Assessment of treatment and monitoring patterns and subsequent outcomes among patients with chronic myeloid leukemia treated with imatinib in a community setting

INTRODUCTION

Real-world treatment and monitoring patterns have not been well documented among imatinib-treated chronic phase chronic myeloid leukemia (CP-CML) patients. Thus, we evaluated these patterns and responses to imatinib in CP-CML patients.

METHODS

This retrospective study, based on the Georgia Cancer Specialists' electronic medical record (EMR) system, identified CP-CML patients initiating treatment with imatinib from 01/01/2002 to 11/01/2011 who were subsequently followed for ≥6 months.

RESULTS

A total of 177 patients met the study criteria. Imatinib dose modification occurred in 59 patients (33%). Rates of treatment interruption, discontinuation, and switching to another therapy were 16%, 24%, and 23%, respectively. Of 27 patients discontinuing imatinib for lack of efficacy, 9 (33%) had initial dose escalation; 26 patients (96%) eventually switched to a second-generation tyrosine kinase inhibitor. By 3 months, 168 patients remained on imatinib, of whom 96 (57%) had undergone cytogenetic and/or molecular testing. The frequency of response monitoring fluctuated over time, with rates as high as 28% for cytogenetic and 69% for molecular testing. Cumulative response rates steadily increased; 18 month rates were 47% for complete cytogenetic response and 26% for major or complete molecular response. There were no cases of progression and/or death among 38 patients who were regularly monitored for molecular response within the first 12 months of imatinib. Ten of 98 patients (10%) not regularly monitored had progressed or died.

CONCLUSIONS

Almost one-third of patients initiating imatinib for CP-CML required dose modification, treatment interruption, or discontinuation. Opportunities for improved monitoring in this setting were identified. Limitations include those inherent to retrospective analyses based on EMR and the uncertain extrapolability of the results.

A randomized, open-label phase II study of efatutazone in combination with FOLFIRI as second-line therapy for metastatic colorectal cancer (mCRC)

535^

Background: Efatutazone, a highly-selective peroxisome proliferator-activated receptor gamma (PPARγ) agonist, has shown efficacy and manageable toxicity in phase I trials in solid tumors, including CRC. This study evaluated efatutazone in combination with chemotherapy for second-line mCRC. Methods: Patients (pts) from the United States and Latin America with mCRC progressing after first-line therapy not containing irinotecan were stratified by Eastern Cooperative Oncology Group (ECOG) status (0/1 vs. 2) and randomized 1:1 to efatutazone + FOLFIRI (E+F) or FOLFIRI alone (F). Treatment was administered in 4-week cycles until disease progression (PD), unacceptable toxicity, or consent withdrawal. Efatutazone (0.5 mg) was administered orally, twice daily; FOLFIRI (irinotecan 180 mg/m2, leucovorin 400 mg/m2, 5-fluorouracil 1200 mg/m2/d x 2 days) was administered intravenously once every 2 weeks immediately after efatutazone. The primary end point, progression-free survival (PFS) rate at week 16, was assessed locally according to Response Evaluation Criteria In Solid Tumors (RECIST) v1.0. Results: Characteristics of the 100 randomized pts were generally well balanced between the E+F and F treatment arms: median age, 59.7 vs. 58.3 years; male, 56% vs 56%; and ECOG 0/1, 98% vs. 92%. Across the arms, more pts discontinued due to PD than toxicity: 49% vs. 19%, respectively. While PFS rate at week 16 was 60% vs. 67% for the E+F vs F arms (p = 0.30), overall, PFS was somewhat longer with E+F than with F (hazard ratio [HR], 0.87; 90% [confidence interval [CI], 0.57–1.32) with medians of 4.4 vs. 4.2 months, respectively. The objective response rate also favored E+F over F (20% vs. 14%). Overall survival was not significantly different (HR, 0.95; 90% CI, 0.65–1.38). Fluid retention, which was managed with diuretics, was more frequent with E+F than with F: 86% vs. 12% (grade 3/4: 12% vs. 0%). Hematologic adverse events, including neutropenia (66% vs. 20%; grade 3/4: 44% vs. 12%) and febrile neutropenia (14% vs 0%), were more common with E+F than with F. Conclusions: Efatutazone minimally improved efficacy of FOLFIRI for CRC and increased neutropenia and fluid retention. Clinical trial information: NCT00967616.

Abstract P1-15-02: Long term follow-up of the neo-adjuvant pilot trial evaluating activity of letrozole in combination with bevacizumab in post-menopausal women with newly diagnosed estrogen and/or progesterone receptor positive primary breast cancer

Introduction: Vascular endothelial growth factor overexpression has been associated with resistance to anti-estrogen therapy (Cancer Res 2008; 68: 6232); our preclinical data showed that anti-VEGF therapy reverse resistance to estrogen therapy. We postulated that anti-VEGF therapy would enhance anti-estrogen therapy and thus designed a pilot study to assess the feasibility and efficacy of neoadjuvant letrozole and bevacizumab in post-menopausal women with stage II/III, ER/PR positive breast cancer.

Patients and Methods: Eligible patients were treated with a neo-adjuvant regimen of letrozole, 2.5 mg/day (PO) and bevacizumab 15 mg/kg every 3 weeks (IV) for a total of 24 weeks prior to surgical treatment of their breast cancer. Patients were followed for toxicity at three week intervals and for tumor assessment at 6 week intervals. Research tumor biopsies were taken before and 6 weeks after initiation of therapy. The primary endpoint was pathological complete remission (pCR). Patients with inflammatory breast cancer were excluded.

Results: Twenty six patients were enrolled and 25 were treated (one patient had a TIA the day before initiation of therapy). The regimen was well tolerated with 2 patients taken off-study due to uncontrolled hypertension. Objective clinical response occurred in 68% of the patients (17/25), 16% with CR and 52% with partial response (PR). Sixteen percent of the patients (4/25) had clinical stable disease (SD) and 2 patients progressed (PD) while on therapy. Three patients had pCR and 1 patient had microscopic residual tumor cells in the LNs but not in the breast (pCR 16%). Thirty two percent of the patients attained stage 0 or 1 status. None of the pCR patients received adjuvant chemotherapy and none have relapsed after a median follow-up of 6.1 years (range, 5.8+ to 7.5+). Eight of the 13 patients with PR did not receive chemotherapy and only one relapsed with a median follow-up of 6.2 years (range, 3.7 to 7.7+). At a median follow-up of 6.4 years, 88% of the patients have not relapsed and 12% relapsed (1 PD [basal-like], 1 PR [Luminal B], 1 SD [HER2] relapsed at 1.7, 4, and 6.8 years respectively). Of the 17 patients with CR and PR, only 1 has relapsed (6%). Next Generation Sequencing Analysis and evaluation of markers of proliferation/apoptosis are underway.

Conclusion: Combination neoadjuvant therapy with letrozole and bevacizumab was well tolerated and resulted in an impressive pCR of 16%. At a median of 6.4 years, the relapse free survival is 88% for all comers and 94% for responding patients (Luminal A and B). Full correlation of clinical and genomic/biomarker analysis will be presented at the time of the meeting. This encouraging data has led The Breast Cancer Translational Research Consortium to complete a randomized phase II trial (TBCRC002) of letrozole ± bevacizumab in this patient population.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-15-02.

Increased survival in pancreatic cancer with nab-paclitaxel plus gemcitabine

BACKGROUND

In a phase 1-2 trial of albumin-bound paclitaxel (nab-paclitaxel) plus gemcitabine, substantial clinical activity was noted in patients with advanced pancreatic cancer. We conducted a phase 3 study of the efficacy and safety of the combination versus gemcitabine monotherapy in patients with metastatic pancreatic cancer.

METHODS

We randomly assigned patients with a Karnofsky performance-status score of 70 or more (on a scale from 0 to 100, with higher scores indicating better performance status) to nab-paclitaxel (125 mg per square meter of body-surface area) followed by gemcitabine (1000 mg per square meter) on days 1, 8, and 15 every 4 weeks or gemcitabine monotherapy (1000 mg per square meter) weekly for 7 of 8 weeks (cycle 1) and then on days 1, 8, and 15 every 4 weeks (cycle 2 and subsequent cycles). Patients received the study treatment until disease progression. The primary end point was overall survival; secondary end points were progression-free survival and overall response rate.

RESULTS

A total of 861 patients were randomly assigned to nab-paclitaxel plus gemcitabine (431 patients) or gemcitabine (430). The median overall survival was 8.5 months in the nab-paclitaxel-gemcitabine group as compared with 6.7 months in the gemcitabine group (hazard ratio for death, 0.72; 95% confidence interval [CI], 0.62 to 0.83; P<0.001). The survival rate was 35% in the nab-paclitaxel-gemcitabine group versus 22% in the gemcitabine group at 1 year, and 9% versus 4% at 2 years. The median progression-free survival was 5.5 months in the nab-paclitaxel-gemcitabine group, as compared with 3.7 months in the gemcitabine group (hazard ratio for disease progression or death, 0.69; 95% CI, 0.58 to 0.82; P<0.001); the response rate according to independent review was 23% versus 7% in the two groups (P<0.001). The most common adverse events of grade 3 or higher were neutropenia (38% in the nab-paclitaxel-gemcitabine group vs. 27% in the gemcitabine group), fatigue (17% vs. 7%), and neuropathy (17% vs. 1%). Febrile neutropenia occurred in 3% versus 1% of the patients in the two groups. In the nab-paclitaxel-gemcitabine group, neuropathy of grade 3 or higher improved to grade 1 or lower in a median of 29 days.

CONCLUSIONS

In patients with metastatic pancreatic adenocarcinoma, nab-paclitaxel plus gemcitabine significantly improved overall survival, progression-free survival, and response rate, but rates of peripheral neuropathy and myelosuppression were increased. (Funded by Celgene; ClinicalTrials.gov number, NCT00844649.).

Low-dose anti-CD20 veltuzumab given intravenously or subcutaneously is active in relapsed immune thrombocytopenia: a phase I study

Low doses of the humanized anti-CD20 monoclonal antibody, veltuzumab, were evaluated in 41 patients with immune thrombocytopenia (ITP), including 9 with ITP ≤1 year duration previously treated with steroids and/or immunoglobulins, and 32 with ITP >1 year and additional prior therapies. They received two doses of 80-320 mg veltuzumab 2 weeks apart, initially by intravenous (IV) infusion (N = 7), or later by subcutaneous (SC) injections (N = 34), with only one Grade 3 infusion reaction and no other safety issues. Thirty-eight response-assessable patients had 21 (55%) objective responses (platelet count ≥30 × 10(9) /l and ≥2 × baseline), including 11 (29%) complete responses (CRs) (platelet count ≥100 × 10(9) /l). Responses (including CRs) occurred with both IV and SC administration, at all veltuzumab dose levels, and regardless of ITP duration. Responders with ITP ≤1 year had a longer median time to relapse (14·4 months) than those with ITP >1 year (5·8 months). Three patients have maintained a response for up to 4·3 years. SC injections resulted in delayed and lower peak serum levels of veltuzumab, but B-cell depletion occurred after first administration even at the lowest doses. Eight patients, including 6 responders, developed anti-veltuzumab antibodies following treatment (human anti-veltuzumab antibody, 19·5%). Low-dose SC veltuzumab appears convenient, well-tolerated, and with promising clinical activity in relapsed ITP.(Clinicaltrials.gov identifier: NCT00547066.).

SPIRITT (study 20060141): A randomized phase II study of FOLFIRI with either panitumumab (pmab) or bevacizumab (bev) as second-line treatment (tx) in patients (pts) with wild-type (WT) KRAS metastatic colorectal cancer (mCRC)

3616

Background: Pmab has demonstrated significant improvement in progression-free survival (PFS) in pts with WT KRAS mCRC as 2nd-line tx in a phase III trial comparing pmab + FOLFIRI vs FOLFIRI alone. Here, we describe the results of SPIRITT, a multicenter, randomized phase II study evaluating pmab + FOLFIRI and bev + FOLFIRI in pts with WT KRAS mCRC previously treated with a 1st-line bev + oxaliplatin (Ox)-based chemotherapy regimen. Methods: Pts were randomized 1:1 to pmab 6.0 mg/kg + FOLFIRI Q2W or to bev 5.0 or 10.0 mg/kg + FOLFIRI Q2W. Eligibility criteria included: WT KRAS mCRC, ECOG ≤ 1, no prior irinotecan or anti-EGFR tx, and tx failure of prior 1st-line bev + Ox-based therapy (≥ 4 cycles). The primary endpoint was PFS; secondary endpoints included overall survival (OS), objective response rate (ORR), and safety. No formal hypothesis was tested. Results: 182 pts with WT KRAS mCRC were randomized. All pts received tx. Efficacy results are shown (Table). Worst grade of 3/4 adverse events (AE) occurred in 78% of pts in the pmab + FOLFIRI arm and 65% in the bev + FOLFIRI arm. Grade 5 AEs occurred in 7% of pts in the pmab + FOLFIRI arm and 7% in the bev + FOLFIRI arm. Tx discontinuation due to any AE was 29% in the pmab + FOLFIRI arm and 25% in the bev + FOLFIRI arm. Conclusions: In this estimation study of pts with WT KRAS mCRC that previously received bev + Ox-based tx, the PFS hazard ratio (HR) was 1.01 (95% CI: 0.68 - 1.50). The OS HR was 1.06 (95% CI: 0.75 - 1.49). The observed ORR was higher in the pmab + FOLFIRI arm. 54% of bev + FOLFIRI pts received subsequent anti-EGFR tx. The safety profile for both arms was similar to previously reported studies. Tx discontinuation rates due to AEs were similar between the arms. Clinical trial information: NCT00418938. [Table: see text]

TBCRC 002: A phase II, randomized, open label trial of preoperative letrozole versus letrozole (LET) in combination with bevacizumab (BEV) in post-menopausal women with newly diagnosed stage II/III breast cancer

527

Background: A study from UAB Breast SPORE showed that expression of vascular endothelial growth factor (VEGF) in MCF7 breast tumor xenografts imparts tamoxifen resistance, increases tumor growth and metastatic potential. We postulated that anti-VEGF therapy would enhance anti-estrogen therapy. Methods: Randomized 2:1 phase II selection trial of LET (2.5 mg/day) with/without BEV (anti-VEGF monoclonal antibody; 15 mg/kg q3 weeks) for 24 weeks prior to surgery in post-menopausal patients with stage II/III, ER+/HER2- breast cancer. Primary objective was pathologic complete remission (pCR). Secondary objectives included response rates, down-staging, and toxicity. The trial was not powered to compare arms, but sized to estimate pCR rates to a certain precision (SE<5% for combination, SE<2% for single agent). Biopsies of the tumor and circulating tumor cells were collected. Results: 75 patients were randomized; 50 in the combination and 25 in the LET alone arm; 45 and 24 patients underwent surgery, respectively. Median age was 61 and 65 years, respectively. 5 patients in the combination arm had a pCR (11%; CI 1.9-20.1%) (no evidence of invasive cancer) , and 3 a near pCR (7%; 0%-14.5%) (microscopic disease only); thus pCR/near pCR rate 18% (6.8-29.2%). No patient treated with LET alone achieved a pCR/near pCR. The objective response rate was 64.5% in the combination arm and 37.5% in the single agent arm. 45% of the patients in the combination arm attained stage 0/I; 25% in the letrozole alone arm attained stage I, none attained stage 0. Therapy was well tolerated in both arms with no grade 4/5 toxicity. The most common AEs in the letrozole arm were hot flashes, fatigue, arthralgias/stiffness, myalgias, nausea/vomiting, and night sweats; in the combination arm they were hypertension, arthralgias/stiffness, hot flashes, headache, fatigue, proteinuria, dyspnea, rash, and myalgias. Conclusions: Neoadjuvant therapy with LET and BEV was well-tolerated and resulted in increased objective responses and down-staging. “Next-Gen” genomic analysis of the biopsies will allow for a trial with a targeted patient enrolment. Clinical trial information: F061229006.

Phase I/IIa study of the novel combination of bendamustine (B) with irinotecan (I) followed by etoposide (E) and carboplatin (C) in untreated patients (Pts) with extensive-stage small cell lung cancer (ESSCLC)

7591

Background: Standard therapy for ESSCLC consisting of E and a platin drug (Plat) yields a median time to progression (TTP) of 4 months (m) and overall survival (OS) of 9 m. DNA damage from B is repaired by excision repair, akin to Plat. The activity of I, a topoisomerase (Top)-1 inhibitor, leads to increases in Top-2, the target of E. The sequence B+I → E+C was hypothesized to increase TTP by exploiting mitotic catastrophe. Methods: This is an open label trial enrolling pts with ESSCLC and evaluable disease. The phase I primary endpoint was to determine the maximum tolerated dose (MTD) of B+I; the phase IIa primary endpoint was TTP after B+I→E+C. Secondary endpoints were objective response rate (ORR) and OS. In the phase I (N=15), cohorts received I (150 mg/m2, d 1) with B at 80, 100, or 120 mg/m2/day (d 1,2) every 3 weeks for 3 cycles. Phase IIa Pts were treated at the recommended dose of B+I for 3 cycles followed by E (100 mg/m2, d 1-3) + C (AUC 6, d 1) for 3 cycles. Restaging was performed after 3 cycles of each regimen. The phase IIa was powered to detect a 30% increase in TTP from 4 to 5.2 m with a of 0.1. The Kaplan-Meier method was used to calculate TTP and OS. Toxicities were evaluated using the NCI CTCAE. Results: The MTD of B was not reached. The recommended phase IIa dose of B was 100 mg/m2; dose-escalation was allowed in subsequent cycles of therapy. Dose limiting toxicities were diarrhea, nausea, and vomiting. One treatment-related death from metabolic encephalopathy occurred in the phase IIa. The commonest grade 3/4 hematologic toxicity was neutropenia. Fatigue, nausea, vomiting, and diarrhea were common non-hematologic toxicities. Conclusions: B+I is an active regimen in ESSCLC and the treatment sequence B+I→E+C seems to improve the TTP and OS in ESSCLC compared to historic values for E+C. Toxicities were increased compared to historic values for E+C, but were manageable. Correlative studies with pre-treatment assessment of tumor ERCC-1, Top-1, and Top-2 as predictors of response are ongoing. Clinical trial information: NCT00856830. [Table: see text]

Results of a randomized phase III trial (MPACT) of weekly nab-paclitaxel plus gemcitabine versus gemcitabine alone for patients with metastatic adenocarcinoma of the pancreas with PET and CA19-9 correlates

4005^

Background: nab-paclitaxel (nab-P; 130 nm albumin-bound paclitaxel) has demonstrated both single-agent activity and synergy with gemcitabine (G) in preclinical models of pancreatic cancer (PC). nab-P + G also demonstrated promising efficacy in a phase I/II study in metastatic PC (J Clin Oncol. 2011:4548-4554), warranting a phase III study of nab-P + G vs G for metastatic PC. Methods: 861 patients (pts) with metastatic PC and a Karnofsky performance status (KPS) ≥ 70 were randomized at 151 community and academic centers 1:1 to receive nab-P 125 mg/m2 + G 1000 mg/m2 days 1, 8, and 15 every 4 weeks or G alone 1000 mg/m2weekly for 7 weeks followed by 1 week of rest (cycle 1) and then days 1, 8, and 15 every 4 weeks (cycle ≥ 2). The primary endpoint was OS; secondary endpoints were PFS and ORR by independent review. Results: The median age was 63 years (range 27 - 88). KPS was 100 (16%), 90 (44%), 80 (32%), and 70 (7%). Pts had advanced disease with liver metastases (84%), ≥ 3 metastatic sites (46%), and CA19-9 ≥ 59 × ULN (46%). nab-P + G was superior to G for all efficacy endpoints: median OS was 8.5 vs. 6.7 mo (HR 0.72; 95% CI, 0.617 - 0.835; P = 0.000015); median PFS was 5.5 vs. 3.7 mo (HR 0.69; 95% CI, 0.581 - 0.821; P = 0.000024), and ORR was 23% vs. 7% (P = 1.1 × 10−10) by RECIST v1.0. Metabolic response by PET in 257 patients was 63% for nab-P + G vs 38% for G (P = 0.000051). CA19-9 response (≥ 90% decrease) was 31% for nab-P + G vs. 14% for G (P < 0.0001). Grade ≥ 3 AEs with nab-P + G vs. G included neutropenia (38% vs. 27%), fatigue (17 % vs. 7%), diarrhea (6% vs 1%), and febrile neutropenia (3% vs. 1%). Grade ≥ 3 peripheral neuropathy (PN) occurred in 17% vs. 1% of pts who received nab-P + G vs. G, respectively; for nab-P + G, PN improved to grade ≤ 1 in a median 29 days, and 44% of patients resumed nab-P treatment. The median duration of treatment was 3.9 mo for nab-P + G and 2.8 mo for G. Conclusions: MPACT was a large, international study performed at community and academic centers. nab-P + G was superior to G across all efficacy endpoints, had an acceptable toxicity profile, and is a new standard for the treatment of metastatic PC that could become the backbone for new regimens. Clinical trial information: NCT00844649.

ARN-509 in men with metastatic castration-resistant prostate cancer (mCRPC)

48

Background: ARN-509 is a novel second-generation anti-androgen that binds directly to the ligand-binding domain of the androgen receptor, impairing nuclear translocation and DNA binding. The Phase II portion of a multicenter Phase I/II study is evaluating the activity of ARN-509 in 3 distinct patient populations of men with CRPC: 1) non-metastatic treatment-naïve CRPC; 2) mCRPC treatment-naïve (tx-naïve); and 3) mCRPC abiraterone acetate pre-treated (AA). Preliminary results for the 2 cohorts of patients with metastatic CRPC are presented here. Methods: All patients had metastatic CRPC with progressive disease based on rising PSA and/or imaging. No prior chemotherapy for metastatic prostate cancer was allowed. Patients on the AA pre-treated cohort had to have been treated with AA for at least 6 months. All patients received ARN-509 at the recommended Phase II dose of 240 mg/day (Rathkopf et al, GU ASCO 2012). The primary endpoint was PSA response rate at 12 weeks according to the Prostate Cancer Working Group 2 Criteria in each of the treatment groups. Secondary endpoints included safety, time to PSA progression and objective response rates. PSA assessments were collected every 4 weeks and tumor imaging was performed every 16 weeks. Results: A total of 46 patients were enrolled: 25 on the tx-naïve and 21 on the post-AA cohorts. The combined median age was 68 (range 48-91) and at baseline, patients presented with ECOG performance status 0 (57%), Gleason Score 8-10 (52%), and median PSA of 14.7 (tx-naïve) and 58.4 (post-AA) ng/mL. All patients received prior treatment with a LHRH analog with or without a first-generation anti-androgen. To date, 15 patients discontinued the study due to disease progression (11), adverse events (2) and consent withdrawn (2). The most common treatment-related adverse events (AE) were fatigue (30%), abdominal pain (24%), nausea (22%), and diarrhea (17). There was only 1 treatment-related Grade 3 AE of abdominal pain. At 12 weeks, the PSA response was 88% (tx-naïve) and 29% (post-AA). Conclusions: In men with mCRPC, ARN-509 is safe and well tolerated, with robust PSA response in the tx-naïve cohort. Post-AA data suggests that ARN-509 has activity in a subset of patients that developed resistance to abiraterone acetate. Clinical trial information: NCT01171898.

Randomized phase III study of weekly nab-paclitaxel plus gemcitabine versus gemcitabine alone in patients with metastatic adenocarcinoma of the pancreas (MPACT)

LBA148

Background: nab-Paclitaxel (nab-P, 130 nm albumin-bound paclitaxel) provides tumor selective localization via transcytosis across the endothelium, potential tumor uptake via macropinocytosis, and improved pharmacokinetics vs cremophor-paclitaxel. In vitro, nab-P increased tumoral gemcitabine (G) levels, and in a phase I/II study in metastatic pancreatic cancer (mPC) nab-P + G showed promising activity. Methods: Patients (pts) with mPC were randomized to nab-P 125 mg/m2, followed by G 1000 mg/m2 on days 1, 8, and 15 every 4 weeks or G 1000 mg/m2 weekly for 7 weeks (cycle 1), then on days 1, 8, and 15 every 4 weeks (≥ cycle 2). For the primary endpoint of overall survival (OS), 608 events from 842 patients provided a power of 0.9 to detect a HR of 0.769 (2-side α = 0.049). Results: 861 pts received therapy. Baseline pt characteristics were well balanced. Median age was 63 years, Karnofsky performance status was 90-100 in 60% and ≤80 in 40% of pts, 43% had head of pancreas lesions, 84% had liver and 39% had lung metastases, and 52% of pts had CA19-9 ≥59 x ULN. Treatment duration was 4 vs 3 months in nab-P + G vs G. The relative protocol G dose was 75% vs 85% in nab-P + G vs G; nab-P dose was 81%. OS, progression-free survival (PFS), time to treatment failure (TTF), and overall response rate (ORR) were significantly improved in the nab-P + G arm (Table). Most common grade ≥3 AEs were neutropenia (38% vs 27%), fatigue (17% vs 7%), and neuropathy (17% vs 1%) in the nab-P + G vs G arms. Grade ≥3 neuropathy improved to grade ≤1 in 29 days. Febrile neutropenia was reported in 3% (nab-P + G) vs 1% (G) pts. Conclusions: In this multinational, multiinstitutional study, nab-P + G was well tolerated and superior to G with statistically significant and clinically meaningful results in all endpoints and across subgroups. Clinical trial information: NCT00844649. [Table: see text]

SPIRITT (study 20060141): A randomized phase II study of FOLFIRI with either panitumumab (pmab) or bevacizumab (bev) as second-line treatment (tx) in patients (pts) with wild-type (WT) KRAS metastatic colorectal cancer (mCRC)

454

Background: Pmab has demonstrated significant improvement in progression-free survival (PFS) in pts with WT KRAS mCRC as 2nd-line tx in a phase III trial comparing pmab + FOLFIRI vs FOLFIRI alone. Here, we describe the results of SPIRITT, a multicenter, randomized phase II study evaluating pmab + FOLFIRI and bev + FOLFIRI in pts with WT KRAS mCRC previously treated with a 1st-line bev + oxaliplatin (Ox)-based chemotherapy regimen. Methods: Pts were randomized 1:1 to pmab 6.0 mg/kg + FOLFIRI Q2W or to bev 5.0 or 10.0 mg/kg + FOLFIRI Q2W. Eligibility criteria included: WT KRAS mCRC, ECOG ≤ 1, no prior irinotecan or anti-EGFR tx, and tx failure of prior 1st-line bev + Ox-based therapy (≥ 4 cycles). The primary endpoint was PFS; secondary endpoints included overall survival (OS), objective response rate (ORR), and safety. No formal hypothesis was tested. Results: 182 pts with WT KRAS mCRC were randomized. All pts received tx. Efficacy results are shown (table). Worst grade of 3/4 adverse events (AE) occurred in 78% of pts in the pmab + FOLFIRI arm and 65% in the bev + FOLFIRI arm. Grade 5 AEs occurred in 7% of pts in the pmab + FOLFIRI arm and 7% in the bev + FOLFIRI arm. Tx discontinuation due to any AE was 29% in the pmab + FOLFIRI arm and 25% in the bev + FOLFIRI arm. Conclusions: In this estimation study of pts with WT KRAS mCRC that previously received bev + Ox-based tx, the PFS hazard ratio (HR) was 1.01 (95% CI: 0.68 - 1.50). The OS HR was 1.06 (95% CI: 0.75 - 1.49). The observed ORR was higher in the pmab + FOLFIRI arm. 54% of bev + FOLFIRI pts received subsequent anti-EGFR tx. The safety profile for both arms was similar to previously reported studies. Tx discontinuation rates due to AEs were similar between the arms. Clinical trial information: NCT00418938. [Table: see text]

Optimizing breast cancer diagnosis in Kenya: Importance of standardization of technical methodologies for comparative breast cancer data

139

Background: An analysis of 322 cases referred to Aga Khan University, Nairobi, revealed 56% estrogen receptor (ER) positive tumors and 35% prevalence of triple-negative breast cancer (TNBC). Findings were retrospective and limited by inability to control pre-analytical variables that could potentially impact results. Methods: As part of an ongoing prospective study assessing prevalence of TNBC in the three major ethnic groups in Kenya, we gathered a multidisciplinary team from 10 collaborating health facilities around Kenya for an educational workshop. The objectives were to assess baseline capabilities and pre-analytic variables at each center, identify gaps and provide hands-on training in order to ensure accuracy and validity of ER/PR/HER2 prevalence data gathered as part of the study. Results: See table. Breast cancer biopsies ranged from one to 20 per month per center. Diagnosis was predominantly by FNA and ER/PR/HER2 was not routinely performed. Buffered formalin fixative and standardized CAP reporting format was employed only at one center. A survey 3 months following the workshop demonstrated increase in diagnostic core biopsiesby 90%, and uniform use of buffered formalin fixative, and adoption of synoptic reporting. 66 prospective cases of breast cancer from the 10 institutions with patients from different ethnic backgrounds have been subsequently collected and IHC data will be presented. Conclusions: Much has been made of the difference in prevalence of TNBC in Africa as compared to North America, yet little attention has been paid to differences in diagnostic methodologies and basic tissue handling techniques that can potentially alter results. Despite limitations of resources, educational workshops make it possible to improve the practice of breast cancer diagnosis, and thereby enable accurate comparative analysis between breast cancers in the developing and the developed world. [Table: see text]

Results of the X-PECT study: A phase III randomized double-blind, placebo-controlled study of perifosine plus capecitabine (P-CAP) versus placebo plus capecitabine (CAP) in patients (pts) with refractory metastatic colorectal cancer (mCRC)

LBA3501

Background: Perifosine (P) is an oral, synthetic alkylphospholipid that inhibits or modifies signal transduction pathways including AKT, NFkB and JNK. A randomized phase II study examined P-CAP vs. CAP in pts with 2nd or 3rd line mCRC. This study showed improvement in mTTP (HR 0.254 [0.117, 0.555]) and mOS (HR 0.370 [0.180,0.763]). Based on these results, a randomized phase III study of P-CAP vs. CAP with a primary endpoint of overall survival (OS) in pts with refractory mCRC was initiated. Methods: The study was a prospective, randomized, double-blind, placebo-controlled randomized phase III trial. Eligible pts had mCRC which was refractory to all standard therapies. Pts randomized 1:1 to Arm A = P-CAP (P 50 mg PO QD + CAP 1000 mg/m2PO BID d1-14) or Arm B = CAP (placebo + CAP 1000 mg/m2 PO BID d 1-14). Cycles were 21 days. Baseline tumor block collection and a biomarker cohort of pts with pre- and on-treatment tumor and blood samples were performed. Results: Between 3/31/10 and 8/12/11, 468 pts were randomized, 234 pts were in each arm. Baseline demographics were balanced between the arms: age < 65y (A: 65%, B: 58.5%), male (A: 57.7%, B: 53.0%), ECOG PS 0 (A: 39.7%, B: 39.7%), K-ras mutant (A: 50.4%, B: 51.3%), and median number of prior therapies (A: 4, B: 4). As of 3/19/12, median follow up was 6.6 months. Median overall survival: Arm A = 6.4 mo, Arm B = 6.8 mo, HR 1.111 [0.905,1.365], p = 0.315. Median overall survival for K-ras WT pts: Arm A = 6.6 mo, Arm B = 6.8 mo, HR 1.020 [0.763,1.365], p = 0.894; K-ras mutant pts: Arm A = 5.4 mo, Arm B = 6.9 mo HR 1.192 [0.890,1.596], p = 0.238. Conclusions: Despite promising randomized phase II data, this phase III study shows no benefit in overall survival adding perifosine to capecitabine in the refractory colorectal cancer setting. Response rate, progression free survival, and safety data will be presented. Biomarker analysis is pending to see if subgroups of patients may have potential benefit.

A randomized, phase II, multicenter, double-blind, placebo-controlled study evaluating onartuzumab (MetMAb) in combination with mFOLFOX6 plus bevacizumab in patients with metastatic colorectal cancer

TPS3640

Background: Dysregulation of the HGF/Met (Met) pathway has been linked with poor prognosis in colorectal cancer. Crosstalk between the Met and vascular endothelial growth factor (VEGF) pathways may be important during tumorigenesis. Aberrant activation of the HGF/Met pathway may promote angiogenesis via tumor cell secretion of angiogenic factors or directly activating endothelial cells. Onartuzumab (MetMAb) is a monovalent, monoclonal antibody that specifically binds to the Met receptor. The combination of onartuzumab and VEGF inhibition in preclinical models resulted in enhanced antitumor activity over either treatment alone. Preclinical efficacy data support the combination of onartuzumab with platinum agents. In phase I studies, onartuzumab has been generally well tolerated alone and in combination with bevacizumab. Adverse events most commonly associated with onartuzumab are peripheral edema and fatigue. Methods: This is a randomized, two-arm, phase II study in patients with previously untreated metastatic colorectal cancer. Patients (n=188) will be randomized (1:1) to either mFOLFOX6/bevacizumab/placebo or mFOLFOX6/bevacizumab/onartuzumab. Oxaliplatin will be discontinued after 8 cycles with remaining drugs continued until progression. The primary endpoint of this study is PFS in all patients. PFS by Met IHC diagnostic status (Met positive vs Met negative) will also be analyzed. Secondary endpoints include OS, ORR, safety, and biomarker analyses. Primary and secondary analyses will include all randomized patients and will be conducted according to assigned treatment arm. Kaplan–Meier methodology will be used to estimate median PFS for each treatment arm. An estimate of HR with 95% CI will be determined using a Cox regression model. Safety will be assessed in all patients receiving at least one dose of any treatment. This study is open for accrual; further details can be found on ClinicalTrials.gov (NCT01418222).

A phase II study of the androgen signaling inhibitor ARN-509 in patients with castration-resistant prostate cancer (CRPC)

TPS4697

Background: ARN-509 is a novel small molecule androgen signaling inhibitor that impairs AR nuclear translocation and binding to DNA, inhibiting tumor growth and promoting apoptosis, with no partial agonist activity. Preclinical data suggests that the maximal therapeutic index of ARN-509 can be achieved at low steady state plasma levels with minimal toxicity (Clegg et al, 2012). Enrollment in the Phase 1 dose escalation study of ARN-509 in patients with progressive CRPC with and without prior chemotherapy was completed in January 2012. The recommended Phase 2 dose of 240 mg was determined based on safety, PSA kinetics, and pharmacokinetic and pharmacodynamic analysis (Rathkopf et al, GU ASCO, 2012). Methods: The primary objective of this Phase 2 study is to determine the PSA response at 12 weeks according to Prostate Cancer Working Group 2 (PCWG2) Criteria (Scher et al, 2008). Three expansion cohorts will enroll a total of 80-90 patients for treatment with 240 mg continuous oral ARN-509 daily. These cohorts include: 1) non-metastatic treatment-naïve CRPC (50 patients); 2) chemotherapy-naïve metastatic (m) CRPC (20 patients); and 3) chemotherapy-naïve, post abiraterone mCRPC (10-20 patients). The effect of food on the PK of ARN-509 and the effect of ARN-509 on ventricular repolarization will also be evaluated. Phase 2 enrollment is ongoing. DOD/PCF PCCTC trial sponsored by Aragon Pharmaceuticals. NCT01171898.

Results of the X-PECT study: A phase III randomized double-blind placebo-controlled study of perifosine plus capecitabine (P-CAP) versus placebo plus capecitabine (CAP) in patients (pts) with refractory metastatic colorectal cancer (mCRC)

LBA3501

The full, final text of this abstract will be available at abstract.asco.org at 12:01 AM (EDT) on Sunday, June 3, 2012, and in the Annual Meeting Proceedings online supplement to the June 20, 2012, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Sunday edition of ASCO Daily News.

Phase I study of bosutinib, a src/abl tyrosine kinase inhibitor, administered to patients with advanced solid tumors

PURPOSE

Bosutinib, a potent ATP-competitive, quinolinecarbonitrile Src/Abl kinase inhibitor, was tested in this first-in-human phase I trial in patients with advanced solid tumor malignancies.

PATIENTS AND METHODS

This trial was conducted in 2 parts. In part 1 (dose escalation), increasing oral bosutinib doses were administered using a 3 + 3 design. In part 2 (dose expansion), approximately 30 patients each with refractory colorectal, pancreas, or non-small cell lung cancer were treated at the recommended phase II dose (RP2D). Primary efficacy endpoints for part 2 were median progression-free survival (colorectal and non-small cell lung) and median overall survival (pancreas).

RESULTS

In part 1, dose-limiting toxicities of grade 3 diarrhea (two patients) and grade 3 rash occurred with bosutinib 600 mg/day and the maximum tolerated dose identified was 500 mg/day. However, the majority of patients treated with 500 mg/day had grade 2 or greater gastrointestinal toxicity, and 400 mg/day was identified as the RP2D. The most common bosutinib-related adverse events were nausea (60% patients), diarrhea (47%), vomiting (40%), fatigue (38%), and anorexia (36%). Bosutinib had a mean half-life of 19 to 20 hours at the RP2D. A partial response (breast) and unconfirmed complete response (pancreas) were observed; 8 of 112 evaluable patients had stable disease for 22 to 101 weeks. However, the primary efficacy endpoints for part 2 were not met.

CONCLUSIONS

Bosutinib was generally well tolerated in patients with solid tumors, with the main toxicity being gastrointestinal. The RP2D was 400 mg/day orally. Further study of bosutinib is planned in combination regimens.

P1-12-10: Phase II Study Evaluating Lapatinib (L) in Combination with Albumin Bound Paclitaxel (ab-Pac) in Women Who Have Received 0–1 Chemotherapy Regimen for HER2 Overexpressing (HER2+) Metastatic Breast Cancer (MBC)

Background: L, a dual kinase inhibitor of epidermal growth factor receptor (EGFR) and the human epidermal growth factor receptor-2 (HER2), approved for the treatment of HER2+ MBC in combination with capecitabine following progression after trastuzumab, anthracycline, and taxane. L in combination with chemotherapy has significantly improved progression free survival in patients (pts) with HER2+ MBC. Ab-Pac is a cremophor free, albumin-bound paclitaxel approved for use in pts with MBC demonstrating superior efficacy and safety when compared to other taxanes.

Methods: Phase II study (LPT111111) evaluated the efficacy and safety of L in combination with ab-Pac in 60 pts with histologically confirmed stage IV HER2+ (IHC 3+/FISH+) invasive MBC. Pts received 0–1 prior chemotherapeutic regimen in the metastatic setting and no prior treatment with L. Prior taxane therapy permitted provided this was &gt; 12 months prior to study entry, LVEF&gt;50%, peripheral neuropathy &lt; 2, prior CNS mets permitted, and prior endocrine therapy permitted. Pts received ab-Pac (125 mg/m2 IV on Days 1, 8, 15, q28 days) plus L (1250 mg daily). Planned safety analysis of the first 5 pts prompted a protocol amendment with a 20% dose reduction for both agents due to Grade (G) 3 neutropenia and diarrhea. Subsequent pts received ab-Pac (100 mg/m2 IV on Day 1, 8, 15, q28 days) in combination with L (1000 mg daily). Pts with SD or a response continued L alone until progression. Response assessments performed every 2 cycles. The primary endpoint was overall response rate (ORR) and secondary endpoints were progression-free survival (PFS), time to response, duration of response and overall survival (OS).

Results: Here we present the final analysis of all subjects receiving at least 6 months of protocol therapy. Median age is 56 years; 45 pts (75%) received treatment as 1st line therapy and 15 (25%) as 2nd line; 57% hormone receptor positive and 43% negative; 42% received trastuzumab and 40% received a taxane in either (neo) adjuvant or metastatic setting. After a median of 5.6 months, 7% pts had a complete response, 47% a partial response and 17% had stable disease, the ORR was 53% [95% CI: 41% to 66%]. The median time to response was 7.8 wks [95% CI: 7.4 to 8.1] with a median duration of response of 48.7 wks [95% CI: 31.7 to 57.1]. The median PFS was 39.7 wks [95% CI: 34.1 to 63.9]. Duration of exposure to ab-Pac; 48% received less than 6 cycles, 30% received 6 cycles and 22% received greater than 6 cycles. Table 1 shows the most common G ≥2 treatment-related toxicities.

Sunitinib plus paclitaxel versus bevacizumab plus paclitaxel for first-line treatment of patients with advanced breast cancer: a phase III, randomized, open-label trial

INTRODUCTION

A multicenter, open-label phase III study was conducted to test whether sunitinib plus paclitaxel prolongs progression-free survival (PFS) compared with bevacizumab plus paclitaxel as first-line treatment for patients with HER2(-) advanced breast cancer.

PATIENTS AND METHODS

Patients with HER2(-) advanced breast cancer who were disease free for ≥ 12 months after adjuvant taxane treatment were randomized (1:1; planned enrollment 740 patients) to receive intravenous (I.V.) paclitaxel 90 mg/m(2) every week for 3 weeks in 4-week cycles plus either sunitinib 25 to 37.5 mg every day or bevacizumab 10 mg/kg I.V. every 2 weeks. [corrected]

RESULTS

The trial was terminated early because of futility in reaching the primary endpoint as determined by the independent data monitoring committee during an interim futility analysis. At data cutoff, 242 patients had been randomized to sunitinib-paclitaxel and 243 patients to bevacizumab-paclitaxel. Median PFS was shorter with sunitinib-paclitaxel (7.4 vs. 9.2 months; hazard ratio [HR] 1.63 [95% confidence interval (CI), 1.18-2.25]; 1-sided P = .999). At a median follow-up of 8.1 months, with 79% of sunitinib-paclitaxel and 87% of bevacizumab-paclitaxel patients alive, overall survival analysis favored bevacizumab-paclitaxel (HR 1.82 [95% CI, 1.16-2.86]; 1-sided P = .996). The objective response rate was 32% in both arms, but median duration of response was shorter with sunitinib-paclitaxel (6.3 vs. 14.8 months). Bevacizumab-paclitaxel was better tolerated than sunitinib-paclitaxel. This was primarily due to a high frequency of grade 3/4, treatment-related neutropenia with sunitinib-paclitaxel (52%) precluding delivery of the prescribed doses of both drugs.

CONCLUSION

The sunitinib-paclitaxel regimen evaluated in this study was clinically inferior to the bevacizumab-paclitaxel regimen and is not a recommended treatment option for patients with advanced breast cancer.

Eltrombopag for management of chronic immune thrombocytopenia (RAISE): a 6-month, randomised, phase 3 study

BACKGROUND

Eltrombopag is an oral thrombopoietin receptor agonist for the treatment of thrombocytopenia. We aimed to compare the response to once daily eltrombopag versus placebo in patients with chronic immune thrombocytopenia during a 6-month period.

METHODS

We undertook a phase 3, double-blind, placebo-controlled study in adults with previously treated immune thrombocytopenia of more than 6 months' duration who had baseline platelet counts lower than 30,000 per μL. Patients were randomly allocated (in a 2:1 ratio) treatment with local standard of care plus 50 mg eltrombopag or matching placebo once daily for 6 months. Randomisation was done centrally with a computer-generated randomisation schedule and was stratified by baseline platelet count (≤ 15,000 per μL), use of treatment for immune thrombocytopenia, and splenectomy status. Patients, investigators, and those assessing data were masked to allocation. Dose modifications were made on the basis of platelet response. Patients were assessed for response to treatment (defined as a platelet count of 50,000-400,000 per μL) weekly during the first 6 weeks and at least once every 4 weeks thereafter; the primary endpoint was the odds of response to eltrombopag versus placebo. Analysis was by intention to treat. This study is registered at ClinicalTrials.gov, number NCT00370331.

FINDINGS

Between Nov 22, 2006, and July 31, 2007, 197 patients were randomly allocated to treatment groups and were included in the intention-to-treat analysis (135 eltrombopag, 62 placebo). 106 (79%) patients in the eltrombopag group responded to treatment at least once during the study, compared with 17 (28%) patients in the placebo group. The odds of responding were greater in patients in the eltrombopag group compared with those in the placebo group throughout the 6-month treatment period (odds ratio 8·2, 99% CI 3·59-18·73; p<0·0001). 37 (59%) patients receiving eltrombopag reduced concomitant treatment versus ten (32%) patients receiving placebo (p=0·016). 24 (18%) patients receiving eltrombopag needed rescue treatment compared with 25 (40%) patients receiving placebo (p=0·001). Three (2%) patients receiving eltrombopag had thromboembolic events compared with none in patients on placebo. Nine (7%) eltrombopag-treated patients and two (3%) in the placebo group had mild increases in alanine aminotransferase concentration, and five (4%) eltrombopag-treated patients (vs none allocated to placebo) had increases in total bilirubin. Four (7%) patients taking placebo had serious bleeding events, compared with one (<1%) patient treated with eltrombopag.

INTERPRETATION

Eltrombopag is effective for management of chronic immune thrombocytopenia, and could be particularly beneficial for patients who have not responded to splenectomy or previous treatment. These benefits should be balanced with the potential risks associated with eltrombopag treatment.

FUNDING

GlaxoSmithKline.

Pilot trial of preoperative (neoadjuvant) letrozole in combination with bevacizumab in postmenopausal women with newly diagnosed estrogen receptor- or progesterone receptor-positive breast cancer

INTRODUCTION

Tumor content or expression of vascular endothelial growth factor (VEGF) is associated with impaired efficacy of antiestrogen adjuvant therapy. We designed a pilot study to assess the feasibility and short-term efficacy of neoadjuvant letrozole and bevacizumab (anti-VEGF) in postmenopausal women with stage II and III estrogen receptor/progesterone receptor-positive breast cancer.

PATIENTS AND METHODS

Patients were treated with a neoadjuvant regimen of letrozole orally 2.5 mg/day and bevacizumab intravenously 15 mg/kg every 3 weeks for a total of 24 weeks before the surgical treatment of their breast cancer. Patients were followed for toxicity at 3-week intervals, and tumor assessment (a physical examination and ultrasound) was performed at 6-week intervals. Positron emission tomography (PET) scans were performed before therapy and 6 weeks after the initiation of therapy.

RESULTS

Twenty-five evaluable patients were treated. The regimen was well-tolerated, except in 2 patients who were taken off the study for difficulties controlling their hypertension. An objective clinical response occurred in 17 of 25 patients (68%), including 16% complete responses (CRs) and 52% partial responses. The 4 patients with clinical CRs manifested pathologic CRs in their breasts (16%), although 1 patient had residual tumor cells in her axillary nodes. Eight of 25 patients (32%) attained stage 0 or 1 status. The PET scan response at 6 weeks correlated with clinical CRs and breast pathologic CRs at 24 weeks (P < .0036).

CONCLUSION

Combination neoadjuvant therapy with letrozole and bevacizumab was well-tolerated and resulted in impressive clinical and pathologic responses. The Translational Breast Cancer Research Consortium has an ongoing randomized phase II trial of this regimen in this patient population.

Analysis of the impact and burden of illness of adult chronic ITP in the US

OBJECTIVE

Chronic idiopathic thrombocytopenic purpura (ITP), the predominant diagnosis in the ICD-9-CM category of primary thrombocytopenia in adults, is an autoimmune disease characterized by autoantibody-mediated platelet destruction and reduced platelet production. The objective of this study was to describe ITP patient demographics, treatment, medical care resource utilization, and costs from a real-world situation.

RESEARCH DESIGN AND METHODS

Managed-care administrative claims data from January 1 2000 to February 29 2004 were used in a retrospective, longitudinal cohort study to evaluate the burden of illness of chronic idiopathic primary thrombocytopenia among adults in the US, with particular emphasis on chronic ITP.

RESULTS

The annual prevalence of chronic, non-secondary, idiopathic thrombocytopenia in adults (out of >5.5 million patients) was 0.08% (i.e., 80 persons in 100 000). The mean age of the total cohort was 56.5 years (men, 60.2; women, 53.3); ratio of women to men was 1.1:1. The most frequently used thrombocytopenia-associated treatments were pharmacological therapy (e.g., immunoglobulins and corticosteroids) and whole blood transfusions; frequently used concomitant medications were antibiotics, antihypertensive agents, analgesics, and antidepressants. These data indicate that idiopathic thrombocytopenia-associated medical resource utilization and the corresponding expenditures for those services were substantive and constant over time. A large proportion of the overall patient care was directed to the treatment of bleeding and bruising symptoms. Although hospital and ER use was infrequent, these services accounted for the majority of ITP-attributable costs (46.1% were attributable to ITP-related hospital admissions; 45.0% were attributable to ER services for ITP).

CONCLUSIONS

There is a need for patient-directed care plans, fuller consideration of available treatments, and the potential reduction in patient burden of illness. Study limitations included a broadly defined cohort and possible underreporting of certain medications. Introduction of highly effective and well-tolerated medications may reduce the cost and resource burden of ITP on the healthcare system.

Multicenter Randomized Phase II Study of Weekly or Twice-Weekly Bortezomib Plus Rituximab in Patients With Relapsed or Refractory Follicular or Marginal-Zone B-Cell Lymphoma

Purpose

To determine overall response rate (ORR), time to progression (TTP), and duration of response (DOR) with twice-weekly/weekly bortezomib plus rituximab, and evaluate safety/tolerability, in patients with relapsed or refractory CD20+ follicular lymphoma (FL) or marginal-zone lymphoma.

Patients and Methods

Patients were randomly assigned (minimization method) to bortezomib 1.3 mg/m2 twice weekly (days 1, 4, 8, and 11; 21-day cycle, five cycles; arm A) or bortezomib 1.6 mg/m2 weekly (days 1, 8, 15, and 22; 35-day cycle, three cycles; arm B) plus rituximab 375 mg/m2 weekly for 4 weeks (both arms). Response/progression was determined by International Workshop Response Criteria using oncologist/radiologist-adjudicated data from independent radiology review and investigator assessment.

Results

Eighty-one patients (arm A, n = 41; arm B, n = 40) were enrolled. Dose-intensity was higher in arm A; mean total bortezomib received was similar between arms (18.5 and 17.1 mg/m2). In arm A, ORR was 49% (14% complete response [CR]/CR unconfirmed [CRu]), median TTP was 7.0 months, and median DOR was not reached. In arm B, ORR was 43% (10% CR/CRu), and median TTP/DOR were 10.0/9.3 months. The weekly combination regimen seemed better tolerated. Grade 3 or worse adverse events seemed more common in arm A (54%) versus arm B (35%), including thrombocytopenia (10% v 0%) and peripheral neuropathy (10% v 5%), but diarrhea seemed less frequent (7% v 15%). No grade 4 toxicities were reported in arm B.

Conclusion

Both bortezomib plus rituximab regimens seem feasible in relapsed or refractory indolent lymphomas. The more convenient weekly combination regimen is being compared with single-agent rituximab in an ongoing phase III study in relapsed FL.