Project Confirm: Accelerated Drug Approvals for Chronic Myeloid Leukemia.

The FDA has an accelerated approval program for drugs that have been identified as promising treatments for serious conditions when the available data suggest that the benefits outweigh the foreseeable risks. All of the currently available treatment options for chronic myeloid leukemia (CML) initially went through the accelerated approval program. Here, a group of academic CML experts, patient panelists, and members from the FDA convened to discuss the utility of the accelerated approval program as it pertains to CML, and the utility of this program in future drug development in this disease. The results of that discussion are summarized here.

An evaluation of ponatinib as a therapy in adult patients with resistant/intolerant chronic-phase chronic myeloid leukemia.

INTRODUCTION: Chronic myeloid leukemia is now a highly treatable leukemia due to the availability of multiple tyrosine kinase inhibitors (TKIs) inhibiting the BCR-ABL1 oncogene. Some patients with CML can display resistance or intolerance to multiple TKIs, oftentimes due to the presence of mutations in BCR-ABL1, such as T315I, which limits effective treatment options. Ponatinib is a third-generation, rationally-designed TKI with clinically meaningful activity in this difficult-to-treat population. Ponatinib is associated with an increased risk of arterial occlusive events (AOEs) which has required a reexamination of its dosing in order to limit the risk of these events. AREAS COVERED: This review will provide an overview of the mechanism of action of ponatinib and the safety and efficacy data from clinical trials in chronic myeloid leukemia. EXPERT OPINION: Ponatinib is a potent pan-BCR-ABL1 TKI with substantial activity in patients with more resistant or advanced CML. Its efficacy needs to be balanced with the increased risk of vascular events, which seems to be at least partially diminished by the implementation of mitigation strategies aimed at modifying cardiovascular risk factors and adaptive dosing of the drug.

Patient- and physician-reported pain after tyrosine kinase inhibitor discontinuation among patients with chronic myeloid leukemia.

For patients with optimally treated chronic myeloid leukemia (CML), discontinuation of tyrosine kinase inhibitor (TKI) therapy can lead to treatment-free remission. In previous trials, TKI discontinuation has been associated with increased musculoskeletal pain in some patients ("withdrawal syndrome"), based on physician-reported adverse events (AE). Patient-reported pain has not been described. The Life After Stopping TKI study was a 14-site prospective, non-randomized clinical trial of TKI discontinuation. We defined increased pain after discontinuation as: (i) a physician-reported pain AE, (ii) a 2-level increase in self-reported musculoskeletal pain (4-level single item), or (iii) initiation of a medication for pain. We plotted the trajectory of patient-reported pain over time using a piecewise mixed-effects ordinal logistic model. Within 3 months of discontinuation, 35 of 172 patients (20.3%) had a physician-reported pain AE, 22 of 172 (12.8%) had an increase in self-reported pain, and 18 of 154 (11.7%) initiated a pain medication. Agreement among these measures was limited; overall, 60 of 172 patients (34.9%) had increased pain. Three patients (1.7%) restarted a TKI because of pain. The modelpredicted trajectory showed an increase in pain in the first 3 months followed by a decrease, returning to baseline levels by 6 months and further decreasing after that. This trajectory was similar among patients who did and did not restart TKI, suggesting that resuming a TKI for withdrawal syndrome may be necessary for some, but other approaches to manage pain should be tried so that patients can remain in treatment-free remission when possible.

Patient-Reported Functional Outcomes in Patients With Chronic Myeloid Leukemia After Stopping Tyrosine Kinase Inhibitors.

Treatment-free remission (TFR) is a goal for patients with chronic myeloid leukemia (CML). Functional outcomes after discontinuing tyrosine kinase inhibitor (TKI) treatment have not been described. Patient-Reported Outcomes Measurement Information System (PROMIS) measures of social, physical, cognitive, and sexual function were assessed over 36 months in 172 adult patients with chronic phase CML from 14 sites at baseline (on TKI) and after discontinuation. Linear mixed-effects models described the average trajectories for each patient-reported outcome measure after discontinuation and in those who restarted TKI. Of 112 patients in TFR at 12 months, 103 (92.0%) had a 3-point or greater improvement in social function, 80 (71.4%) in social isolation, 11 (9.8%) in satisfaction with sex life, 4 (3.6%) in physical function, and no patients had a 3-point or greater improvement in cognitive function or interest in sexual activity. Patients' scores worsened after restarting TKI. This novel information on functional outcomes in TFR can help guide patient and clinician decision making.

How to Effectively Decrease Patient Co-Payments of High-Cost Drugs Through Innovation: Lessons From the Karmanos Specialty Pharmacy.

PURPOSE: High-cost drugs impose a financial burden on patients with cancer. Karmanos Specialty Pharmacy (KSP) developed a process to automate financial assistance (FA) applications to decrease patient drug cost. We evaluate the outcomes of this program on cost to patients and payers. METHODS: This is an observational, retrospective study of the KSP claims data set from January to December 2019, accessed by 13 statewide cancer centers within Michigan. Drug cost of patients, payers, FA (funds to lower patient drug cost), and types of FA were obtained. A subset analysis was performed to determine drug delivery times. RESULTS: In 2019, 869 prescriptions and 1,722 prescription fills were provided to 463 patients through KSP. The total cost of drug claims was approximately $10 million US dollars (USD) among Medicare patients (58%), approximately $3.4 million USD for privately insured patients (20%), and approximately $3.7 million USD for Medicaid patients (22%). Twenty-seven percent of patients (22% of all prescription fills) required additional FA with initial total co-payment claims of $335,216 USD. $280,988 USD of FA was obtained, which substantially lowered total patient costs by 81%. $250,818 USD of FA obtained was from foundation grants (327 fills), and $21,441 USD from manufacturer co-pay cards (47 fills). An additional $12,260 USD (12 fills) from a Karmanos Patient Assistance Fund was used. There was high dependence on foundation grant assistance among Medicare patients (33% of claims). In a subset analysis, the median time from prescription written to delivery to the patient was < 7 days (0-56 days). CONCLUSION: Twenty-seven percent of patients (22% of prescriptions fills) in 2019 required additional FA for high-cost drugs. KSP substantially reduced patient cost by implementing an efficient process using additional pharmacy assistants to obtain FA.

Ponatinib dose-ranging study in chronic-phase chronic myeloid leukemia: a randomized, open-label phase 2 clinical trial.

In PACE (Ponatinib Ph+ ALL and CML Evaluation), a phase 2 trial of ponatinib that included patients with chronic-phase chronic myeloid leukemia (CP-CML) resistant to multiple prior tyrosine kinase inhibitors (TKIs), ponatinib showed deep and durable responses, but arterial occlusive events (AOEs) emerged as notable adverse events. Post hoc analyses indicated that AOEs are dose dependent. We assessed the benefit/risk ratio across 3 ponatinib starting doses in the first prospective study to evaluate a novel, response-based, dose-reduction strategy for TKI treatment. Adults with CP-CML resistant to or intolerant of at least 2 prior BCR-ABL1 TKIs or with a BCR-ABL1 T315I mutation were randomly assigned 1:1:1 to 3 cohorts receiving ponatinib 45, 30, or 15 mg once daily. In patients who received 45 or 30 mg daily the dose was reduced to 15 mg upon response (BCR-ABL1IS transcript levels ≤1%). The primary end point was response at 12 months. From August 2015 through May 2019, 283 patients were randomly assigned to the cohorts: 282 (94 per dose group) received treatment (data cutoff, 31 May 2020). The primary end point (98.3% confidence interval) was achieved in 44.1% (31.7-57.0) in the 45-mg cohort, 29.0% (18.4-41.6) in the 30-mg cohort, and 23.1% (13.4-35.3) in the 15-mg cohort. Independently confirmed grade 3 or above treatment-emergent AOEs occurred in 5, 5, and 3 patients in the 45-, 30-, and 15-mg cohorts, respectively. All cohorts showed benefit in this highly resistant CP-CML population. Optimal benefit/risk outcomes occurred with the 45-mg starting dose, which was decreased to 15 mg upon achievement of a response. This trial is registered on www.clinicaltrials.gov as NCT02467270.

Phase 2 study of ibrutinib in classic and variant hairy cell leukemia.

Hairy cell leukemia (HCL) is a rare B-cell malignancy, and there is a need for novel treatments for patients who do not benefit from purine analogs. Ibrutinib, an oral agent targeting Bruton tyrosine kinase in the B-cell receptor signaling pathway, is highly effective in several malignancies. Its activity in HCL was unknown, so we conducted a multisite phase 2 study of oral ibrutinib in patients with either relapsed classic or variant hairy cell leukemia. The primary outcome measure was the overall response rate (ORR) at 32 weeks, and we also assessed response at 48 weeks and best response during treatment. Key secondary objectives were characterization of toxicity and determination of progression-free survival (PFS) and overall survival (OS). Thirty-seven patients were enrolled at 2 different doses (24 at 420 mg, 13 at 840 mg). The median duration of follow-up was 3.5 years (range, 0-5.9 years). The ORR at 32 weeks was 24%, which increased to 36% at 48 weeks. The best ORR was 54%. The estimated 36-month PFS was 73% and OS was 85%. The most frequent adverse events were diarrhea (59%), fatigue (54%), myalgia (54%), and nausea (51%). Hematologic adverse events were common: anemia (43%), thrombocytopenia (41%), and neutropenia (35%). Ibrutinib can be safely administered to patients with HCL with objective responses and results in prolonged disease control. Although the initial primary outcome objective of the study was not met, the observation of objective responses in heavily pretreated patients coupled with a favorable PFS suggests that ibrutinib may be beneficial in these patients. This trial was registered at www.clinicaltrials.gov as #NCT01841723.

Lenalidomide-Epoetin Alfa Versus Lenalidomide Monotherapy in Myelodysplastic Syndromes Refractory to Recombinant Erythropoietin.

PURPOSE: Impaired response to erythropoietin underlies ineffective erythropoiesis and anemia in myelodysplastic syndromes (MDS). We investigated whether treatment with lenalidomide (LEN), which augments erythropoietin receptor signaling in vitro, can restore and improve hemoglobin response to epoetin (EPO) alfa in patients with lower-risk, non-del(5q) MDS who have anemia that is refractory to or have low probability of benefit from treatment with recombinant erythropoietin. METHODS: In a phase III, US intergroup trial, we randomly assigned patients to receive either LEN and EPO alfa or LEN alone following stratification by serum erythropoietin concentration and prior erythropoietin treatment. RESULTS: A total of 195 evaluable patients were randomly assigned: 99 patients to the LEN-EPO alfa cohort and 96 to LEN alone. After four cycles of treatment, the primary end point of major erythroid response (MER) was significantly higher (28.3%) with the combination compared with LEN alone (11.5%) (P = .004). Among 136 patients who completed 16 weeks of study treatment, 38.9% and 15.6% achieved MER, respectively (P = .004). Additionally, minor erythroid response was achieved in 18.2% and 20.8% of patients, for an overall erythroid response rate of 46.5% versus 32.3%. Among LEN nonresponders, 38 crossed over to the addition of EPO alfa with 10 patients (26.3%) achieving a MER. Responses to the combined treatment were highly durable with a median MER duration of 23.8 months compared with 13 months with LEN alone. CONCLUSION: LEN restores sensitivity to recombinant erythropoietin in growth factor-insensitive, lower-risk, non-del(5q) MDS, to yield a significantly higher rate and duration of MER compared with LEN alone (funded by the National Cancer Institute; E2905 ClinicalTrials.gov identifier: NCT02048813).

Distinctive phenotypes in two children with novel germline RUNX1 mutations - one with myeloid malignancy and increased fetal hemoglobin.

RUNX1 associated familial platelet disorder (FPD) is a rare autosomal dominant hematologic disorder characterized by thrombocytopenia and/or altered platelet function. There is an increased propensity to develop myeloid malignancy (MM) - acute myeloid leukemia, myeloproliferative neoplasms or myelodysplastic syndrome often in association with secondary somatic variants in other genes. To date, 23 FPD-MM pediatric cases have been reported worldwide. Here, we present two new kindreds with novel RUNX1 pathogenic variants in which children are probands. The first family is a daughter/mother diad, sharing a heterozygous frameshift variant in RUNX1 gene (c.501delT p.Ser167Argfs*9). The daughter, age 13 years, presented with features resembling juvenile myelomonocytic leukemia - severe anemia, thrombocytopenia, high white cell count with blast cells, monocytosis, increased nucleated red cells and had somatic mutations with high allele burden in CUX1, PHF6, and SH2B3 genes. She also had increased fetal hemoglobin and increased LIN28B expression. The mother, who had a long history of hypoplastic anemia, had different somatic mutations- a non-coding mutation in CUX1 but none in PHF6 or SH2B3. Her fetal hemoglobin and LIN28B expression were normal. In the second kindred, the proband, now 4 years old with thrombocytopenia alone, was investigated at 3 months of age for persistent neonatal thrombocytopenia with large platelets. Molecular testing identified a heterozygous intragenic deletion in RUNX1 encompassing exon 5. His father is known to have increased bruising for several years but is unavailable for testing. These two cases illustrate the significance of secondary mutations in the development and progression of RUNX1-FPD to MM.

Assessment of Outcomes After Stopping Tyrosine Kinase Inhibitors Among Patients With Chronic Myeloid Leukemia: A Nonrandomized Clinical Trial.

IMPORTANCE: Tyrosine kinase inhibitors (TKIs) have been associated with improved survival of patients with chronic myeloid leukemia (CML) but are also associated with adverse effects, especially fatigue and diarrhea. Discontinuation of TKIs is safe and is associated with the successful achievement of treatment-free remission (TFR) for some patients. OBJECTIVE: To evaluate molecular recurrence (MRec) and patient-reported outcomes (PROs) after TKI discontinuation for US patients with CML. DESIGN, SETTING, AND PARTICIPANTS: The Life After Stopping TKIs (LAST) study was a prospective single-group nonrandomized clinical trial that enrolled 172 patients from 14 US academic medical centers from December 18, 2014, to December 12, 2016, with a minimum follow-up of 3 years. Participants were adults with chronic-phase CML whose disease was well controlled with imatinib, dasatinib, nilotinib, or bosutinib. Statistical analysis was performed from August 13, 2019, to March 23, 2020. INTERVENTION: Discontinuation of TKIs. MAIN OUTCOMES AND MEASURES: Molecular recurrence, defined as loss of major molecular response (BCR-ABL1 International Scale ratio >0.1%) by central laboratory testing, and PROs (Patient-Reported Outcomes Measurement Information System computerized adaptive tests) were monitored. Droplet digital polymerase chain reaction (ddPCR) was performed on samples with undetectable BCR-ABL1 by standard real-time quantitative polymerase chain reaction (RQ-PCR). RESULTS: Of 172 patients, 89 were women (51.7%), and the median age was 60 years (range, 21-86 years). Of 171 patients evaluable for molecular analysis, 112 (65.5%) stayed in major molecular response, and 104 (60.8%) achieved TFR. Undetectable BCR-ABL1 by either ddPCR or RQ-PCR at the time of TKI discontinuation (hazard ratio, 3.60; 95% CI, 1.99-6.50; P < .001) and at 3 months (hazard ratio, 5.86; 95% CI, 3.07-11.1; P < .001) was independently associated with MRec. Molecular recurrence for patients with detectable BCR-ABL1 by RQ-PCR was 50.0% (14 of 28), undetectable BCR-ABL1 by RQ-PCR but detectable by ddPCR was 64.3% (36 of 56), and undetectable BCR-ABL1 by both ddPCR and RQ-PCR was 10.3% (9 of 87) (P ≤ .001). Of the 112 patients in TFR at 12 months, 90 (80.4%) had a clinically meaningful improvement in fatigue, 39 (34.8%) had a clinically meaningful improvement in depression, 98 (87.5%) had a clinically meaningful improvement in diarrhea, 24 (21.4%) had a clinically meaningful improvement in sleep disturbance, and 5 (4.5%) had a clinically meaningful improvement in pain interference. Restarting a TKI resulted in worsening of PROs. CONCLUSIONS AND RELEVANCE: In this study, TKI discontinuation was safe, and 60.8% of patients remained in TFR. Discontinuation of TKIs was associated with improvements in PROs. These findings should assist patients and physicians in their decision-making regarding discontinuation of TKIs. Detectable BCR-ABL1 by RQ-PCR or ddPCR at the time of TKI discontinuation was associated with higher risk of MRec; clinical application of this finding should be confirmed in other studies. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02269267.

The costs of treating and not treating patients with chronic myeloid leukemia with tyrosine kinase inhibitors among Medicare patients in the United States.

BACKGROUND: Patients with high cost-sharing of tyrosine kinase inhibitors (TKIs) experience delays in treatment for chronic myeloid leukemia (CML). To the authors' knowledge, the clinical outcomes among and costs for patients not receiving TKIs are not well defined. METHODS: Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, the authors evaluated differences in TKI initiation, health care use, cost, and survival among patients with CML with continuous Medicare Parts A and B and Part D coverage who were diagnosed between 2007 and 2015. RESULTS: A total of 941 patients were included. Approximately 29% of all patients did not initiate treatment with TKIs within 6 months (non-TKI users), and had lower rates of BCR-ABL testing and more hospitalizations compared with TKI users. Approximately 21% were not found to have any TKI claims at any time. TKI initiation rates within 6 months of diagnosis increased for all patients over time (61% to 85%), with greater improvements observed in patients receiving subsidies (55% to 90%). Total Medicare costs were greater in patients treated with TKIs, with approximately 50% because of TKI costs. Non-TKI users had more inpatient costs compared with TKI users. Trends in cost remained significant when adjusting for age and comorbidities. The median overall survival was 40 months (95% confidence interval [95% CI], 34-48 months) compared with 86 months (95% CI, 73 months to not reached), respectively, for non-TKI users versus TKI users, a finding that remained consistent when adjusting for age, comorbidities, and subsidy status (hazard ratio, 2.23; 95% CI, 1.77-2.81). CONCLUSIONS: Approximately 21% of all patients with CML did not receive TKIs at any time. Cost-sharing subsidies consistently are found to be associated with higher initiation rates. Non-TKI users had higher inpatient costs and poorer survival outcomes. Interventions to lower TKI costs for all patients are desirable.

Discontinuation of tyrosine kinase inhibitors in chronic myeloid leukemia: when and for whom?

Treatment discontinuation is considered one of the main goals of therapy for patients with chronic myeloid leukemia. Several criteria are felt to be necessary to consider discontinuation, while others may predict a better chance of achieving treatment-free remission. Criteria for discontinuation include patients in chronic phase chronic myeloid leukemia, a minimum duration of tyrosine kinase inhibitor therapy of 3 years, sustained deep molecular response for at least 2 years and a molecular response of at least MR4. In addition, proper education of the patient on the need for more frequent monitoring, possible side effects related to stopping and having a reliable real-time quantitative polymerase chain reaction laboratory are paramount to the safety and success of treatment-free remission. Realistically though, a maximum of only 20-30% of newly diagnosed patients will be able to achieve a successful treatment-free remission. In this article we will review for whom and when a trial of discontinuation should be considered.