Faculty Bibliography

Overexpression of antiapoptotic members of the Bcl-2 family are observed in approximately 80% of B-cell lymphomas, contributing to intrinsic and acquired drug resistance. Nullifying antiapoptotic function can potentially overcome this in-trinsic and acquired drug resistance. AT-101 is a BH3 mimetic known to be a potent inhibitor of antiapoptotic Bcl-2 family members including Bcl-2, Bcl-X(L), and Mcl-1. In vitro, AT-101 exhibits concentration- and time-dependent cytotoxicity against lymphoma and multiple myeloma cell lines, enhancing the activity of cytotoxic agents. The IC(50) for AT-101 is between 1 and 10 microM for a diverse panel of B-cell lymphomas. AT-101 was synergistic with carfilzomib (C), etoposide (E), doxorubicin (D), and 4-hydroxycyclophosphamide (4-HC) in mantle cell lymphoma (MCL) lines. In a transformed large B-cell lymphoma line (RL), AT-101 was synergistic when sequentially combined with 4-HC, but not when both drugs were added simultaneously. AT-101 also induced potent mitochondrial membrane depolarization (Delta Psi m) and apoptosis when combined with carfilzomib, but not with bortezomib in MCL. In severe combined immunodeficient (SCID) beige mouse models of drug-resistant B-cell lymphoma, 35 mg/kg per day of AT-101 was safe and efficacious. The addition of AT-101 to cyclophosphamide (Cy) and rituximab (R) in a schedule-dependent manner enhanced the efficacy of the conventional therapy

Recent advances in understanding the complex biology of the ubiquitin-proteasome pathway have led to the identification of many potentially 'drugable' targets within this pathway. One such inhibitor, bortezomib (formerly known as PS341), has proven to be an effective reversible inhibitor of the chymotryptic protease in the 26S proteasome. Proteasome inhibitors represent a new approach for the treatment of many forms of cancer, especially select hematological malignancies. The proteasome plays an important role in regulating the availability of different intracellular proteins. While only some of the consequences of inhibiting this activity are understood, a growing amount of data suggests that inhibition of the proteasome is associated with a remarkable panoply of different biological effects that include cell cycle arrest, apoptosis, changes in cell surface adhesion markers, and an increased sensitivity to standard chemotherapy and radiation therapy. Bortezomib was recently approved by the US FDA for the treatment of relapsed or refractory multiple myeloma. In addition, bortezomib has also shown encouraging results in the treatment of select types of non-Hodgkin lymphomas (NHLs). Ongoing phase II clinical trials in pretreated patients are exploring bortezomib in different histologies of NHLs and in combination with conventional chemotherapy. Preliminary data have shown interesting activity, especially in patients with follicular, marginal zone, and mantle cell lymphoma; in these populations, durable complete and partial remissions have been reported. The toxicity profile of this drug, coupled with its unusual mechanism of action, make it a potentially important agent warranting further preclinical and clinical attention. However, many unanswered questions remain regarding how best to employ bortezomib in the conventional treatment of lymphoma. The apparent lack of activity in different subtypes of lymphoma, such as small lymphocytic lymphoma/chronic lymphocytic leukemia and diffuse large B-cell lymphoma, as well as a lack of understanding about the best way to combine bortezomib with standard therapies for indolent NHLs, raises important questions regarding the mechanistic basis for its effects. We will undoubtedly need to understand these effects better in order to fully exploit the potential of this new class of drugs

Although the overall cure rate for advanced germ cell tumor (GCT) is high, the prognosis for patients with cisplatin-refractory GCT remains poor. Gemcitabine, paclitaxel, and oxaliplatin have shown significant activity as single agents in these patients. We investigated the activity and tolerance of a weekly gemcitabine, paclitaxel, oxaliplatin chemotherapy regimen. From September 2000 to February 2002, 9 patients with cisplatin-refractory GCT were treated with gemcitabine 800 mg/m2, paclitaxel 70 mg/m2, and oxaliplatin 50 mg/m2, days 1, 8, and 15, every 4 weeks. Only 1 patient stayed on schedule. In 7 patients, chemotherapy treatment was modified due to grade 3-4 hematological toxicity, whereas in another patient, who received high-dose chemotherapy 2 months before, chemotherapy was administered biweekly. In total, 21 cycles were administered with a median of 2 cycles for each patient. One patient achieved a partial remission lasting 5 months, 1 had disease stabilization for 5 months, whereas 7 had progressive disease. This chemotherapy regimen was not feasible in our patient population. Recently, oxaliplatin at full doses, but not as weekly administration, has appeared to possess activity in cisplatin-refractory GCT. Thus, we plan a phase II study protocol of the oxaliplatin and gemcitabine combination at full doses every 3 weeks.

The uridine diphosphate glucuronosyltransferase (UGT) 1A1 and 1A9 isoforms are involved in the phase II biotransformation of the irinotecan metabolite, SN-38. Recently, several variants in the UGT1A1 and UGT1A9 genes have been described with altered functionality in vitro. The aim of this study was to evaluate the functional consequence of the UGT1A1(TA)(7)TAA (UGT1A1(*)28), UGT1A9 766G>A (D256N; UGT1A9(*)5), and UGT1A9 98T>C (M33T; UGT1A9(*)3) variants in Caucasian patients treated with irinotecan. Pharmacokinetic studies were performed after the first course of irinotecan in 47 males and 47 females. The mean (SD) area under the curves (AUCs) of irinotecan and SN-38 were 20,348 +/- 6466 ng x h/mL and 629 +/- 370 ng x h/mL, respectively, which is in line with earlier findings. For UGT1A9(*)5,novariant alleles were observed, whereas for UGT1A9(*)3, 1 patient with the variant allele was found (allele frequency, 0.633%). The distribution of the UGT1A1(*)28 variant showed 44 wild-type patients (Wt), 37 heterozygotes (Het), and 5 homozygotes (Var). The median AUC ratio of SN-38G to SN-38 was significantly reduced in carriers of the variant UGT1A1(*)28 allele (7.00 [Wt] vs. 6.26 [Het] vs. 2.51 [Var]; p =.022). It is concluded that UGT1A9 functional variants are rare in Caucasians and likely to be clinically insignificant in irinotecan regimens. Screening for the UGT1A1(*)28 polymorphism may identify patients with altered SN-38 pharmacokinetics.

Radiation-induced acute and late injuries often represent a limit to the optimal delivery of radiotherapy in cancer patients. Chung et al. reported that histone deacetylase (HDAC) inhibitors, a novel class compound of gene modulators, might have a role in controlling different adverse effects from radiotherapy in preclinical models. They also showed how protection of normal tissues and inhibition of tumor growth might be possible at the same time.

BACKGROUND: Recent studies have shown a good activity/tolerability for weekly paclitaxel and 5-fluorouracil in protracted continuous infusion (p.c.i.) in metastatic breast cancer patients pretreated with anthracyclines. MATERIALS AND METHODS: To define the MTD of weekly paclitaxel (days 1-8-15-22, every 4 weeks with a starting dose of 75 mg/m2 and subsequent dose escalation: 90 mg/m2 and 105 mg/m2) in combination with a fixed dose of 5-fluorouracil in p.c.i. (250 mg/m2/day for 3 weeks + 1 week of rest). RESULTS: Eleven patients were enrolled; on Step III two patients experienced DLT (1 G 3 mucositis and 1 febrile neutropenia). G 3-4 toxicities were: G 3 mucositis (2 out of 11), G 3-4 neutropenia (1 out of 11). CONCLUSION: The recommended schedule for phase II studies is: paclitaxel 90 mg/m2/w + 5-fluorouracil 250 mg/m2 in p.c.i. for 21 days. This is the first phase I trial with the combination of weekly paclitaxel and 5-fluorouracil p.c.i. in advanced breast cancer patients.

BACKGROUND: Oxaliplatin, a new DACH-platinum compound, has provided high response rates both in untreated and 5-FU-resistant patients. AIM: To define the feasibility and toxicity profile of Oxaliplatin administered as a continuous hepatic aterial infusion. PATIENTS AND METHODS: Seventeen patients with pretreated metastatic liver colorectal cancer were treated with Oxaliplatin 20 mg/m2/day by HACI x 5 days every 3 weeks. RESULTS: Toxicity grade 3 included pain (4 out of 17), asthenia (1 out of 17) and nausea (1 out of 17). Abdominal pain grade 4 (WHO) was noted in only one patient. Overall, severe abdominal pain (main dose-limiting toxicity) was observed in 41% of patients and no chemical hepatitis and sclerosing cholangitis pain-related was proven by an endoscopic retrograde cholangiography. The response rate was not a primary end-point; nonetheless among 15 evaluable patients we observed partial responses (PR) in 7 patients (46%) and stable disease (SD) in 21% of cases for an overall tumor growth control of 67%. Progression to disease (PD) was 33%. Following chemotherapy, one patient underwent surgical removal of residual metastases, with curative intent. The 1-year survival rate was 64%. The median duration of survival was 19 months. The median delay to hepatic progression was 10 months. CONCLUSION: Further studies are required to define the role of HACI Oxaliplatin, the schedule of administration (bolus vs continuous infusion) and the combination, also in this setting, with fluoropyrimidines.

OBJECTIVE: The objectives of this phase I/II study were to define the maximum tolerated dose (MTD), safety, and activity of cisplatin, etoposide, and gemcitabine (PEG) in the treatment of previously untreated patients with small-cell lung cancer (SCLC). PATIENTS AND METHODS: Chemonaive patients received fixed doses of gemcitabine (1000 mg/m(2) on days 1 and 8) and cisplatin (70 mg/m(2) on day 2) and escalating doses of etoposide (starting dose of 50 mg/m(2) on days 3, 4, and 5) every 3 weeks. No prophylactic granulocyte colony-stimulating factors were used. RESULTS: From September 1998 to April 2000, 56 patients with limited- or extensive-stage SCLC were enrolled and received a total of 235 cycles. Two different etoposide doses were tested in eight patients. At the second level (75 mg/m(2)), two out of two patients experienced dose-limiting toxicities (neutropenia and thrombocytopenia) and no further dose-escalation was attempted, thus an etoposide dose of 50 mg/m(2) was defined as the MTD. In the subsequent phase II evaluation, 48 additional patients were enrolled, for a total of 54 patients treated at the MTD. Grade 3/4 neutropenia and thrombocytopenia occurred in 66.7 and 53.7% of patients, respectively. Non-hematologic toxicity was mild, with grade 3 diarrhea and fatigue as the main side effects. Two patients died of neutropenic sepsis (one at 75 mg/m(2) and the other at 50 mg/m(2) etoposide). Ten complete and 29 partial responses were reported, for an overall response rate of 72.2% (95% confidence interval, 56.6-85.0%). The median duration of response and median survival were 8.0 and 10 months, respectively, with a 1-year survival probability of 37.5%. CONCLUSIONS: The combination of PEG is feasible and well tolerated as front-line chemotherapy in SCLC. A randomized comparison of this triplet is underway.