Randomized phase II trial of panitumumab (P), erlotinib (E), and gemcitabine (G) versus erlotinib-gemcitabine in patients with untreated, metastatic pancreatic adenocarcinoma

238

Background: Dual inhibition of the EGFR pathway using erlotinib and the monoclonal antibody panitumumab results in greater antitumor activity in preclinical pancreatic cancer models. A trial evaluating this approach was conducted.

Methods: A safety analysis was initially performed with 6 patients at P 4 mg/kg every two weeks, E 100 mg daily, G 1000 mg/m2 weekly of a 28-day cycle. PGE was well tolerated with a grade 3 fatigue as only dose-limiting toxicity. Patients (pts) were then randomized to either PGE or GE alone. Eligibility included: no prior chemo, ECOG PS 0-1, bilirubin <2x UL, AST <2.5x UL. CT scans every 2 cycles.

Results: 93 pts (46-GE; 47-PGE) were randomized from January to August, 2010. Median age 61 years and 65% male. ECOG PS 0 (51%) and PS 1 (49%). No significant differences in baseline characteristics observed between treatment arms. 81 pts evaluable for AEs; 37 (46%) had a maximum grade 3 (at least possibly related to treatment), and 12 (15%) maximum grade 4 or 5. Treatment arms similar with respect to the overall AEs with exception grade 1-3 acneiform rash, GE (65%) vs. PGE (85%). Commonly occurring grade 4 AEs (at least possibly related) consisted of thrombosis (3 pts) and thrombocytopenia (2 pts). Two grade 5 events occurred in PGE arm—duodenal hemorrhage (possibly related) and pancolitis with multisystem failure (unlikely). An additional PGE pt died 30 days off study (grade 5 CHF, possibly). 54 patients (67%; 31-GE, 23-PGE) ended treatment; 38 (70%) for disease progression (24-GE; 14-PGE). Other reasons for treatment discontinuation: AEs (9; 17%), pt refusal (4; 7%), death on study (2; 4%), other (1). In 81 pts with at least 1 cycle of chemotherapy, the median PFS for GE 2.0 months and 3.3 months for PGE. Accrual for the study was recently completed and overall and 6-month survival data will be presented.

Conclusions: This study involved an initial run-in design to define tolerable doses of dual EGFR inhibitors, PGE, in pancreatic cancer patients. Although preliminary, the randomized phase II portion has been completed and differences between GE and PGE in terms of relevant clinical outcomes, PFS, are observed.

No significant financial relationships to disclose.

The diagnostic conundrum and liver transplantation outcome for combined hepatocellular-cholangiocarcinoma

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare primary liver malignancy with mixed hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) histological features. It is almost impossible to obtain an accurate, preoperative noninvasive diagnosis of cHCC-CC with tumor markers or cross-sectional abdominal imaging due to the mixed histological features. Despite these difficulties, accurate cHCC-CC diagnosis remains an important goal with prognostic significance. In our study, we retrospectively reviewed the tumor markers: AFP and CA 19-9, and cross-sectional liver imaging, in light of liver explant findings, to identify and characterize cHCC-CC features followed by liver transplantation (LT) outcome analysis. The results from this 12 patient cohort failed to identify characteristic features for cHCC-CC. None of the imaging features helped to identify the cHCC-CC tumor and they mimicked either HCC or CC, depending on the degree of glandular differentiation expressed histologically. In our cHCC-CC LT recipients, the 1-, 3- and 5-year cumulative survival probabilities were 79%, 66% and 16%, respectively with a 5-year survival comparable to or better than LT for intrahepatic CC but poorer than LT for HCC following the Milan criteria. Conceivably explained by its cholangiocarcinoma component the LT outcome for this rare and hard to diagnose tumor appears poor.

Phase II trial of bevacizumab, gemcitabine, oxaliplatin in patients with metastatic pancreatic adenocarcinoma

4553

Background: The combinations of gemcitabine and oxaliplatin (GemOx) and bevacizumab and gemcitabine have activity in pancreatic cancer. Based on these observations, the NCCTG initiated a multicenter phase II study to evaluate the combination of an active cytotoxic doublet and a targeted agent to determine whether improvement in 6-month survival in previously untreated patients with metastatic pancreas cancer could be achieved. Methods: Treatment consists of gemcitabine 1000 mg/m2 IV over 100 minutes and bevacizumab 10 mg/kg IV given on day 1, 15; oxaliplatin 100 mg/m2 IV is given on day 2, 16, repeated every 28 days. Eligibility includes: no prior chemotherapy, ECOG PS 0–2, bili< 2x UNL, AST< 5x UNL. Pts with stable full dose anticoagulation are eligible. Bevacizumab specific exclusions include no recent stroke, heart attack, embolus, tumor invasion or significant proteinuria. CT scans are obtained every 2 cycles. Treatment continues until disease progression, severe adverse events (AEs), or patient refusal. Results: Eighty-two patients were enrolled from 7/05 to 2/06. Median age was 63 (range: 32 - 86). 24 of 82 (29%) evaluable pts had a maximum grade ≥ 4 AE (at least possibly related to treatment). Grade 4 events included (% of pts): neutropenia (7%), thrombosis (6%), thrombocytopenia (5%), pneumonitis (2%), ischemia-cerebral (1%), abdominal infection (1%), small intestine perforation (1%), and small bowel leak (1%). Three patients died from grade 5 events (1-gastric perforation, 1-cerebral ischemia, 1-multi-organ failure). 80 patients were evaluable for outcome assessment (excludes 2 ineligible cases). Median follow-up was 10.3 months (range: 6.3 - 14.7) in the 19 patients still alive. 6-month survival was 65.0% (95% CI: 53.5% - 75.3%). Median survival was 8.1 months (95% CI: 6.5 - 9.3) and median TTP was 5.7 months (95% CI: 4.4 - 6.4). The confirmed response rate was 11.3% (95% CI: 5.3 - 20.3%) with 1 complete and 8 partial responses. Conclusions: In this multi-centered, cooperative group study, promising efficacy with this three-drug combination was observed especially in regards to six- month and median survival. The observed adverse events are comparable to historical controls although caution should be exercised in light of the three grade 5 events.

[Table: see text]

NCCTG phase II trial of bevacizumab, gemcitabine, oxaliplatin in patients with metastatic pancreatic adenocarcinoma

4113

Background: The combination of gemcitabine and oxaliplatin (GemOx) is a highly active regimen in pancreatic cancer. A recent study with the biologic agent, bevacizumab, and gemcitabine has also demonstrated significant activity. A phase II study is ongoing to evaluate whether combining an active cytotoxic doublet with an effective targeted agent improves 6-month survival and is tolerable in previously untreated patients (pts) with metastatic pancreas cancer. Methods: Treatment consists of gemcitabine 1000 mg/m2 IV over 100 minutes and bevacizumab 10 mg/kg IV given on day 1 and 15; oxaliplatin 100 mg/m2 IV is given on day 2 and 16. A treatment cycle consists of 28 days. Eligibility includes: no prior chemotherapy, ECOG PS 0–2, bili < 2× UNL, AST < 5× UNL. Pts with stable full-dose anticoagulation are eligible. Bevacizumab specific exclusions include no recent stroke, heart attack, embolus, tumor invasion or significant proteinuria. CT scans are obtained every 2 cycles. Treatment continues until disease progression, toxicity or patient refusal. Results: Sixty-three patients of a planned 75 were enrolled from 7/05 to 1/06; 2 cycles of toxicity data are available on 31 of the first 32 consecutive pts. The overall grade 3+ toxicity rate is 52% (16/31); more specifically, the grade 3 toxicities were 42% (13/31) and the grade 4 rate is 10% (3/31). Grade 3 adverse events are nausea (4), vomiting (4), alk phos (3), dehydration (3), thrombosis (2), leukopenia (2), neutropenia (4), abdominal pain (2), hypokalemia (4), and one each of the following: anorexia, low consciousness, pneumonia, rectal pain, diarrhea, and proctitis. There was one patient death due to cerebral ischemia (grade 5: 1/31 or 3%). Conclusions: Early assessment of toxicity in this trial reveals a reasonably tolerable regimen. Addition of bevacizumab to GemOx appears to have grade 3/4 toxicity rates similar to historical observations (ECOG 6201). Toxicity data for all patients, after at least 2 cycles of treatment, will be presented.

[Table: see text]

PS-341 and gemcitabine in patients with metastatic pancreatic adenocarcinoma: a North Central Cancer Treatment Group (NCCTG) randomized phase II study

BACKGROUND

PS-341 is a proteasome inhibitor with preclinical activity in pancreatic cancer tumor models and synergistic activity with gemcitabine. This randomized phase II study determined the tumor response rate (RR) for PS-341 alone and the 6-month survival and RR for the combination of gemcitabine and PS-341 in patients with metastatic pancreatic adenocarcinoma.

PATIENTS AND METHODS

Patients were randomized to receive 3-week cycles of either arm A: PS-341 1.5 mg/m(2) i.v. bolus (over 3--5 s) on days 1, 4, 8 and 11 or arm B: PS-341 1.0 mg/m(2) (same as arm A otherwise) plus gemcitabine 1,000 mg/m(2) i.v. on days 1 and 8. Patients progressing on arm A were allowed to receive arm B treatment.

RESULTS

Arm A: 42 evaluable patients were enrolled with a confirmed RR of 0% (95% CI 0% to 8%), median survival of 2.5 months (95% CI 2.0-3.3), and median time to progression (TTP) of 1.2 months (95% CI 1.1--1.3). Twelve of 43 evaluable patients (28%) experienced at least one grade 4+ AE. Arm B: 39 evaluable patients yielded a 6-month survival rate of 41% (16/39, 95% CI 29.8% to 67.0%), median survival of 4.8 months (95% CI 2.4--7.4), median TTP of 2.4 months (95% CI 1.5--3.1), and confirmed RR of 10% (4 partial responses/0 complete responses, 95% CI 3% to 24%). Eleven of 43 evaluable patients (26%) experienced at least one grade 4+ AE. One patient had grade 5 hypotension.

CONCLUSION

The use of PS-341 alone or in combination with gemcitabine did not result in an overall survival and RR better than that expected for gemcitabine alone. Based on the lack of efficacy and the toxicity seen in our trial, there does not appear to be a role for PS-341 in pancreatic adenocarcinoma with either of the schedules used in this trial.

Natural killer cell activity depression in peripheral blood and ascites from gastric cancer patients with high TGF-beta 1 expression

Transforming growth factor beta 1 (TGF-beta 1) has been shown to inhibit the function of various types of cells in vitro such as natural killer (NK) cells. However, this activity has not been well characterized in vivo. Therefore, twenty three patients with advanced gastric adenocarcinoma (AGC), with cytologically-proven malignant ascites, were evaluated in this study. We determined whether the NK activities of their lymphocytes from either peripheral blood or ascites were suppressed by tumor cell TGF-beta 1 expression. We also examined whether NK activity was more suppressed in peripheral blood versus in ascites where tumor cell-derived TGF-beta 1 is potentially more locally concentrated. The expression of TGF-beta 1 mRNA was examined in the tumor cells from the ascitic fluid of the AGC patients. The NK activities of lymphocytes in peripheral blood and ascites were measured by the 4-hour 51Cr-release assay. We determined that eleven of twenty three patients had tumor cells expressing high levels of TGF-beta 1 mRNA. The NK activity in these eleven patients was significantly lower than the NK activity in peripheral blood and ascites from twelve patients with low TGF-beta 1 expression. In addition, the NK activity in malignant ascites was significantly lower than the activity in peripheral blood in these high TGF-beta 1-expressing cancer patients (p < 0.05). We also monitored survival time in these advanced gastric cancer patients. However, the patients with high expression of TGF-beta 1 showed a trend towards reduced survival although this was not statistically significant. The data in this study are consistent with observations in the previous experiments that showed inhibitory effects of TGF-beta 1 on NK activities in vitro, we reported the same phenomenon in patients with advanced gastric cancer.