Efficacy of recombinant adeno-associated viral vectors serotypes 1, 2, and 5 for the transduction of pancreatic and colon carcinoma cells

BACKGROUND

The development of efficient and specific vector systems remains a central issue in gene therapy. Several different adeno-associated virus (AAV) serotypes have so far been characterized so far which show different tissue tropisms.

MATERIALS AND METHODS

The vectors used here contained AAV2 transgene cassette containing green fluorescent protein (GFP) in AAV1, AAV2, or AAV5 capsids, producing the recombinant pseudotypes rAAV2/1, rAAV2/2, and rAAV2/5. The transduction efficiency of the different pseudotyped AAV vectors was tested in vitro in pancreatic and colon cancer cells lines (HT-29, BXPC3, and Hs766T).

RESULTS

For all three serotypes, the percentage of GFP-positive cells was below 10% at multiplicities of infection (MOI) 100 rAAV vectors when used alone for infection. However, transduction efficiency for rAAV vectors increased dramatically when the cells were co-infected with wild-type adenovirus (wtAd). The percentage of GFP-positive cells ranged from 19.8-65.3% for AAV2/1 and 16.9-70.2% for AAV2/5, respectively. It was highest for rAAV2/2, at 40.9-88.4%. Variation between the cell lines was observed, with BXPC3 scoring the highest transduction rates and HT-29 the lowest.

CONCLUSION

This study indicates that vectors based on distinct AAV serotypes 1, 2, and 5 all transduce pancreatic and colon cell lines poorly when used alone. Co-infection with wtAd increase transduction rates dramatically indicating that slow second-strand synthesis is a reason for the poor transduction efficiency. Due to the poor transduction rates, none of the rAAV serotypes tested here seem to be feasible for the treatment of malignant tumors.

[Analysis of the statistical value of various commercially available stool tests - a comparison of one stool sample in correlation to colonoscopy]

INTRODUCTION

Guajac based fecal occult blood tests have proven to reduce mortality of colorectal cancer - despite their unsatisfactory statistical values. The potential of newer tests is yet inconclusive. We compared two guajac based, four immunochemical and the M2-PK test with colonoscopic and histological results as a reference.

METHODS

In 1128 stool samples of patients undergoing (screening) colonoscopy the mentioned tests were performed.

RESULTS

Positivity rate was 1.9 to 4.1 % for guajac based and immunochemical tests, M2-PK reached 11.6 %. In case of advanced neoplasias, no significant differences in sensitivity (7.3 - 20 %), specifity (96.6 - 98.4 %), positive predictive value (16.7 - 30.6 %) or accuracy (92.9 - 94.0 %) between guajac based and immunochemical tests were encountered. The slightly higher sensitivity of M2-PK (27.3 %) did not reach statistical significance - however the comparatively low specifity (89.2 %) and accuracy (86.2 %) were clearly lower compared to all other tests. Regarding all neoplasia, immunochemical tests performed better than conventional hemoccult, but the difference did not reach statistical significance. In this group, the sensitivity of M2-PK is clearly better, but specifity is clearly inferior to all other tests.

DISCUSSION

Low sensitivity and low predictive values are explained by the study design with single test and low prevalence of neoplasia. Due to small numbers, there is only a trend, but no significant difference between the performance of conventional hemoccult compared with immunochemical and high senstitive guajac tests. Because of its low specificity, M2-PK is not an appropriate screening test for colorectal neoplasia.

Combination of bortezomib, thalidomide, and dexamethasone in the treatment of relapsed, refractory IgD multiple myeloma

The use of the proteasome inhibitor bortezomib has been recently introduced into the treatment of relapsed, refractory multiple myeloma (MM). We here demonstrate a case of a patient with IgD MM who was successfully treated with a combination of bortezomib, thalidomide, and dexamethasone. Relapse of the disease occurred following tandem autologous transplantation and was refractory to a salvage therapy consisting of thalidomide, cyclophosphamide, etoposide, and dexamethasone. While the administration of thalidomide was continued, the addition of bortezomib and dexamethasone led to a complete remission after 2 cycles of therapy. The feasibility of this treatment is supported by a recently reported phase I/II trial that used a lower dose of thalidomide in combination with an equal dose of bortezomib. This is the first report of a patient with IgD MM treated accordingly, suggesting that this entity is highly sensitive to the novel therapy.

Predictive and prognostic value of microsatellite instability in patients with advanced colorectal cancer treated with a fluoropyrimidine and oxaliplatin containing first-line chemotherapy. A report of the AIO Colorectal Study Group

BACKGROUND AND AIMS

Microsatellite instability (MSI) is a potential indicator of prognosis in patients with colorectal cancer (CRC). To date, there are a limited number of studies which investigated its role in advanced CRC. Our study investigated the value of high degree of MSI (MSI-H) in patients treated with 5-FU/oxaliplatin-based chemotherapy which has been done by only one further study recently.

PATIENTS AND METHODS

In this study, we investigated tumour tissues from 108 patients with metastatic CRC who were treated in a prospective, randomised trial comparing two oxaliplatin and 5-FU-based therapy regimens (FUFOX vs. CAPOX) involving a total of 474 patients. We determined the incidence and prognostic value of a high degree of microsatellite instability. The specimens were analysed by PCR corresponding to the National Institute of Health reference panel. In addition, immunostaining of the mismatch repair proteins MLH1, MSH2 and MSH6 was performed.

RESULTS AND FINDINGS

The incidence of MSI-H was 4%. MSI-H was correlated with a lower rate of disease control compared to non-MSI-H patients (p = 0.02). However, there was no correlation between MSI-H and progression-free survival or overall survival.

INTERPRETATION AND CONCLUSION

MSI-H incidence in metastatic CRC was low. Our data suggest that MSI-H may be correlated with a poorer response to a 5-FU/oxaliplatin treatment. This finding needs confirmation in a larger cohort.

The addition of rituximab to front-line therapy with CHOP (R-CHOP) results in a higher response rate and longer time to treatment failure in patients with lymphoplasmacytic lymphoma: results of a randomized trial of the German Low-Grade Lymphoma Study Group (GLSG)

Lymphoplasmacytic lymphoma (LPL) is an indolent lymphoma with moderate sensitivity to conventional chemotherapy. This study investigated whether the addition of rituximab to standard chemotherapy improves treatment outcome in LPL and the subgroup of LPL patients fulfilling the criteria of Waldenstroem's macroglobulinemia (WM). A total of 69 patients with previously untreated LPL were enrolled into the trial; 64 patients were evaluable for treatment outcome. In all, 48 of the 64 LPL patients fulfilled the criteria of WM. Patients were randomly assigned to R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone, n=34) or CHOP (n=30). R-CHOP resulted in significantly higher overall response (OR) rate (94 vs 67%, P=0.0085) in the LPL patients and in the WM subgroup (91 vs 60%, P=0.0188). With a median observation time of 42 months, R-CHOP induced a significantly longer time to treatment failure (TTF) with a median of 63 months for R-CHOP vs 22 months in the CHOP arm in the LPL patients (P=0.0033) and in the WM subgroup (P=0.0241). There was no major difference of treatment-associated toxicity between both treatment groups. These data indicate that the addition of rituximab to front-line chemotherapy improves treatment outcome in patients with LPL or WM.

Comparable safety and response rate with bevacizumab in combination with capecitabine/oxaliplatin (CapOx/Bev) versus capecitabine/irinotecan (CapIri/Bev) in advanced CRC (mCRC): A randomized phase II study of the AIO GI tumor study group

4034

Background: Bevacizumab (Bev) combined with 5-FU/FA and both, irinotecan or oxaliplatin are standard regimens for mCRC. Recently, a phase III trial has demonstrated that infusional 5-FU can be substituted by capecitabine (cape) when combined with oxaliplatin and Bev whereas conflicting data are available for feasibility and efficacy of cape/irinotecan combinations. This randomized phase II trial was to compare safety and efficacy of Bev with either CapOx or CapIri in untreated mCRC. Methods: Eligibility criteria: untreated mCRC pts, ECOG PS <= 2, measurable lesion(s), adequate hematologic and organ function. Primary endpoint was % of pts progression-free after 6 months. Treatment plan: Bev 7.5 mg/kg day (d)1 with either oxaliplatin (130 mg/m2 d1)/cape (1,000 mg/m2 bid d1–14; CapOx/Bev, arm A) or irinotecan (200 mg/m2 d1)/cape (800 mg/m2 bid d 1–14; CapIri/Bev, arm B), all q d22. Arm B doses were 20% lower for both, cape and irinotecan, compared to previous trials reporting an unacceptable toxicity profile (Köhne, ASCO 2005). Treatment was continued until progression or unacceptable toxicity. Results: So far, toxicity data are available on 228 (118/110 pts arm A/B) of total 240 pts. Baseline characteristics (arm A/B): median age 64/65 yrs, male 67%/68%. A total of 684/719 cycles (median 6/6 cycles) have been administered. Most common CTC grade 3/4 toxicities (% of pts): Diarrhea 17.0/15.5, hand-foot-syndrome 5.9/2.7, peripheral neuropathy 15.3/0.0. Specific AE′s such as thrombosis, 3° hypertension and GI perforation occurred in 3.4/4.5%, 3.4/0.9% and 0.9/0.9% of pts, respectively. Among 185 evaluable pts (96/89), tumor control rates (CR+PR+SD) in arm A/B were 81.4%/82.8%, overall response rates (CR+PR) were 49.0%/52.7%. Conclusions: Both regimens, CapOx/Bev and CapIri/Bev, are well tolerated without differences in toxicity (except neuropathy). Interestingly, despite the protocol defined dose reduction of CapIri there is seemingly no difference in efficacy as measured by tumor control and response rate. Meanwhile, the trial has finished accrual and data including PFS rate will be presented at the meeting.

[Table: see text]

[Systemic therapy of colorectal carcinoma]

The therapeutic strategy for colorectal carcinoma is based upon the UICC stage. For stages 0 and I, endoscopic and operative methods are available. For stage II colon cancer, the indication for adjuvant chemotherapy has not been verified. On the other hand, beginning with stage III, the benefit of this therapy for lymph node metastases is undisputed. Although neoaduvant therapy is not indicated for colon cancer, it is standard procedure for rectal carcinoma in this stage. The objective of palliative chemotherapy in UICC stage IV is to extend the quality of life.

Phase III study of capecitabine plus oxaliplatin compared with fluorouracil and leucovorin plus oxaliplatin in metastatic colorectal cancer: a final report of the AIO Colorectal Study Group

PURPOSE

To compare the use of capecitabine plus oxaliplatin (CAPOX) with infusional fluorouracil (FU)/folinic acid plus oxaliplatin (FUFOX) as first-line therapy for patients with metastatic colorectal cancer (MCRC).

PATIENTS AND METHODS

A total of 474 patients with MCRC received either CAPOX (capecitabine 1,000 mg/m2 bid, days 1 to 14 plus oxaliplatin 70 mg/m2 days 1 and 8, repeated every 22 days) ) or FUFOX (oxaliplatin 50 mg/m2 followed by leucovorin 500 mg/m2 plus FU 2,000 mg/m2 as a 22-hour infusion days 1, 8, 15, and 22, repeated every 36 days). The primary end point was progression-free survival (PFS). Secondary end points were response rate (RR), overall survival (OS), time to treatment failure, and toxicity. The study was designed to determine noninferiority for the CAPOX regimen.

RESULTS

Median PFS was 7.1 months in the CAPOX arm and 8.0 months in the FUFOX arm (hazard ratio [HR], 1.17; 95% CI, 0.96 to 1.43; P = .117). Median OS was 16.8 months (CAPOX) and 18.8 months (FUFOX; HR, 1.12; 95% CI, 0.92 to 1.38; P = .26). Overall RRs were 48% for CAPOX (95% CI, 41% to 54%) and 54% for FUFOX (95% CI, 47% to 60%). Both regimens were generally well tolerated, although there was a significantly higher incidence of grade 2/3 hand-foot syndrome (HFS) in the CAPOX arm (P = .028).

CONCLUSION

CAPOX resulted in a slightly inferior efficacy than FUFOX. With respect to PFS, the best estimate of the HR of 1.17 was within the prespecified equivalence range. However, a relevant inferiority cannot be excluded. Both regimens were generally well tolerated but there was a significantly higher rate of grade 2/3 HFS in the CAPOX arm.

A Randomised Phase II Study of Irinotecan in Combination with 5-FU/FA Compared with Irinotecan Alone as Second-Line Treatment of Patients with Metastatic Colorectal Carcinoma

BACKGROUND

We conducted a randomised phase II study to compare irinotecan monotherapy with irinotecan in combination with infusional 5-fluorouracil/folinic acid (5-FU/FA) regarding efficacy and safety of these regimens in second-line therapy after failed fluoropyrimidine therapy in patients with metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

55 patients with mCRC after failure of a first-line therapy were randomised to receive either irinotecan 80 mg/m2 followed by FA 500 mg/m2 and 5-FU 2,000 mg/m2 24 h weekly for 6 weeks, with courses repeated on day 50 (arm A), or irinotecan 125 mg/m2 weekly for 4 weeks, with cycles repeated on day 43 (Arm B).

RESULTS

Both regimens yielded a partial response rate of 11% with identical progression-free survival (3.7 months for both regimens) and similar overall survival (9.5 months for the combination therapy vs. 10.7 months for the monotherapy). Both regimens were very well tolerated, and the combination of irinotecan with 5-FU/FA did not result in increased toxicity.

CONCLUSION

Our study confirms that irinotecan alone or in combination with infusional 5-FU/FA is an effective and safe regimen for CRC patients who failed first-line therapies. However, the role of 5-FU in addition to irinotecan for fluoropyrimidine failures remains unclear. Due to the small sample size, a decision cannot be made which therapy should be preferred, and a significant contribution to the efficacy of single-agent irinotecan is not obvious from this small randomised phase II trial.

Phase I study of the humanised anti-EGFR monoclonal antibody matuzumab (EMD 72000) combined with gemcitabine in advanced pancreatic cancer

The humanised anti-epidermal growth factor receptor (EGFR) monoclonal antibody matuzumab (formerly EMD 72000) is active against pancreatic cancer in preclinical studies. This phase I study assessed the safety and potential benefit of combined treatment with matuzumab and standard-dose gemcitabine. Three groups of chemotherapy-naive advanced pancreatic adenocarcinoma patients (n=17) received escalating doses of matuzumab (400 mg weekly, 800 mg biweekly, or 800 mg weekly) and gemcitabine (1000 mg m-2 weekly in weeks 1-3 of each 4-week cycle). Toxicity, antitumour activity, pharmacokinetic (PK) parameters, and pharmacodynamic (PD) markers in skin biopsies were evaluated. Severe treatment-related toxicities were limited to grade 3 neutropenia (n=3), leucopenia (n=1), and decreased white blood cell count (n=1). Common study drug-related adverse events were skin toxicities (grade 2=6, grade 1=7) and fever (grade 1=4). Matuzumab inhibited phosphorylated EGFR and affected receptor-dependent signalling and transduction; effects were seen even in the lowest-dose group. Pharmacokinetic data were consistent with results of matuzumab monotherapy. Partial response (PR) or stable disease occurred in eight of 12 evaluated patients (66.7%), with three PRs among six evaluated patients in the group receiving 800 mg weekly. Matuzumab in biologically effective doses with standard gemcitabine therapy appears well tolerated. The combination is feasible and may have enhanced activity.

Continuous complete hematological and cytogenetic remission with molecular minimal residual disease 9 years after discontinuation of interferon-alpha in a patient with Philadelphia chromosome-positive chronic myeloid leukemia

Interferon-alpha has been used as standard therapy for patients with Philadelphia-positive chronic myeloid leukemia (CML) for more than 20 years. Recently randomized trials have shown a superiority of the tyrosine kinase inhibitor imatinib in respect to its efficacy to induce complete hematological and cytogenetic remissions and more importantly in overall survival. Although follow-up is much shorter for imatinib than for interferon-alpha, this data changed the treatment algorithms in this disease. At the end of the era of interferon-alpha as a single-drug first-line treatment for most patients we present a case report which exemplifies a rare but exciting property of interferon-alpha in CML: the induction of complete hematological and cytogenetic remissions which can persist over years after discontinuation of the drug. Hence, the enrollment of CML patients in clinical trials which explore a combination treatment of imatinib and interferon-alpha is warranted.

[ASCO-Update 2005--Highlights of the 41st Meeting of the American Society of Clinical Oncology/ASCO 2005]

Currently, the treatment of gastrointestinal cancers is rapidly changing due to the implementation of novel chemotherapeutic agents as well as the introduction of targeted therapies into treatment protocols. The following review provides an overview of the most important clinical trials in esophageal, gastric, colorectal, pancreatic and hepatobiliary cancer that were presented at the annual meeting of the American Society of Clinical Oncology.

[Which role do new therapeutic options play in palliative care of colorectal cancer?]

Therapeutic options in the treatment of metastatic colorectal cancer have recently been expanded by the introduction of two new monoclonal antibodies: bevacizumab and cetuximab. These antibodies were the proof of principle of two exciting new antitumor strategies: antiangiogenesis and inhibition of epidermal growth factor (EGF) receptor. Bevacizumab binds to vascular endothelial growth factor and thus blocks its angiogenic effects. In a randomized phase III trial bevacizumab in combination with irinotecan + 5-fluorouracil/leucovorin (IFL) was compared to chemotherapy alone as first-line treatment. The combination showed a superior response rate, a prolonged progression-free and overall survival. Cetuximab binds to the EGF receptor and thus inhibits its activation by its natural ligand. In a randomized phase II trial irinotecan refractory patients were treated with cetuximab alone or cetuximab plus irinotecan. The combination showed a response rate of 22,5% and a prolonged progression-free survival identifying cetuximab as an important new option for this patient group.