINION

We provide prospective views on how it is possible to optimize treatment for patients in stable MMR but not in DMR in order to finalize the therapeutic strategy.

Chronic Myeloid Leukemia Prognosis and Therapy: Criticisms and Perspectives

Ph+ chronic myeloid leukemia (CML) is a clonal myeloproliferative disease whose clinical course is characterized by progression disease from the early chronic phase (CP) to the fatal blastic phase (BP). This programmed course is closely related to the translocation t(9;22)(q22;q11) and the resulting BCR-ABL1 fusion protein (p210) that drives the leukemic transformation of hematopoietic stem cells. Therefore, the cure of CML can only pass through the abrogation of the Ph+ clone. Allogeneic stem cell transplantation (allo-SCT) and interferon-alpha (IFNα) have been proven to reduce the Ph+ clone in a limited proportion of CML population and this translated in a lower rate of progression to BP and in a significant prolongation of survival. Tyrosine-kinase inhibitors (TKIs), lastly introduced in 2000, by preventing the disease blastic transformation and significantly prolonging the survival in up to 90% of the patient population, radically changed the fate of CML. The current therapy with TKIs induces a chronicization of the disease but several criticisms still persist, and the most relevant one is the sustainability of long-term therapy with TKIs in terms of compliance, toxicity and costs. The perspectives concern the optimization of therapy according to the age, the risk of disease, the potency and the safety profiles of the TKIs. The prolongation of survival is the most important end point which should be guaranteed to all patients. The treatment free remission (TFR) is the new goal that we would like to give to an increasing number of patients. The cure remains the main objective of CML therapy.

Low-dose tyrosine kinase inhibitors before treatment discontinuation do not impair treatment-free remission in chronic myeloid leukemia patients: Results of a retrospective study

BACKGROUND

Long-term treatment-free remission (TFR) represents a new goal for chronic myeloid leukemia (CML). In clinical practice, tyrosine kinase inhibitor (TKI) dose reductions can be considered a means of preventing adverse effects and improving quality of life. We hypothesized that administration of low-dose TKIs before treatment discontinuation does not impair TFR in patients with CML who have a deep molecular response (DMR, ≥MR⁴ ).

METHODS

We conducted a retrospective analysis of 77 patients with CML who discontinued treatment with TKIs. Twenty-six patients had been managed with low-dose TKIs before stopping treatment. Patients were to be exposed to TKIs for ≥5 years and to low-dose TKIs for ≥1 year and in DMR for ≥2 years. The loss of major molecular response (MMR) was considered a trigger for restarting therapy.

RESULTS

In the low-dose group, 61.5% of patients received second-generation TKIs, and dose reduction was ≥50% for 65.4% of patients. With a median follow-up of 61.5 months, TFR at 12 months was 56.8% in the full-dose TKI group and 80.8% in the low-dose group, and TFR at 60 months was 47.5% and 58.8%, respectively. The median time to molecular recurrence (≥MMR) from TKI discontinuation in the entire cohort was 6.2 months. All patients quickly achieved MMR after resuming TKI therapy. Results appear independent of both dose reduction and potential pretreatment with interferon-α.

CONCLUSION

This retrospective study shows that TFR was not impaired by low-dose TKI regimens before TKI cessation in Patients with CML. Nevertheless, prospective randomized clinical trials must be undertaken to analyze the probability of successful TFR in patients managed with TKI dose de-escalation strategies before TKI discontinuation.

Epigenetics and metabolism at the crossroads of stress-induced plasticity, stemness and therapeutic resistance in cancer

Despite the recent advances in the treatment of cancers, acquired drug resistance remains a major challenge in cancer management. While earlier studies suggest Darwinian factors driving acquired drug resistance, recent studies point to a more dynamic process involving phenotypic plasticity and tumor heterogeneity in the evolution of acquired drug resistance. Chronic stress after drug treatment induces intrinsic cellular reprogramming and cancer stemness through a slow-cycling persister state, which subsequently drives cancer progression. Both epigenetic and metabolic mechanisms play an important role in this dynamic process. In this review, we discuss how epigenetic and metabolic reprogramming leads to stress-induced phenotypic plasticity and acquired drug resistance, and how the two reprogramming mechanisms crosstalk with each other.

Feasibility of tumor‑derived exosome enrichment in the onco‑hematology leukemic model of chronic myeloid leukemia

Due to the discovery of their role in intra-cellular communications, exosomes, which carry information specific to the cell of origin, have garnered considerable attention in cancer research. Moreover, there is evidence to suggest the possibility of isolating different exosome sub-populations based on target antigens at the cell surface. Philadelphia chromosome-positive (Ph⁺) chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasia characterized by the break-point cluster region-proto-oncogene 1 tyrosine-protein kinase (BCR-ABL1) fusion-gene, derived from the t (9;22) translocation. Tyrosine kinase inhibitors (TKIs) target BCR-ABL1 protein and induce major or deep molecular responses in the majority of patients. Despite the fact that several studies have demonstrated the persistence of leukemic cells in the bone marrow niche, even following treatment, TKIs prolong patient survival time and facilitate treatment-free remission. These characteristics render CML a plausible model for investigating the feasibility of tumor-derived exosome fraction enrichment. In the present study, patients in the chronic phase (CP) of CML were treated with TKIs, and the quantification of the BCR-ABL1 exosomal transcript was performed using digital PCR (dPCR). The possibility of tumor-derived exosomes enrichment was confirmed, and for the first time, to the best of our knowledge, the detection of the BCR-ABL1 transcript highlighted the presence of active leukemic cells in patients with CP-CML. According to these findings, tumor-derived exosomes may be considered a novel tool for the identification of active leukemic cells, and for the assessment of innovative monitoring focused on the biological functions of exosomes in CML.

A systematic review of non-standard dosing of oral anticancer therapies

Background

The use of oral systemic anticancer therapies (SACT) has increased and led to improved cancer survival outcomes, particularly with the introduction of small molecule targeted agents and immunomodulators. Oral targeted SACT are, however, associated with toxicities, which might result in reduced quality of life and non-adherence. To reduce treatment-related toxicity, the practice of non-standard dosing is increasing; however guidance to govern this practice is limited. A systematic review was conducted to identify evidence of, and outcomes from, non-standard dosing of oral SACT in oncology and malignant haematology.

Methods

A comprehensive search of 78 oral SACT was conducted in the following databases: MEDLINE®, EMBASE®, Cochrane Library©, and Cumulative Index to Nursing and Allied Health Literature (CINAHL©). Studies were selected based on predefined inclusion/exclusion criteria, and were critically appraised. Extracted data were tabulated to summarise key findings. Due to diversity of study designs and heterogeneity of reported outcomes, studies were categorised and evidence was synthesised in three main themes: dose interruption; dose reduction; and other dosing strategies.

Results

Thirty-four studies were eligible for inclusion: four clinical trials, fifteen cohort studies and fifteen case reports. Evidence for non-standard dosing was reported for eleven oral SACT. Dose interruptions were the most commonly reported strategy (14 studies); nine studies reported dose reductions; and eleven reported other dosing strategies. Eight retrospective cohort studies reported dose interruption of sunitinib in renal cell carcinoma and showed either similar or improved responses and survival outcomes, and fewer or equivalent high grade toxicities, compared to the standard schedule. Four cohort studies retrospectively evaluated dose reductions of imatinib, gefitinib or erlotinib, for chronic myeloid leukaemia and non-small cell lung cancer, respectively. Other dosing strategies included alternate-day dosing. The quality of the evidence was limited by the small sample size in many studies, retrospective study designs, and lack of reported toxicity and/or QoL outcomes.

Conclusions

This review identified limited evidence to support current non-standard dosing strategies, but some of findings, e.g. dose interruption of sunitinib, warrant further investigation in large-scale prospective clinical trials.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5066-2) contains supplementary material, which is available to authorized users.

Treatment outcomes in older patients with advanced gastrointestinal stromal tumor (GIST)

BACKGROUND

The aim of the study was to analyze the treatment results of advanced GIST in the largest, homogenous series of older patients.

METHODS

Between 2001 and 2016, 686 patients with metastatic/unresectable GIST were treated initially with imatinib and 656 were included in the analysis. Subsequently 232 patients were treated with sunitinib after imatinib failure. We have analyzed the outcomes of patients who have been treated with the tyrosine kinase inhibitor at the age ≥ 70 years and compared to control group of patients younger than 70 years old.

RESULTS

In the group of patients treated with imatinib, 139 (21%) started therapy at the age of at least 70 years (median age of the entire cohort: 60). Median progression-free survival (PFS) on 1st line imatinib did not differ between patients ≥70 yo (years old) and < 70yo (38.5 vs 44.9 months), but median overall survival (OS) was significantly better for younger patients (81 months vs. 50; p = 0.0001; although disease-specific survival - DSS was similar). Distribution of primary tumor mutational status was generally similar in older and younger patients. Permanent dose reduction (300-100 mg/day) was required for 23 patients (16.9%) in the older group and was significantly more frequent as compared to younger patients (5%). Drug-related adverse events were mainly of grades 1/2, but grade 3/4 toxicity occurred more frequently in older (14.7%) than in younger patients (3.8%). Similarly in group of patients treated with second-line sunitinib median PFS and DSS were comparable in groups of patients ≥70 yo (n = 55) and < 70yo (9.7 months vs 10.3 months; p = 0.7, and 21.5 vs 22.9 months). >40% of patients in both groups required dose adjustments to 37.5-25 mg daily.

CONCLUSIONS

Our study confirms that current therapy of advanced GIST with tyrosine kinase inhibitors (both in 1st and 2nd line) in older patients enable to achieve the similar disease control rate and final outcomes as in younger patients, but it demands close cooperation of experienced oncologist with patients for dose modifications and side effects management. Limitation of our study is that the patients did not undergo a comprehensive geriatric assessment, what might be helpful for personalized management of patients. Nevertheless, we confirm that older patients with GIST should not receive less treatment irrespective of comorbidities.