The DOT1L inhibitor pinometostat reduces H3K79 methylation and has modest clinical activity in adult acute leukemia.

Pinometostat (EPZ-5676) is a first-in-class small-molecule inhibitor of the histone methyltransferase disrupter of telomeric silencing 1-like (DOT1L). In this phase 1 study, pinometostat was evaluated for safety and efficacy in adult patients with advanced acute leukemias, particularly those involving mixed lineage leukemia (MLL) gene rearrangements (MLL-r) resulting from 11q23 translocations. Fifty-one patients were enrolled into 6 dose-escalation cohorts (n = 26) and 2 expansion cohorts (n = 25) at pinometostat doses of 54 and 90 mg/m2 per day by continuous intravenous infusion in 28-day cycles. Because a maximum tolerated dose was not established in the dose-escalation phase, the expansion doses were selected based on safety and clinical response data combined with pharmacodynamic evidence of reduction in H3K79 methylation during dose escalation. Across all dose levels, plasma pinometostat concentrations increased in an approximately dose-proportional fashion, reaching an apparent steady-state by 4-8 hours after infusion, and rapidly decreased following treatment cessation. The most common adverse events, of any cause, were fatigue (39%), nausea (39%), constipation (35%), and febrile neutropenia (35%). Overall, 2 patients, both with t(11;19), experienced complete remission at 54 mg/m2 per day by continuous intravenous infusion, demonstrating proof of concept for delivering clinically meaningful responses through targeting DOT1L using the single agent pinometostat in MLL-r leukemia patients. Administration of pinometostat was generally safe, with the maximum tolerated dose not being reached, although efficacy as a single agent was modest. This study demonstrates the therapeutic potential for targeting DOT1L in MLL-r leukemia and lays the groundwork for future combination approaches in this patient population. This clinical trial is registered at www.clinicaltrials.gov as NCT01684150.

Tazemetostat, an EZH2 inhibitor, in relapsed or refractory B-cell non-Hodgkin lymphoma and advanced solid tumours: a first-in-human, open-label, phase 1 study.

BACKGROUND: Activating enhancer of zeste homolog 2 (EZH2) mutations or aberrations of the switch/sucrose non-fermentable (SWI/SNF) complex (eg, mutations or deletions of the subunits INI1 or SMARCA4) can lead to aberrant histone methylation, oncogenic transformation, and a proliferative dependency on EZH2 activity. In this first-in-human study, we aimed to investigate the safety, clinical activity, pharmacokinetics, and pharmacodynamics of tazemetostat, a first-in-class selective inhibitor of EZH2. METHODS: We did an open-label, multicentre, dose-escalation, phase 1 study using a 3 + 3 design with planned cohort expansion at the two highest doses below the maximally tolerated dose. The study was done at two centres in France: Institut Gustave Roussy (Villejuif, Val de Marne) and Institut Bergonié (Bordeaux, Gironde). Eligible patients had relapsed or refractory B-cell non-Hodgkin lymphoma or an advanced solid tumour and were older than 18 years, with Eastern Cooperative Oncology Group performance status of 0 or 1, and adequate end-organ function. Tazemetostat was administered orally from 100 mg twice daily to 1600 mg twice daily in 28-day cycles. The primary endpoint was to establish the maximum tolerated dose or recommended phase 2 dose of tazemetostat, as determined by dose-limiting toxicities, laboratory values, and other safety or pharmacokinetic measures in cycle one according to local investigator assessment. Safety was assessed in patients who received at least one dose of tazemetostat; antitumour activity was assessed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT01897571. The phase 1 part of the study is complete, and phase 2 is ongoing. FINDINGS: Between June 13, 2013, and Sept 21, 2016, 64 patients (21 with B-cell non-Hodgkin lymphoma, and 43 with advanced solid tumours) received doses of tazemetostat. The most common treatment-related adverse events, regardless of attribution, were asthenia (21 [33%] of 64 treatment-related events), anaemia (nine [14%]), anorexia (four [6%]), muscle spasms (nine [14%]), nausea (13 [20%]), and vomiting (six [9%]), usually grade 1 or 2 in severity. A single dose-limiting toxicity of grade 4 thrombocytopenia was identified at the highest dose of 1600 mg twice daily. No treatment-related deaths occurred; seven (11%) patients had non-treatment-related deaths (one at 200 mg twice daily, four at 400 mg twice daily, and two at 1600 mg twice daily). The recommended phase 2 dose was determined to be 800 mg twice daily. Durable objective responses, including complete responses, were observed in eight (38%) of 21 patients with B-cell non-Hodgkin lymphoma and two (5%) of 43 patients with solid tumours. INTERPRETATION: Tazemetostat showed a favourable safety profile and antitumour activity in patients with refractory B-cell non-Hodgkin lymphoma and advanced solid tumours, including epithelioid sarcoma. Further clinical investigation of tazemetostat monotherapy is ongoing in phase 2 studies in adults and a phase 1 study for children, which are currently enrolling patients who have B-cell non-Hodgkin lymphoma and INI1-negative or SMARCA4-negative tumours. FUNDING: Epizyme and Eisai.

Dose-dense doxorubicin and cyclophosphamide followed by dose-dense albumin-bound paclitaxel plus bevacizumab is safe as adjuvant therapy in patients with early stage breast cancer.

UNLABELLED: Every-2-week (dose-dense) adjuvant doxorubicin (A) plus cyclophosphamide (C) followed by cremophor-formulated paclitaxel (cf-P) was efficacious in metastatic breast cancer (BC). Albumin-bound paclitaxel (ab-P) was safe and more effective than cf-P, and the addition of bevacizumab to cf-P improved efficacy. This study compared the safety of dose-dense ab-P vs cf-P plus bevacizumab following dose-dense adjuvant AC for early-stage BC. PATIENTS AND METHODS: Women with operable, histologically confirmed BC were randomized to 4 cycles of dose-dense A 60 mg/m(2) plus C 600 mg/m(2) IV with SC pegfilgrastim, followed by 4 cycles of either dose-dense IV ab-P 260 mg/m(2) or cf-P 175 mg/m(2). Bevacizumab was given during and following chemotherapy. 97 and 96% of patients completed 4 cycles of AC therapy, while 84 and 85% of patients completed 4 cycles of taxane therapy in the ab-P and cf-P arms, respectively (N = 197). Baseline patient characteristics were similar. The most common grade ≥3 taxane-related adverse events (AEs) were fatigue and neutropenia. Dose reductions were similar between the treatment arms. During AC therapy, the majority of dose reductions were due to febrile neutropenia; during taxane therapy, the majority of cases were due to neuropathy. No taxane-related dose interruption occurred in the ab-P arm, while 3 occurred in the cf-P arm due to hypersensitivity reactions. The mean cumulative paclitaxel dose was 950.5 and 660.8 mg/m(2) in the ab-P and cf-P arms, respectively. A 44% higher paclitaxel dose was delivered in the ab-P compared with the cf-P arm (P < 0.0001), while achieving a similar safety profile. ab-P plus bevacizumab following AC therapy without prophylactic premedications was tolerable in early-stage BC patients.

Adjuvant dose-dense doxorubicin plus cyclophosphamide followed by dose-dense nab-paclitaxel is safe in women with early-stage breast cancer: a pilot study.

Every-2-week (dose-dense) adjuvant doxorubicin (A) plus cyclophosphamide (C) followed by paclitaxel is a safe and effective adjuvant chemotherapy regimen. Every-3-week nab-paclitaxel is safe and more effective at 50% higher dose than every-3-week paclitaxel in metastatic breast cancer (BC). This study evaluated the safety of adjuvant dose-dense AC followed by dose-dense nab-paclitaxel for early-stage BC. Women with operable, histologically confirmed BC received four cycles of dose-dense A 60 mg/m(2) plus C 600 mg/m(2) with pegfilgrastim, followed by dose-dense 260 mg/m(2) nab-paclitaxel (with pegfilgrastim given as needed). Endpoints were adverse events (AEs), including myelosuppression. Patients with neuropathy were followed until symptom improvement to grade ≤ 1. Thirty women received four cycles of dose-dense AC with no unanticipated AEs, one withdrew after AC therapy. Of 29 women who began nab-paclitaxel therapy, 27 received all the four doses (mean cumulative dose, 959 mg/m(2)); one discontinued nab-paclitaxel after two doses due to unacceptable AEs. Four patients had a grade 3 nab-paclitaxel-related neuropathy (no grade 4 event). Of 29 patients, 34% received pegfilgrastim during nab-paclitaxel therapy and 31% had a nab-paclitaxel treatment delay, mainly due to hematologic toxicity. Based on the Kaplan-Meier probability estimates, the percentage of patients having ≤ 1 grade neuropathy at the end of treatment, 2, and 8 months after treatment were 59, 79, and 97%. Administering adjuvant dose-dense AC followed by 260 mg/m(2) dose-dense nab-paclitaxel was feasible in women with early-stage BC, with manageable AEs. Most patients had ≤ 1 grade neuropathy 2 months after treatment completion.

Phase II study of weekly albumin-bound paclitaxel for patients with metastatic breast cancer heavily pretreated with taxanes.

PURPOSE: Nanoparticle albumin-bound paclitaxel, a solvent-free, albumin-bound paclitaxel, demonstrated antitumor activity in patients with taxane-naive metastatic breast cancer (MBC). We examined albumin-bound paclitaxel (100 mg/m2 or 125 mg/m2 administered weekly) to determine the antitumor activity in patients with MBC whose disease progressed despite conventional taxane therapy. PATIENTS AND METHODS: Women with MBC that was previously treated with taxanes were eligible for participation. Taxane failure was defined as metastatic disease progression during taxane therapy or relapse within 12 months of adjuvant taxane therapy. Primary objectives were response rates (RRs) and the safety/tolerability of albumin-bound paclitaxel. RESULTS: Women were treated with albumin-bound paclitaxel 100 mg/m2 (n = 106) or 125 mg/m2 (n = 75) on days 1, 8, and 15 of a 28-day cycle. Response rates were 14% and 16% for the 100-mg/m2 and 125-mg/m2 cohorts, respectively; an additional 12% and 21% of patients, respectively, had stable disease (SD) > or = 16 weeks. Median progression-free survival times were 3 months at 100 mg/m2 and 3.5 months at 125 mg/m2; median survival times were 9.2 months and 9.1 months, respectively. Survival was similar for responding patients and those with SD. No severe hypersensitivity reactions were reported. Patients who developed treatment-limiting peripheral neuropathy typically could be restarted on a reduced dose of albumin-bound paclitaxel after a 1-2-week delay. Grade 4 neutropenia occurred in < 5% of patients. CONCLUSION: Albumin-bound paclitaxel 100 mg/m2 given weekly demonstrated the same antitumor activity as albumin-bound paclitaxel 125 mg/m2 weekly and a more favorable safety profile in patients with MBC that had progressed with previous taxane therapy. Survival of patients with SD > or = 16 weeks was similar to that of responders.

Randomized phase II trial of weekly vs. every 2 weeks vs. every 3 weeks nanoparticle albumin-bound paclitaxel with bevacizumab as first-line chemotherapy for metastatic breast cancer.

BACKGROUND: Nanoparticle albumin-bound paclitaxel (nab-P) and bevacizumab have each demonstrated efficacy in patients with MBC. This trial was designed to further develop nab-P by evaluating its efficacy and safety using every 3 weeks (q3w), every 2 weeks (q2w), or weekly scheduling in combination with bevacizumab as first-line treatment of MBC. PATIENTS AND METHODS: This open-label phase II study randomized patients to nab-P 260 mg/m(2) q3w (arm A) vs. 260 mg/m(2) q2w with filgrastim (arm B) vs. 130 mg/m(2) weekly uninterrupted, all with bevacizumab (15 mg/kg q3w arm A, 10 mg/kg q2w arms B and C). The primary endpoints were overall response rate (ORR) and toxicity. Time to tumor progression (TTP) and overall survival were secondary endpoints. RESULTS: Of 212 patients randomized, 208 (arm A, 75; arm B, 54; arm C, 79) were treated. Arm B was closed early due to toxicity, with more grade ≥ 2 fatigue (arm A, 46%; arm B, 62%; arm C, 62%) and bone pain (arm A, 11%; arm B, 23%; arm C, 5%). Neurotoxicity grade ≥ 2 was equivalent across the arms (> 50%) and reversible for most patients. Febrile neutropenia occurred in ≤ 3% of patients in all arms. ORR was similar among the arms (arm A, 45%; arm B, 41%; arm C, 46%). Median TTP was slightly longer in arm C (9.0 months) vs. arms A (8.0 months) and B (5.8 months) (overall, P = .105). CONCLUSIONS: Significant antitumor activity was observed in all the arms. Weekly nab-P with bevacizumab appeared to have the highest therapeutic index. However, sensory neuropathy was treatment limiting, which suggests that a 3 weeks on and 1 week off schedule should be explored.

Phase II trial of nab-paclitaxel compared with docetaxel as first-line chemotherapy in patients with metastatic breast cancer: final analysis of overall survival.

BACKGROUND: A randomized phase II study in first-line MBC demonstrated superior efficacy and safety of weekly nab-paclitaxel compared with docetaxel. Final survival analyses and updated safety results are reported. PATIENTS AND METHODS: Three hundred two patients with no previous chemotherapy for MBC were randomized to receive nab-paclitaxel 300 mg/m(2) q3w, nab-paclitaxel 100 mg/m(2) or 150 mg/m(2) the first 3 of 4 weeks (qw 3/4), or docetaxel 100 mg/m(2) q3w. The trial was powered for analyses of antitumor activity and safety. RESULTS: Treatment with nab-paclitaxel 150 mg/m(2) qw 3/4 resulted in a median overall survival (OS) of 33.8 months compared with 22.2, 27.7, and 26.6 months for nab-paclitaxel 100 mg/m(2) qw 3/4, nab-paclitaxel 300 mg/m(2) q3w, and docetaxel, respectively (overall P = .047). Patients receiving 150 mg/m(2)nab-paclitaxel had prolonged median OS compared with those in the 100 mg/m(2)nab-paclitaxel arm (hazard ratio, 0.575; P = .008). A trend toward a longer OS was noted in the 150 mg/m(2)nab-paclitaxel arm versus docetaxel arm (hazard ratio, 0.688). Grade 3 or 4 fatigue, neutropenia, and febrile neutropenia were less frequent in all nab-paclitaxel arms compared with docetaxel. CONCLUSIONS: Consistent with previously published efficacy results, these data suggest that 150 mg/m(2) qw 3/4 may represent the most clinically efficacious nab-paclitaxel dosing regimen for patients with no previous chemotherapy for MBC. A phase III trial confirming these results would be necessary and prudent before widespread adoption of the 150 mg/m(2) dose in clinical practice.

A phase 2 clinical trial of nab-paclitaxel in previously treated and chemotherapy-naive patients with metastatic melanoma.

BACKGROUND: nab-Paclitaxel (ABI-007, Abraxane), a 130-nM, albumin-bound (nab) particle form of Cremophor-free paclitaxel, is approved for metastatic breast cancer. In the current study, the efficacy and safety of nab-paclitaxel were evaluated in previously treated and chemotherapy-naive patients with metastatic melanoma (MM). METHODS: Patients with histologically or cytologically confirmed, measurable MM were enrolled. nab-Paclitaxel was administered intravenously weekly for 3 of 4 weeks at a dose of 100 mg/m(2) (in previously treated patients) or 150 mg/m(2) (in chemotherapy-naive patients). RESULTS: Thirty-seven patients were treated in each cohort. The response rate was 2.7% in the previously treated cohort and 21.6% in the chemotherapy-naive cohort; the response plus stable disease rate was 37.8% and 48.6% in the previously treated and chemotherapy-naive cohorts, respectively. The median progression-free survival (PFS) was 3.5 months and 4.5 months, and the median survival was 12.1 months and 9.6 months, respectively. The probability of being alive and free of disease progression at 6 months was 27% for the previously treated cohort and 34% for the chemotherapy-naive cohort; the probability of surviving 1 year was 49% and 41%, respectively, for the previously treated and chemotherapy-naive cohorts. Approximately 78% of the previously treated patients and 49% of the chemotherapy-naive patients were treated without dose reduction. Eight (22%) chemotherapy-naive patients discontinued therapy because of toxicities. Drug-related toxicities included grade 3 to 4 (graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 3.0]) neuropathy, alopecia, neutropenia, and fatigue. CONCLUSIONS: nab-Paclitaxel was found to be well tolerated and demonstrated activity in both previously treated and chemotherapy-naive patients with MM. The response rate, PFS, and survival compared favorably with current standard dacarbazine therapy and combination therapies for melanoma. nab-Paclitaxel therapy of MM should be investigated further in controlled clinical trials. Cancer 2010. (c) 2010 American Cancer Society.

Phase II trial of weekly nanoparticle albumin-bound paclitaxel with carboplatin and trastuzumab as first-line therapy for women with HER2-overexpressing metastatic breast cancer.

PURPOSE: This multicenter phase II trial evaluated the efficacy and safety of weekly nanoparticle albumin-bound paclitaxel with carboplatin and weekly trastuzumab as first-line therapy for women with HER2-overexpressing metastatic breast cancer (MBC). PATIENTS AND METHODS: We treated 32 patients who had measurable MBC that was HER2-positive defined by an immunohistochemical staining score of 3+ or gene amplification by fluorescence in situ hybridization, required for those with an IHC of 2+. Patients were treated with albumin-bound paclitaxel 100 mg/m2 and carboplatin at area under the curve (AUC) = 2 on days 1, 8, and 15 of a 28-day cycle. Trastuzumab was administered at 2 mg/kg weekly after a loading dose of 4 mg/kg. Because of hypersensitivity reactions occurring during carboplatin infusion numbers 6-8 in 4 of the first 13 patients with this premedication-free regimen, the protocol was amended for carboplatin and dosed at AUC = 6 day 1 each 28-day cycle, in lieu of introducing steroid prophylaxis. Patients were treated with 6 cycles and allowed to continue with all 3 drugs or trastuzumab alone if free of progression and unacceptable toxicity after 6 cycles. RESULTS: The overall response rate (ORR) was 62.5% (95% CI, 45.7%-79.3%) with 3 confirmed complete responders (CRs; 9%) and 17 confirmed partial responses (PRs; 53%). An additional 6 patients (19%) had stable disease (SD) for greater than 16 weeks for a clinical benefit rate (ORR + SD > 16 weeks) of 81%. As of April 16, 2009, 20 patients (63%) had progressed with a median progression-free survival (PFS) of 16.6 months (95% CI, 7.5-26.5 months). Antitumor activity was similar for patients treated with weekly carboplatin and every-4-week carboplatin (ORR, 65% vs. 67%, respectively). Hematologic toxicities were the only grade 4 toxicities noted and were infrequent with grade 4 neutropenia in 3 patients (9%) and 1 febrile neutropenia. Grade 2/3 peripheral neuropathy was uncommon (13%/3%). CONCLUSION: Weekly albumin-bound paclitaxel with carboplatin and trastuzumab is highly active in HER2-overexpressing MBC. In the absence of corticosteroid premedication, which we avoided with albumin-bound paclitaxel, carboplatin seems best dosed every 4 weeks rather than weekly because of carboplatin-associated hypersensitivity reactions. The regimen was very well tolerated with few grade 3 and 4 nonhematologic toxicities experienced, and severe hematologic toxicity and peripheral neuropathy were infrequent.

Significantly longer progression-free survival with nab-paclitaxel compared with docetaxel as first-line therapy for metastatic breast cancer.

PURPOSE: In patients with metastatic breast cancer (MBC), nab-paclitaxel produced significantly higher antitumor activity compared with patients who received solvent-based paclitaxel. This phase II study examined the antitumor activity and safety of weekly and every 3 week (q3w) nab-paclitaxel compared with docetaxel as first-line treatment in patients with MBC. PATIENTS AND METHODS: In this randomized, multicenter study, patients (N = 302) with previously untreated MBC received nab-paclitaxel 300 mg/m(2) q3w, 100 mg/m(2) weekly, or 150 mg/m(2) weekly or docetaxel 100 mg/m(2) q3w. RESULTS: nab-Paclitaxel 150 mg/m(2) weekly demonstrated significantly longer progression-free survival (PFS) than docetaxel by both independent radiologist assessment (12.9 v 7.5 months, respectively; P = .0065) and investigator assessment (14.6 v 7.8 months, respectively; P = .012). On the basis of independent radiologist review, both 150 mg/m(2) (49%) and 100 mg/m(2) (45%) weekly of nab-paclitaxel demonstrated a higher overall response rate (ORR) than docetaxel (35%), but this did not reach statistical significance. This trend was supported by statistically significant investigator ORR for both weekly nab-paclitaxel doses versus docetaxel. nab-Paclitaxel q3w versus docetaxel was not different for PFS or ORR. On the basis of both the independent radiologist and investigator review, disease control rate was significantly higher for patients receiving either dose of weekly nab-paclitaxel compared with docetaxel. Grade 3 or 4 fatigue, neutropenia, and febrile neutropenia were less frequent in all nab-paclitaxel arms. The frequency and grade of peripheral neuropathy were similar in all arms. CONCLUSION: This randomized study in first-line MBC demonstrated superior efficacy and safety of weekly nab-paclitaxel compared with docetaxel, with a statistically and clinically significant prolongation of PFS (> 5 months) in patients receiving nab-paclitaxel 150 mg/m(2) weekly compared with docetaxel 100 mg/m(2) q3w.