Phase Ib study of talimogene laherparepvec in combination with atezolizumab in patients with triple negative breast cancer and colorectal cancer with liver metastases

BACKGROUND

Talimogene laherparepvec (T-VEC), a first-in-class oncolytic viral immunotherapy, enhances tumor-specific immune activation. T-VEC combined with atezolizumab, which blocks inhibitor T-cell checkpoints, could provide greater benefit than either agent alone. Safety/efficacy of the combination was explored in patients with triple negative breast cancer (TNBC) or colorectal cancer (CRC) with liver metastases.

METHODS

In this phase Ib, multicenter, open-label, parallel cohort study of adults with TNBC or CRC with liver metastases, T-VEC (10⁶ then 10⁸ PFU/ml; ≤4 ml) was administered into hepatic lesions via image-guided injection every 21 (±3) days. Atezolizumab 1200 mg was given on day 1 and every 21 (±3) days thereafter. Treatment continued until patients experienced dose-limiting toxicity (DLT), had complete response, progressive disease, needed alternative anticancer treatment, or withdrew due to an adverse event (AE). The primary endpoint was DLT incidence, and secondary endpoints included efficacy and AEs.

RESULTS

Between 19 March 2018 and 6 November 2020, 11 patients with TNBC were enrolled (safety analysis set: n = 10); between 19 March 2018 and 16 October 2019, 25 patients with CRC were enrolled (safety analysis set: n = 24). For the 5 patients in the TNBC DLT analysis set, no patient had DLT; for the 18 patients in the CRC DLT analysis set, 3 (17%) had DLT, all serious AEs. AEs were reported by 9 (90%) TNBC and 23 (96%) CRC patients, the majority with grade ≥3 [TNBC, 7 (70%); CRC, 13 (54%)], and 1 was fatal [CRC, 1 (4%)]. Evidence of efficacy was limited. Overall response rate was 10% (95% confidence interval 0.3-44.5) for TNBC; one (10%) patient had a partial response. For CRC, no patients had a response; 14 (58%) were unassessable.

CONCLUSIONS

The safety profile reflected known risks with T-VEC including risks of intrahepatic injection; no unexpected safety findings from addition of atezolizumab to T-VEC were observed. Limited evidence of antitumor activity was observed.

A Randomized, Double-Blind, Placebo-Controlled Phase II Study of the Efficacy and Safety of Monotherapy Ontuxizumab (MORAb-004) Plus Best Supportive Care in Patients with Chemorefractory Metastatic Colorectal Cancer

Purpose: The purpose of this study was to evaluate the safety and efficacy of ontuxizumab (MORAb-004), a monoclonal antibody that interferes with endosialin (tumor endothelial marker-1) function, in patients with chemorefractory metastatic colorectal cancer and to identify a responsive patient population based on biomarkers.Experimental Design: This was a randomized, double-blind, placebo-controlled, phase II study. Patients were randomly assigned in a 2:1 ratio to receive weekly intravenous ontuxizumab (8 mg/kg) or placebo plus best supportive care until progression or unacceptable toxicity. Tissue and blood biomarkers were evaluated for their ability to identify a patient population that was responsive to ontuxizumab.Results: A total of 126 patients were enrolled. No significant difference between the ontuxizumab and placebo groups was evident for the primary endpoint of progression-free survival (PFS), with a median PFS of 8.1 weeks in each group (HR, 1.13; 95% confidence interval, 0.76-1.67; P = 0.53). There were no significant differences between groups for overall survival (OS) or overall response rate (ORR). The most common treatment-emergent adverse events (TEAEs) in the ontuxizumab group (vs. the placebo group, respectively) were fatigue (53.7% vs. 47.5%), nausea (39.0% vs. 35.0%), decreased appetite (34.1% vs. 27.5%), and constipation (28.0% vs. 32.5%). The most common grade 3/4 TEAE in the ontuxizumab group versus placebo was back pain (11.0% vs. 0%). No single biomarker clearly identified patients responsive to ontuxizumab.Conclusions: No benefit with ontuxizumab monotherapy compared with placebo for clinical response parameters of PFS, OS, or ORR was demonstrated. Ontuxizumab was well tolerated. Clin Cancer Res; 24(2); 316-25. ©2017 AACR.

Abstract PR08: Antitumor activity and immune correlates of PEGylated human IL-10 (AM0010) alone or in combination with anti-PD-1

Background: The success of and the durability of immune therapy of cancer is thought to depend on the activation and expansion of tumor reactive and infiltrating CD8+ T cells. The response to immune checkpoint blockade, depends on a pre-existing, CD8 T cell-rich tumor microenvironment. IL-10 stimulates the antigen mediated cytotoxicity, survival and proliferation of intra-tumoral CD8+ T cells and simultaneously dampens chronic inflammation. T cell receptor mediated activation of CD8 T cells induces the expression of IL-10 receptors on these cells. IL-10 activates with STAT3 an essential survival and proliferation signal in antigen activated CD8 T cells. This also provides a mechanistic rationale for combining AM0010 and anti-PD1 in the clinic. To evaluate the clinical activity, tolerability and anti-tumor activity of AM0010 alone or in combination with chemotherapy or immune checkpoint inhibitors a multi-basket phase 1 study was conducted. Additional disease specific expansion cohorts for the combination of AM0010 with FOLFOX in pancreatic cancer or with nivolumab in RCC or NSCLC are currently evaluated

Results: Tolerability and anti-tumor activity of AM0010 alone or in combination with chemotherapy or immune checkpoint inhibitors was established in this multi-basket phase 1 study. In monotherapy, objective responses were observed in pts with uveal melanoma, cutaneous T cell lymphoma and in 4 of 15 pts with RCC. Patients with advanced melanoma, RCC or NSCLC were also treated with AM0010 (daily SC) in combination with anti-PD-1 immune checkpoint blockade. Tumor responses were monitored following irRC. Immune responses were measured by analysis of serum cytokines, activation of blood derived T cells, peripheral T cell clonality and immunohistochemistry of tumor infiltrating CD8 T cells. In 19 pts, AMO010 10 μg/kg (n = 13) or 20 μg/kg (n = 6) in combination with anti-PD1 - pembrolizumab (2mg/kg) was well tolerated (observation period 10-15 months). Immune related TrAE occured in the frequency and severity as expected from pembrolizumab montherapy. The combination of AM0010 with pembrolizumab achieved objective responses (PR/CR) in 4 of 8 RCC pts, 2 of 5 NSCLC pts and 2 of 6 melanoma pts. 2 additional melanoma pts had tumor increase followed by decrease (pseudoprogression). Independent of the combination with either chemotherapy or anti-PD-1, AM0010 increased Th1 cytokines (IL-18, IFNγ, IL-7) in a dose dependent fashion. FasL and lymphotoxin beta - products of cytotoxic T cells - were also increased in the serum of AM0010 treated patients. In contrast, mediators of chronic inflammation, such as IL-23 and IL-17 and the immune suppressive cytokine TGFbeta were reduced in the serum of patients. AM0010 increased the number and proliferation of PD1+ activated CD8 T cells while decreasing the proliferation of FoxP3+ Tregs and TGFβ in the blood. AM0010 induced de-novo oligoclonal expansion of T cell clones in the blood of patients without affecting total lymphocyte counts. This clonal expansion appeared enhanced and accelerated in patients treated with a AM0010 anti PD-1 combination, but was also seen in patients which received a AM0010 - chemotherapy combination. AM0010 also increased the number of tumor infiltrating Phospho-STAT3+ CD8 T cells in tumors and the number of Granzyme+ PD1+ CD8+ T cells in tumor biopsies of treated patients.

Conclusion: AM0010 alone or in combination with anti-PD1 is well-tolerated. The clinical activity and the observed CD8 T cell activation encourages the phase 2/3 studies of AM0010 in combination with anti-PD1 planned for later in 2016. Trial registration: www.clinicaltrials.gov NCT02009449.

Citation Format: Aung Naing, Jeffrey R. Infante, Kyriakos P. Papadopoulos, Deborah J. Wong, Karen A. Autio, Gerald S. Falchook, Manish Patel, Shubham Pant, Amita Patnaik, Melinda Whiteside, Johanna C. Bendell, John Mumm, Ivan H. Chan, Gail L. Brown, Peter VanVlasselaer, J. R. Hecht, David S. Hong, Nizar M. Tannir, Martin Oft. Antitumor activity and immune correlates of PEGylated human IL-10 (AM0010) alone or in combination with anti-PD-1 [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr PR08.

Phase II trial of modified FOLFOX6 and erlotinib in patients with metastatic or advanced adenocarcinoma of the oesophagus and gastro-oesophageal junction

BACKGROUND

There is increased recognition that cancers of the upper GI tract comprise distinct epidemiological and molecular entities. Erlotinib has shown activity in patients with adenocarcinoma of the oesophagus/gastro-oesophageal junction (GEJ), but not in distal gastric cancer. mFOLFOX6 is one of several active regimens used to treat adenocarcinoma of the Eso/GEJ. This study evaluates the efficacy and safety of mFOLFOX6 and erlotinib in patients with metastatic or advanced Eso/GEJ cancers.

METHODS

Patients with previously untreated advanced or metastatic Eso/GEJ adenocarcinoma are treated with oxaliplatin 85 mg m(-2), 5-FU 400 mg m(-2), LV 400 mg m(-2) on day 1, 5-FU 2400 mg m(-2) over 48 h and erlotinib 150 mg PO daily. Treatment was repeated every 14 days. The primary objective was response rate (RR), secondary objectives include toxicity, progression-free survival (PFS), overall survival (OS) and to correlate clinical outcome with expression patterns and molecular alterations in the epidermal growth factor receptor-dependent pathways.

RESULTS

A total of 33 patients were treated and evaluable: there were two complete responses, 15 partial responses for an objective RR of 51.5% (95% CI, 34.5-68.6%). Median PFS was 5.5 months (95% CI, 3.1-7.5 months) and median OS was 11.0 months (95% CI, 8.0-17.4 months). The most common grade 3-4 toxicities were: diarrhoea (24%), nausea/vomiting (11%), skin rash (8%) and peripheral neuropathy (8%). The frequency of alterations was KRAS mutations (8%), EGFR mutations (0%) and HER2 amplification (19%).

CONCLUSION

In patients with Eso/GEJ adenocarcinoma, mFOLFOX6 and erlotinib is active, has an acceptable toxicity profile and FOLFOX ± erlotinib could be considered for further development.

Pooled safety results from SPIRITT: A multicenter, open-label, randomized, phase II study of FOLFIRI with panitumumab (pmab) or bevacizumab (bev) as second-line treatment (tx) in patients (pts) with metastatic colorectal cancer (mCRC)

477

Background: Pmab is a fully human monoclonal antibody against the epidermal growth factor receptor (EGFR) approved as monotherapy in pts with chemorefractory mCRC. Many pts with mCRC who have progressed on a bev-containing regimen receive second-line bev + chemotherapy despite the lack of prospective, randomized data supporting this approach. A phase III study recently showed that pmab + second-line FOLFIRI improved progression-free survival (PFS) in pts with wild-type (WT) KRAS tumors vs chemotherapy alone. This study was amended after enrollment began to focus hypothesis testing on the WT KRAS population and is evaluating the safety and efficacy of pmab + FOLFIRI vs bev + FOLFIRI in pts who received first-line therapy with an oxaliplatin-based regimen + bev.

Methods: This is a randomized, phase II, open-label study in pts with mCRC with disease progression or intolerability after ≥ 4 doses of first-line oxaliplatin-based chemotherapy + bev. Pts are randomized 1:1 to receive either 6 mg/kg pmab Q2W + FOLFIRI or bev (given at institutional standard dose Q2W) + FOLFIRI. Tx is administered until disease progression (PD), death, or withdrawal from study. The primary endpoint is PFS in patients with WT KRAS tumors. Other endpoints include objective response rate, overall survival, safety, and patient-reported outcomes.

Results: At the time of data cutoff, 216 of 277 planned pts were enrolled. 175 (81%) pts discontinued study tx and 39 (18%) pts remain on tx. Any grade adverse events (AEs) were reported in 197 (92%) pts. 38 (18%) pts had AEs that led to withdrawal from tx or study. Serious AEs were reported in 66 (31%) pts and included gastrointestinal disorders (13%), infections and infestations (8%), respiratory disorders (7%), and metabolism and nutrition disorders (7%). Fatal AEs were reported in 18 (8%) pts of which 9 (4%) were related to disease progression.

Conclusions: The aggregate safety profile is consistent with expected toxicities of FOLFIRI in combination with an anti-EGFR or an anti-VEGF targeted therapy in second-line mCRC. Detailed pooled safety results will be presented at the meeting.

[Table: see text]

Progression-free survival in intention to treat populations versus total KRAS populations in patients treated for metastatic colorectal cancer: A pooled review

4054

Background: In treatment trials of patients with metastatic colorectal cancer (mCRC), KRAS mutation status of tumor samples has been retrospectively demonstrated to be predictive of treatment benefit. Historically, clinical trials have not required tissue samples to be tested for KRAS mutation status as a condition of enrollment. Therefore, KRAS analyses have been based on available tissue samples representing only a portion of patients retrospectively analyzed for KRAS status and correlated with treatment end- points. Methods: A weighted analysis of pooled data was performed using six recently presented or published clinical trials of targeted therapy in mCRC which tested for the association of KRAS status with Progression Free Survival (PFS). The goal of the analysis was to determine whether there is a significant difference in PFS between the intention to treat (ITT) population and KRAS population in both the treatment and control arms. Results: The total ITT population of the pooled studies is 3864, and for the total KRAS population, 2295; a 59.4% retrieval rate (range 28–92%) for tissue samples available for KRAS analysis. The weighted Δ PFS across all arms between the ITT population and the KRAS population was 0.2 months with a range of 0–0.7 months. Of the 12 subgroups (6 control and 6 treatment arms), five had no difference in PFS between ITT and KRAS evaluable populations at all, and two additional subgroups demonstrated a difference PFS of only 0.1 months. The two studies with the lowest tissue retrieval rates (28% and 45%) had the largest Δ PFS. Conclusions: There is no meaningful difference in the PFS between the ITT and KRAS populations based on our analysis of pooled data. The difference in PFS was greatest in the two studies with the lowest rate of retrieval of tissue samples for KRAS testing. As such, subgroup analysis is better able to estimate and reflect the ITT population if a higher percentage of samples is able to be obtained. Further, our results suggest that there is not an inherent systemic bias influencing any potentially observed differences in PFS. Tissue samples should be required for all patients entering a clinical trial to avoid this issue and to make retrospective analysis more valid.

[Table: see text]

Pegfilgrastim in colorectal cancer (CRC) patients (pts) receiving every-two-week (Q2W) chemotherapy (CT): Long-term results from a phase II, randomized, controlled study

4072

Background: Survival in advanced CRC is prolonged by adding oxaliplatin (Ox) and/or irinotecan (Iri) to Q2W 5-fluorouracil/leucovorin (5FU/LV). Combination therapy, however, has a higher incidence of febrile neutropenia (FN) and related toxicities. This study evaluated pegfilgrastim dosing on day 4 of Q2W regimens in CRC. Here we present long-term follow-up of these pts. Methods: Advanced CRC pts were randomized (1:1) to pegfilgrastim 6mg or placebo, which was stratified by CT regimen received: FOIL, FOLFOX, or FOLFIRI. We previously reported grade 3/4 neutropenia (primary endpoint) in 43% placebo and 13% pegfilgrastim pts in the 4-cycle treatment phase (odds ratio = 0.19, 95% CI: 0.10–0.37; p < 0.0001). After end of treatment, pts were followed long term for ≤ 2 years (inclusive of ≤ 8 additional cycles) for serious adverse events (SAEs), overall survival (OS), and progression-free survival (PFS). Median follow-up time was 519 days. Kaplan-Meier methods estimated OS and PFS from study day 1. The study was not powered to detect PFS or OS differences between treatment groups. Results: Of 241 pts analyzed (123 pegfilgrastim, 118 placebo), 49% received FOLFOX, 26% FOLFIRI, and 25% FOIL. In the treatment period, 8% placebo and 2% pegfilgrastim pts had grade 3/4 FN ( Table ). Pegfilgrastim was well tolerated with no dose delays attributed to leukocytosis. Pegfilgrastim and placebo had similar PFS and OS ( Table ). No SAEs related to study drug were reported in the follow-up period. Conclusions: In this randomized, placebo-controlled study, pegfilgrastim significantly lowered neutropenic risk. Bone pain incidence in this CRC population was lower than in breast cancer pts treated with a taxane (Vogel J Clin Oncol 2005); the incidence in pegfilgrastim pts was modestly increased over placebo. Leukocytosis was not a concern despite the 11-day dosing interval. Long-term results suggest similar PFS and OS in the pegfilgrastim and placebo pts in this CRC study.

[Table: see text]

[Table: see text]

Panitumumab activity in metastatic colorectal cancer (mCRC) patients (pts) with low or negative tumor epidermal growth factor receptor (EGFr) levels: An updated analysis

4082

Background: Panitumumab, a fully human monoclonal antibody against EGFr, is approved for EGFr-expressing mCRC pts with disease progression (PD) on or after fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy. However, the predictive value of EGFr tumor-membrane staining as measured by immunohistochemistry (IHC) is undetermined. Methods: This multicenter, single arm, phase 2 study enrolled pts with documented PD during or after fluoropyrimidine and adequate doses of irinotecan and oxaliplatin, and within 6 months after the most recent chemotherapy regimen (determined by an independent eligibility review committee [IERC]), 2–3 prior regimens, and low (1%-9%) or negative (<1%) EGFr tumor membrane staining (by IHC). Pts received panitumumab 6mg/kg Q2W until PD or intolerability. Tumor assessments (modified WHO, blinded central review) were performed every 8 weeks until PD or discontinuation. Endpoints were objective response rate (ORR) through wk 16 (+ =4 wk confirmation; primary), overall ORR, response duration, progression-free survival (PFS), and safety (secondary). Results: In this interim analysis, 91 pts had =20 wks of potential follow-up and comprised the IERC efficacy set; 118 pts comprised the evaluable safety set (=20 wks potential follow-up). In the IERC efficacy set, 57% were male, 86% were white, and median age (range) was 61 (26–85) years. ORR through week 16 is shown; overall ORR was the same ( Table ). The most common adverse events (all, grade 3/4) were dermatitis acneiform (72%, 6%), erythema (69%, 6%), pruritus (65%, 4%), and hypomagnesaemia by lab values (53%, 10%). Four pts (3%) had an infusion reaction per investigator (1 was grade 3). Conclusions: This analysis confirms earlier findings that panitumumab has anti-tumor activity in pts with low or undetectable EGFr tumor membrane levels as measured by IHC. This study has completed enrollment, and updated data will be presented.

[Table: see text]

No significant financial relationships to disclose.

Predictive value of skin toxicity severity for response to panitumumab in patients with metastatic colorectal cancer (mCRC): A pooled analysis of five clinical trials

4134

Background: Panitumumab, a fully human monoclonal antibody against the epidermal growth factor receptor (EGFr), is approved for EGFr-expressing mCRC patients (pts) with disease progression (PD) on or following fluoropyrimidine (5FU)-, oxaliplatin (Ox)-, and irinotecan (Ir)-containing chemotherapy. Skin toxicities are common with panitumumab; we examined the association between severity of skin toxicity and panitumumab efficacy. Methods: Data from 5 clinical trials were pooled (4 phase II studies and 1 phase III study). Pts with mCRC had documented PD on or after 5FU, Ox, and/or Ir. Pts received panitumumab 6 mg/kg every two weeks (Q2W) or 2.5 mg/kg weekly (QW) until PD or intolerability. Tumors were assessed using modified WHO or RECIST criteria (blinded central review in 4/5 studies). Endpoints included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). PFS and OS were measured from enrollment. Only pts with =2 infusions (exposure over 2 wks for QW dosing or over 4 weeks for Q2W dosing) were analyzed to help correct for lead-time bias. Results: 612 of 640 pts were included in the analysis set (62% were male, 92% were white, and median age [range] was 61 [21, 88] years). The median (95% CI) duration of PFS was 8.4 weeks (8.0 to 11.3), the median (95% CI) survival was 6.9 months (6.2 to 7.9), and the ORR (95% CI) was 9.0% (6.8 to 11.5). The most common skin toxicities (any grade, grade 3/4) were erythema (54%, 4%) pruritus (53%, 2%), dermatitis acneiform (52%, 5%), and rash (39%, 2%). ORR, PFS, and OS appeared to favor pts with grade 2–4 skin toxicity vs pts with grade 0- 1 skin toxicity ( table ). Conclusion: In this large combined analysis, severity of skin rash was correlated with increased efficacy of panitumumab in terms of ORR, PFS, and OS.

[Table: see text]

No significant financial relationships to disclose.

Final results of CONFIRM 2: A multinational, randomized, double-blind, phase III study in 2nd line patients (pts) with metastatic colorectal cancer (mCRC) receiving FOLFOX4 and PTK787/ZK 222584 (PTK/ZK) or placebo

4033

Background: PTK/ZK, a novel, oral, anti-angiogenic compound that inhibits all VEGF receptors has been investigated in two multinational randomized phase 3 studies in 1st (CONFIRM 1) and 2nd line (CONFIRM 2) mCRC. Interim analyses (IA) have been presented at ASCO 2005 and 2006, respectively. Methods: In CONFIRM 2, 855 pts were randomized to FOLFOX4 plus PTK/ZK (1250 mg, qd), or placebo. Eligibility included histologically documented mCRC, pre-treatment for metastatic disease with irinotecan-/fluoropyrimidine- based therapy, measurable disease by RECIST, PS of 0–2 and adequate organ function. Pts were stratified based on PS (0 vs. 1–2) and baseline serum Lactate Dehydrogenase (LDH = vs. >1.5 × ULN). The primary endpoint is overall survival (OS). Secondary endpoints included OS and PFS in high LDH pts (LDH > 1.5 × ULN). Results: At the time of IA in July 2005, OS was 12.1 mo in the PTK/ZK and 11.8 mo in the placebo arm (HR: 0.94; p=0.511). PFS was significantly longer in the PTK/ZK arm (5.5 mo vs. 4.1 mo; HR: 0.83; p=0.026). LDH, a marker for poor prognosis in mCRC, is predictive of the outcome in the PTK/ZK arm. When treated with PTK/ZK, high LDH pts showed a strong improvement in PFS (5.6 mo vs. 3.8 mo; HR: 0.63; p<0.001) and in OS (9.6 mo vs. 7.5 mo; HR: 0.78; p=0.10). Adverse events (AE) were similar to that of the CONFIRM 1 trial. Final analysis for OS, PFS and safety is planned for Feb. 2007 after 732 events (compared to 413 in the IA) and will be presented at the meeting. Conclusions: While the primary endpoint for OS was not met in the IA, PTK/ZK improves PFS significantly in the overall population, and shows strong activity (improved PFS and OS) in patients with high baseline serum LDH. Final results of the study will be presented at the meeting.

No significant financial relationships to disclose.

Safety of panitumumab, a fully human monoclonal antibody against the epidermal growth factor receptor (EGFr), in patients (pts) with metastatic colorectal cancer (mCRC) across clinical trials

4138

Background: Panitumumab is indicated in pts with EGFr-expressing mCRC refractory to chemotherapy. We present a summary of safety with panitumumab monotherapy in mCRC pts across 10 clinical trials. Methods: Data were pooled from pts enrolled in 10 clinical trials (including 2 extension studies). Pts received at least 1 dose of panitumumab at 2.5 mg/kg QW, 6 mg/kg Q2W, or 9 mg/kg Q3W. Adverse events were graded using NCI-CTC or CTCAE criteria. Results: A total of 920 mCRC pts were included in this analysis: 60% were male; 88% were white; median age (range) was 61 (20, 88) years. All pts had prior therapy; 77% had failed prior fluoropyrimidine, irinotecan, and/or oxaliplatin. Most (80%) pts received panitumumab 6 mg/kg Q2W; 17% and 3% of pts received panitumumab 2.5 mg/kg QW and 9 mg/kg Q3W, respectively. Median (range) follow-up time was 21 (1–124) weeks. A total of 7264 panitumumab infusions were administered with a median (range) of 5 (1–94) infusions/pt. Treatment-related adverse events (AE) were experienced by 94% (grade = 3, 20%) of pts. All pts had = 1 AE. The most common AEs were skin-related and GI toxicities ( table ). Skin-related AEs resulted in discontinuation in 2% of pts. Overall, 12% of pts discontinued panitumumab due to toxicity. Four (0.4%) pts had grade = 3 infusion reactions. In pts with postdose samples (n = 613), increased and persistent postdose levels of anti-panitumumab antibodies were detected in 0.5% of pts by ELISA and in 4.6% of pts by Biacore assay. Conclusions: Skin toxicity was common, but rarely treatment-limiting. Most AEs were mild to moderate and infrequently resulted in discontinuation. Infusion reactions and formation of anti-panitumumab antibodies were rare. The safety profile of 9 mg/kg Q3W panitumumab appeared consistent with other dosages; however, because of the small pt size further evaluation is needed. Panitumumab at 2.5 mg/kg QW and 6 mg/kg Q2W was well tolerated across 10 clinical studies.

[Table: see text]

No significant financial relationships to disclose.

Panitumumab antitumor activity in patients (pts) with metastatic colorectal cancer (mCRC) expressing ≥ 10% epidermal growth factor receptor (EGFr)

3548

Background: Panitumumab is a fully human monoclonal antibody directed against EGFr. We investigated panitumumab antitumor activity in pts who failed prior therapy and had EGFr tumor expression levels ≥ 10%. Methods: In this multicenter, phase 2 study of 300 planned pts, pts had documentation of disease progression (PD) during or following adequate doses of fluoropyrimidine, irinotecan, and oxaliplatin (centrally confirmed refractory disease [CCRD]), 2–3 prior regimens, ECOG score 0–2, and EGFr staining (by IHC) in ≥ 10% of evaluable tumor cells. Pts received panitumumab at 6 mg/kg Q2W until PD. Tumor assessments (modified WHO, blinded central review) were taken periodically from wk 8–48 until PD. Study endpoints were objective response rate (ORR) at wk 16 (+ ≥ 4 wk confirmation; primary) and ORR throughout study, response duration, progression-free survival (PFS) time, survival time, and safety (secondary). Results: In this interim analysis (5/05), 91 enrolled pts received ≥ 1 dose of panitumumab (safety set); 39 had ≥ 20 wks before the cutoff and CCRD (efficacy set). The efficacy set consisted of 23M/16W, mean (SD) age of 58.6 (10.1) years, 82% white, 95% ECOG ≤ 1, 74% colon cancer and 26% rectal cancer; all had ≥ 2 prior regimens (equivalent characteristics for safety set). At wk 16, 3 (8%) had a partial response, 8 (21%) had stable disease, and 19 (49%) had PD as best OR (9 not done/unevaluable). At the time of this interim analysis, response durations were 12.4, 13.2, and 14.0 wks. In the safety set, 96% had at least 1 treatment-related adverse event (24% grade [gr] 3, 1% gr 4, 1% gr 5). Integument and eye toxicities were: 96% skin, 30% nail, 8% eye, 5% hair, and 7% chelitis. 25 (27%) had diarrhea (3 gr 3); 11 (12%) had hypomagnesemia (3 gr 3/4). One pt had a gr 3 hypersensitivity reaction considered related to panitumumab, received medication, and the event resolved; this pt continued treatment with premedication; no further reactions occurred. In 66 pts with both a baseline and postdose sample, no human anti-human antibodies to panitumumab were detected.Additional data will be presented. Conclusions: Panitumumab has antitumor activity and is well tolerated in pts with EGFr tumor expression levels ≥ 10% who failed standard chemotherapy.

[Table: see text]

The PACT trial: Interim results of a randomized trial of TNFerade biologic plus chemoradiation (CRT) compared to CRT alone in locally advanced pancreatic cancer (LAPC)

4102

Background: TNFerade is a second-generation replication-deficient adenovector, carrying the transgene encoding human TNF-α, regulated by the stress-inducible promoter Egr-1. In a phase I trial of TNFerade + radiation in 36 patients with advanced or refractory solid tumors, a 47% objective tumor response rate was observed, including 100% complete responses in 3 stage 4 melanoma patients, with 2/3 disease-free at >3.5 years. Methods: This controlled phase II trial randomizes 74 patients with newly diagnosed unresectable LAPC to 5-wks of TNFerade (4 × 1011 pu via weekly intratumoral injection) + CRT (5-FU [200 mg/m2/day CIV × 5 days/wk] and 50.4 Gy radiation) or CRT alone. All patients receive maintenance gemcitabine. Endpoints: Progression-free survival, safety, radiographic tumor response, CA 19–9 and survival. Results: In dose escalation (n=50) dose-limiting toxicities occurred in 3 patients at 1 × 1012 pu (pancreatitis in 2 and biliary obstruction), setting the MTD at 4 × 1011 pu. Compared with the first two cohorts (n=30), the MTD (n = 11) was associated with greater locoregional control and progression-free survival, a higher rate of stable or decreasing CA 19–9, improved overall survival (median = 11.2), and a high (45%) resection rate. Accrual continues in the randomized phase of the study at 20+ centers. The most frequent adverse events in the first 16 enrolled patients have been nausea (75%), abdominal pain (63%), constipation (50%), anemia (38%), diarrhea (38%), vomiting (38%), and weight loss (38%), with no significant difference in severity or frequency between the TNFerade + CRT and CRT groups. No thromboembolic events have been reported. Serum TNF-alpha levels have remained low (peak = 45.3 pg/mL, in a CRT patient). CA 19–9 has been stable (no change > 100 U/mL) or decreased in all but one CRT patient. Conclusions: These initial data indicate that TNFerade plus CRT, given as weekly intratumoral injections to patients with LAPC, is feasible and tolerable compared to CRT alone. With continued accrual, comparative tumor response and toxicity data will be available and updated.

No significant financial relationships to disclose.

Low-dose trimetrexate glucuronate and protracted 5-fluorouracil infusion in previously untreated patients with advanced pancreatic cancer

BACKGROUND

5-Fluorouracil (5-FU)-based regimens have not been shown to prolong survival or provide clinical benefit in patients with advanced pancreatic cancer. The purpose of this study was to determine the tolerability of protracted venous infusion (PVI) of 5-FU, modulated by a low dose of the synthetic antifolate trimetrexate, in patients with advanced pancreatic cancer.

PATIENTS AND METHODS

Twenty-three chemotherapy-naïve patients were evaluated. Patients were enrolled in four consecutive cohorts in which the weekly dose of trimetrexate was escalated in 10 mg/m2 increments, from 20 to 50 mg/m2. PVI 5-FU was administered at a fixed dose of 225 mg/m2/day. Treatment was administered for 6 successive weeks, every 8 weeks.

RESULTS

Twenty-two patients were assessable. The maximum tolerated dose of trimetrexate was 40 mg/m2. The most common grade 3 and 4 toxicity was diarrhea. There were no treatment-related deaths. Preliminary analysis of activity revealed a response rate of 9%, with 41% of the patients having stable disease for a median duration of 3.8 months. The median survival for the entire group was 6.9 months (range 1-29 months). A clinical benefit response was experienced by 27.2% of patients.

CONCLUSIONS

Low-dose trimetrexate can be safely administered in combination with PVI 5-FU. This treatment is well tolerated and is associated with palliative activity in advanced pancreatic cancer.

Adjuvant therapy for gastric cancer: a reality at last

Gastric cancer remains a significant healthcare problem throughout the world and is usually diagnosed at a fairly advanced stage in the West. Despite complete resection of the primary tumor, most patients eventually experience a relapse and die of recurrent disease. Extended surgery has not been shown to improve survival in Western studies. There have been a large number of adjuvant chemotherapy trials over the past several decades, most with negative results. More recently, there is hope for improving these dismal results with a meta-analysis showing a benefit for adjuvant chemotherapy and a large randomized trial, INT-0116, which has just reported a significant survival advantage with combined chemoradiation. These results make adjuvant therapy for completely resected gastric carcinoma the new standard of care, except in the uncommon setting of early intramucosal cancers.

CT colonography: value of scanning in both the supine and prone positions

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of CT colonography when patients were imaged in both the supine and prone positions. We evaluated whether imaging in two positions decreased the number of collapsed colonic segments and increased sensitivity for polyp detection.

MATERIALS AND METHODS

Twenty-three patients underwent CT colonography in both the supine and prone positions. Colonic distention for each of the 46 scans was graded. Adequacy of distention for either position alone was compared with that of the combination of the two positions. Polyp data revealed by colonoscopy were reviewed, and the CT data were then retrospectively reviewed for polyp detection.

RESULTS

When each scan was considered alone without benefit of the scan obtained in the opposite position, 27 (58.7%) of 46 scans showed inadequate distention. When scans obtained in both positions were considered together, 20 (87.0%) of 23 patients had adequate distention with the grading system used. However, this value increased to 23 (100%) of 23 patients when the reasons for inadequate distention in the three patients were considered. Of the 27 polyps detected with colonoscopy, 21 (77.8%) were also detected retrospectively with CT colonography. Colonoscopy showed 20 polyps that were 5 mm or larger; nineteen (95.0%) of these 20 polyps were also detected retrospectively with CT colonography, nine (47.4%) of which were seen in only one position.

CONCLUSION

Use of both the supine and prone positions for patients undergoing CT colonography improves evaluation of the colon and increases sensitivity for polyp detection.

Metastasis in colorectal cancer: what makes the tumor aggressive?

While local control of colorectal cancer can usually be obtained, distant spread is frequent and nearly always results in incurable disease and death. Therefore, the critical determinant of aggressiveness of colorectal cancers is the ability to disseminate widely. While the molecular biology of colorectal carcinogenesis is comparatively well understood, the mechanisms important in metastasis remain relatively cryptic. Conceptually, metastasis is a multistep process with a number of potential therapeutic targets. Critical steps include angiogenesis, local invasion, embolization to distant sites, and extravasation. Identification of high risk tumors may allow more judicious use of effective, but nonselective, cytotoxic adjuvant therapy. Specific inhibitors of particular steps of metastasis are already in various stages of testing.

Immunohistochemical evaluation of K-ras, p53, and HER-2/neu expression in hyperplastic, dysplastic, and carcinomatous lesions of the pancreas: evidence for multistep carcinogenesis

The pathobiology of precursor lesions leading to invasive pancreatic adenocarcinoma remains a controversial area, but knowledge of the mechanisms of tumorigenesis may lead to possibly earlier detection, prevention, and treatment in the future. We hypothesize that ductal hyperplasia and dysplasia of the pancreas represent precursor lesions and are part of a continuous developmental spectrum evolving into ductal adenocarcinoma of the pancreas. To further define this sequence, we studied the immunohistochemical markers HER-2/neu, K-ras, and p53 in 15 adenocarcinomas and 15 nonmalignant specimens of the pancreas. The 15 nonmalignant specimens of the pancreas included both normal pancreas and chronic pancreatitis. Overall, HER-2/neu was positive in normal ducts, ductal hyperplasia, dysplasia, and carcinoma cells in 0 of 30, 11 of 20 (55%), 10 of 15 (67%), and 12 of 15 (80%), respectively, with progressive increase in the intensity of staining; p53 was positive in 1 of 30 (3%), 0 of 20, 3 of 15 (20%), and 13 of 15 (80%), respectively, and K-ras was positive in 1 of 30 (3%), 6 of 20 (30%), 11 of 15 (73%), and 8 of 15% (53%), respectively. These data support the hypothesis that ductal hyperplasia and dysplasia of the pancreas represent precursor lesions, and, in a fashion similar to that in colorectal tumorigenesis, pancreatic cancer seems to accumulate progressive genetic alterations.

Gastrointestinal toxicity or irinotecan

Irinotecan (CPT-11 [Camptosar]) is an important new chemotherapeutic drug that demonstrates activity against a broad spectrum of malignancies, including carcinomas of the colon, stomach, and lung. Unfortunately, frequent and often severe gastrointestinal toxicities, particularly diarrhea, have limited its more widespread use. A cholinergic syndrome resulting from the inhibition of acetylcholinesterase activity by irinotecan is frequently seen within the first 24 hours after irinotecan administration but is easily controlled with atropine. Late diarrhea occurs in the majority of patients, however, and is National Cancer Institute (NCI) grade 3 or 4 in up to 40%. The late syndrome appears to be related to the effects on the bowel of SN-38, the active metabolite of irinotecan, which undergoes biliary excretion and inactivation. Early recognition and treatment of late diarrhea with high-dose loperamide have reduced, although not entirely eliminated, patient morbidity. Further study is needed to identify the mechanism of irinotecan-induced late diarrhea and to evaluate potential new therapies.

Gastrin-releasing peptide-induced expression of prostaglandin synthase-2 in Swiss 3T3 cells

Prostaglandins, produced in response to mitogens and cytokines, are potent modulators of gastrointestinal physiology and pathophysiology. We investigated modulation of Prostaglandin synthase 2 (PGS-2) expression by the gastrin-releasing peptide (GRP) receptor in Swiss 3T3 cells. PGS-2 mRNA expression in Swiss 3T3 cells was determined by Northern blot analysis. PGS-2 protein expression in Swiss 3T3 cells was measured by Western blot analysis. GRP caused a transient induction of PGS-2 mRNA in Swiss 3T3 cells that resulted in GRP-dependent expression of PGS-2 protein. Transcriptional activation of PGS-2 by GRP was independent of de novo protein synthesis and was not affected by pertussis toxin. Comparison of signaling pathways used by PMA or EGF to those used by GRP showed that PGS-2 induction by GRP increased under conditions that inhibit PKC activity. Dexamethasone, which blocks PMA and EGF induction of PGS-2, also inhibited GRP-induced accumulation of PGS-2 mRNA. These results show that PGS-2 expression in Swiss 3T3 cells is not only controlled by PKC and receptor tyrosine kinase pathways but also by G-protein coupled receptor signaling pathways.

Prolonged nausea and vomiting after high dose chemotherapy and autologous peripheral stem cell transplantation in the treatment of high risk breast carcinoma

BACKGROUND

Nausea and vomiting immediately after chemotherapy is a well recognized complication of cancer drug treatment; it is usually short-lived and controllable by modem antiemetics. The authors report a high incidence of prolonged nausea and vomiting after high dose chemotherapy with autologous peripheral stem cell transplantation (PSCT) in the treatment of high risk breast carcinoma patients.

METHODS

Patients with high risk breast carcinoma were conditioned with high dose carmustine, cisplatin, and cyclophosphamide followed by autologous PSCT. In Part I of the study, patients who received PSCT at UCLA Medical Center were identified if they were either readmitted with dehydration secondary to nausea and vomiting or referred to a gastroenterology specialist for the treatment of intractable nausea and vomiting. In Part II of the study, the authors examined a series of 38 women treated at UCLA Medical Center in 1993 for high risk breast carcinoma to determine the incidence of prolonged postchemotherapy nausea and vomiting (PPNV) after PSCT. These women were followed at 2-week intervals with a quality of life evaluation that included questions about nausea and vomiting.

RESULTS

In Part I of the study, the authors identified 9 women with more than 1 month of significant nausea and vomiting after PSCT without evidence of obstruction or mucositis. Hospitalization was frequently required for hydration. Gastroparesis was found in all four patients who underwent gastric emptying studies. The nausea and vomiting responded to the promotility drug cisapride and high dose corticosteroids. In Part II of the study, the authors found that PPNV was frequent; 24% of patients had significant nausea and 18% had significant vomiting 6 weeks after PSCT, despite treatment with standard antiemetics.

CONCLUSIONS

PPNV is a frequent complication of high dose chemotherapy with the aforementioned regimen. It may be due to gastroparesis and represents a form of gastrointestinal toxicity to chemotherapy not previously reported.

Polymerase chain reaction-based K-ras mutation detection of pancreatic adenocarcinoma in routine cytology smears

The cytologic diagnosis of pancreatic carcinoma is notoriously difficult, particularly in distinguishing benign atypia from well-differentiated adenocarcinoma. Mutation of codon 12 in the K-ras oncogene is frequently found with pancreatic cancers. Detection by polymerase chain reaction (PCR) followed by restriction endonuclease digestion can provide a powerful tool to improve and confirm diagnosis. The authors examined the utility of PCR-based detection in the diagnosis of pancreatic carcinoma using routinely obtained cytology smears that could be collected at most hospitals. Pancreatic cytology smears were collected retrospectively from 60 patients. DNA was extracted from the slides and amplified by PCR using mismatched primers that generated a Bst-N1 recognition site with the wild type codon 12 but not with the mutant allele. Results were compared with clinical follow-up. K-ras codon 12 mutations were observed in 44 of 46 (95.7%) cases of pancreatic cancer, but not in 12 benign cases nor in 2 cases of islet cell tumor. The amplification and digestion steps proved robust and sensitive, capable of detecting mutant K-ras alleles from cytology smears that contained only small foci of suspicious cells. Our results indicate that K-ras mutation analysis can be done reliably within 1 to 2 days from routine cytology slides without special handling, increasing the sensitivity of diagnosis in ambiguous cases while maintaining cost-effective and relatively noninvasive sampling strategy.

Dietary fat and colon cancer

Dietary fat in general, and perhaps animal and polyunsaturated fats in particular, appear to increase colon carcinogenesis in animal models and epidemiologic studies. This observation holds the potential to shed light on the underlying mechanisms of colorectal carcinogenesis and reduce morbidity and mortality from the disease by dietary and chemoprevention. While research continues into the relationship between prostglandins and other putative mediators of the effects of fats on the colon, we can suggest that a diet which protects against colorectal cancer would be low in fat with most of that fat coming from vegetable sources. Prospective dietary trials are ongoing which may strengthen or modify these preliminary recommendations.

Male breast cancer

Breast cancer in men is a rare condition affecting only 1,000 men each year in the United States. Hormonal, genetic, and perhaps environmental factors appear to be important in development of the disease. Clinically, breast cancer in men resembles that seen in woman. Histologically the diseases are indistinguishable, although lobular cancer is rare in men. Tumors from men are more likely to be estrogen-receptor positive. Treatment strategies draw from experience in women and usually begin with surgical removal of the tumor. Additional modalities often include hormonal, radiation, and cytotoxic therapies. The prognosis corrected for age and stage is similar to that of women. The study of breast cancer in men may provide new insights into epidemiologic and pathogenic factors that affect both sexes.

Clostridium difficile colitis secondary to intravenous vancomycin

Nearly every known antibiotic has been implicated as a cause of Clostridium difficile colitis. We report the first case resulting from monotherapy with intravenous vancomycin. The patient was on chronic hemodialysis and was treated with intravenous vancomycin for presumed cervical osteomyelitis. After 29 days of therapy he developed abdominal pain and diarrhea and his stool was found to contain both C. difficile and cytotoxin. The patient responded with symptomatic and microbiological recovery to withdrawal of the drug and treatment with oral metronidazole. The prolonged elevation of serum vancomycin levels in patients with renal failure may predispose them to the development of C. difficile colitis.