Tyrosine Kinase Inhibitors Initiation Research Articles

Retrospective study assessing the use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers to reduce toxicity from tyrosine kinase inhibitors in metastatic renal cell carcinoma.

411 Background: The main toxicities associated with tyrosine-kinase inhibitors (TKIs) in the treatment of renal cell carcinoma (RCC) are proteinuria and hypertension. Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) have established reno-protective and anti-hypertensive effects and can help with toxicity in mRCC. We hypothesize that use of ACEIs/ARBs is an effective method to decrease the degree of proteinuria and hypertension in patients treated with TKIs for metastatic/advanced renal cell carcinoma (mRCC). Methods: Single Institution retrospective study; mRCC patients (pts) who received TKI and ACEIs/ARBs and had urine protein measurements available at baseline and at 4-6 wk follow up post ACEs/ARBs were included in the analysis. Primary endpoints included improvement in grade of proteinuria and BP in mRCC pts on TKI treatment at baseline and with addition of ACEIs/ARBs. Secondary endpoints included number of dose interruptions (DI), BUN and creatinine changes. Paired statistical tests were used to compare the selected outcome variables between baseline and post ACE/ARB measures: for example, nonparametric Wilcoxon Signed-rank test for paired quantitative data and McNemar test for paired binary data. Results: Out of 71 screened patients between 2020-2023, N of 22 mRCC (N=22, 72.7% male, 77.3% white; 9% Hispanic; N=14 for TKI+ immunotherapy; N=8 TKI alone) pts were selected. ACEIs/ARBs treatment was associated with significantly reduced levels of proteinuria at 4–6wk follow-up. At baseline vs. follow-up, pts were found to have significantly lower proteinuria overall after ACEI/ARBs (p=0.0147), and 45.4% of pts had clinically insignificant proteinuria vs. 22.7% at baseline. Additionally, DI rates for TKI were significantly lower for pts placed on ACEIs/ARBs, with an 81% chance that pts with prior DI would not experience similar event in the follow-up period (p=0.003). Reductions in BP, creatinine, and TKI dosing were seen but not statistically significant (p>0.05 for all measures). Conclusions: In our small study, degree of proteinuria was notably reduced with administration of ACEIs/ARBs. Further findings show fewer DI of TKIs with ACEIs/ARBs use. Our findings suggest a potential role for ACEIs/ARBs in managing toxicity in patients undergoing TKI based therapy for mRCC. Future studies are needed to evaluate the use of ACE/ARB from the time of initiation of TKI based therapy to reduce the toxicities and improve the adherence to mRCC treatment which may result in better outcomes.

Effect of Tyrosine Kinase Inhibitor Therapy on Estimated Glomerular Filtration Rate in Patients with Chronic Myeloid Leukemia

IntroductionThe advent of tyrosine kinase inhibitors (TKIs) was revolutionary in the management of chronic myeloid leukemia (CML). Although TKIs were generally considered to be safe, they can be associated with renal injury. We evaluated the effect of TKIs on renal functions in a cohort of patients with long-term follow-up. Material and MethodsWe retrospectively examined patients with chronic phase CML treated with TKIs. We analyzed the estimated glomerular filtration rate (eGFR) of patients from the initiation of TKI to the last follow-up. eGFR values of CML patients were compared to those of patients with stage 1 or 2 chronic kidney disease (CKD). ResultsA total of 195 patients with CML and 138 patients with CKD were examined. eGFR decline was 1.556 ml/min/1.73m2/year for patients with CML (P = .221). Patients receiving second-generation TKIs (2GTKI) were estimated to have 0.583 ml/min/1.73m2 higher eGFR value than that of the imatinib group, but it was not significant (P = .871). eGFR of patients who had used bosutinib had a downward trend. Duration of TKI therapy, age, and hypertension were found to be significant factors in eGFR decline for CML patients. Lower baseline GFR was associated with an increased risk of CKD development. ConclusionImatinib could result in a decline in eGFR which was clinically similar to early-stage CKD patients. We did not observe significant kidney function deterioration in patients receiving 2GTKIs including dasatinib and nilotinib. We recommend close renal function monitoring in patients receiving imatinib, especially for elderly patients with lower baseline eGFR and hypertension.

Tyrosine Kinase Inhibitor (TKI) Treatment Patterns in 5,261 Chronic Phase (CP) Chronic Myeloid Leukemia (CML) Patients in “Real-Life” Settings: A Population-Based Study Using a Nationwide Claim Database

Introduction The introduction of TKI in CP-CML enabled responders to reach a similar survival to that of the general population. However, recent small-sized real-life studies showed that 1 in 5 CP-CML patients (pts) received at least 3 lines of TKI, mainly due to resistance or the onset of adverse events (AE). The objective of this study is to document real-life TKI treatment patterns nationwide in CML pts with a long-term follow-up, with a focus on pts who initiated at least a 3 rd line and associated disease burden. Methods This real-life non-interventional study was conducted using the French nationwide claim database (SNDS, Système National des Données de Santé), covering over 99% of French beneficiaries. Pts who initiated their first TKI with an indication for CML (imatinib, dasatinib, nilotinib, bosutinib, ponatinib) between January 2010 and December 2018, aged 18 years old or older at TKI initiation (index date T 0), and with healthcare resource use (HCRU) markers of CML - i.e., reasons for hospitalization and reported Long-Term Disease - without markers of confounding disease for the use of TKIs, were included. Treatment patterns were assessed from T 0 to December 2020 or death, through the description of TKI treatment sequences (TKI lines), adherence - discontinuations (≥ 3 months) during a TKI line and Medication Possession Ratio (MPR) -, and line duration (Time to Next Treatment (TTNT) estimates). TTNT was calculated as cumulative incidence of TKI switches, with death as competing risk; switches were defined as discontinuation of a TKI followed by the start of a different TKI. Results A total of 5,261 CML pts initiated their 1 st line TKI, with a median age at T 0 of 59.5 years (IQR: 23.2) and a M/F ratio of 1.2. The median follow-up from T 0 was 5.6 years (IQR: 4.6). Respectively 2,299, 1,017 and 426 pts initiated 2 nd, 3 rd and 4 th TKI line. Most frequent TKIs used as 1 st and 2 nd lines were imatinib (73.1%), and dasatinib (60.4%; Figure 1), respectively. From the 3 rd line, TKI patterns changed following the reimbursement of bosutinib in 2015 and ponatinib in 2016, and subsequently stabilized; shares in pts treated in 3 rd line and more at the beginning of 2020 were roughly equally distributed between marketed TKIs. TKI discontinuations rates during a line varied from 76.2% for 1 st line to 56.2% for 4 th lines. The median cumulative duration of discontinuations tended to decrease across lines (2.9, 2.5, 2.3 and 2.1 months for 1 st, 2 nd, 3 rd, and 4 th line, respectively); IQRs across lines were similar. The proportion of pts with a good medication adherence (MPR ≥ 80%) was around 80% for all TKI lines. TTNT was similar across all TKIs and all lines; 10-year TTNT rates were 48% (95CI: [47%; 50%]), 56% [53%; 59%], 56% [51%; 61%], 48% [42%; 54%] for 1 st, 2 nd, 3 rd, and 4 th lines. For pts who switched, most of switches occurred during the first year following line initiation (51% of switches observed in the first year for both 1 st, 2 nd, 3 rd, and 4 th lines), 24% occurred during the second year, and 10% during the third year. The 10-year cumulative incidences of death were 12% (95CI: [11%; 14%]), 9% [8%; 11%], 12% [9%; 16%], 14% [6%; 25%] for 1 st, 2 nd, 3 rd, and 4 th lines, respectively. The proportion of CML pts who initiated at least 3 lines of TKIs was 19.3% from raw estimates (n=1,017/5,261) and would be 27% based on TTNT estimates. Their characteristics were similar to pts who initiated 1 st line TKI (sociodemographic, comorbidities). Regarding HCRU, respectively 37.2% and 29.8% of pts had at least one hospitalization during 1 st and 6 th semesters following 3 rd line initiation; 7.9% to 5.8% visited emergency room, and around 10% had at least one sick leave per semester. Conclusion Using one of the largest cohorts of CML pts ever studied, with a follow-up period up to 10 years (median 5.6 years), this real-life study confirmed that multiple TKI switches are now common. We confirmed that at least 1 out of 5 CML patient fails at least two TKI lines. From TTNT estimates, surrogate marker for the duration of clinical benefit, lines of TKI would be effective over the long-term for around half of pts, and half of the switches occur within the first two years, regardless of line position. Finally, this real-world study illustrates the need for permanent care of these pts and alternative treatment options to avoid resistance or intolerance and induce a similar survival as the general population of the same age.

Abstract 13214: Arrhythmic Burden After Bruton's Tyrosine Kinase Inhibitor Initiation and Major Cardiovascular Events

Background: Bruton’s tyrosine kinase inhibitors (BTKi) have dramatic efficacy against B cell malignancies. BTKi’s also cause cardiotoxic arrhythmias, including atrial fibrillation (AF) and ventricular arrhythmias (VA). Yet, the true burden and long term effects of arrhythmias after BTKi therapy are unknown. Research Question: In patients with suspected BTKi related arrhythmias, what is the relative AF burden? Does it prognosticate future events? Methods: Leveraging a cohort of consecutive B cell malignancy patients initiated on BTKi from 2009-2020, we identified patients with available ambulatory rhythm monitors. The primary outcome was AF burden after BTKi initiation. Secondary outcomes included VA burden, conduction blocks, and other arrhythmias of probable or definite BTKi association. Observed incident AF rates and burden with next generation BTKi’s were compared to ibrutinib. Multivariable regression and survival analysis were used to define factors associated with AF related hospitalizations and major adverse cardiac events (MACE), as well as the relationship between AF burden and mortality. Outcomes were stratified by high (≥5%) vs low (<5%) AF burden. Results: Of 890 BTKi treated patients, 98 wore ambulatory rhythm monitors, including 38 on next generation BTKi’s [age 67.7 years, 24.2% prior AF]. Median duration BTKi use was 34 months. Among next generation BTKi treated patients, 8.7% developed incident AF compared to 25.5% with ibrutinib ( P =0.048). Ten patients (26.3%) developed symptomatic or >1% PVCs, at a mean burden of 7.1% compared to eight patients (13.3%) with mean burden 9.4% on ibrutinib. In a multivariable model accounting for traditional CV risk factors, prior AF associated with increased post BTKi AF burden. In follow up, high AF burden associated with increased MACE (HR 3.49, P =0.001) and mortality (HR 3.2, P =0.002); Figure . Conclusions: In BTKi treated patients, cardiotoxic AF burden prognosticates future MACE and mortality.

Toxicities Associated with Tyrosine Kinase Inhibitor Maintenance Following Allogeneic Hematopoietic Cell Transplantation in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia

Background Use of tyrosine kinase inhibitor (TKI) maintenance following allogeneic hematopoietic cell transplantation (HCT) in Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia may help to prevent post HCT relapse but is difficult to administer due to toxicity. However, these toxicities and their impact on maintenance is not fully characterized. Herein, we report our experience at a single, large transplant center to describe toxicities encountered with post HCT TKI maintenance in Ph+ ALL. Methods Ph+ ALL patients (pts) who underwent 1st allogeneic HCT at City of Hope between 2003-2021 and received at least one dose of TKI maintenance were included in this retrospective analysis. Baseline characteristics and toxicities were summarized via descriptive analysis, and groups were compared via Fischer test. Survival analyses were calculated from the time of TKI initiation. Results Baseline characteristics are described in Table 1. Of the 186 pts studied, 50 (26.8%) received imatinib and 136 (73.2%) received a newer generation TKI (NG-TKI: 112 dasatinib, 6 nilotinib, 1 bosutinib, 17 ponatinib) at a median time of 78 days (IQR, 41-134) and 91 days (IQR, 58-129), respectively. A total of 96 patients (51.6%) began TKI maintenance within 90 days of HCT. Post HCT TKI was started prophylactically in 149 patients (80.1%) while 37 patients (19.9%) received TKI preemptively for positive MRD. The MRD status at time of HCT differed between the imatinib group and NG-TKI group. In the imatinib group MRD was negative in 33 of 50 patients (66.0%) compared with 78 of 136 patients (57.4%) in the NG-TKI group (P<0.01). There were 12 (24.0%) vs 18 (13.2%) with an unknown MRD-status at HCT in the imatinib vs NG-TKI groups, respectively ( P<0.01). The median follow-up duration for surviving patients in the entire cohort was 5.5 years (range, 1.0-17.5). The median cumulative TKI exposure was 413.5 days (range, 4-2740). The median cumulative imatinib exposure in patients initially receiving imatinib was 328 days (range, 3-2216), while the median cumulative NG-TKI exposure in patients initially receiving NG-TKI was 268.5 days (range, 3-2740), respectively. The median cumulative exposure of dasatinib, nilotinib, bosutinib and ponatinib were 249 days (range, 3-2740), 222 days (range, 114-839), 371 days, and 576 days (range, 72-921), respectively. Twenty-seven (54.0%) vs 75 (55.2%) patients completed >12 months of initial imatinib and NG-TKI maintenance (P=1.0), respectively. Of the treated patients, 78 pts (41.9%) required at least one dose reduction of their initial TKI due to toxicity; 19 of them (10.2%) required ≥2 dose reductions. When imatinib maintenance was used as the initial TKI, a dose reduction due to toxicity was required in 18 patients (36.0%), of whom 7 patients (14.0%) required ≥2 dose reductions. Initial NG-TKI maintenance required a dose reduction due to toxicity in 60 (44.1%), of whom 12 (8.8%) required ≥2 dose reductions. One hundred and thirty-nine patients (74.7%) had their maintenance TKI therapy interrupted, 122 (65.6%) due to toxicity. Sixty-seven patients (36.0%) did not complete their pre-determined maintenance period owing to toxicity; 70 pts (37.6%) discontinued one TKI, and 11 (5.9%) discontinued two TKIs, due to toxicity. The most common reasons for discontinuing the initial TKI are listed in Table 2, including 45.2% of patients due to toxicity, and 12.9% due to progressive disease. Toxicity-related discontinuations occurred within 6 months on that TKI in 63.0% of patients, and 75.3% within the first 12 months. Five-year overall survival and progression-free survival from the start of TKI were similar between the imatinib and NG-TKI group; 83.1% vs 76.9% (P=0.74) and 72.8% vs 70.5% (P=0.63), respectively (Figure 1). Conclusion Toxicities resulting in dose reductions, interruptions, and discontinuation are common in TKI maintenance post HCT. The toxicity profile (mainly GI and blood count related), frequency, and severity of TKIs in the post HCT setting appears to be different than what has been previously reported in the pre-HCT setting, making it a formidable challenge to meet the recommended cumulative TKI maintenance exposure (2 years) per the NCCN guidelines. While the choice of TKI did not appear to impact on long-term outcomes and relapse rates were not excessive in our analysis, further studies are needed to develop tolerable and personalized TKI maintenance strategies.

Treatment Patterns and Modifications of Tyrosine Kinase Inhibitors (TKI) Therapy in Early Lines in Patients with Chronic Myeloid Leukemia in Chronic Phase (CML-CP): Real-World Analysis from a Large Commercial Claims Database in the United States (US)

Introduction: Although current TKI options are often successful in managing CML-CP in early lines of therapy, patients may experience issues related to tolerability or resistance to TKIs. Physicians often have to proceed with treatment modifications including discontinuation, switching, temporary interruptions, or dose modifications when the patient's current treatment is not working as expected. This retrospective cohort study assessed these TKI therapy management patterns in patients with CML in first-line (1L) or second-line (2L) treatment in the US. Methods: A large administrative claims database of commercially insured patients, the OptumInsight Clinformatics database (January 2007-June 2022), was used to select adult patients with CML who received 1L TKI therapy (imatinib, dasatinib, nilotinib, or bosutinib; 1L cohort) and those who received 2L TKI therapy (imatinib, dasatinib, nilotinib, bosutinib, or ponatinib; 2L cohort), with treatment initiation (index date) on or after 2012. Patients were required to have ≥6 months of continuous health plan enrollment pre-index, with no hematopoietic stem cell transplantation (HSCT) or CML-related chemotherapy treatments for accelerated phase (AP) or blast crisis (BC) pre-index. Treatment modifications assessed post-index included 1) treatment discontinuation, defined as the earliest of HSCT/treatment switch (defined below)/initiation of a CML-related chemotherapy for AP or BC, 2) treatment switch defined as initiation of another TKI/omacetaxine mepesuccinate, 3) temporary treatment interruption defined as gap of ≥ 14 days followed by resuming the index TKI, and 4) dose reduction (as compared to the initial dose) were assessed. Time to first event post-index were conducted using Kaplan Meier analyses for each of these treatment modifications, in 1L and 2L cohorts, separately. Results: A total of 2,043 patients were included in the 1L cohort with 47.8% of them receiving imatinib, 31.0% dasatinib, 19.2% nilotinib, and 2.0% bosutinib (median age: 64 years; 44.9% female; 69.7% White; 49.5% with Medicare advantage plan operated by commercial insurance [Part C]). Patients in the 1L cohort were observed for a mean (SD) period of 29.1 (27.3) months from index date to earliest of loss of follow-up/end of data. Overall, more than a quarter of patients (27.3%) experienced treatment discontinuation, with rates of discontinuation of 16.1% at 6 months, 25.0% at 12 months, and 33.5% at 24 months post-index ( Figure 1). Treatment switch was observed in 26.0% of the patients, with rates of 15.5% at 6 months and 24.4% at 12 months post-index. The proportion of patients with temporary treatment interruption was 18.6%, with rates of 20.6% at 6 months and 22.2% at 12 months post-index. Dose reduction (as compared to initial dose) occurred in 21.9% of patients, with rates of 18.8% at 6 months and 23.3% at 12 months post-index. A total of 586 patients were included in the 2L cohort with 23.0% of them receiving imatinib, 36.9% dasatinib, 26.6% nilotinib, 10.9% bosutinib and 2.6% ponatinib (median age: 65 years; 47.3% female; 72.5% White; 48.3% with Medicare advantage plan operated by commercial insurance [Part C]). Patients in the 2L cohort were observed for a mean (SD) period of 28.4 (25.4) months from index date to earliest of loss of follow-up/end of data. Almost a third of patients (32.8%) experienced treatment discontinuation, with rates of discontinuation of 22.1% at 6 months, 29.9% at 12 months, and 43.1% at 24 months post-index ( Figure 1). Treatment switch was observed in 30.5% of patients, with rates of 20.5% at 6 months and 28.3% at 12 months post-index. The proportion of patients with temporary treatment interruption was 21.3%, with rates of 24.8% at 6 months and 25.4% at 12 months post-index. Dose reduction as compared to initial dose occurred in 20.6% of patients, with rates of 17.5% at 6 months and 27.2% at 12 months post-index. Conclusions: Findings from this real-world study demonstrate that almost a quarter of patients with CML treated with current TKI treatment options in 1L or 2L experienced treatment discontinuation/switch in the first year from TKI initiation suggesting lack of optimal response/tolerability to currently available TKIs, with more pronounced rates in 2L. This suggests that unmet clinical needs still persist in this population, warranting optimal 1L and 2L treatment options with better tolerability profile for CML management.

Brief Report: Droplet Digital Polymerase Chain Reaction Versus Plasma Next-Generation Sequencing in Detecting Clearance of Plasma EGFR Mutations and Carcinoembryonic Antigen Levels as a Surrogate Measure

IntroductionTo compare the performance of droplet digital polymerase chain reaction (ddPCR) and plasma next-generation sequencing (NGS) in detecting clearance of plasma EGFR (pEGFR) mutations. MethodsPatients with treatment-naive advanced EGFR-mutated lung cancer treated with first-line tyrosine kinase inhibitors (TKIs) were included. pEGFR were measured at baseline and first response assessment using ddPCR and NGS. Clearance of pEGFR was defined as undetectable levels after a positive baseline result. Results were correlated with time-to-treatment failure (TTF). In exploratory analysis, corresponding change in carcinoembryonic antigen (CEA) levels was evaluated. ResultsBetween January 1, 2020, and December 31, 2021, 27 patients were recruited. Ex19del comprised 74% (20 of 27) and L858R 26% (seven of 27). Osimertinib was used in 59% (16 of 27), dacomitinib 4% (one of 27), and gefitinib/erlotinib 37% (10 of 27). Sensitivity of ddPCR and NGS in detecting pEGFR mutation at baseline was 70% (19 of 27) and 78% (21 of 27), respectively (p = 0.16). All patients with detectable pEGFR by ddPCR were detected by NGS.At a median of 8 (range 3–24) weeks post-TKI initiation, clearance of pEGFR was achieved in 68% (13 of 19) and 71% (15 of 21) using ddPCR and NGS, respectively. Concordance between ddPCR and NGS was 79% (kappa = 0.513, p = 0.013). Clearance of pEGFR was associated with longer median TTF (not reached versus 6 months, p = 0.03) and median decrease in CEA levels by 70% from baseline.In another cohort of 124 patients, decrease in CEA levels by greater than 70% within 90 days of TKI initiation was associated with doubling of both TTF and overall survival. ConclusionsPlasma NGS trended toward higher sensitivity than ddPCR in detecting pEGFR, although both had similar concordance in detecting pEGFR clearance. Our results support using NGS at diagnosis and interchangeability of NGS and ddPCR for monitoring, whereas CEA could be explored as a surrogate for pEGFR clearance.

Tyrosine kinase inhibitor therapy in pediatric sarcoma: Prognostic implications of pulmonary metastatic cavitation.

This study aims to ascertain the prevalence of cavitations in pulmonary metastases among pediatric and young adult patients with sarcoma undergoing tyrosine kinase inhibitor (TKI) therapy, and assess whether cavitation can predict clinical response and survival outcomes. In a single-center retrospective analysis, we examined chest computed tomography (CT) scans of 17 patients (median age 16years; age range: 4-25years) with histopathologically confirmed bone (n=10) or soft tissue (n=7) sarcoma who underwent TKI treatment for lung metastases. The interval between TKI initiation and the onset of lung nodule cavitation and tumor regrowth were assessed. The combination of all imaging studies and clinical data served as the reference standard for clinical responses. Progression-free survival (PFS) was compared between patients with cavitating and solid nodules using Kaplan-Meier survival analysis and log-rank test. Five out of 17 patients (29%) exhibited cavitation of pulmonary nodules during TKI therapy. The median time from TKI initiation to the first observed cavitation was 79days (range: 46-261days). At the time of cavitation, all patients demonstrated stable disease. When the cavities began to fill with solid tumor, 60% (3/5) of patients exhibited progression in other pulmonary nodules. The median PFS for patients with cavitated pulmonary nodules after TKI treatment (6.7months) was significantly longer compared to patients without cavitated nodules (3.8months; log-rank p-value=.03). Cavitation of metastatic pulmonary nodules in sarcoma patients undergoing TKI treatment is indicative of non-progressive disease, and significantly correlates with PFS.

Older patients with chronic myeloid leukemia face suboptimal molecular testing and tyrosine kinase inhibitor adherence.

Tyrosine kinase inhibitor (TKI) use is critical in the care of patients with chronic myeloid leukemia (CML). Quantitative polymerase chain reaction (qPCR) testing for BCR-ABL1 every 3months during the first year of TKI treatment is recommended to assure achievement of milestone response goals. Real-world evidence for the patterns of qPCR monitoring and TKI adherence in the older patient population is lacking. Using the Surveillance, Epidemiology, and End Results-Medicare database, we identified 1192 patients aged ≥66 years (median age, 74 years) with newly diagnosed CML who were followed up for ≥13months from TKI initiation. In total, 965 patients (81.0%) had ≥1 test, with 425 (35.7%) and 540 (45.3%) of the patients tested during 1, 2, and ≥3 quarters (optimal monitoring) of the first year from TKI initiation, respectively. In multivariable analysis, diagnosis in later years and influenza vaccination before diagnosis, a proxy for health care access, were associated with optimal qPCR monitoring. Use of low-income subsidy and residing in census tracts with the lowest socioeconomic status were associated with less optimal monitoring. Patients with optimal monitoring were 60% more likely to be TKI adherent (odds ratio, 1.60; 95%CI, 1.11-2.31; P= .01) and had improved 5-year survival (hazard ratio, 0.66; 95%CI, 0.49-0.90; P< .01) than those without such monitoring. In this large, real-world study of CML management patterns, many older patients had suboptimal molecular monitoring, which was associated with decreased TKI adherence and worse survival.

Concomitant BCR-ABL and JAK2 V617F in a Patient with Myeloproliferative Neoplasm: A Case Report

Myeloproliferative neoplasm (MPN) is a clonal proliferation of the haematopoietic stem cells leading to activated tyrosine kinase signaling activity. Myeloproliferative neoplasm is classified into BCR-ABL positive chronic myeloid leukemia (CML) and BCR-ABL negative MPN which harbors JAK2 V617F mutation in most cases. The genetic combination of BCR-ABL and JAK2 V617F mutation is rare with estimated frequency of 0.4% based on recent study. Herein, we reported a case of a man diagnosed with CML detected by fluorescence in-situ hybdridisation (FISH) showing atypical BCR-ABL fusion pattern in 29% nucleated cells (cut-off levels ≥5% for positive signals) in the presence of JAK2 V617F mutation. However, the BCR-ABL transcript was not detected by the conventional reverse transcriptase-polymerase chain reaction (RT-PCR) method which was specific for major fragments. Interestingly, complete hematological remission was not achieved despite initiation of tyrosine kinase inhibitor (Imatinib). In conclusion, it is imperative to scrutinise CML cases for concomitant JAK2 V617F mutation especially patients with atypical clinical or laboratory findings. Therefore, close monitoring with clinical and ancillary technique especially FISH and molecular methods such as DNA sequencing were crucial to help achieve complete hematological, cytogenetic and deep molecular response alongside targeted therapy.

Fertility and pregnancy in chronic myeloid leukemia: real-world experience from an Indian tertiary care institution.

Chronic myeloid leukemia (CML) management during pregnancy is challenging. In this retrospective study, hospital records of CML patients treated between 2000 and 2021 were screened to identify patients who tried to conceive/got pregnant (planned and unplanned) on TKIs (tyrosine kinase inhibitors)/were pregnant at CML onset/fathered a child. We found ninety-three pregnancies involving thirty-three women and thirty-eight men, and they were analyzed for the pregnancy outcomes and the strategies utilized for CML management during pregnancy and the pre-conception period. There were two women and four men with primary infertility and five women with secondary infertility. TKIs were discontinued before conception in four planned pregnancies and at the time of recognition of pregnancy in unplanned pregnancies (n = 21). Unplanned pregnancy outcomes were two miscarriages, eight elective terminations, and eleven live births. Planned pregnancies led to four healthy babies. Outcomes of pregnancies at CML onset (n = 17) were six live births, one stillbirth, five elective terminations, and five abortions. Except for one child with congenital micro-ophthalmia, no other child born to thewomen on TKI had any malformations. Thirty-eight men fathered 51 healthy children. All but two patients (one planned and one unplannedpregnancy) lost theirhematological responses during pregnancy and gained their previous best response after restarting TKI. In women who were pregnant at CML onset, complete cytological remission (CCYR) was achieved between 7 and 24months (median:14months) after starting TKI. During pregnancy, intermittent hydroxyurea ± TKI (in the second and third trimesters) was used to keep WBCs less than 30,000/mm3. Outcomes of pregnancies in CML patients can be optimized with our approach. TKIs(Imatinib and Nilotinib) can be safely used in the second and third trimesters. Delayed initiation or interruption of TKI during pregnancy does not negatively affect response to TKIs.

Longitudinal, prospective cardiovascular and metabolic risk in treatment-naive patients with chronic myeloid leukemia in chronic phase (CML-CP) starting tyrosine kinase inhibitor (TKI) therapy in a real-world setting.

7053 Background: Multiple TKIs used in the treatment (tx) of CML have been associated with the development of cardiovascular/metabolic (CV/Met) comorbidities, yet no study to date has prospectively and systematically assessed CV/Met parameters after TKI initiation. CA180-653 (NCT03045120) is a non-interventional, prospective, real-world study characterizing the effects of TKIs (dasatinib [DAS], imatinib [IM], nilotinib [NIL], and bosutinib [BOS]) on CV/Met risk factors in patients (pts) with CML-CP in routine care. Baseline CV/Met risks were previously reported (Mauro, GCOS 2019). Here, we report data from the final 2-year follow-up. Methods: Adult pts with newly diagnosed CML-CP due to start tx with DAS, IM, NIL, or BOS were enrolled; the BOS cohort was not analyzed independently due to small sample size. Pts were followed for 24 mo. Blood/urine samples, CV/Met assessments, coronary calcium scoring, echocardiography, and cytogenetic/molecular response assessments were collected at routine office visits at predetermined timepoints. The primary endpoint was change in CV/Met risk from baseline. Results: At the end of follow-up, 118 pts were enrolled; 49 received DAS, 47 IM, 16 NIL, and 6 BOS. Of these, 83 (70.3%) pts completed the study and 35 (29.7%) discontinued; the most common reason for discontinuation was withdrawal of consent (n = 19). No pts died from CML. At baseline, median age was 57 (range, 20–97) y; 59.3% of pts were male and 83.9% were White. Sixty-two (52.5%) pts had CV/Met risk factors at baseline, including hypertension (n = 45/62; 72.6%), hyperlipidemia (n = 33/62; 53.2%), diabetes (n = 19/62; 30.6%), and arrhythmia (n = 10/62; 16.1%). Over the study period, 1 (3.4%) patient receiving DAS and 2 (6.9%) receiving IM developed coronary artery calcification; 2 (9.1%) pts receiving IM developed pericardial effusion. Median left ventricular ejection fraction on 2D echocardiogram was normal for all TKIs at baseline (65.4% [range, 27–81]) and end of study (65.4% [range, 40–80]). Systolic and diastolic blood pressure increased from baseline only in pts who received NIL. Blood glucose levels increased from baseline for DAS, IM, and NIL (median: 1.9, 4.9, and 5.8 mg/dL, respectively), and low-density lipoprotein levels decreased from baseline in all 3 cohorts (median: 72.7, 52.1, and 56.3 U/L, respectively); data from the NIL group were limited by the small sample size. There was 1 death from myocardial infarction related to NIL. Conclusions: These findings suggest more than half of pts with CML-CP have CV/Met risk factors at baseline. At end of study, there was indication of CV/Met effects based on TKI selection. This highlights the importance of appropriate TKI selection based on pt comorbidity characteristics, along with close monitoring and management of CV/Met risks throughout tx. Clinical trial information: NCT03045120 .

First results from the RETgistry: A global consortium for the study of resistance to RET inhibition in RET-altered solid tumors.

9065 Background: Rearranged during transfection ( RET) gene alterations are the oncogenic driver in diverse tumor types, including RET fusions identified in 1-2% of non-small cell lung cancers (NSCLC). While RET-selective tyrosine kinase inhibitors (TKIs) selpercatinib and pralsetinib are effective, acquired drug resistance remains a challenge. Here, we report the initial results from the RETgistry, an international consortium aimed at elucidating mechanisms of resistance to RET TKIs across RET-altered solid tumors. Methods: This was a retrospective analysis performed across 16 institutions. Patients (pts) were eligible if they had advanced solid tumor harboring an oncogenic RET alteration, received ≥1 RET TKI with disease progression, and underwent resistant tumor or liquid biopsy for next-generation sequencing (NGS). Results: A total of 103 time-distinct biopsies (62 tissue, 30 plasma, 11 paired tissue/plasma) were included in analysis, obtained from 88 pts with progression on a RET-selective TKI [selpercatinib (n = 70), pralsetinib (n = 14), selpercatinib and pralsetinib sequentially (n = 4)]. Pts had the following tumor types: 72 NSCLC (69% KIF5B-RET, 21% CCDC6-RET, 10% other RET fusion), 13 medullary thyroid cancer (TC) (54% RET M918T, 46% other RET mutation), and 2 papillary and 1 anaplastic TC (all, RET fusion). Median age was 58 (range, 21-86); 48% were male with 89% never/light smokers. Median duration of RET TKI preceding biopsies [first-line, n = 32 (31%); second-line, n = 42 (41%); third-/greater-line, n = 29 (28%)] was 16.5 months (mos) (95% CI, 14.0-19.6); median PFS was 14.1 mos (95% CI, 9.3-17.0). Resistant biopsies were obtained at median 15.0 mos from TKI initiation (range, 1.8-58.8). Acquired RET mutations were detected in 14 (14%), most common being G810 substitutions in 12 (12%). Potential off-target resistance gene alterations identified in 43 cases (42%) included MET amplification (14%), BRAF V600E or fusion (2%), KRAS gain or mutation (5%), ERBB2 amplification (2%), EGFR amplification (3%), ROS1 fusion (1%), and activating PIK3CA mutation or PTEN loss (4%). No resistant lung cancer biopsy demonstrated small cell transformation. The duration of TKI therapy (HR 0.64, p = 0.11) or PFS (HR 0.75, p = 0.33) did not differ according to the presence of on-target vs off-target resistance. NGS analyses of pre-RET-selective TKI tumors (n = 92) revealed frequent co-occurring alterations in TP53 (29%) and CDKN2A/B (12%). Conclusions: On-target resistance to RET inhibition due to acquired RET mutations was less common than off-target resistance, identified in 14%. The majority of RET TKI resistance is mediated by off-target mechanisms such as bypass receptor tyrosine kinase activation. Further studies are warranted to enable the development of therapeutic strategies to address resistance in pts with RET-altered tumors. The RETgistry accrual and data analyses continue.

Analysis on real-world chemotherapy outcomes in patients (pts) with tyrosine kinase inhibitor (TKI) resistant advanced EGFR-mutant non–small-cell lung cancer (NSCLC) in the United States.

e21088 Background: Chemotherapy is the current standard of care for pts with EGFR-mutant NSCLC whose tumor develops EGFR TKI resistance. We are conducting a real-world study to understand resistance mechanisms to EGFR TKI and outcomes with subsequent therapies (targeted and non-targeted). Here we report outcome results for standard of care given after resistance to a first-line (1L) EGFR TKI. Methods: This is a non-interventional descriptive cohort study using electronic medical record data and biomarker data from the United States TEMPUS database, which will continue until end of 2024 with new pts entering the study cohort over time. The study period for this reported analysis on real-world chemotherapy outcomes was any time until June 2022. Drug resistance was defined as disease progression on an EGFR TKI. Pts entering the study cohort were adult, with stage IIIB–IV NSCLC, had received an EGFR TKI either as a monotherapy or in combination with other systemic therapies, and had disease progression after EGFR TKI initiation. Pts were followed after tumor progression and from the initiation of a chemotherapy regimen, to describe treatment patterns and treatment outcomes (real-world progression-free survival [rw-PFS] and overall survival [OS]). Results: Of 21,425 pts with NSCLC, 1,087 patients were eligible for inclusion into the study cohort, with their stage IIIB–IV NSCLC diagnosis spanning from 1999 to 2021. A total of 588 pts (54.1%) received a 1L EGFR TKI and a subsequent second-line (2L) systemic therapy after disease progression. Of these, 100 pts received 2L chemotherapy regimens (platinum-based chemotherapy, n = 48; taxane monotherapy, n = 12; taxane + other chemotherapy, n = 3; pemetrexed, n = 28; other chemotherapy-only regimens, n = 9). Overall, these chemotherapy-treated pts had a median rw-PFS of 4.3 months (95% CI: 3.3, 5.1), and a median OS of 14.2 months (95% CI: 11.8, 22.2). Conclusions: Here, we show that after disease progression on a 1L EGFR TKI, patients had poor disease outcomes on 2L chemotherapy, indicating an unmet medical need as these pts likely developed EGFR TKI resistance. Treatment adaptation based on identified mechanism of resistance such as MET amplification, may improve outcomes for these patients.

Gene Expression Pattern of ESPL1, PTTG1 and PTTG1IP Can Potentially Predict Response to TKI First-Line Treatment of Patients with Newly Diagnosed CML.

The achievement of major molecular response (MMR, BCR::ABL1 ≤ 0.1% IS) within the first year of treatment with tyrosine kinase inhibitors (TKI) is a milestone in the therapeutic management of patients with newly diagnosed chronic myeloid leukemia (CML). We analyzed the predictive value of gene expression levels of ESPL1/Separase, PTTG1/Securin and PTTG1IP/Securin interacting protein for MMR achievement within 12 months. Relative expression levels (normalized to GUSB) of ESPL1, PTTG1 and PTTG1IP in white blood cells of patients (responders n = 46, non-responders n = 51) at the time of diagnosis were comparatively analyzed by qRT-PCR. 3D scatter plot analysis combined with a distance analysis performed with respect to a commonly calculated centroid center resulted in a trend to larger distances for non-responders compared to the responder cohort (p = 0.0187). Logistic regression and analysis of maximum likelihood estimates revealed a positive correlation of distance (cut-off) with non-achieving MMR within 12 months (p = 0.0388, odds ratio 1.479, 95%CI: 1.020 to 2.143). Thus, 10% of the tested non-responders (cut-off ≥ 5.9) could have been predicted already at the time of diagnosis. Future scoring of ESPL1, PTTG1 and PTTG1IP transcript levels may be a helpful tool in risk stratification of CML patients before initiation of TKI first = line treatment.

Somatostatin Receptor-Directed PET/CT for Therapeutic Decision-Making and Disease Control in Patients Affected With Small Cell Lung Cancer.

Somatostatin receptor (SSTR)-targeted PET/CT is used for patients affected with small cell lung cancer (SCLC), but the clinical impact has not been elucidated yet. We aimed to determine whether SSTR PET/CT can trigger relevant therapeutic management changes in patients with SCLC and whether those modifications achieve disease control and are associated with prolonged survival. One hundred patients with SCLC received SSTR PET/CT. In a retrospective setting, we evaluated the diagnostic performance of PET versus CT and compared therapies before and after PET/CT to determine the impact of molecular imaging on treatment decision. We also determined the rate of disease control after therapeutic modifications and assessed survival in patients with and without changes in the therapeutic regimen. Relative to CT, SSTR PET alone was superior for assessing bone lesions in 19 of 39 instances (49%). Treatment was modified in 59 of 100 (59%) after SSTR PET/CT. Forty of 59 (74.6%) received systemic treatment after hybrid imaging, with the remaining 15 of 59 (25.4%) scheduled for nonsystemic therapy. In the latter group, 13 of 15 (86.7%) received local radiation therapy or active surveillance (2/15 [13.3%]). Individuals scheduled for systemic treatment after imaging received peptide receptor radionuclide therapy (PRRT) in 28 of 44 (63.6%), followed by chemotherapy in 10 of 44 (22.7%), change in chemotherapy regimen in 3 of 44 (6.8%), and initiation of tyrosine kinase inhibitor in the remaining 3 of 44 (6.8%). Among patients with modified treatment, follow-up was available in 53 subjects, and disease control was achieved in 14 of 53 (26.4%). However, neither change to systemic treatment (155 days; hazard ratio, 0.94; 95% confidence interval, 0.53-1.67) nor change to nonsystemic treatment (210 days; hazard ratio, 0.67; 95% confidence interval, 0.34-1.34) led to a prolonged survival when compared with subjects with no change (171 days, P ≥ 0.22, respectively). In patients with SCLC, SSTR-targeted hybrid imaging provides complementary information on the disease status. PET/CT led to management changes in 59% (mainly PRRT), achieving disease control in >26%. The high fraction of patients scheduled for PRRT may lay the foundation for combination strategies to achieve synergistic antitumor effects, for example, by combining PRRT plus recently introduced RNA polymerase II inhibitors.

CNS Downstaging: An Emerging Treatment Paradigm for Extensive Brain Metastases in Oncogene-Addicted Lung Cancer

IntroductionFor extensive brain metastases (BrM) presentations arising from oncogene-addicted lung cancer, tyrosine kinase inhibitors (TKIs) with high response rates in the central nervous system (CNS) could potentially downstage the CNS disease burden, allowing for the avoidance of upfront whole-brain radiotherapy (WBRT) and the conversion of some patients into candidates for focal stereotactic radiosurgery (SRS). MethodsWe describe the outcomes of patients with ALK, EGFR, and ROS1-driven NSCLC with extensive BrM presentations (defined as > 10 BrMs or leptomeningeal disease) treated with upfront newer generation CNS-active TKIs alone, including osimertinib, alectinib, brigatinib, lorlatinib, and entrectinib, from 2012 to 2021 at our institution. All BrMs were contoured at study entry, best CNS response (nadir), and first CNS progression. ResultsTwelve patients met criteria including 6 with ALK, 3 with EGFR, and 3 with ROS1-driven NSCLC. The median number and volume of BrMs at presentation were 49 and 19.6 cm3, respectively. Eleven patients (91.7 %) achieved a CNS response by modified-RECIST criteria to upfront TKI (10 partial responses, 1 complete response, 1 stable disease) with nadir observed at a median of 5.1 months. At nadir, the median number and volume of BrMs were 5 (median 91.7 % reduction per-patient) and 0.3 cm3(median 96.5 % reduction per-patient), respectively. Eleven patients (91.6 %) developed subsequent CNS progression (7 local failures, 3 local + distant, 1 distant) at a median of 17.9 months. At CNS progression, the median number and volume of BrMs were 7 and 0.7 cm3, respectively. Seven patients (58.3 %) received salvage SRS and no patients received salvage WBRT. The median overall survival from initiation of TKI for the extensive BrM presentation was 43.2 months. ConclusionIn this initial case series, we describe CNS downstaging as a promising multidisciplinary treatment paradigm involving the upfront administration CNS-active systemic therapy and close MRI surveillance for extensive BrMs as a strategy to avoid upfront WBRT and to convert some patients into SRS candidates.

Patterns of Failure by Driver Mutation Status for Patients with Locally Advanced Non-Small Cell Lung Cancer Treated with Chemoradiation and Consolidative Durvalumab

<h3>Purpose/Objective(s)</h3> The standard of care for patients with unresectable locally advanced non-small cell lung cancer (LA-NSCLC) is concurrent chemoradiation (CRT) followed by consolidative durvalumab. Increasingly, mutational profiling has been used to guide treatment decisions. In this study, we investigated whether driver mutation status influences the patterns of failure and rates of oligometastatic disease. <h3>Materials/Methods</h3> Using a single institution database, we identified patients who were treated with CRT followed by consolidative durvalumab for LA-NSCLC from June 2017 to May 2020 and divided them by whether they had driver mutations as defined by EGFR exon 19 deletion, EGFR exon 20 insertion, HER2 exon 20 insertion, EGFR exon 21 mutation (L858R), ALK-EML4 fusion, MET exon 14 skipping, NTRK2 fusion, or KRAS mutation. There mutations were all targetable with the exception that only KRAS G12C is a targetable KRAS mutation. We then identified patients who had disease progression and recorded their patterns of failure (distant vs locoregional) and oligometastatic status (3 or fewer sites). These rates were compared by driver mutation status using Chi-squared tests. Comparisons of time to second progression (PFS2) by oligometastatic and driver mutation status were made using Kaplan-Meier analyses. <h3>Results</h3> The 63 patients in our cohort (of which 36 had driver mutations) had a median follow up of 21.5 months, age of 64.8 yrs, and ECOG of 1 at completion of CRT. 52% were female, 86% had a history of smoking, and 87% were white. 65% had adenocarcinoma. All were treated with concurrent CRT with radiation doses ranging from 60Gy to 77Gy. All received at least one dose of consolidative durvalumab prior to disease progression. A similar proportion of first progressions were distant failures in patients with driver mutations and those without (64% vs. 59%, p=0.71). They also had similar rates of oligometastatic disease (28% vs 48%, p=0.09). Patients with oligometastatic disease did not have improved PFS2 (5.9 months vs 5.9 months, p=0.76) compared to those with polymetastatic disease. However, oligometastatic patients with targetable driver mutations who received salvage local therapy (surgery and/or radiation) without tyrosine kinase inhibitors (TKIs) had dramatically worse PFS2 (4.1 months vs 21.4 months, p=0.01) compared to all patients with driver mutations. Conversely, the use of local therapy without systemic therapy did not lead to worse PFS2 in oligometastatic patients without targetable driver mutations (3.5 months vs 4.5 months, p=0.46). <h3>Conclusion</h3> We show similar patterns of failure and rates of oligoprogression for unresectable LA-NSCLC patients treated with concurrent CRT and consolidative durvalumab regardless of driver mutation status. Initial oligometastatic disease did not decrease the likelihood of subsequent progression. Oligometastatic patients with targetable driver mutations should not receive salvage local therapy alone without initiation of TKIs.

CML-428 Real World Data of Treatment Free Remission (TFR) in Patients With Chronic Myeloid Leukemia (CML) Treated at a Tertiary Care Oncology Center in India

TFR has emerged as a new treatment goal in treatment of CML. To describe the outcomes of CML patients undergoing treatment free remission (TFR) in clinical practice. Retrospective analysis of CML patients treated from January 2018 to December 2021 who underwent TFR. Tertiary care cancer center Patients: 38 patients who opted for TFR after counselling or tyrosine kinase inhibitor (TKI) stopped due to various reasons in deep molecular response (DMR) were included. 92% were treated with imatinib at diagnosis. Median duration of TKI treatment was 135 months (6-242). 97.5% achieved DMR on TKI and median time from TKI initiation to DMR was 96 months (12-228). Median duration of DMR prior to TKI discontinuation was 41 months (0-67). TKI was discontinued after counselling for TFR in 26 patients (68%) while it was discontinued due to intolerance in 10 patients (29%). Data was analyzed for molecular relapse (MR), survival without molecular relapse (SWMR), TFR duration, and factors affecting MR. At median follow up of 25 months, nine patients (23.7%) had molecular relapse and three patients died. Median SWMR was not reached, and 2-year estimated SWMR was 65.2% (95%CI,47.2-83.2). After censoring for the competing events of death, 2-year cumulative molecular relapse was 26.8% (95%CI, 10.5-43). Median time to MR was 4 months. Of all relapses, 55.5% occurred in the first six months of TFR. Nine patients (23.7%) were restarted on TKI. Two patients with MR were not restarted on TKI as one patient died immediately after MR and another patient was not keen on restarting TKI despite repeated counselling. Median TFR duration was not reached, and 2-year estimated TFR was 73.4% (95%CI, 58.3-88.5). After restart of TKI, median duration to achieve MMR was 6 months (range, 1-17) in patients with molecular relapse. At the time of analysis, molecular disease statuses were DMR, MMR and less than MMR in 23, 10 and 2 patients respectively. TKI can be safely discontinued in real life practice in chronic phase CML patients in DMR and comparable TFR outcomes can be achieved. Grant acknowledgement: None.

Efficacy of epidermal growth factor receptor tyrosine kinase inhibitors in patients with recurrent non-small cell lung cancer after definitive concurrent chemoradiation or radiotherapy.

Whether prior radiotherapy (RT) affects the response of EGFR-mutated non-small cell lung cancer (NSCLC) to EGFR tyrosine kinase inhibitor (TKI) remains elusive. Patients with EGFR-mutated NSCLC treated with EGFR TKIs who recurred after curative treatment at Asan Medical Center, Seoul, Korea were included. The progression-free survival (PFS) and overall survival (OS) from the initiation of EGFR TKI in patients who recurred after definitive RT were analyzed and compared to the outcomes of RT-naïve patients with advanced NSCLC treated with EGFR TKIs from previously reported prospective clinical trial results. A total of 60 patients who recurred after definitive RT were included. The median age was 70years (range, 38-88), with 24 patients (40.0%) being males. Among the 60 patients, 52 patients (86.7%) had exon 19 deletion or L858R mutation, with 49 patients (81.7%) receiving gefitinib as the first-line EGFR TKI. The median PFS and OS from the initiation of EGFR TKI were 10.4months (95% confidence interval [CI], 7.4-13.2) and 21.3months (95% CI, 13.4-28.8), respectively. The EGFR TKI efficacy in EGFR-mutated patients with NSCLC who recurred after RT was comparable with that in historic controls of RT-naïve patients with advanced NSCLC treated with EGFR TKIs, indicating that RT may not affect EGFR TKI efficacy.