Association between Liver Metastases and Treatment Response in Patients with Metastatic, Microsatellite Stable Colorectal Cancer Treated with Radiation Therapy and Dual Immune Checkpoint Blockade

PURPOSE/OBJECTIVE(S)

Most patients with metastatic colorectal cancer (CRC) have microsatellite stable (MSS) disease with a limited response to immune checkpoint inhibitors (ICIs). In our phase 2 trial (NCT03104439), 27 patients with metastatic MSS CRC received ipilimumab, nivolumab, and RT (24 Gy/3 fractions) on C2D1 with a disease control rate (DCR) of 37% (10/27) and overall response rate (ORR) of 15% (4/27). Our follow up phase 2 study with ipilimumab, nivolumab, and RT moved to C1D1 (NCT04361162) showed a DCR of 33% (10/30) and an ORR of 13% (4/30). Clinical and preclinical data suggest liver metastases are less responsive to systemic ICIs and complementary liver-directed RT can potentially overcome this effect. To address this, we investigated the association between liver metastases and response rates among patients treated with and without liver-directed RT in a pooled analysis of our phase 2 studies of nivolumab and ipilimumab with RT.

MATERIALS/METHODS

In this pooled secondary analysis of two open-label, single-arm, phase 2 studies, eligible patients had metastatic MSS CRC, ECOG PS 0-1, and progressed on at least one line of chemotherapy. Treatment consisted of ipilimumab 1 mg/kg q6weeks for 4 cycles, nivolumab 240 mg q2weeks on a 6-week cycle, and RT (24 Gy/3 fractions) on C1D1 or C2D1 to one site. Responses were defined outside of the RT field by RECIST 1.1 with centrally reviewed imaging q3months. ORR/DCR and PFS/OS were compared between patients with and without liver metastases with the Fisher's exact and log-rank tests, respectively. P-values are two-sided.

RESULTS

We treated 57 patients (median age 57 years [range, 26-85], 61% male, 88% white, 65% with liver metastases) from 07/2017 to 05/2022. Patients received a median of 3 (range, 1-10) prior lines of systemic therapy. The combined ORR was 14% (8/57; 95% CI, 6-26%) and DCR was 35% (20/57; 95% CI, 23-49%). The ORR was 30% (6/20; 95% CI, 12-54%) in patients without liver metastases and 5% (2/37; 95% CI, 1-18%) in patients with liver metastases (p = 0.017). The DCR was 55% (11/20; 95% CI, 32-77%) in patients without liver metastases and 24% (9/37; 94% CI, 12-41%) in patients with liver metastases (p = 0.040). 76% (28/37) of patients with liver metastases received liver-directed RT including 2/2 (100%) patients with a PR. The ORR was 0% in patients with liver metastases without liver-directed RT. The median PFS was 1.8 months (95% CI, 1.2-2.4 months) and OS was 9.8 months (95% CI, 6.8-12.8). OS was longer in patients without liver metastases (median 13.6 v 6.8 months, p = 0.010) and in patients treated with liver-directed RT among those with liver metastases (median 7.5 months v 4.5 months, p = 0.025).

CONCLUSION

Among patients with metastatic MSS CRC treated with ICIs and RT in two phase 2 studies, ORR, DCR, and OS are significantly higher in patients without liver metastases. Liver-directed RT may improve ICI efficacy and OS in patients with liver metastases. Further analysis of PFS and prospective study of ICIs with comprehensive liver-directed RT are warranted.

Parkour LIMS: high-quality sample preparation in next generation sequencing

MOTIVATION

This paper presents Parkour, a software package for sample processing and quality management of next generation sequencing data and samples.

RESULTS

Starting with user requests, Parkour allows tracking and assessing samples based on predefined quality criteria through different stages of the sample preparation workflow. Ideally suited for academic core laboratories, the software aims to maximize efficiency and reduce turnaround time by intelligent sample grouping and a clear assignment of staff to work units. Tools for automated invoicing, interactive statistics on facility usage and simple report generation minimize administrative tasks. Provided as a web application, Parkour is a convenient tool for both deep sequencing service users and laboratory personal. A set of web APIs allow coordinated information sharing with local and remote bioinformaticians. The flexible structure allows workflow customization and simple addition of new features as well as the expansion to other domains.

AVAILABILITY AND IMPLEMENTATION

The code and documentation are available at https://github.com/maxplanck-ie/parkour.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Pilot randomized trial of an electronic symptom monitoring intervention for hospitalized patients with cancer

BACKGROUND

Hospitalized patients with cancer experience a high symptom burden, which is associated with poor health outcomes and increased health care utilization. However, studies investigating symptom monitoring interventions in this population are lacking. We conducted a pilot randomized trial to assess the feasibility and preliminary efficacy of a symptom monitoring intervention to improve symptom management in hospitalized patients with advanced cancer.

PATIENTS AND METHODS

We randomly assigned patients with advanced cancer who were admitted to the inpatient oncology service to a symptom monitoring intervention or usual care. Patients in both arms self-reported their symptoms daily (Edmonton Symptom Assessment System and Patient Health Questionnaire-4). Patients assigned to the intervention had their symptom reports presented graphically with alerts for moderate/severe symptoms during daily team rounds. The primary end point of the study was feasibility. We defined the intervention as feasible if >75% of participants hospitalized >2 days completed >2 symptom reports. We observed daily rounds to determine whether clinicians discussed and developed a plan to address patients' symptoms. We used regression models to assess intervention effects on patients' symptoms throughout their hospitalization, readmission risk, and hospital length of stay (LOS).

RESULTS

Among 150 enrolled patients (81.1% enrollment), 94.2% completed >2 symptom reports. Clinicians discussed 60.4% of the symptom reports and developed a plan to address the symptoms highlighted by the symptom reports 20.8% of the time. Compared with usual care, intervention patients had a greater proportion of days with lower psychological distress (B = 0.12, P = 0.008), but no significant difference in the proportion of days with improved Edmonton Symptom Assessment System-physical symptoms (B = 0.07, P = 0.138). Intervention patients had lower readmission risk (hazard ratio = 0.68, P = 0.224), although this difference was not significant. We found no significant intervention effects on hospital LOS (B = 0.16, P = 0.862).

CONCLUSIONS

This symptom monitoring intervention is feasible and demonstrates encouraging preliminary efficacy for improving patients' symptoms and readmission risk.ClinicalTrials.gov identifier NCT02891993.

A paternal methyl donor-rich diet altered cognitive and neural functions in offspring mice

Dietary intake of methyl donors, such as folic acid and methionine, shows considerable intra-individual variation in human populations. While it is recognized that maternal departures from the optimum of dietary methyl donor intake can increase the risk for mental health issues and neurological disorders in offspring, it has not been explored whether paternal dietary methyl donor intake influences behavioral and cognitive functions in the next generation. Here, we report that elevated paternal dietary methyl donor intake in a mouse model, transiently applied prior to mating, resulted in offspring animals (methyl donor-rich diet (MD) F1 mice) with deficits in hippocampus-dependent learning and memory, impaired hippocampal synaptic plasticity and reduced hippocampal theta oscillations. Gene expression analyses revealed altered expression of the methionine adenosyltransferase Mat2a and BK channel subunit Kcnmb2, which was associated with changes in Kcnmb2 promoter methylation in MD F1 mice. Hippocampal overexpression of Kcnmb2 in MD F1 mice ameliorated altered spatial learning and memory, supporting a role of this BK channel subunit in the MD F1 behavioral phenotype. Behavioral and gene expression changes did not extend into the F2 offspring generation. Together, our data indicate that paternal dietary factors influence cognitive and neural functions in the offspring generation.

Genetic parameters of ovarian and uterine reproductive traits in dairy cows

The objective of the study was to estimate genetic parameters of detailed reproductive traits derived from ultrasound examination of the reproductive tract as well as their genetic correlations with traditional reproductive traits. A total of 226,141 calving and insemination records as well as 74,134 ultrasound records from Irish dairy cows were used. Traditional reproductive traits included postpartum interval to first service, conception, and next calving, as well as the interval from first to last service; number of inseminations, pregnancy rate to first service, pregnant within 42 d of the herd breeding season, and submission in the first 21 d of the herd breeding season were also available. Detailed reproductive traits included resumed cyclicity at the time of ultrasound examination, incidence of multiple ovulations, incidence of early postpartum ovulation, heat detection, ovarian cystic structures, embryo loss, and uterine score; the latter was a subjectively assessed on a scale of 1 (little fluid with normal uterine tone) to 4 (large quantity of fluid with a flaccid uterine tone). Variance (and covariance) components were estimated using repeatability animal linear mixed models. Heritability for all reproductive traits were generally low (0.001-0.05), with the exception of traits related to cyclicity postpartum, regardless if defined traditionally (0.07; calving to first service) or from ultrasound examination [resumed cyclicity at the time of examination (0.07) or early postpartum ovulation (0.10)]. The genetic correlations among the detailed reproductive traits were generally favorable. The exception was the genetic correlation (0.29) between resumed cyclicity and uterine score; superior genetic merit for cyclicity postpartum was associated with inferior uterine score. Superior genetic merit for most traditional reproductive traits was associated with superior genetic merit for resumed cyclicity (genetic correlations ranged from -0.59 to -0.36 and from 0.56 to 0.70) and uterine score (genetic correlations ranged from -0.47 to 0.32 and from 0.25 to 0.52). Genetic predisposition to an increased incidence of embryo loss was associated with both an inferior uterine score (0.24) and inferior genetic merit for traditional reproductive traits (genetic correlations ranged from -0.52 to -0.42 and from 0.33 to 0.80). The results from the present study indicate that selection based on traditional reproductive traits, such as calving interval or days open, resulted in improved genetic merit of all the detailed reproductive traits evaluated in this study. Additionally, greater accuracy of selection for calving interval is expected for a relatively small progeny group size when detailed reproductive traits are included in a multitrait genetic evaluation.

Factors associated with the differential in actual gestational age and gestational age predicted from transrectal ultrasonography in pregnant dairy cows

The objective of the study was to determine (1) how gestational age predicted using transrectal ultrasonography related to actual gestational age derived as the number of days from the most recent artificial insemination date, (2) what factors, if any, were associated with the differential between the two measures, and (3) the association between this differential in gestational age and the likelihood of subsequent pregnancy loss, stillbirth, or calving dystocia. The data set contained 7340 ultrasound records from 6805 Holstein Friesian dairy cows in 175 herds. Ultrasonography assessment underestimated gestational age relative to days since last service by 0.51 days (standard error [SE]: 0.040), although the differential was less during embryonic development phase (i.e., ≤42 days of gestation; mean overestimation of 0.31 days) versus fetal development phase (i.e., >42 days of gestation; mean underestimation of 0.81 days). Predicted calving date calculated from ultrasonography was 1.41 days (SE: 0.040) later than the actual subsequent calving date and was, on average, 0.52 days later than predicted calving date, assuming a gestation length of 282 days. Parity of the dam (P < 0.05), stage of pregnancy (P < 0.001), and sex of the calf born (P < 0.001) were all associated with the differential in gestational age based on ultrasonography versus days since last service. No obvious trend among parities was evident in the difference between the methods in predicting gestational age. Ultrasonography underestimated gestational age by 0.83 (SE: 0.15) days in parity 5+ cows and underestimated gestational age by 0.41 (SE: 0.14) days in the first-parity cows. Relative to gestational age predicted from the most recent service, ultrasonography underestimated gestational age by 0.75 (SE: 0.13) days for heifer fetuses and underestimated gestational age by 0.36 (SE: 0.13) days for bull fetuses. The heritability of the differential in gestational age between the methods of prediction was low 0.05 (SE: 0.022), corroborating heritability estimates for most cow reproductive traits. Overestimation of gestational age using ultrasonography was associated with an increased likelihood of pregnancy loss (P < 0.001). Gender of calf born (P < 0.001), sire breed of calf (P < 0.001), and parity (P < 0.001) were all associated with gestation length. Gestation length was 1.27 days longer (SE: 0.01) for bull calves compared to heifer calves. Calves from beef sires had a longer gestation length than calves from dairy sires, and older parity cows had a longer gestation length than younger cows. The results highlight factors associated with differences in gestational age obtained from ultrasonography and insemination data and illustrate the value of ultrasonography for the prediction of calving date and pregnancy loss.

Phase I/II study of neoadjuvant bevacizumab, erlotinib and 5-fluorouracil with concurrent external beam radiation therapy in locally advanced rectal cancer

BACKGROUND

To determine the maximal tolerated dose of erlotinib when added to 5-fluorouracil (5-FU) chemoradiation and bevacizumab and safety and efficacy of this combination in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

Patients with Magnetic resonance imaging (MRI) or ultrasound defined T3 or T4 adenocarcinoma of the rectum and without evidence of metastatic disease were enrolled. Patients received infusional 5-FU 225 mg/M2/day continuously, along with bevacizumab 5 mg/kg days 14, 1, 15 and 29. Standard radiotherapy was administered to 50.4 Gy in 28 fractions. Erlotinib started at a dose of 50 mg orally daily and advanced by 50 mg increments in the subsequent cohort. Open total mesorectal excision was carried out 6-9 weeks following the completion of chemoradiation.

RESULTS

Thirty-two patients received one of three dose levels of erlotinib. Erlotinib dose level of 100 mg was determined to be the maximally tolerated dose. Thirty-one patients underwent resection of the primary tumor, one refused resection. Twenty-seven patients completed study therapy, all of whom underwent resection. At least one grade 3-4 toxicity occurred in 46.9% of patients. Grade 3-4 diarrhea occurred in 18.8%. The pathologic complete response (pCR) for all patients completing study therapy was 33%. With a median follow-up of 2.9 years, there are no documented local recurrences. Disease-free survival at 3 years is 75.5% (confidence interval: 55.1-87.6%).

CONCLUSIONS

Erlotinib added to infusional 5-FU, bevacizumab and radiation in patients with locally advanced rectal cancer is relatively well tolerated and associated with an encouraging pCR.

Phase II study of gemcitabine, oxaliplatin in combination with panitumumab in KRAS wild-type unresectable or metastatic biliary tract and gallbladder cancer

BACKGROUND

Current data suggest that platinum-based combination therapy is the standard first-line treatment for biliary tract cancer. EGFR inhibition has proven beneficial across a number of gastrointestinal malignancies; and has shown specific advantages among KRAS wild-type genetic subtypes of colon cancer. We report the combination of panitumumab with gemcitabine (GEM) and oxaliplatin (OX) as first-line therapy for KRAS wild-type biliary tract cancer.

METHODS

Patients with histologically confirmed, previously untreated, unresectable or metastatic KRAS wild-type biliary tract or gallbladder adenocarcinoma with ECOG performance status 0-2 were treated with panitumumab 6 mg kg(-1), GEM 1000 mg m(-2) (10 mg m(-2) min(-1)) and OX 85 mg m(-2) on days 1 and 15 of each 28-day cycle. The primary objective was to determine the objective response rate by RECIST criteria v.1.1. Secondary objectives were to evaluate toxicity, progression-free survival (PFS), and overall survival.

RESULTS

Thirty-one patients received at least one cycle of treatment across three institutions, 28 had measurable disease. Response rate was 45% and disease control rate was 90%. Median PFS was 10.6 months (95% CI 5-24 months) and median overall survival 20.3 months (95% CI 9-25 months). The most common grade 3/4 adverse events were anaemia 26%, leukopenia 23%, fatigue 23%, neuropathy 16% and rash 10%.

CONCLUSIONS

The combination of gemcitabine, oxaliplatin and panitumumab in KRAS wild type metastatic biliary tract cancer showed encouraging efficacy, additional efforts of genetic stratification and targeted therapy is warranted in biliary tract cancer.

A multi-institutional, phase II open-label study of ganitumab (AMG 479) in advanced carcinoid and pancreatic neuroendocrine tumors

The IGF pathway has been implicated in the regulation of neuroendocrine tumor (NET) growth, and preliminary studies suggested that ganitumab (AMG 479), a human MAB against IGF1R, may have antitumor activity in this setting. We performed a two-cohort phase II study of ganitumab in patients with metastatic progressive carcinoid or pancreatic NETs (pNETs). This open-label study enrolled patients (≥18 years) with metastatic low- and intermediate-grade carcinoid or pNETs. Inclusion criteria included evidence of progressive disease (by Response Evaluation Criteria in Solid Tumors (RECIST)) within 12 months of enrollment, ECOG PS 0-2, and fasting blood sugar <160  mg/dl. Prior treatments were allowed and concurrent somatostatin analog therapy was permitted. The primary endpoint was objective response. Secondary endpoints included overall survival (OS), progression-free survival (PFS), and safety. Sixty patients (30 carcinoid and 30 pNETs) were treated with ganitumab 18  mg/kg every 3 weeks, among whom 54 patients were evaluable for survival and 53 patients for response. There were no objective responders by RECIST. The median PFS duration was 6.3 months (95% CI, 4.2-12.6) for the entire cohort; 10.5 months for carcinoid patients, and 4.2 months for pNET patients. The OS rate at 12 months was 66% (95% CI, 52-77%) for the entire cohort. The median OS has not been reached. Grade 3/4 AEs were rare and consisted of hyperglycemia (4%), neutropenia (4%), thrombocytopenia (4%), and infusion reaction (1%). Although well tolerated, treatment with single-agent ganitumab failed to result in significant tumor responses among patients with metastatic well-differentiated carcinoid or pNET.

Sunitinib in combination with gemcitabine for advanced solid tumours: a phase I dose-finding study

BACKGROUND

This phase I, dose-finding study determined the maximum tolerated dose (MTD), safety, and pharmacokinetics of sunitinib plus gemcitabine in patients with advanced solid tumours.

METHODS

Two schedules with sunitinib (25-50 mg per day) and IV gemcitabine (750-1250 mg m(-2)) in escalating doses were studied. First, patients received sunitinib on a 4-weeks-on-2-weeks-off schedule (Schedule 4/2) plus gemcitabine on days 1, 8, 22, and 29. Second, patients received sunitinib on a 2-weeks-on-1-week-off schedule (Schedule 2/1) plus gemcitabine on days 1 and 8. The primary endpoint was determination of MTD and tolerability.

RESULTS

Forty-four patients received the combination (Schedule 4/2, n=8; Schedule 2/1, n=36). With no dose-limiting toxicities (DLTs) at maximum dose levels on Schedule 2/1, MTD was not reached. Grade 4 treatment-related AEs and laboratory abnormalities included cerebrovascular accident, hypertension, and pulmonary embolism (n=1 each), and neutropenia (n=3), thrombocytopenia and increased uric acid (both n=2), and lymphopenia (n=1). There were no clinically significant drug-drug interactions. Antitumor activity occurred across dose levels and tumour types. In poor-risk and/or high-grade renal cell carcinoma patients (n=12), 5 had partial responses and 7 stable disease ≥ 6 weeks.

CONCLUSION

Sunitinib plus gemcitabine on Schedule 2/1 with growth factor support was well tolerated and safely administered at maximum doses of each drug, without significant drug-drug interactions.

Gastric adenocarcinoma treated with radiation with or without epirubicin-based chemotherapy: Evaluation of radiation-induced liver disease

110

Background: Anthracycline chemotherapy has been associated with radiation-induced liver disease (RILD). We sought to compare the incidence of liver toxicity among patients with gastric adenocarcinoma treated with radiotherapy (RT) with or without epirubicin-based chemotherapy.

Methods: We performed a retrospective analysis of 94 patients with gastric adenocarcinoma treated at Massachusetts General Hospital since November 2005 and the Dana-Farber Cancer Institute since August 1998. All patients underwent definitive surgery and RT (median dose 45 Gray) with a minimum follow up of 6 months. Primary endpoints were development of ascites, radiographic liver change and elevations in liver function tests (LFTs), including alkaline phosphatase (ALP), aspartate transaminase (AST) and alanine transaminase (ALT).

Results: In total, 34 patients received epirubicin-based chemotherapy including 9 perioperatively (6 with oxaliplatin and capecitabine [EOX]; 2 with cisplatin and 5-flourouracil [ECF]; 1 with oxaliplatin and 5-flourouracil [EOF]) and 25 postoperatively (2 EOX; 22 ECF; 1 combination). Seven patients were treated with neoadjuvant RT; 87 received adjuvant RT a median of 88 days after surgery (interquartile range 73-108 days). Twenty-one patients developed ascites within 6 months of completing RT, all but one of whom developed peritoneal carcinomatosis or metastatic disease. Among 57 patients that did not develop metastases, maximum elevations in LFTs were similar in patients that received epirubicin-based chemotherapy compared to those who did not (ALP/AST/ALT 150/44/50 vs. 142/41/44, p=0.25/0.36/0.14, respectively), as were rates of radiographic liver change (22% vs. 13%, p=0.44).

Conclusions: Epirubicin-based chemotherapy does not significantly increase the risk of RILD in a recent cohort of patients treated with modern RT techniques and dose-constraints. In this setting, treatment of gastric adenocarcinoma with RT and either pre- or postoperative chemotherapy is well tolerated with low rates of liver toxicities. Development of liver toxicity, particularly ascites, within six months of RT may be a harbinger of metastatic disease.

No significant financial relationships to disclose.

A single-arm trial of panitumumab in cetuximab refractory KRAS wild-type colorectal cancer

428

Background: While FOLFOX or FOLFIRI with bevacizumab are the standard first-line regimens in the treatment of metastatic colorectal cancer, a role for epidermal growth factor receptor inhibitiion in KRAS wild-type colorectal cancer has been established in the second and third line setting. Cetuximab is a chimeric antibody that consists of approximately 30% murine protein, and panitumumab is a fully human monoclonal antibody. Correspondingly, the rates of severe hypersensitivity reactions are somewhat increased with cetuximab (3%) compared to panitumumab (1%). Presently, cetuximab is typically used in combination with irinotecan in the second or third line setting, and panitumumab is occasionally substituted if hypersensitivity occurs. The value of panitumumab as a salvage agent in cetuximab-resistant colorectal cancer is unknown.

Methods: Panitumumab (6 mg/kg every 14 days) was administered to patients with KRAS wild-type metastatic colorectal cancer that had progressed on prior cetuximab. Treatment was continued until disease progression, death, inability to tolerate panitumumab, or study withdrawal. The primary endpoint was response rate (RR). Twenty patients were enrolled in the first stage and, if at least one responded, 12 additional patients were to be enrolled in a second stage. This two-stage design tested the null hypothesis that the RR is less than or equal to 1% versus greater than or equal to 10% with a type I error of 3.6% and 80% power. Blood samples were collected at baseline and prior to cycles 2 and 3 to evaluate for the presence of anti-cetuximab and anti-panitumumab antibodies using the Biacore immunoassay.

Results: 22 patients with ECOG PS 0-2 were treated for a median of two cycles. The best response was stable disease (45%) and the RR was 0%. There were a total of 266 toxicities reported, the majority of which were mild (n = 184, 69%) or moderate (n = 63, 24%) in severity. There were 19 grade 3 and 0 grade 4 toxicities. Median overall survival was 1.9 months. Immunologic data will be reported at the time of presentation.

Conclusions: Panitumumab is not active as salvage therapy for patients with cetuximab-resistant, KRAS wild-type metastatic colorectal cancer.

[Table: see text]

A multicenter phase II trial of single-agent cetuximab in advanced esophageal and gastric adenocarcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) is overexpressed in a significant proportion of esophageal and gastric carcinomas. Although previous studies have examined tyrosine kinase inhibitors of EGFR, there remains limited data regarding the role of EGFR-directed monoclonal antibody therapy in these malignancies. We carried out a multi-institutional phase II study of cetuximab, a monoclonal antibody against EGFR, in patients with unresectable or metastatic esophageal or gastric adenocarcinoma.

PATIENTS AND METHODS

Thirty-five patients with previously treated metastatic esophageal or gastric adenocarcinoma were treated with weekly cetuximab, at an initial dose of 400 mg/m(2) followed by weekly infusions at 250 mg/m(2). Patients were followed for toxicity, treatment response, and survival.

RESULTS

Treatment with cetuximab was well tolerated; no patients were taken off study due to drug-related adverse events. One (3%) partial treatment response was noted. Two (6%) patients had stable disease after 2 months of treatment. Median progression-free survival and overall survival were 1.6 and 3.1 months, respectively.

CONCLUSION

Although well tolerated, cetuximab administered as a single agent had minimal clinical activity in patients with metastatic esophageal and gastric adenocarcinoma. Ongoing studies of EGFR inhibitors in combination with other agents may define a role for these agents in the treatment of esophageal and gastric cancer.

Toxicity and outcomes after chemoradiation for esophageal cancer in patients age 75 or older

Randomized trials of chemoradiation for esophageal cancer have included very few patients age > or = 75. In this retrospective study, we describe the outcomes and toxicity of full-dose chemoradiation in elderly patients with esophageal cancer. Patients, age > or = 75, treated with full-dose chemoradiation for esophageal carcinoma from 2002 to 2008 were retrospectively reviewed. Thirty-four patients were identified with a median age of 79.5 (range 75-89). The median Eastern Cooperative Oncology Group performance status was 1 (range 0-3) and the median Adult Comorbidity Evaluation-27 score was 1 (range 0-3). Twenty-eight patients received definitive and six received neoadjuvant chemoradiation. The median radiation dose delivered was 50.4 Gray (range 3.6-68.4 Gray). Platinum-based chemotherapy was used in 79.4% of patients. Fifty percent of the patients completed all planned radiation therapy (RT) and chemotherapy; 85.3% completed RT. Acute toxicity > or = grade 4 occurred in 38.2% of patients, and 70.6% of the patients required hospitalization, emergency department visit, and/or RT break. Median follow-up was 14.5 months among 7 survivors, and median survival was 12.0 months (95% confidence interval [CI]: 9.7 to 24.1 months). The actuarial overall survival at 2 years was 29.7% (95% CI: 16.6 to 52.6%). There were four treatment-related deaths. The median time to any recurrence was 10.4 months. Nineteen patients had a local and/or distant recurrence. In conclusion, elderly patients experienced substantial morbidity from chemoradiation, and long-term survival was low. Future efforts to improve treatment tolerability in the elderly are needed.

Follicular development during early pregnancy and the estrous cycle of the sow

The objective of this study was to monitor and compare follicle populations and follicular development in pregnant and nonpregnant sows from Day 3 to Day 20 after breeding. Twenty-four sows were paired within parity on the day of artificial insemination and were randomly allocated within pair for insemination with either killed (n=12) or live spermatozoa (n=12). All the sows were artificially inseminated with the pooled ejaculate of the same boar. From Day 3 through Day 20 post estrus, ovarian follicles were scanned daily by ultrasonography. Ultrasound images were recorded on videotape and were retrospectively analyzed. Follicles were mapped to identify the existence of follicular waves. The follicles were then classified as small (< 3 mm), medium (3-5 mm), or large (> or =5 mm). Pregnancy diagnosis was performed on Day 21 by ultrasonography. Pregnant sows maintained a constant proportion of the follicle population in the small, medium and large follicle categories. However, in the nonpregnant sows, the proportion of follicles in the various size categories remained constant until Day 15. Thereafter, the proportion of small follicles decreased (P < 0.05) from Day 15 to 20, and the proportions of medium and large follicles increased (P < 0.05). The predictability of pregnancy status on Day 20 based on follicle populations in any of the 3 follicle categories was low. Moreover, there was no evidence of follicular waves during the estrous cycle or early pregnancy. In conclusion, the proportion of small follicles decreased while medium and large follicle increased from Day 15 through Day 20 of the estrous cycle, but not during a similar stage of pregnancy. This latter finding concurs with follicle recruitment from the pool of small follicles for ovulation following PGF2alpha secretion to induce luteolysis, which reduces progesterone concentrations and thereby allows for the stimulation of the pool of small follicles by gonadotropins.

A phase I/II study of bevacizumab (beva), erlotinib (erl), and 5-fluorouracil (5-FU) with concurrent external beam radiation therapy (RT) in locally advanced rectal cancer (LARC)

4106

Background: The German Rectal Cancer Study Group established neoadjuvant therapy as a standard of care in patients with T3/T4 rectal cancer. Beva, a vascular endothelial growth factor (VEGF) inhibitor with demonstrated activity in colorectal cancer, and erl, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor may both serve as radiation sensitizers. Methods: Twenty one pts with LARC, defined as T3 or T4 disease by MRI or endorectal ultrasound, were enrolled from May 2006-December 2008. Pts had adequate hepatic, renal and hematopoietic function, and an ECOG performance status of ≤2. Treatment consisted of 5-FU 225 mg/M2/day by continuous infusion for the duration of radiation (50.4 Gy). Beva 5 mg/kg was administered on days 1, 15 and 29. The first cohort received erl 50 mg, the second cohort 100 mg, and third cohort 150 mg daily until completion of radiation. Pts underwent surgery 6–9 weeks following the radiation. The primary endpoints were determination of the maximally tolerated dose (MTD) and pathologic complete response (pCR). Secondary endpoints included toxicity (TOX), local control (LC), progression free survival and median survival. A total of 25 pts will be treated at the MTD. Results: Twenty-one pts began study therapy: 2 withdrew consent prior to completing study therapy, and 2 pts were removed prior to completion for clostridium difficile colitis and cardiac ischemia. No dose limiting toxicities were achieved. Erl 100 mg was chosen as the MTD. Two pts have not yet completed study treatment. Fifteen pts have completed study therapy and have undergone surgery, of whom 7 (47%) have demonstrated a pCR. At a median follow-up of 7 months, there have been no local recurrences in patients who completed study therapy. Grade 3–4 treatment related TOX included: lymphopenia 6 (59%), diarrhea 4 (24%), rash 2(12%), cardiac ischemia 1(6%), transaminitis 1(6%), mucositis 1(6%). One pt developed an anastomotic leak. Conclusions: Beva and erl in combination with infusional 5-FU and RT appears to be a highly active preoperative regimen for locally advanced rectal cancer.

[Table: see text]

Phase I study of preoperative (pre-op) short course chemoradiation (CRT) with proton beam therapy (PBT) and capecitabine (cape) for resectable pancreatic ductal adenocarcinoma (PDAC) of the head

e15536

Background: Standard adjuvant 6 week CRT may delay and reduce tolerability of adjuvant gemcitabine-based chemotherapy. We explore the feasibility of a one-week course of pre-op CRT with PBT and cape followed by pancreaticoduodenectomy (PD). Methods: 15 pts with radiographically resectable, biopsy-proven PDAC of the head were enrolled from May 2007- September 2008. Eligibility included no CT involvement of SMA or celiac artery; adequate renal, hepatic and hematopoetic function; and ECOG PS 0/1. Dose level 1 consisted of PBT delivered 3 Gy x 10 Monday to Friday. Pts in subsequent dose levels received 5 Gy x 5 in progressively shortened schedules: level 2 (wk 1 M W F, wk 2 T Th), level 3 (wk 1 M T Th F, wk 2 M), level 4 (wk 1 M-F). Radiation was targeted at pancreatic mass with elective nodal coverage. Pts received Cape 825 mg/m2 BID wk 1 and 2 M-F. PD was performed 1–6 wks after completion of chemotherapy. Results: 15 pts were enrolled on study. 3 pts were treated at each of dose levels 1–3. 6 pts were at dose level 4, which was selected as MTD. No dose limiting toxicities were observed. Gr 3 toxicity was noted in 4 pts (pain-1, GI-1, stent obstruction/infxn- 2). 11 pts underwent resection. Reasons for no resections were: metastatic disease-3 and unresectable tumor- 1. Mean time from last therapy to surgery was 28 d (10–44). Mean post-PD length of stay was 6 days (range 5–10). No unexpected 30-d post-op complications, including leak or infection, were noted in comparison to historical controls. 9/11 resected pts had R0 resection. 9/11 had positive nodes. Mean resected tumor diameter was 2.9 cm (2.2–4.3). Average percentage of fibrosis in tumor mass was 74%. Conclusions: Pre-op CRT with 1 wk of PBT and capecitabine followed by early surgery is feasible. A phase II study is underway.

No significant financial relationships to disclose.

Weekly docetaxel, cisplatin, and irinotecan (TPC): results of a multicenter phase II trial in patients with metastatic esophagogastric cancer

BACKGROUND

Recent studies have examined the addition of docetaxel to fluorouracil and cisplatin in advanced esophagogastric cancer.

PATIENTS AND METHODS

We carried out a phase I dose-escalation study of weekly docetaxel, cisplatin, and irinotecan (TPC), given on days 1 and 8 every 3 weeks, in patients with chemonaive solid tumors. Subsequently, we completed a multiinstitutional phase II study of TPC in patients with previously untreated, metastatic esophagogastric cancer.

RESULTS

Thirty-nine patients were enrolled in the phase I trial; a weekly schedule of TPC was well tolerated. On that basis, docetaxel 30 mg/m(2), cisplatin 25 mg/m(2), and irinotecan 65 mg/m(2) were selected for the phase II trial, where in the first 18 patients irinotecan 65 mg/m(2) caused too much diarrhea and was reduced to 50 mg/m(2). Among 56 eligible patients with previously untreated, metastatic esophagogastric cancer enrolled in the phase II trial, three complete and 27 partial responses were observed (overall response rate=54%), and 15 patients (30%) had stable disease. Median progression-free survival was 7.1 months, and median survival was 11.9 months. At the final irinotecan dose of 50 mg/m(2), grade 3 or higher toxicity included diarrhea (26%), neutropenia (21%), nausea (18%), fatigue (16%), anorexia (13%), and thrombosis/embolism (13%).

CONCLUSIONS

Weekly TPC is an active and well-tolerated regimen for patients with esophagogastric cancer.

Prediction of response to temozolomide (TMZ)-based therapy by loss of MGMT expression in patients with advanced neuroendocrine tumors (NET)

4505

Background: TMZ, an oral alkylating agent, has recently been shown to be active in a subset of patients with NETs. In other tumor types, methyl-guanine methyl transferase (MGMT) expression is associated with TMZ resistance through its ability to remove methyl/alkyl groups from the O6 -position of guanine, thereby preventing TMZ-induced DNA damage. Methods: To better define NET pts who benefit from TMZ, we performed a retrospective analysis of 76 NET pts treated with TMZ-based regimens at 3 institutions, identified using IRB-approved observational and clinical trial databases. Immunohistochemical MGMT expression was measured in a subset of pts with available paraffin-embedded archival tissue specimens in a blinded fashion, utilizing mouse monoclonal antibodies to MGMT. Nuclear MGMT expression was scored as either present or absent in tumor cells and correlated with tumor type and treatment outcome. Results: Of 76 pts, 30 received TMZ/thalidomide and 46 received TMZ/bevacizumab. Both regimens incorporate oral TMZ, administered at a dose of 150 mg/m2 qd for 7d, every other week. 63 pts were enrolled on phase II studies, and 13 pts were treated outside a formal study protocol. Pt characteristics were: M:F=42:34; median age 57.5 (20–75); tumor type carcinoid (38), pancreatic NET (35), paraganglioma/pheochromocytoma (3). PR or CR (as measured by RECIST) was observed in 11/35 (31%) pancreatic NETs and 0/38 carcinoid pts (P<0.001), as well as 1/3 pts with paraganglioma/pheo. In 21 pts with available specimens, complete absence of MGMT expression was observed in 5/8 pancreatic NET and 0/13 carcinoid tumors (P<0.01). In this pt subset, absence of MGMT expression was associated with response to TMZ ( Table 1 ). Conclusions: Treatment with TMZ is associated with radiologic response in approximately one third of pts with pancreatic NET, but not in pts with carcinoid tumors. Absence of MGMT expression appears to define pts with pancreatic NET who achieve significant benefit from TMZ.

[Table: see text]

No significant financial relationships to disclose.

A phase II study of sunitinib in patients with advanced hepatocellular carcinoma

4637

Background: Patients (pts) with advanced hepatocellular carcinoma (HCC) have a poor prognosis. HCC is a highly vascular tumor with increased levels of angiogenic factors including VEGF and VEGFR. Sunitinib is an oral multitargeted receptor tyrosine kinase inhibitor with activity against VEGFR, PDGFR, and c-KIT. We performed a phase II study to evaluate the efficacy and toxicity of sunitinib in advanced HCC. Methods: Eligibility criteria included unresectable or metastatic measurable HCC, 0–1 prior chemotherapy regimens, performance status = 1, CLIP score = 3, and adequate organ functions. Pts were treated with sunitinib at 37.5 mg po qd on a standard 4 weeks on, 2 weeks off regimen (6 weeks/cycle). Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed to assess changes in tumor permeability. Plasma angiogenic markers were assayed by multiplex array. The primary endpoint of the study is progression-free survival (PFS). Results: 19 pts have been enrolled since May 2, 2006: median age = 59 (30–77), M/F = 16/3, ECOG 0/1 = 7/12, CLIP 1/2/3=7/7/5. The treatment was generally well tolerated. Grade 3/4 toxicities included neutropenia (n=4, 21%), lymphopenia (n=3, 16%), SGOT/SGPT (n=3, 16%), fatigue (n=2, 11%), rash (n=2, 11%), and thrombocytopenia (n=2, 11%). One pt had a partial response and 8 pts had stable disease of at least 12 weeks; 8 pts currently remain on study. The median number of treatment cycles received per patient was 2 (range 1–6). The mean tumor permeability (Ktrans) following 2 weeks of sunitinib administration in 13 pts decreased from mean baseline value of 3.77 to 1.06 (an average of 52% decrease). Of the 15 pts analyzed, changes in plasma angiogenic markers from baseline to day 15 following sunitinib treatment were observed as follows: sVEGFR1 remained constant in 15 pts; 8/15 had decreased sVEGFR2 levels; 13/15 and 11/15 pts had increased PlGF and VEGF levels respectively; bFGF levels decreased in 9 and increased in 5 patients. Conclusions: Sunitinib administered in the current dose schedule can be safely given with close monitoring in HCC patients. Preliminary evidence of antitumor activity was observed. Changes in angiogenic parameters on DCE-MRI and in blood markers were seen following sunitinib administration.

[Table: see text]

A phase II study of docetaxel in combination with ZD1839 (gefitinib) in previously treated patients with metastatic pancreatic cancer

15080

Background: The reported activity of docetaxel in pancreatic cancer and high level of EGFR expression in pancreatic carcinomas led us to examine the efficacy of combination docetaxel and gefitinib in patients with metastatic pancreatic cancer. Methods: Eligibility criteria included PS = 1, failed prior adjuvant ot metastatic gemcitabine-containing regimen, = 1 prior regimen for metastatic disease, no prior taxane or EGFR inhibitor, and adequate organ function. Patients received docetaxel 40 mg/m2 intravenously weekly for 2 of every 3 weeks and daily oral gefitinib 250 mg. The primary endpoint was CA19–9 response (>50% decrease in tumor marker CA19–9 levels). Additional endpoints included radiologic response, toxicity, and survival. Results: Fifteen patients received docetaxel and gefitinib between 11/2/04 and 11/26/05. The median age of patients was 60 (46–76), and included 7 women and 8 men. The regimen was generally well tolerated, and there were no unanticipated toxicities. Grade 3 or 4 toxicities included lymphopenia (6 pts), hyperglycemia (3 pts), leucopenia (3 pts), infection (2 pts), fatigue (2 pts), elevated transaminases (2 pts), neutropenia (2 pts), pleural effusion (2 pts), irregular menses (1 pt), anorexia (1 pt), dysphagia/esophagitis (1 pt), diarrhea (1 pt), alkaline phosphatase (1 pt), and sensory neuropathy (1 pt). No treatment-related deaths occurred. No patient experienced a biochemical (CA 19–9) response to treatment. All 15 patients were evaluable for radiologic response, of which 9 experienced stable disease and 6 progressive disease as their best response to therapy. The trial was stopped due to lack of efficacy, in accordance with an early stopping rule incorporated into the trial design. Conclusions: In the doses and schedule used in this trial, the combination of docetaxel and gefitinib does not appear to be active in patients with pancreatic cancer who have failed prior gemcitabine-based chemotherapy.

No significant financial relationships to disclose.

Phase II study of FOLFOX, bevacizumab and erlotinib as first-line therapy for patients with metastatic colorectal cancer

BACKGROUND

Targeting the epidermal growth factor receptor and angiogenesis have proven useful strategies against metastatic colorectal cancer. The benefit of combining inhibitors of both pathways is unknown.

PATIENTS AND METHODS

Patients with previously untreated metastatic colorectal cancer were enrolled in a phase II trial of infusional 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX), bevacizumab and erlotinib. The primary end point was progression-free survival.

RESULTS

Thirty-five patients were enrolled and all came off trial for reasons other than progression; 18 (51%) had protocol-defined adverse events requiring removal, nine (26%) withdrew consent due to toxicity, six pursued surgery or localized therapies and two requested a treatment holiday. Principal toxic effects included rash, neuropathy and diarrhea. Seven patients came off trial before first restaging. By intention-to-treat analysis, one patient had a confirmed complete response, 10 had confirmed partial responses and one had an unconfirmed partial response (response rate = 34%). One patient had progressive disease at time of withdrawal from the trial, thus progression-free survival could not be calculated.

CONCLUSION

The combination of FOLFOX, bevacizumab and erlotinib led to higher than expected early withdrawal due to toxicity, limiting conclusions regarding efficacy. These findings raise concern regarding the tolerability of adding more agents to already complex combination regimens for metastatic colorectal cancer.

Phase II study of cetuximab in patients with unresectable or metastatic hepatocellular carcinoma

14096

Background: Patients with advanced hepatocellular carcinoma (HCC) have a poor prognosis with no established systemic treatment regimen. Epidermal growth factor receptor/human epidermal growth factor receptor 1 (EGFR/HER1) and ligand expression is frequently seen in HCC. Recent studies suggest that erlotinib, an EGFR/HER1 tyrosine kinase inhibitor, may have benefit in stabilizing HCC. We performed a phase II study with cetuximab, a chimeric monoclonal antibody that binds selectively to EGFR, in advanced HCC. Methods: Eligibility criteria include unresectable or metastatic measurable HCC, up to two prior systemic regimens, performance status ≤ 2, CLIP score ≤ 3, and adequate organ functions. The initial dose of cetuximab is 400 mg/m2 intravenously (IV) administered over 120 minutes, followed by weekly infusions at 250 mg/m2 IV over 60 minutes. Each cycle is defined as 6 consecutive weekly treatments. EGFR expression was assayed by immunohistochemistry and trough serum concentrations of cetuximab were determined during the first cycle. The primary endpoint of the study was progression free survival (PFS). Results: The planned 30 patients have been enrolled: median age = 58 (33–82), M/F = 23/7, ECOG 0/1/2 = 16/12/2, CLIP 0/1/2/3=2/9/14/5. No responses were seen. Five patients had stable disease. The median number of cycles on study per patient was 1 (range, 1–3). 16 patients developed progressive disease following one cycle of treatment. Only one patient remains on study. The median PFS and OS were 41 days (95% CI, 36 to 79) and 157 days (95% CI, 112 to not available), respectively. The treatment was generally well tolerated. No treatment related deaths occurred. Treatment related grade 1–2 toxicities included rash (83%), fatigue (47%), hypomagnesemia (27%), nausea (20%), anemia (13%), diarrhea (13%), anorexia (13%), and elevation of SGOT/SGPT (10%). Grade 3 SGOT, hypomagnesemia, and fever without neutropenia were seen in one patient (3%) each. Conclusions: Cetuximab has no activity in HCC in this phase II study. It can be safely given with tolerable toxicity profiles in HCC patients. Updated information on toxicity, efficacy, EGFR expression and pharmacokinetics will be presented at the meeting. Supported by Bristol-Myers Squibb.

[Table: see text]

Phase II study of FOLFOX, bevacizumab and erlotinib as initial therapy for patients with metastatic colorectal cancer (MCRC)

3545

Background: Cytotoxic chemotherapy with targeted therapy against the vascular endothelial growth factor (VEGF) or the epidermal growth factor receptor (EGFR) has become a standard approach in MCRC, though combining VEGF and EGFR inhibition with chemotherapy as initial treatment is not well established. We conducted a phase II study of the combination of infusional 5-fluorouracil (5-FU), leucovorin, oxaliplatin (FOLFOX), bevacizumab, and erlotinib in chemotherapy naïve patients with MCRC. Methods: Eligible patients had measurable MCRC, no prior systemic therapy for MCRC or at least one year since completion of adjuvant therapy (only 5-FU and leucovorin acceptable), performance status 0–1. The regimen consisted of 14-day cycles of FOLFOX started on day 1 (oxaliplatin 85 mg/m2, bolus 5-FU 400 mg/m2, leucovorin 400 mg/m2 and 46-hour infusion 5-FU 2.4 g/m2), day 1 bevacizumab 5 mg/kg and erlotinib 150 mg daily. This isa single stage trial with goal of 35 patients. The primary endpoint was progression-free survival (PFS). Results: Between Jan and Dec 2005, 31 patients have been enrolled with the following characteristics: male/female, 19/12; PS ECOG 0/1, 15/16; median age 58, range 38–81. Of the 28 patients who completed at least 1 cycle, the most common grade 3/4 adverse events include: 8/28 (29%) diarrhea, 8/28 (29%) neutropenia, 5/28 (18%) rash, 4/28 (14%) fatigue, 3/28 (11%) nausea/vomiting, 3/28 (11%) neuropathy. 22/28 (78%) of patients had at least 1 grade 3/4 toxicity. 14/31 patients remain on trial, 13/31 (42%) came off for toxicity or withdrew consent due to treatment-related toxicities, 4 withdrew consent for other reasons. Efficacy data is not available at time of submission but will be more mature by June 2006. Conclusions: The combination of FOLFOX, bevacizumab and erlotinib appears to have moderate toxicity, with ∼40% of patients coming off trial due to side effects. Further characterization of the tolerability profile will be necessary when interpreting the efficacy of the combination. We expect full accrual as well as reasonable point estimates of PFS by June 2006. Supported by: Sanofi-Synthelabo, a member of the Sanofi-Aventis group, Genentech

[Table: see text]

Ecteinascidin-743 (ET-743) for chemotherapy-naive patients with advanced soft tissue sarcomas: multicenter phase II and pharmacokinetic study

PURPOSE

To evaluate the response rate, toxicity profile, and pharmacokinetics of ecteinascidin-743 (ET-743) as first-line therapy in patients with unresectable advanced soft tissue sarcoma (STS).

PATIENTS AND METHODS

Thirty-six patients with STS were enrolled onto the study between September 1999 and August 2000. Patients were treated with 1.5 mg/m2 of ET-743 given as a 24-hour continuous intravenous (IV) infusion every 21 days. Pharmacokinetic sampling was performed in 23 patients.

RESULTS

One complete and five partial responses were achieved in 35 assessable patients for an overall response rate of 17.1% (95% CI, 6.6% to 33.6%). In addition, one patient had a minor response, leading to an overall clinical benefit of 20%. Neutropenia and transaminitis were the main grade 3 to 4 toxicities, which occurred in 33% and 36% of the patients. The estimated 1-year progression-free and overall survival rates were 21% (95% CI, 11% to 41%) and 72% (95% CI, 59% to 88%), respectively. Total body clearance (L/h) was not significantly correlated with body-surface area (r = -0.28; P = .21). Mild hepatic impairment or the extent of prior cytotoxic therapy does not seem to contribute significantly to the high interpatient variability (49%) in the clearance of this drug. Severity of treatment-related toxicity was not correlated with pharmacokinetic variables.

CONCLUSION

ET-743 demonstrates clinical activity as first-line therapy against STS with acceptable toxicity. Additional studies to establish empirical dosing guidelines may be necessary to improve the safety of the drug in patients with varying degrees of hepatic dysfunction and definitively establish the role of ET-743 for patients with these malignancies.

Proteasome Inhibition With Bortezomib (PS-341): A Phase I Study With Pharmacodynamic End Points Using a Day 1 and Day 4 Schedule in a 14-Day Cycle

Purpose

We performed a phase I study of a day (D) 1 and D4 bortezomib administration once every 2 weeks to determine the recommended phase II dose and toxicity profile, and the extent of 20S proteasome inhibition obtained.

Patients and Methods

Patients with solid tumors or lymphomas were treated with bortezomib at 0.25 to 1.9 mg/m2on D1 and D4, every 2 weeks. 20S proteasome levels in blood were assayed at baseline and at 1, 4, and 24 hours postdose in cycle 1.

Results

On this D1 and D4 every 2 weeks' schedule, dose-limiting toxicity (DLT) was evident at the 1.75 and 1.9 mg/m2dose levels, most commonly in patients receiving individual total doses ≥ 3.0 mg. The main DLT was peripheral neuropathy evident at the higher doses and in patients previously exposed to neurotoxic agents. Other DLTs included diarrhea and fatigue; grade 3 thrombocytopenia was also noted. Reversible inhibition of 20S proteasome activity was dose dependent and best fit a total dose (mg) per fraction rather than mg/m2; 70% of baseline activity was inhibited by a dose of 3.0 to 3.5 mg given on D1 and on D4 every other week. Antitumor effects short of confirmed partial responses were observed in patients with melanoma, non–small-cell lung cancer, and renal cell carcinoma.

Conclusion

Bortezomib (PS-341) is a novel antineoplastic agent that is well tolerated at doses not exceeding 3.0 mg (equivalent to 1.75 mg/m2), repeated on D1 and D4 every other week. This dose correlates with 70% inhibition of 20S proteasome activity. DLTs include neuropathy, fatigue, and diarrhea.