Phase 1/2 clinical study of dasatinib in Japanese patients with chronic myeloid leukemia or Philadelphia chromosome-positive acute lymphoblastic leukemia

Inotuzumab ozogamicin versus standard of care in Asian patients with relapsed/refractory acute lymphoblastic leukemia

Inotuzumab ozogamicin (InO) is a targeted treatment for adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). InO was previously studied in INO-VATE, an international, open-label, randomized phase 3 trial comparing InO against standard of care (SoC). In the present subgroup analysis, we evaluated outcomes in the 55 Asian patients who were randomized in INO-VATE (31 InO and 24 SoC). Complete remission (CR) or CR with incomplete hematologic recovery (CRi) was achieved in 22/31 patients treated with InO versus 5/24 treated with SoC. In the InO arm, more of the patients achieving CR/CRi were minimal residual disease (MRD)-negative (17/22 versus 1/5), and more patients proceeded directly to hematopoietic stem cell transplantation (15/31 versus 3/24). Median overall survival for the respective arms was 5.8 versus 3.9 months (hazard ratio 0.67; 97.5% CI 0.28, 1.62). In the safety analysis (n = 51), the most common adverse events were hematologic. Sinusoidal obstruction syndrome was reported in five InO patients and one SoC patient. In conclusion, Asian patients with relapsed or refractory B-cell ALL experienced improved efficacy with InO versus SoC, with an efficacy and safety profile consistent with results of the overall INO-VATE population.Clinical trial registration: ClinicalTrials.gov identifier: NCT01564784.

The Efficacy of Reduced-dose Dasatinib as a Subsequent Therapy in Patients with Chronic Myeloid Leukemia in the Chronic Phase: The LD-CML Study of the Kanto CML Study Group

Objective The aim of this study was to prospectively investigate the efficacy and safety profiles of low-dose dasatinib therapy (50 mg once daily). Methods Patients with chronic myeloid leukemia in the chronic phase (CML-CP) who were being treated with low-dose imatinib (≤200 mg/day), but were resistant to this agent were enrolled in the current study (referred to as the LD-CML study). Results There subjects included 9 patients (4 men and 5 women); all were treated with dasatinib at a dose of 50 mg once daily. Among 8 patients who had not experienced major molecular response (MMR; BCR-ABL1 transcript ≤0.1% according to International Scale [IS]) at study enrollment, 5 attained MMR by 12 months. In particular, 3 of 9 patients demonstrated a deep molecular response (DMR; IS ≤0.0069%) by 18 months. Five patients developed lymphocytosis accompanied by cytotoxic lymphocyte predominance. There was no mortality or disease progression, and all continue to receive dasatinib therapy at 18 months with only 2 patients requiring dose reduction. Toxicities were mild-to-moderate, and pleural effusion was observed in 1 patient (grade 1). Conclusion Low-dose dasatinib can attain MMR and DMR without severe toxicity in patients with CML-CP who are unable to achieve MMR with low-dose imatinib. Switching to low-dose dasatinib should therefore be considered for patients in this setting, especially if they are otherwise considering a cessation of treatment.

Ponatinib in Japanese patients with Philadelphia chromosome-positive leukemia, a phase 1/2 study

In this ongoing Phase 1/2 study (NCT01667133), we evaluated ponatinib and assessed its recommended dose in Japanese patients with chronic myeloid leukemia (CML) resistant/intolerant to dasatinib or nilotinib, or with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph⁺ALL) resistant/intolerant to ≥1 tyrosine kinase inhibitor (TKI). The primary endpoints were safety of the recommended dose (Phase 1) and major cytogenetic response (MCyR) by 12 months in chronic-phase CML (CP-CML) patients or major hematologic response (MaHR) by 6 months in patients with advanced phase disease (Phase 2). MCyR was achieved/maintained by 12 months in 65% of CP-CML patients; MaHR was achieved by 6 months in 61% of patients with advanced phase disease. The most common nonhematologic grade 3/4 treatment-emergent adverse event (AE) was hypertension (37%); common hematologic grade 3/4 AEs were thrombocytopenia (57%), neutropenia (34%), and leukopenia (26%). Overall, five (14%) patients experienced arterial occlusive events (AOEs); no grade 5 AOEs were reported. The steady-state accumulation ratio of ponatinib (based on area under the curve) ranged from 2.6 (15 mg/day) to 1.3 (45 mg/day). In summary, ponatinib demonstrated efficacy in Japanese patients with CML and Ph⁺ALL resistant/intolerant to prior TKI treatment; safety data support a recommended starting dose of 45 mg/day in these patients.

Long-term treatment with bosutinib in a phase 1/2 study in Japanese chronic myeloid leukemia patients resistant/intolerant to prior tyrosine kinase inhibitor treatment

This long-term follow-up of a completed phase 1/2 study assessed the safety and efficacy of bosutinib in Japanese Philadelphia chromosome-positive, chronic phase (CP) or advanced phase (ADV) chronic myeloid leukemia patients who were resistant/refractory or intolerant to prior tyrosine kinase inhibitor treatment. This analysis included 63 patients with a median bosutinib follow-up of 132 weeks (range 3‒372). In the CP second-line (2L) cohort, the cumulative major cytogenetic response (MCyR) and major molecular response (MMR) rates throughout the study were 73 and 53%, respectively. In the CP third-line (3L) cohort, the cumulative MCyR and MMR rates throughout the study were 70 and 40%, respectively. Of the eight ADV patients, MCyR was attained or maintained by 50% of patients, and complete hematologic response was attained or maintained by 25% of patients. Progression-free survival rate and overall survival rate at 96 weeks were, respectively, 91 and 98% in CP2L, 88 and 100% in CP3L, and 33 and 50% in ADV patients. The most common adverse events (>50%) reported were diarrhea (95%), nasopharyngitis (57%), and rash (57%). Bosutinib demonstrated durable efficacy and a manageable tolerability profile over long-term use in Japanese patients.ClinicalTrials.gov: NCT00811070.

Diagnostic and treatment of adult Philadelphia chromosome-positive acute lymphoblastic leukemia

The outcome of adult patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) has improved substantially with the introduction of tyrosine kinase inhibitors (TKIs). TKIs are now integral components of therapy for Ph+ ALL. The current consensus is that they improve patient outcomes compared with historical control patients treated with chemotherapy alone, and increase the number of patients able to receive stem cell transplant. New challenges have emerged with respect to induction of resistance mainly via Abelson tyrosine kinase mutations. Several novel kinase inhibitors with significantly more potent antileukemic activity are currently being developed. Furthermore novel immune therapies, which recruit or modify patient's own T cells to fight leukemic cells, are being developed and could find an important place in Ph+ ALL therapy by few years. In this article, we reviewed treatment approaches in adults with Ph+ ALL with a focus on TKIs and combined chemotherapy regimens.

The role of dasatinib in the management of chronic myeloid leukemia

Dasatinib is a second-generation tyrosine kinase inhibitor (TKI) for chronic, blastic, or accelerated phase chronic myeloid leukemia (CML) patients who are resistant or intolerant to previous treatment. It potently inhibits BCR/ABL and SRC-family kinases (SRC, LCK, HCK, YES, FYN, FGR, BLK, LYN, FRK), as well as c-KIT, PDGFR-a and -b, and ephrin receptor kinase. Various clinical trials have provided evidence that it has more durable complete hematologic and cytogenetic responses, as well as more potency in imatinib-resistant or -intolerant CML, and it has also shown its advantages in newly diagnosed CML compared to imatinib. In this review, we mainly focus on the structure, mechanisms, pharmacokinetics, and pharmacogenetics of dasatinib. We also summarize clinical trials with dasatinib on CML and provide our recommendations for dasatinib in the treatment of CML.

A phase 1/2 study of bosutinib in Japanese adults with Philadelphia chromosome-positive chronic myeloid leukemia

This phase 1/2 study evaluated the safety and pharmacokinetics (part 1) and efficacy and safety (part 2) of bosutinib in Japanese Philadelphia chromosome-positive (Ph+) chronic-phase (CP) or advanced-phase chronic myeloid leukemia (CML) patients resistant/intolerant to previous imatinib (2L) or imatinib+dasatinib/nilotinib (3L). Based on dose-limiting toxicities and previous studies, the part 2 bosutinib starting dose was 500 mg/day (n = 63). For CP CML 2L (n = 28), the cumulative major cytogenetic response (MCyR) rate by week 24 was 36 % (primary endpoint); the cumulative major molecular response (MMR) rate through the study was 43 %. Transformation to accelerated/blast phase (AP/BP) was observed in one patient. Progression-free survival (PFS) and overall survival (OS) rates at 96 weeks were 94 and 96 %, respectively. Of seven advanced-phase 2L patients, one had confirmed complete hematologic response at week 84, and one had AP/BP transformation. PFS and OS rates at week 96 were 21 and 43 %. For 3L (n = 11), cumulative MCyR rate by week 24 was 18 %; cumulative MMR rate was 18 %; no transformations occurred. Common non-hematologic adverse events (AEs) were diarrhea (95 %), rash (57 %), and nasopharyngitis (51 %). Sixteen patients discontinued due to adverse events; no deaths occurred within 30 days of the last dose. Bosutinib 500 mg/day demonstrated efficacy and manageable toxicity in Japanese Ph+ CML patients resistant/intolerant to imatinib.

Evidence-based guidelines for the use of tyrosine kinase inhibitors in adults with Philadelphia chromosome-positive or BCR-ABL-positive acute lymphoblastic leukemia: a Canadian consensus

Adult Philadelphia chromosome-positive (Ph+) or BCR-ABL-positive (BCR-ABL+) acute lymphoblastic leukemia (all) is an acute leukemia previously associated with a high relapse rate, short disease-free survival, and poor overall survival. In adults, allogeneic hematopoietic cell transplant in first remission remains the only proven curative strategy for transplant-eligible patients. The introduction of tyrosine kinase inhibitors (tkis) in the treatment of patients with Ph+ or BCR-ABL+ all has significantly improved the depth and duration of complete remission, allowing more patients to proceed to transplantation. Although tkis are now considered a standard of care in this setting, few randomized trials have examined the optimal use of tkis in patients with Ph+ all. Questions of major importance remain, including the best way to administer these medications, the choice of tki to administer, and the schedule and the duration to use. We present the results of a systematic review of the literature with consensus recommendations based on the available evidence.

Philadelphia chromosome-positive acute lymphoblastic leukemia with extramedullary and meningeal relapse after allogeneic hematopoietic stem cell transplantation that was successfully treated with dasatinib

Central nervous system (CNS) relapse is a critical issue while treating Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). A 58-year-old woman with Ph-positive ALL who relapsed after bone marrow transplantation for meningeal leukemia was treated with high-dose methotrexate, which resulted in remission. She underwent allogeneic cord blood transplantation followed by reduced intensity conditioning chemotherapy with imatinib; however, she experienced CNS relapse and developed an extramedullary mass on the right side of the temporal region. We treated 40 mg of dasatinib once daily, which had to be temporarily discontinued because she developed grade 2 pleural effusion and grade 2 hematemesis. After reinitiation of dasatinib, the extramedullary mass disappeared and meningeal leukemia ameliorated almost immediately. With 40 mg dasatinib administered once daily, its trough level and cerebrospinal fluid (CSF) concentration were 32 ng/mL and below the sensitivity threshold of 1 ng/mL, respectively. Treatment was continued, and the patient remained in complete remission until she died of pneumonia 7 years after the initial diagnosis of ALL. Dasatinib can be an effective treatment for Ph-positive ALL with CNS relapse. Although the concentration in the CSF seems low, it may be sufficient to exert anti-leukemic effects in the human CNS.

Efficacy and safety of dasatinib versus imatinib in the East Asian subpopulation of the DASISION trial of newly diagnosed chronic myeloid leukemia in chronic phase

Asian patients with chronic myeloid leukemia (CML) tend to have different characteristics compared with patients from other regions, including younger age and smaller body size. The phase 3, open-label, randomized DASISION trial (NCT00481247), comparing dasatinib 100 mg once daily (QD) (n = 259) with imatinib 400 mg QD (n = 260) in newly diagnosed chronic phase CML (CML-CP), included a sizeable East Asian population (n = 60: dasatinib; n = 48: imatinib). In East Asian patients, dasatinib showed favorable 24-month rates of major molecular response (68% vs. 50% for imatinib) and complete cytogenetic response (92% vs. 88%), and more patients achieved BCR-ABL1 transcript levels ≤ 10% at 3 months with dasatinib (91% vs. 69%), similar to the overall population. Relative to non-East Asian patients, the incidence of rash, fluid-related events and grade 3/4 neutropenia and thrombocytopenia appeared to be higher in East Asians, regardless of treatment. Pharmacokinetic analysis revealed statistically non-significant increased dasatinib exposure among East Asian patients. Results support the use of dasatinib 100 mg QD as first-line CML treatment in both East Asian and non-East Asian patients.

Efficacy and safety of dasatinib versus imatinib in Japanese patients with newly diagnosed chronic-phase chronic myeloid leukemia (CML-CP): Subset analysis of the DASISION trial with 2-year follow-up

Dasatinib is a highly potent BCR-ABL kinase inhibitor with established efficacy and safety in imatinib-resistant or -intolerant patients with chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia. In the global phase III DASISION trial in patients with newly diagnosed chronic phase CML (CML-CP), dasatinib was found to have an acceptable safety profile and demonstrated significantly faster and higher rates of complete cytogenetic response (CCyR) and major molecular response (MMR) compared with imatinib. Here, we report the results of a subset analysis of Japanese patients enrolled in the DASISION trial, showing safety and efficacy profiles generally consistent with patients enrolled worldwide, including higher response rates (CCyR, MMR) with dasatinib compared with imatinib and similar high rates of progression-free and overall survival with both therapies. However, the small sample size of the present study limits the strength of these conclusions, and further exploration is needed to confirm any differences observed in Japanese patients compared with the total treated population. These findings support the use of dasatinib 100 mg QD as a first-line treatment in Japanese patients with newly diagnosed CML-CP.

Evolution of clinical trial design in early drug development: systematic review of expansion cohort use in single-agent phase I cancer trials

PURPOSE

To evaluate the use and objectives of expansion cohorts in phase I cancer trials and to explore trial characteristics associated with their use.

METHODS

We performed a systematic review of MEDLINE and EMBASE, limiting studies to single-agent phase I trials recruiting adults and published after 2006. Eligibility assessment and data extraction were performed by two reviewers. Data were assessed descriptively, and associations were tested by univariable and multivariable logistic regression.

RESULTS

We identified 611 unique phase I cancer trials, of which 149 (24%) included an expansion cohort. The trials were significantly more likely to use an expansion cohort if they were published more recently, were multicenter, or evaluated a noncytotoxic agent. Objectives of the expansion cohort were reported in 74% of trials. In these trials, safety (80%), efficacy (45%), pharmacokinetics (28%), pharmacodynamics (23%), and patient enrichment (14%) were cited as objectives. Among expansion cohorts with safety objectives, the recommended phase II dose was modified in 13% and new toxicities were described in 54% of trials. Among trials aimed at assessing efficacy, only 11% demonstrated antitumor activity assessed by response criteria that was not previously observed during dose escalation.

CONCLUSION

The utilization of expansion cohorts has increased with time. Safety and efficacy are common objectives, but 26% fail to report explicit aims. Expansion cohorts may provide useful supplementary data for phase I trials, particularly with regard to toxicity and definition of recommended dose for phase II studies.

Rash with the multitargeted kinase inhibitors nilotinib and dasatinib: meta-analysis and clinical characterization

OBJECTIVES

Nilotinib and dasatinib are second-generation tyrosine kinase inhibitors approved for the treatment of chronic myeloid leukemia (CML). In clinical trials, they have both been reported to cause rash in a significant number of patients, but its incidence varies significantly and has not been characterized clinically or histologically. The aim of this study was to determine the incidence of rash with nilotinib and dasatinib, and to provide a clinical and histopathological description of the rash.

METHODS

We conducted a meta-analysis of clinical trials evaluating nilotinib and dasatinib to determine and compare the incidence of rash with these medications. Additionally, we performed a retrospective chart review to analyze the clinical presentation and histology of patients presenting with rash.

RESULTS

The incidence of all-grade (grade 1-4) rash with nilotinib was 34.3% (95% CI, 27.9-41.3), higher (P = 0.017) than with dasatinib (23.3%; 95% CI, 18.8-28.6). Similarly, the incidence of high-grade rash with nilotinib (2.6%; 95% CI, 2.1-3.4) was higher (P = 0.002) than with dasatinib (1.1%; 95% CI, 0.8-1.6). The clinical presentation often consisted of a pruritic, perifollicular hyperkeratotic, occasionally erythematous papular rash affecting most areas of the body, depending on the severity.

CONCLUSIONS

Both nilotinib and dasatinib are associated with rash in a significant number of patients. Further studies to prevent and treat rash with nilotinib and dasatinib are required to improve patient quality of life, adherence with therapy and oncologic outcome.

A sharp fluctuation in peripheral blood cells shortly after dasatinib administration

Dasatinib, a tyrosine kinase inhibitor, has a reduced plasma half-life and a more extensive inhibition profile, including targeting of Src family kinases. We monitored the peripheral blood count and the serum concentration of dasatinib over time. Interestingly, we found a transient fluctuation of blood cells, which correlated with the dasatinib level. The peripheral blood count before intake of dasatinib was compared with counts measured 2 h later in blood samples from 23 patients. Total white blood cells (WBCs) increased by 2,186 ± 1,960/μL from baseline (P = 0.00002), whereas platelets decreased from a baseline of 185 ± 47 × 10(3)/μL to 164 ± 52 × 10(3)/μL (P = 0.0007). Similar phenomena were not observed in patients treated with imatinib or nilotinib. In addition, in contrast to imatinib, dasatinib strongly attenuated the expression of CD18, CD62P and CD63 by blood cells both in vivo and in vitro. These results suggest that this drug may influence the distribution of blood cells in vivo by regulating its specific adhesion molecule expression on blood cells.

Dasatinib for the treatment of chronic myeloid leukemia

Earlier use of more potent tyrosine kinase inhibitors such as dasatinib improves response rates for patients with chronic myeloid leukemia (CML). The SRC-ABL Tyrosine Kinase Inhibition Activity Research Trials series displayed dasatinib efficacy in patients with all phases of CML who are resistant or intolerant to imatinib. More recently, dasatinib has been shown to induce rapid and high rates of response and has gained approval for newly diagnosed patients with CML in chronic phase. The future of CML therapy may incorporate more potent tyrosine kinase inhibitors such as dasatinib into initial treatment for newly diagnosed patients. The ability of dasatinib to induce rapid and high rates of response with a low progression to advanced forms of CML may translate into improvements in survival.

Managing Philadelphia chromosome-positive acute lymphoblastic leukemia: role of tyrosine kinase inhibitors

Before the introduction of tyrosine kinase inhibitors, the prognosis for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia was poor. The treatment of choice, stem cell transplantation, is a potentially curative option, but it is available only for a minority of patients and is associated with significant risk of morbidity and mortality. Although imatinib is largely effective, a substantial proportion of patients become resistant or intolerant to it. The activity of imatinib may be enhanced by coadministration with chemotherapy; such treatment is effective in many patients. Dasatinib is established as a second-line treatment in patients with resistance to or intolerance of imatinib. Recent data suggest that dasatinib, either alone or in combination with chemotherapy, has utility as first-line therapy. Dasatinib is more potent than imatinib, is less susceptible to drug-resistance mechanisms, and has been shown to penetrate the blood-brain barrier, making it potentially effective for treating central nervous system disease. Patients who relapse during treatment with dasatinib frequently carry the T315I mutation of BCR-ABL. Future regimens combining dasatinib with an agent able to inhibit this mutation may further improve outcome.

Translating cyclooxygenase signaling in patch heterozygote mice into a randomized clinical trial in basal cell carcinoma

This different perspective on Tang et al. (beginning on p. 25 in this issue of the journal) discusses the pivotal role of cyclooxygenase (COX) signaling in the pathogenesis of basal cell carcinoma (BCC). These investigators conducted elegant experiments showing increased BCC burden in patch heterozygous mice overexpressing COX-2 in the epidermis. Genetic deletion of COX-1 or COX-2 resulted in a robust decrease in BCC burden in patch heterozygote mice. They then studied pharmacologic COX inhibition in mice and humans with loss of patch, finding a trend in humans toward decreased BCC burden. This finding has implications for public health.