Phase 2 study of bosutinib in Japanese patients with newly diagnosed chronic phase chronic myeloid leukemia

Population modeling of bosutinib exposure-response in patients with newly diagnosed chronic phase chronic myeloid leukemia

BACKGROUND

The BELA and BFORE trials compared bosutinib starting doses of 500 mg once daily (QD) and 400 mg QD, respectively, with imatinib in adults with newly diagnosed chronic phase chronic myeloid leukemia (CP-CML). The B1871048 trial evaluated bosutinib 400 mg QD in Japanese patients with newly diagnosed CP-CML.

AIM

This analysis assessed the impact of a lower bosutinib starting dose on key efficacy and safety outcomes.

MATERIALS & METHODS

A pharmacokinetic model was used to estimate metrics of bosutinib exposure, and logistic regression was used to investigate relationships with efficacy (cumulative major molecular response [MMR] and cumulative complete cytogenetic response [CCyR]) and safety outcomes (eight prespecified adverse events).

RESULTS

Totals of 573 and 574 patients were included in the efficacy and safety endpoint analyses, respectively. Cumulative MMR and CCyR were similar across studies. Log(Ctrough ) and log(Cavg ) were significant predictors of MMR and CCyR, and the probability of achieving MMR or CCyR increased 1.3-fold or 2.7-fold for every 1 unit increase in log(Ctrough ) or log(Cavg ), respectively. An exposure-response relationship was identified between time-to-event and risk of diarrhea, nausea, and vomiting. Significant relationships were also observed between time-to-event and log(Cavg ), Ctrough , and Cavg with diarrhea, nausea, and vomiting, respectively.

DISCUSSION

A bosutinib exposure-response relationship with safety and efficacy was observed.

CONCLUSION

Compared with 500 mg QD, a bosutinib starting dose of 400 mg QD improved tolerability in some patients with newly diagnosed CP-CML without compromising efficacy.

CLINICALTRIALS

gov identifiers: NCT00574873; NCT02130557; NCT03128411.

Safety and tolerability of bosutinib in patients with amyotrophic lateral sclerosis (iDReAM study): A multicentre, open-label, dose-escalation phase 1 trial

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease caused by the loss of motor neurons, and development of effective medicines is urgently required. Induced pluripotent stem cell (iPSC)-based drug repurposing identified the Src/c-Abl inhibitor bosutinib, which is approved for the treatment of chronic myelogenous leukemia (CML), as a candidate for the molecular targeted therapy of ALS.

METHODS

An open-label, multicentre, dose-escalation phase 1 study using a 3 + 3 design was conducted in 4 hospitals in Japan to evaluate the safety and tolerability of bosutinib in patients with ALS. Furthermore, the exploratory efficacy was evaluated using Revised ALS Functional Rating Scale (ALSFRS-R), predictive biomarkers including plasma neurofilament light chain (NFL) were explored, and single-cell RNA sequencing of iPSC-derived motor neurons was conducted. Patients, whose total ALSFRS-R scores decreased by 1-3 points during the 12-week, received escalating doses starting from 100 mg quaque die (QD) up to 400 mg QD based on dose-limiting toxicity (DLT) occurrence, and all participants who received one dose of the study drug were included in the primary analysis. This trial is registered with ClinicalTrials.gov, NCT04744532, as Induced pluripotent stem cell-based Drug Repurposing for Amyotrophic Lateral Sclerosis Medicine (iDReAM) study.

FINDINGS

Between March 29, 2019 and May 7, 2021, 20 patients were enrolled, 13 of whom received bosutinib treatment and 12 were included in the safety and efficacy analyses. No DLTs were observed up to 300 mg QD, but DLTs were observed in 3/3 patients of the 400 mg QD cohort. In all patients receiving 100 mg-400 mg, the prevalent adverse events (AEs) were gastrointestinal AEs in 12 patients (92.3%), liver function related AEs in 7 patients (53.8%), and rash in 3 patients (23.1%). The safety profile was consistent with that known for CML treatment, and ALS-specific AEs were not observed. A subset of patients (5/9 patients) was found to respond well to bosutinib treatment over the 12-week treatment period. It was found that the treatment-responsive patients could be distinguished by their lower levels of plasma NFL. Furthermore, single-cell RNA sequencing of iPSC-derived motor neurons revealed the pathogenesis related molecular signature in patients with ALS showing responsiveness to bosutinib.

INTERPRETATION

This is the first trial of a Src/c-Abl inhibitor, bosutinib, for patients with ALS. The safety and tolerability of bosutinib up to 300 mg, not 400 mg, in ALS were described, and responsiveness of patients on motor function was observed. Since this was an open-label trial within a short period with a limited number of patients, further clinical trials will be required.

FUNDING

AMED and iPS Cell Research Fund.

Bosutinib in Japanese patients with newly diagnosed chronic-phase chronic myeloid leukemia: final 3-year follow-up results of a phase 2 study

Bosutinib has been evaluated for treatment of chronic-phase chronic myeloid leukemia (CP-CML) in several clinical studies, including in Japan. This open-label, single-arm, phase 2 study evaluated the efficacy and safety of bosutinib at a starting dose of 400 mg once daily in Japanese patients (n = 60) with newly diagnosed CP-CML. The minimum follow-up period was 3 years and median duration of treatment was 35.9 months. At study completion, 60% of patients were still on treatment. Cumulative rates of major molecular response (MMR), molecular response⁴ (MR⁴), and MR^4.5 at any time were 70.0%, 53.3%, and 48.3%, respectively. No patient who achieved MMR or MR⁴ had a confirmed loss of response. No patient experienced on-treatment transformation to accelerated/blast phase or died within 28 days of the last bosutinib dose. Any-grade treatment-emergent adverse events (TEAEs) occurred in 100% (grade ≥ 3: 81.7%) of patients. The most common TEAEs were diarrhea (86.7%), increased alanine aminotransferase (55.0%), and increased aspartate aminotransferase (46.7%). No new safety signals emerged during the follow-up period. Bosutinib continues to demonstrate a favorable benefit/risk profile and is an important treatment option for Japanese patients with newly diagnosed CP-CML. Optimal management of TEAEs during initial treatment with bosutinib should be prioritized.

Trial Registration: ClinicalTrials.gov ID: NCT03128411.

Safety profile of bosutinib in Japanese versus non-Japanese patients with chronic myeloid leukemia: a pooled analysis

Bosutinib has been investigated in multiple clinical trials globally, including Japan, for treatment of chronic myeloid leukemia (CML). A pooled analysis of seven Pfizer-sponsored clinical trials evaluated the safety of bosutinib in Japanese (n = 138) vs non-Japanese (n = 1210) patients with CML. First-line bosutinib was administered in 54.3% vs 41.4% of patients, and second-line or later bosutinib in the remainder. Median treatment duration was 1.4 vs 2.3 years, and median relative dose intensity 78.1% vs 90.0%. Any-grade treatment-emergent adverse events (TEAEs) occurred in 100.0% vs 98.9% (grade ≥ 3: 81.9% vs 75.2%). In both groups, the most common TEAEs relevant to bosutinib were gastrointestinal (92.8% vs 84.7%), liver function (72.5% vs 34.8%), rash (63.8% vs 37.4%), and myelosuppression (55.1% vs 50.7%). TEAEs led to dose reduction in 65.2% vs 50.6%, dose interruption in 78.3% vs 68.8%, and permanent treatment discontinuation in 30.4% vs 25.4% of patients. The safety profile of bosutinib in Japanese patients was generally consistent with that in non-Japanese patients, despite a higher incidence of gastrointestinal, liver function, and rash events. TEAEs were largely manageable with dose modifications and supportive care in both groups. These data may help optimize TEAE management and outcomes in Japanese patients receiving bosutinib for CML. Trial registration ClinicalTrials.gov: NCT02130557, NCT03128411, NCT00574873, NCT00261846, NCT01903733, NCT00811070, NCT02228382.

Which Tyrosine Kinase Inhibitors Should Be Selected as the First-Line Treatment for Chronic Myelogenous Leukemia in Chronic Phase?

Simple Summary

This review discusses the optimal selection of BCR-ABL1 tyrosine kinase inhibitors (TKIs) as the first-line treatment for newly diagnosed chronic myelogenous leukemia in chronic phase (CML-CP). With the advent of TKIs, the treatment goals for CML-CP patients have changed from “simply survival” to “survival with adequate quality of life”, hence the number of CML-CP patients aiming to achieve treatment-free remission has increased, irrespective of age or comorbidities. Therefore, optimal selection of TKIs for maximizing the number of patients to achieve treatment-free remission is an important factor for consideration in future studies. To this end, we must understand the advantages and disadvantages of each TKI in terms of treatment response, disease risk at diagnosis, comorbidities, and medical expenses, and use of effective 2GTKIs based on patient background. This review provides insights into “shared decision-making” in individual cases, including the elderly population.

Abstract

With the use of tyrosine kinase inhibitors (TKIs), chronic myelogenous leukemia in chronic phase (CML-CP) has been transformed into a non-fatal chronic disease. Hence, “treatment-free remission (TFR)” has become a possible treatment goal of patients with CML-CP. Currently, four types of TKIs (imatinib, nilotinib, dasatinib, and bosutinib) are used as the first-line treatment for newly diagnosed CML-CP. However, the second-generation TKI (2GTKI), the treatment response of which is faster and deeper than that of imatinib, is not always recommended as the first-line treatment for CML-CP. Factors involved in TKI selection in the first-line treatment of CML-CP include not only patients’ medical background, but also patients’ choice regarding the desired treatment goal (survival or TFR?). Therefore, it is important that clinicians select an appropriate TKI to successfully achieve the desired treatment goal for each patient, while minimizing the development of adverse events. This review compares the pros and cons of using imatinib and 2GTKI for TKI selection as the first-line treatment for CML-CP, mainly considering treatment outcomes, medical history (i.e., desire for pregnancy, aging factor, and comorbidity), and cost. The optimal use of 2GTKIs is also discussed.

Arterial Hypertension and Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia: A Systematic Review and Meta-Analysis

Background: Off-target effects in chronic myeloid leukemia (CML) patients treated with tyrosine kinase inhibitors (TKIs) are associated with cardiovascular toxicity. Hypertension represents an important cardiovascular complication and, if not appropriately managed, can contribute to developing thrombotic events. Third-generation TKI ponatinib is associated with hypertension development, and its use is more restricted than in the past. Few data are reported for second-generation TKI, nilotinib, dasatinib, and bosutinib. The aim of this article was to evaluate with a systematic review and meta-analysis the real incidence of hypertension in CML patients treated with second- or third-generation TKI.

Methods: The PubMed database, Web of Science, Scopus, and ClinicalTrials.gov were systematically searched for studies published between January 1, 2000, and January 30, 2021; the following terms were entered in the database queries: Cardiovascular, Chronic Myeloid Leukemia, CML, Tyrosine kinases inhibitor, TKI, and Hypertension. The study was carried out according to the Preferred Reporting Items for Systematic and Meta-Analyses (PRISMA) statement.

Results: A pooled analysis of hypertension incidence was 10% for all new-generation TKI, with an even higher prevalence with ponatinib (17%). The comparison with the first-generation imatinib confirmed that nilotinib was associated with a significantly increased risk of hypertension (RR 2; 95% CI; 1.39-2.88, I²=0%, z=3.73, p=0.0002). The greatest risk was found with ponatinib (RR 9.21; 95% CI; 2.86-29.66, z=3.72, p=0.0002).

Conclusion: Hypertension is a common cardiovascular complication in CML patients treated with second- or third-generation TKI.

Nilotinib vs. imatinib in Japanese patients with newly diagnosed chronic myeloid leukemia in chronic phase: 10-year follow‑up of the Japanese subgroup of the randomized ENESTnd trial

In the 10-year analysis of Japanese patients with newly diagnosed CML-CP in the ENESTnd trial, nilotinib yielded higher cumulative response rates. There were no new occurrences of disease progression or deaths since the 5-year analysis. Cumulative 10-year rates of MMR and MR^4.5 were higher in the nilotinib arms [300 mg twice daily (BID), 86.2% and 69.0%, respectively; 400 mg BID, 78.3% and 69.6%, respectively] than the imatinib arm (400 mg once daily, 60.0% and 48.0%, respectively). Nasopharyngitis (85.7%, 77.3%, 79.2%), rash (50.0%, 68.2%, 37.5%), headache (39.3%, 45.5%, 25.0%), and back pain (39.3%, 50.0%, 29.2%) were the most frequently reported all-grade adverse events (AEs) for nilotinib 300 and 400 mg BID and imatinib, respectively. Cardiovascular AEs were more common with nilotinib than with imatinib. More patients on nilotinib had pre-diabetic and diabetic levels of HbA1c (300 mg BID, 17.9% and 10.7%, respectively; 400 mg BID, 22.7% and 18.2%, respectively) compared with imatinib (4.2% each). Overall, 10-year results from the Japanese cohort are consistent with prior results from the full ENESTnd cohort and the Japanese subgroup, and continue to support the long-term use of nilotinib in Japanese patients with newly diagnosed CML-CP, but with proper monitoring and management of comorbidities.

Efficacy and safety of bosutinib versus imatinib for newly diagnosed chronic myeloid leukemia in the Asian subpopulation of the phase 3 BFORE trial

Bosutinib is approved in the United States, Europe, Japan, and other countries for treatment of newly diagnosed chronic phase (CP) chronic myeloid leukemia (CML), and CML resistant/intolerant to prior therapy. In the phase 3 BFORE trial (Clinicaltrials.gov, NCT02130557), patients were randomized 1:1 to first-line bosutinib or imatinib 400 mg once daily. We examined efficacy, safety, and patient-reported outcomes of bosutinib vs imatinib and pharmacokinetics of bosutinib in the Asian (n = 33 vs 34) and non-Asian (n = 235 vs 234) subpopulations of BFORE followed for at least 24 months. At the data cutoff date, 72.7 vs 66.7% of Asian and 70.6 vs 66.4% of non-Asian patients remained on treatment. The major molecular response rate at 24 months favored bosutinib vs imatinib among Asian (63.6 vs 38.2%) and non-Asian (60.9 vs 52.6%) patients, as did the complete cytogenetic response rate by 24 months (86.7 vs 76.7%, 81.5 vs 76.3%). Treatment-emergent adverse events in both subpopulations were consistent with the primary BFORE results. Trough bosutinib concentration levels tended to be higher in Asian patients. Health-related quality of life was maintained after 12 months of bosutinib in both subpopulations. These results support bosutinib as a first-line treatment option in Asian patients with CP CML.

Dual targeting of TAM receptors Tyro3, Axl, and MerTK: Role in tumors and the tumor immune microenvironment

In both normal and tumor tissues, receptor tyrosine kinases (RTKs) may be pleiotropically expressed. The RTKs not only regulate ordinary cellular processes, including proliferation, survival, adhesion, and migration, but also have a critical role in the development of many types of cancer. The Tyro3, Axl, and MerTK (TAM) family of RTKs (Tyro3, Axl, and MerTK) plays a pleiotropic role in phagocytosis, inflammation, and normal cellular processes. In this article, we highlight the cellular activities of TAM receptors and discuss their roles in cancer and immune cells. We also discuss cancer therapies that target TAM receptors. Further research is needed to elucidate the function of TAM receptors in immune cells toward the development of new targeted immunotherapies for cancer.