Evaluating anticancer agents on 3D bioprinted organoid tumors (BOT) to reduce cost and accelerate therapeutic discovery

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Background: Despite recent advances in therapeutics, cancer remains the second leading cause of death worldwide. Next generation cancer models hold the promise of breaking this stranglehold. However, extracting adequate tissue for precision and personalized medicine ex vivo models can be difficult depending on tumor type and tissue site. Mechanisms to expand tissue include patient derived xenografts and patient derived organoids. The former imposes a large time window to establish while the latter is constrained in space by sizescales. Advances in 3D bioprinting have improved the ability to reproduce the three-dimensionality and heterogeneity of the tumor microenvironment. Here we present a novel mechanism to address space and time constrains with 3D bioprinted organoid tumors (BOT) that mimic core needle biopsy tissue to reduce both cost and time to market for novel therapeutics making effective cancer therapy more accessible and equitable. The aim of this study is to produce and use BOT core biopsy tissue in ex vivo precision and personalized medicine applications. Methods: Bioinks prepared with MDA-MB-231 cells, fibrinogen, and thrombin will be deposited layer-by-layer on microporous substrate, in various geometrical configurations, and cured in stages to allow cells and matrix to self-assemble with limited degrees of freedom. Bioprinted organoid tissue will be fully cured to mimic patient biopsy cores, which will then be loaded in ex vivo bioreactors to evaluate sensitivity and resistance of small molecule and biologics. Results: Tissue 3D microarchitecture was validated using high-content fluorescence imaging and custom image processing applications. Diffusion of mock agents, small molecule, and nucleic acid stains was measured 200 mm deep in tissue. Differential activity in spatially distinct regions of intact BOT cores was quantified using advanced image processing modules. Conclusions: Patient derived BOT cores could be used both as a predictive model to screen drugs on an individualized basis and to uncover new therapeutic targets to improve efficacy and reduce toxicity. Due to their ability to replicate the physical and biochemical characteristics of a tumor and its microenvironment, BOT based precision and personalized medicine models can provide more accurate data on drug efficacy and toxicology when compared to in vitro cancer models.

Phase 1 Trial of ALRN-6924, a Dual Inhibitor of MDMX and MDM2, in Patients with Solid Tumors and Lymphomas Bearing Wild-type TP53

PURPOSE

We describe the first-in-human dose-escalation trial for ALRN-6924, a stabilized, cell-permeating peptide that disrupts p53 inhibition by mouse double minute 2 (MDM2) and MDMX to induce cell-cycle arrest or apoptosis in TP53-wild-type (WT) tumors.

PATIENTS AND METHODS

Two schedules were evaluated for safety, pharmacokinetics, pharmacodynamics, and antitumor effects in patients with solid tumors or lymphomas. In arm A, patients received ALRN-6924 by intravenous infusion once-weekly for 3 weeks every 28 days; arm B was twice-weekly for 2 weeks every 21 days.

RESULTS

Seventy-one patients were enrolled: 41 in arm A (0.16-4.4 mg/kg) and 30 in arm B (0.32-2.7 mg/kg). ALRN-6924 showed dose-dependent pharmacokinetics and increased serum levels of MIC-1, a biomarker of p53 activation. The most frequent treatment-related adverse events were gastrointestinal side effects, fatigue, anemia, and headache. In arm A, at 4.4 mg/kg, dose-limiting toxicities (DLT) were grade 3 (G3) hypotension, G3 alkaline phosphatase elevation, G3 anemia, and G4 neutropenia in one patient each. At the MTD in arm A of 3.1 mg/kg, G3 fatigue was observed in one patient. No DLTs were observed in arm B. No G3/G4 thrombocytopenia was observed in any patient. Seven patients had infusion-related reactions; 3 discontinued treatment. In 41 efficacy-evaluable patients with TP53-WT disease across both schedules the disease control rate was 59%. Two patients had confirmed complete responses, 2 had confirmed partial responses, and 20 had stable disease. Six patients were treated for >1 year. The recommended phase 2 dose was schedule A, 3.1 mg/kg.

CONCLUSIONS

ALRN-6924 was well tolerated and demonstrated antitumor activity.

Safety and efficacy of pemigatinib plus pembrolizumab combination therapy in patients (pts) with advanced malignancies: Results from FIGHT-101, an open-label phase I/II study

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Background: Pemigatinib (INCB054828) is a selective fibroblast growth factor receptor (FGFR) 1–3 inhibitor with demonstrated efficacy as monotherapy in phase 1/2 (FIGHT-101) and phase 2 (FIGHT-201, -202, -203) trials in pts with advanced cancer. Here, we present preliminary safety, efficacy, and pharmacokinetic (PK) data for pemigatinib (PEMI) combined with pembrolizumab (PEMBRO), a programmed cell death protein-1 (PD-1) inhibitor, in pts with refractory advanced malignancies enrolled in the ongoing FIGHT-101 trial (NCT02393248). Methods: FIGHT-101 includes monotherapy (part 1 and 2) and combination therapy (part 3) cohorts. This analysis is based on pts enrolled in the PEMI + PEMBRO combination dose finding (3a) and dose expansion (3b) cohorts. Eligible adults had advanced malignancies who had progressed after prior therapy and for whom PEMBRO treatment was relevant; pts in part 3b had FGF/FGFR alterations. Pts received oral PEMI at 9 mg or 13.5 mg QD on an intermittent dosing (ID) schedule (21-day cycle, 14-day on/7-day off), or 13.5 mg QD on a continuous dosing (CD) schedule, plus PEMBRO 200 mg IV on day 1 of each 21-day cycle. Results: At data cutoff (August 30, 2019), 23 pts had received PEMI + PEMBRO; 22 (96%) had discontinued therapy (disease progression, 70%). Most frequent tumors were NSCLC (n = 3), bladder (n = 3), pancreatic, testicular, and sarcoma (each n = 2). Of 19 enrolled pts with baseline FGF/FGFR data; 5 had FGFR mutations or rearrangements. No dose-limiting toxicities occurred with PEMI + PEMBRO. The recommended PEMI dose combined with PEMBRO was 13.5 mg QD. Most frequent all-cause, all-grade (Gr) adverse events for ID (n = 17) were hyperphosphatemia (n = 14 [82%]; Gr ≥3, n = 0), anemia (n = 9 [53%]; Gr ≥3, n = 3 [18%]), and decreased appetite (n = 9 [53%]; Gr ≥3, n = 0); for CD (n = 6), hyperphosphatemia (n = 5 [83%]; Gr ≥3, n = 0), and dry mouth (n = 4 [67%]; Gr ≥3, n = 0). One pt discontinued, 2 reduced dose, and 13 interrupted dose due to AEs (none for hyperphosphatemia; dose interruption mainly for gastrointestinal AEs [n = 5]). One fatal AE occurred (suicide, not treatment-related). PK parameters for PEMI in the PEMI + PEMBRO combination were comparable with those for PEMI monotherapy. Five pts had partial response (3 had FGFR rearrangements or mutations); 5 pts had stable disease. Conclusions: PEMI + PEMBRO combination therapy was tolerable with no new safety signals, and demonstrated preliminary antitumor activity in pts with advanced malignancies including those with FGF/FGFR alterations. Clinical trial information: NCT02393248 .

TBCRC 002: a phase II, randomized, open-label trial of preoperative letrozole with or without bevacizumab in postmenopausal women with newly diagnosed stage 2/3 hormone receptor-positive and HER2-negative breast cancer

Background

In preclinical studies, the expression of vascular endothelial growth factor (VEGF) in hormone receptor-positive breast cancer is associated with estrogen-independent tumor growth and resistance to endocrine therapies. This study investigated whether the addition of bevacizumab, a monoclonal antibody against VEGF, to letrozole enhanced the antitumor activity of the letrozole in the preoperative setting.

Methods

Postmenopausal women with newly diagnosed stage 2 or 3 estrogen and/or progesterone receptor-positive, HER2-negative breast cancer were randomly assigned (2:1) between letrozole 2.5 mg PO daily plus bevacizumab 15 mg/kg IV every 3 weeks (Let/Bev) and letrozole 2.5 mg PO daily (Let) for 24 weeks prior to definitive surgery. Primary objective was within-arm pathologic complete remission (pCR) rate. Secondary objectives were safety, objective response, and downstaging rate.

Results

Seventy-five patients were randomized (Let/Bev n = 50, Let n = 25). Of the 45 patients evaluable for pathological response in the Let/Bev arm, 5 (11%; 95% CI, 3.7–24.1%) achieved pCR and 4 (9%; 95% CI, 2.5–21.2%) had microscopic residual disease; no pCRs or microscopic residual disease was seen in the Let arm (0%; 95% CI, 0–14.2%). The rates of downstaging were 44.4% (95% CI, 29.6–60.0%) and 37.5% (95% CI, 18.8–59.4%) in the Let/Bev and Let arms, respectively. Adverse events typically associated with letrozole (hot flashes, arthralgias, fatigue, myalgias) occurred in similar frequencies in the two arms. Hypertension, headache, and proteinuria were seen exclusively in the Let/Bev arm. The rates of grade 3 and 4 adverse events and discontinuation due to adverse events were 18% vs 8% and 16% vs none in the Let/Bev and Let arms, respectively. A small RNA-based classifier predictive of response to preoperative Let/Bev was developed and confirmed on an independent cohort.

Conclusion

In the preoperative setting, the addition of bevacizumab to letrozole was associated with a pCR rate of 11%; no pCR was seen with letrozole alone. There was additive toxicity with the incorporation of bevacizumab. Responses to Let/Bev can be predicted from the levels of 5 small RNAs in a pretreatment biopsy.

Trial registration

This trial is registered with ClinicalTrials.gov (Identifier: NCT00161291), first posted on September 12, 2005, and is completed.

An open label phase 1/2A study to evaluate the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of TRC253, an androgen receptor antagonist, in patients with metastatic castration-resistant prostate cancer

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Background: TRC253 is a high-affinity, orally active small molecule antagonist of the androgen receptor (AR) and specific mutated variants of AR that does not possess agonist activity towards either wild type or mutated AR. TRC253 inhibits AR nuclear translocation as well as AR binding to DNA and is a transcription antagonist. TRC253 treatment is efficacious in an LNCaP xenograft model driven by F877L mutant AR. Methods: In P1 dose escalation, pts with mCRPC previously treated with an AR inhibitor were assigned to increasing TRC253 doses of 40-320 mg daily. Dose escalation followed single-pt dose escalation design for the 40, 80 mg cohorts and expanded to 3+3 design in the 160, 240, 280, and 320 mg cohorts to assess safety, determine the recommended phase 2 dose (RP2D), and evaluate prostate-specific antigen response at week 12. Toxicity and efficacy assessments used NCI-CTCAE v4.03 and PCWG3 criteria, respectively. Pts were centrally screened by circulating tumor DNA using the BEAMing digital PCR assay. Results: Twenty-two pts were enrolled in phase 1 at TRC253 doses of 40 (n = 1), 80 (n = 1), 160 (n = 2), 240 (n = 6), 280 (n = 4), and 320 mg (n = 8) daily in 28-day cycles. One DLT of G3 QTcF prolongation occurred at 320 mg. No drug-related SAEs were reported. Drug-related AEs ≥ G2 included QTcF prolongation (2 G2, 2 G3), elevated lipase (1 G3), fatigue (4 G2), arthralgia (1 G2), diarrhea (1 G2), and platelet count decrease (1 G2). One pt on study had AR F877L at baseline and remained on treatment for 49 wks with PR by RECIST. The remaining 21 pts did not have AR F877L at baseline and of these, 48% (10) remained on study > 6 cycles and one pts had a > 50% decrease in PSA. Target PK exposures were achieved consistently at 280 mg. 280 mg was selected as the RP2D based on safety and PK data. Conclusions: TRC253 daily at 280 mg was well-tolerated and selected as the RP2D. P2 dose expansion is currently enrolling 2 cohorts: 15 pts with AR F877L and 30 pts without AR F877L. The objectives of P2 include collection of additional data for safety, PK, PET and efficacy of TRC253 in mCRPC pts with specific AR mutations. Clinical trial information: NCT02987829.

Changes in health-related quality of life with long-term eltrombopag treatment in adults with persistent/chronic immune thrombocytopenia: Findings from the EXTEND study

Patients with persistent/chronic immune thrombocytopenia (cITP) have low platelet counts, increased risk of bleeding and bruising, and often suffer from reduced health‐related quality of life (HRQoL). cITP treatments may either improve HRQoL by increasing platelet counts or decrease it because of side effects. The open‐label EXTEND study (June 2006 to July 2015) evaluated long‐term safety, tolerability, and efficacy of eltrombopag (an oral thrombopoietin‐receptor‐agonist) in adults with cITP who completed a previous eltrombopag ITP trial. The final results of EXTEND were published and used to assess changes in patient‐reported HRQoL over time and association between HRQoL and platelet response. Four validated HRQoL instruments were administered: SF‐36v2 including physical component summary (PCS) and Mental Component Summary; Motivation and Energy Inventory Short Form (MEI‐SF); Fatigue Subscale of FACIT (FACIT‐Fatigue); and FACT‐Thrombocytopenia Subscale Six‐Item Extract (FACT‐Th6). For the 302 patients enrolled, median duration of eltrombopag treatment was 2.37 years. All 4 HRQoL instruments demonstrated positive mean changes from baseline over time adjusted for patient baseline characteristics and rescue therapy use, and had positive association with platelet response (platelet count ≥30 × 10⁹/L; ≥50 × 10⁹/L; and ≥50 × 10⁹/L and >2 times baseline). Improvements from baseline started within 3 months and persisted through 5 years of treatment for FACIT‐Fatigue and FACT‐Th6 (P <.05 for nearly all time points); through 2.5 years for SF‐36v2 PCS and less consistently for the MEI‐SF. In conclusion, in addition to eltrombopag increasing platelet counts and reducing bleeding/bruising, it also alleviated fatigue, concerns about bleeding and bruising, and improved physical function in many patients, especially responders.

An open-label phase 1/2a study to evaluate the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of TRC253, an androgen receptor antagonist, in patients with metastatic castration-resistant prostate cancer (mCRPC)

TPS403

Background: Resistance to AR-targeted therapy is a challenge in the treatment of mCRPC. Single amino acid mutations of the AR ligand binding domain may mediate resistance to second generation AR inhibitors, including enzalutamide (Rathkopf, Annals of Oncology 2017). Development of potent antagonists of wild-type (WT) AR as well as mutated AR is a priority. TRC253 is an orally available, high-affinity, small molecule antagonist of AR with inhibitory activity against WT AR as well as mutated variants. TRC253 blocks AR nuclear translocation and AR binding to DNA and antagonizes transcription. TRC253 does not have agonist activity toward WT or mutated ARs. Methods: This phase 1/2a study of TRC253 in patients with mCRPC will be conducted in two parts: dose-escalation (part 1) and dose-expansion (part 2). Objectives include assessment of safety, selection of a phase 2 dose, and to evaluate PSA response at week 12. Secondary objectives include the evaluation of the extent of receptor occupancy (FDHT PET) and anti-tumor effects of TRC253. Toxicity and efficacy assessments will be determined using NCI-CTCAE and PCWG3 criteria. Dose escalation will begin with single-patient cohorts. Cohorts will be expanded to 3 patients when pre-defined grades of drug-related toxicity occur. TRC253 doses in part 1 are 40 mg, 80 mg, 160 mg, 240 mg, 320 mg, and 400 mg. The DLT evaluation period will be the first 28 days of continuous daily dosing. Six patients have been enrolled to Part 1 to date. Part 2 will consist of two cohorts of up to 30 patients each. Cohort 1 (AR F876L mutation positive) and cohort 2 (AR F876L mutation negative) will receive TRC253 at the RP2D. Circulating tumor DNA will be analyzed in plasma samples to test for AR mutations. In Part 1 patients must have received ≥ 2 prior therapies. Part 2 patients must have demonstrated acquired resistance to enzalutamide or apalutamide. Descriptive statistics will be used to summarize patient characteristics, safety, efficacy, PK, and immunologic biomarkers. Clinical trial information: NCT02987829.

Phase I trial of a novel stapled peptide ALRN-6924 disrupting MDMX- and MDM2-mediated inhibition of WT p53 in patients with solid tumors and lymphomas

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Background: ALRN-6924 is a cell-penetrating stapled alpha-helical peptide designed to equipotently disrupt the interaction between the p53 tumor suppressor protein and its endogenous inhibitors, murine double minute X (MDMX) and 2 (MDM2). For TP53 wild-type (WT) tumors, pharmacological disruption of this interaction offers a means to restore p53-dependent cell cycle arrest and apoptosis, resulting in antitumor efficacy via a novel mechanism. Methods: The study evaluated safety, PK, PD and anti-tumor effects of ALRN-6924 in patients (pts) with advanced solid tumors or lymphomas in a standard 3+3 design. Pts received ALRN-6924 IV once weekly for 3 consecutive wks on a 28-day cycle (arm A), or 2/wk for 2 consecutive wks on a 21-day cycle (arm B). Results: As of Dec 2016, 69 pts were enrolled with median age 61 yrs (25-78). Pts received a median of 2 (1-19) cycles in arm A [0.16-4.4 mg/kg] and 3 (1-19) cycles in arm B [0.32-2.7 mg/kg]. ALRN-6924 showed a t1/2 of 5.5 hours, dose-dependent PK, and an increase in serum macrophage inhibitory cytokine-1. Treatment-related AEs seen in 96% of pts were primarily grade 1 and 2; most frequent were GI side effects, fatigue, anemia, and headache. DLTs were G3 fatigue at 3.1 mg/kg, and G3 hypotension, G3 alkaline phosphatase elevation, G3 anemia and G4 neutropenia at 4.4 mg/kg all in 5 pts in arm A. No G3/4 thrombocytopenia was observed. All DLTs resolved with dose hold. Infusion-related reactions were seen in 7 pts, with 3 treatment discontinuations. The RP2D was determined to be at MTD: 3.1 mg/kg QW for 3 wks every 28 days. In 55 pts evaluable for efficacy, disease control rate (DCR) was 45%, including 2 CR (Peripheral T-cell Lymphoma [PTCL], Merkel Cell Carcinoma), 2 PRs (Colorectal Cancer, Liposarcoma) and 21 pts with SD. In WT TP53 pts who initiated ALRN-6924 at ≥0.8 mg/kg, DCR was 57%. 9 pts remain on treatment post data cutoff including 3 pts exceeding 1 year of treatment. Conclusions: ALRN-6924 was well tolerated and demonstrated intriguing anti-tumor activity in this first-in-human phase I trial. An expansion phase IIa cohort in PTCL opened in August 2016 using 3.1 mg/kg (arm A) and is currently enrolling. Clinical trial information: NCT02264613.

Epacadostat plus nivolumab in patients with advanced solid tumors: Preliminary phase I/II results of ECHO-204

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Background: ECHO-204 is an ongoing, open-label, phase 1/2 (P1/2) study of epacadostat (E; potent and selective oral inhibitor of the immunosuppressive enzyme indoleamine 2,3-dioxygenase 1) plus PD-1 inhibitor nivolumab (N) in patients (pts) with advanced cancers (NSCLC, MEL, OVC, CRC, SCCHN, B-cell NHL [including DLBCL], GBM). Preliminary P1/2 safety and tolerability outcomes for the overall study population and P2 response for select tumor types (SCCHN, MEL, OVC, CRC) are reported. Methods: In P1 dose escalation, pts received E (25, 50, 100, 300 mg BID) + N (3 mg/kg Q2W); in P2 cohort expansion, pts received E (100 or 300 mg BID) + N (240 mg Q2W). Safety/tolerability was assessed in pts receiving ≥1 E + N dose. Response was assessed in RECIST v1.1 evaluable pts; for recently enrolled pt subgroups, only preliminary DCR (CR+PR+SD) is presented. Results: As of 29OCT2016,241 pts (P1, n = 36; P2, n = 205) were enrolled. No DLT was observed in P1. Most common TRAEs (≥15%) in pts treated with E 100 mg (n = 70) and E 300 mg (n = 135) were rash (33% and 22%, respectively), fatigue (26% and 31%), and nausea (24% and 19%). Rash was the most common grade ≥3 TRAE in E 100 mg and E 300 mg subgroups (10% and 12%). TRAEs led to discontinuation in 7% (E 100 mg) and 13% (E 300 mg) of pts. There were no TR-deaths. For the 23 recently enrolled, efficacy-evaluable SCCHN pts treated with E 300 mg, preliminary DCR was 70% (n = 16). Of 30 MEL pts, 8 were treated with E 100 mg and 22 were more recently enrolled and treated with E 300 mg. ORR (CR+PR) and DCR in MEL pts treated with E 100 mg were 75% (n = 6; all PR) and 100% (n = 8; 2 SD), respectively. Preliminary DCR in MEL pts treated with E 300 mg was 64% (n = 14). Of 29 OVC pts, 18 were treated with E 100 mg and 11 with E 300 mg.ORR and DCR for OVC pts treated with E 100 mg were 11% (n = 2; 2 PR) and 28% (n = 5; 3 SD); for 11 OVC pts treated with E 300 mg, ORR and DCR were 18% (n = 2; 2 PR) and 36% (n = 4; 2 SD).For 25 CRC pts (all E 100 mg), ORR and DCR were 4% (n = 1; PR) and 24% (n = 6; 5 SD).Safety/efficacy evaluations are ongoing for all cohorts. Conclusions: E + N was generally well tolerated up to the maximum E 300-mg dose. P2 ORR/DCR outcomes are promising, particularly in SCCHN and MEL pts. Updated data will be presented at the meeting. Clinical trial information: NCT02327078.

Academic Cancer Center Phase I Program Development

This commentary assesses the factors necessary for the effectiveness of academic phase I cancer programs. The metrics presented here may be useful as a rubric for new and established programs.

Multiple factors critical to the effectiveness of academic phase I cancer programs were assessed among 16 academic centers in the U.S. Successful cancer centers were defined as having broad phase I and I/II clinical trial portfolios, multiple investigator‐initiated studies, and correlative science. The most significant elements were institutional philanthropic support, experienced clinical research managers, robust institutional basic research, institutional administrative efforts to reduce bureaucratic regulatory delays, phase I navigators to inform patients and physicians of new studies, and a large cancer center patient base. New programs may benefit from a separate stand‐alone operation, but mature phase I programs work well when many of the activities are transferred to disease‐oriented teams. The metrics may be useful as a rubric for new and established academic phase I programs.

Comparison of two dosing schedules for subcutaneous injections of low-dose anti-CD20 veltuzumab in relapsed immune thrombocytopenia

We compared two dosing schedules for subcutaneous injections of a low-dose humanized anti-CD20 antibody, veltuzumab, in immune thrombocytopenia. Fifty adults with primary immune thrombocytopenia, in whom one or more lines of standard therapy had failed and who had a platelet count <30×10⁹/L but no major bleeding, initially received escalating 80, 160, or 320 mg doses of subcutaneous veltuzumab administered twice, 2 weeks apart; the last group received once-weekly doses of 320 mg for 4 weeks. In all dose groups, injection reactions were transient and mild to moderate; there were no other safety issues. Forty-seven response-evaluable patients had 23 (49%) objective responses (platelet counts ≥30×10⁹/L and ≥2 × baseline) including 15 (32%) complete responses (platelets ≥100×10⁹/L). Responses (including complete responses) and bleeding reduction occurred in all dose groups and were not dose-dependent. In contrast, response duration increased progressively with total dose, reaching a median of 2.7 years with the four once-weekly 320-mg doses. Among nine responders retreated at relapse, three at higher dose levels responded again, including one patient who was retreated four times. In all dose groups, B-cell depletion occurred after the first dose until recovery starting 12 to 16 weeks after treatment. Veltuzumab serum levels increased with dose group according to total dose administered, but terminal half-life and clearance were comparable. Human anti-veltuzumab antibody titers developed without apparent dose dependence in nine patients, of whom six responded including five who had complete responses. Subcutaneous veltuzumab was convenient, well-tolerated, and active, without causing significant safety concerns. Platelet responses and bleeding reduction occurred in all dose groups, and response durability appeared to improve with higher doses. Clinicaltrials.gov identifier: NCT00547066.

EMERGE: A Randomized Phase II Study of the Antibody-Drug Conjugate Glembatumumab Vedotin in Advanced Glycoprotein NMB-Expressing Breast Cancer

PURPOSE

Glycoprotein NMB (gpNMB), a negative prognostic marker, is overexpressed in multiple tumor types. Glembatumumab vedotin is a gpNMB-specific monoclonal antibody conjugated to the potent cytotoxin monomethyl auristatin E. This phase II study investigated the activity of glembatumumab vedotin in advanced breast cancer by gpNMB expression.

PATIENTS AND METHODS

Patients (n = 124) with refractory breast cancer that expressed gpNMB in ≥ 5% of epithelial or stromal cells by central immunohistochemistry were stratified by gpNMB expression (tumor, low stromal intensity, high stromal intensity) and were randomly assigned 2:1 to glembatumumab vedotin (n = 83) or investigator's choice (IC) chemotherapy (n = 41). The study was powered to detect overall objective response rate (ORR) in the glembatumumab vedotin arm between 10% (null) and 22.5% (alternative hypothesis) with preplanned investigation of activity by gpNMB distribution and/or intensity (Stratum 1 to Stratum 3).

RESULTS

Glembatumumab vedotin was well tolerated as compared with IC chemotherapy (less hematologic toxicity; more rash, pruritus, neuropathy, and alopecia). ORR was 6% (five of 83) for glembatumumab vedotin versus 7% (three of 41) for IC, without significant intertreatment differences for predefined strata. Secondary end point revealed ORR of 12% (10 of 83) versus 12% (five of 41) overall, and 30% (seven of 23) versus 9% (one of 11) for gpNMB overexpression (≥ 25% of tumor cells). Unplanned analysis showed ORR of 18% (five of 28) versus 0% (0 of 11) in patients with triple-negative breast cancer (TNBC), and 40% (four of 10) versus 0% (zero of six) in gpNMB-overexpressing TNBC.

CONCLUSION

Glembatumumab vedotin is well tolerated in heavily pretreated patients with breast cancer. Although the primary end point in advanced gpNMB-expressing breast cancer was not met for all enrolled patients (median tumor gpNMB expression, 5%), activity may be enhanced in patients with gpNMB-overexpressing tumors and/or TNBC. A pivotal phase II trial (METRIC [Metastatic Triple-Negative Breast Cancer]) is underway.

First-in-human study of MM-141: A novel tetravalent monoclonal antibody targeting IGF-1R and ErbB3

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Background: MM-141 is a novel tetravalent bispecific monoclonal antibody that binds IGF-1R and ErbB3 and blocks both ligand dependent and independent IGF-1R/ErbB3/PI3K/AKT/mTOR signaling. MM-141 potentiated gemcitabine, nab-paclitaxel, docetaxel, irinotecan, tamoxifen, and everolimus in preclinical models. A multi-arm Phase 1 study is ongoing and the monotherapy dose-escalation portion of the study is completed. Hepatocellular carcinoma (HCC) patients were enrolled to an expansion cohort of Arm A to receive MM-141 as a monotherapy. Another arm of treatment combined MM-141 with gemcitabine and nab-paclitaxel. Methods: This is a Phase 1 dose-escalation study evaluating safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) properties of MM-141 as monotherapy (n=15) and in combination with everolimus (Arm B) or with nab-paclitaxel and gemcitabine (Arm C). Three HCC patients in the Arm A expansion cohort received MM-141 as a monotherapy at a weekly dose of 20 mg/kg. These patients underwent mandatory pre-treatment and optional post-treatment biopsies. Patients in the dose-escalation portion of Arm C received MM-141 at a weekly dose of 12 or 20 mg/kg or a bi-weekly dose of 40 mg/kg in combination with gemcitabine (1000 mg/m2) and nab-paclitaxel (125 mg/m2). Results: 15 patients with advanced solid tumors were enrolled into the dose escalation portion of Arm A. No dose-limiting toxicities were observed at any of the studied doses. The safety, tolerability, PK and PD profile support weekly and bi-weekly MM-141 dosing. The Arm A expansion enrolled 3 patients with sorafenib-refractory HCC. The analysis of pre- and post-treatment biopsies confirmed that IGF-1R and ErbB3 are expressed in patients previously exposed to sorafenib, and their levels are decreased after MM-141 exposure. Arm C, combining MM-141, gemcitabine, and nab-paclitaxel in a “3+3” dose-escalation design is on-going. Conclusions: MM-141 was well tolerated as a monotherapy and translational analysis of pharmacodynamic parameters suggest appropriate target engagement. Combination data with gemcitabine/nab-paclitaxel will be presented and preparations for a randomized Phase 2 study in front-line pancreatic cancer are underway. Clinical trial information: NCT01733004.

Abstract CT239: ARN-509 in patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with abiraterone acetate (AA)

Background:

ARN-509 is a novel second-generation antiandrogen that binds directly to the ligand-binding domain of the androgen receptor (AR), impairing AR nuclear translocation and DNA binding to the androgen response element. Phase 2 of a multicenter phase 1/2 study evaluates ARN-509 activity in 3 distinct patient populations of men with CRPC: 1) nonmetastatic chemotherapy-naive CRPC; 2) chemotherapy-naïve mCRPC; 3) mCRPC post-AA treatment. Study ARN-509-001 is the first to prospectively examine response to novel second-generation antiandrogens post-AA treatment. We present the results of the post-AA treated cohort, as of July 2013.

Methods:

All patients had mCRPC with progressive disease based on rising prostate-specific antigen (PSA) and/or imaging. No prior chemotherapy for CRPC was allowed. Patients in the AA-pretreated cohort had to have been treated with AA for at least 6 months. All patients received ARN-509 at the recommended phase 2 dose of 240 mg/d (Rathkopf et al. J Clin Oncol. 2013). The primary end point was PSA response at 12 weeks according to the Prostate Cancer Working Group 2 criteria. Secondary end points included safety, time to PSA progression, and objective response rates. PSA assessments were collected every 4 weeks and tumor imaging was performed every 12 weeks.

Results:

By July 2013, 21 patients were enrolled and treated in the post-AA cohort. The median age was 67 years (range 48-83). At baseline, 62% of patients had an Eastern Cooperative Oncology Group performance status 0, and 29% had a Gleason score ≥ 8; median PSA was 58.4 ng/mL. Median duration on ARN-509 treatment post AA was 5.6 months (range 1.9-16.7). At 12 weeks, 24% (5/21) of patients had ≥ 50% decline in PSA from baseline. Median time to PSA progression was 16 weeks (95% confidence interval, 12-31 weeks). The best objective response was stable disease in 4 (36%) patients. Patients discontinued the study due to disease progression (n = 13), adverse events (n = 2), consent withdrawn (n = 1), and other reasons (n = 4). The most common treatment-related adverse events were fatigue (n = 11), nausea (n = 5), and diarrhea (n = 3).

Conclusions:

In men with mCRPC, post-AA treatment, ARN-509 is safe and well tolerated, with modest activity in a subset of patients who develop resistance to AA. Clinical trial information: NCT01171898.

Citation Format: Dana E. Rathkopf, Emmanuel S. Antonarakis, Neal D. Shore, Ronald Tutrone, Joshi J. Alumkal, Charles J. Ryan, Mansoor N. Saleh, Ralph J. Hauke, Rajesh Bandekar, Edna Chow Maneval, Carla de Boer, Mary Todd, Margaret K. Yu, Howard I. Scher. ARN-509 in patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with abiraterone acetate (AA). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT239. doi:10.1158/1538-7445.AM2014-CT239

A randomized, phase II study of the anti-insulin-like growth factor receptor type 1 (IGF-1R) monoclonal antibody robatumumab (SCH 717454) in patients with advanced colorectal cancer

Overexpression of insulin-like growth factor receptor type 1 (IGF-1R) may promote tumor development and progression in some cancer patients. Our objective was to assess tumor uptake of fluorodeoxyglucose by positron-emission tomography in patients with chemotherapy-refractory colorectal cancer treated with an anti-insulin-like growth factor receptor type 1 (anti-IGF-1R) monoclonal antibody, robatumumab. This was a randomized, open-label study with two periods (P1 and P2). Patients were randomized 3:1 into treatment arms R/R and C/R that received, respectively, one cycle of 0.3 mg/kg robatumumab or one or more cycles of second-line chemotherapy in P1, followed in either case by 10 mg/kg robatumumab biweekly in P2. The primary measure of fluorodeoxyglucose uptake was maximum standardized uptake value (SUV_max). The primary endpoint was the proportion of patients in the R/R arm having a mean percent decrease from baseline in SUV_max (DiSUV) greater than 20% 12–14 days postdose in P2. Secondary endpoints included Response Evaluation Criteria in Solid Tumors (RECIST)-defined tumor response and pharmacodynamic measures of target engagement. Among 41 patients who were evaluable for the primary endpoint, seven (17%, 95% CI 7%–32%) had DiSUV greater than 20%. Fifty robatumumab-treated patients were evaluable for RECIST-defined tumor response and six (12%) had stable disease lasting greater than or equal to 7 weeks in P2. Pharmacodynamic endpoints indicated target engagement after dosing with 10 mg/kg robatumumab, but not 0.3 mg/kg. The most frequently reported adverse events were fatigue/asthenia, nausea, anorexia, and gastrointestinal disturbances. In this study, few patients with chemotherapy-refractory colorectal cancer appeared to benefit from treatment with the IGF-1R antagonist robatumumab.

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.