Sunitinib: bridging present and future cancer treatment.

Tyrosine kinase receptors (RTKs) are a heterogeneous group of transmembrane proteins involved in signal transduction. These receptors are expressed in many different cells and regulate cellular growth, differentiation and angiogenesis. Overexpression and/or the structural alteration of different RTKs classes are generally associated to cancer and, when RTKs-mediated signal transduction pathways are abnormally activated, generate cancer growth, angiogenesis and metastatization. Therapeutic intervention targeting RTKs concerns antagonist drugs as little molecules or monoclonal antibodies. Sunitinib malate is a little molecule able to block intracellular tyrosine kinase domain of RTKs, which has both direct anticancer and antiangiogenetic activity. Sunitinib targets selectively vascular endothelial growth factor, KIT, Flt3 and platelet-derived growth factor receptors and the receptor encoded by the ret proto-oncogene. This drug is used in the treatment of gastrointestinal stromal cancer (GIST) resistant to imatinib and metastatic renal cell carcinoma (RCC). In this review, we report preclinical data of sunitinib, even about synergism with chemotherapy and radiotherapy, data relative to phase III trials of sunitinib in the treatment of GIST and RCC, and we try to plan what will be future applications of sunitinib in different types of cancer, even in association to chemotherapy, radiotherapy and monoclonal antibodies.

Circadian optimisation of irinotecan and oxaliplatin efficacy in mice with Glasgow osteosarcoma.

The relevance of circadian rhythms in irinotecan and oxaliplatin tolerability was investigated with regard to antitumour activity. Mice bearing Glasgow osteosarcoma (GOS) received single agent irinotecan (50 or 60 mg kg(-1) per day) or oxaliplatin (4 or 5.25 mg kg(-1) per day) at one of six dosing times expressed in hours after light onset (3, 7, 11, 15, 19 or 23 hours after light onset). Irinotecan (50 mg kg(-1) per day) and oxaliplatin (4 or 5.25 mg kg(-1) per day) were given 1 min apart at 7 or 15 hours after light onset, or at their respective times of best tolerability (7 hours after light onset for irinotecan and 15 hours after light onset for oxaliplatin) or worst tolerability (15 hours after light onset for irinotecan and 7 hours after light onset for oxaliplatin). Tumour growth rate was nearly halved and per cent increase in estimated life span (% ILS) was - doubled in the mice receiving irinotecan at 7 hours after light onset as compared to 15 hours after light onset (P<0.05). Results of similar magnitude were obtained with oxaliplatin for both endpoints, yet with 7 hours after light onset corresponding to least efficacy and 15 hours after light onset to best efficacy (P<0.05). Irinotecan addition to oxaliplatin proved therapeutic benefit only if the schedule consisted of irinotecan administration at 7 hours after light onset and oxaliplatin delivery at 15 hours after light onset, i.e. when both drugs were given near their respective "best" circadian times. These would correspond to the middle of the night for irinotecan and the middle of the day for oxaliplatin in humans.

Experimental chronotherapy of mouse mammary adenocarcinoma MA13/C with docetaxel and doxorubicin as single agents and in combination.

The therapeutic index of docetaxel, doxorubicin and their combination may be improved by an adequate selection of the circadian time of administration. The present study constitutes a prerequisite to testing the clinical relevance of chronotherapy in human breast cancer. Three experiments were performed in C3H/HeN mice. Each treatment modality was administered i.v. once a week for 3 weeks at one of six circadian stages, during the light span, when the mice were resting: 3, 7, and 11 h after light onset (HALO), or during darkness, when the mice were active: 15, 19, and 23 HALO. The circadian time dependency of single agent tolerability was investigated in healthy mice using four dose levels for docetaxel (38.8, 23.3, 14, and 8.4 mg/kg/injection) and for doxorubicin (13.8, 8.3, 5 and 3 mg/kg/injection; experiment 1). The circadian time dependency of each single agent efficacy was studied in MA13/C-bearing mice, using two dose levels of docetaxel (38.8 or 23.3 mg/kg/injection) or doxorubicin (8.3 or 5 mg/kg/injection; experiment 2). The toxicity and the efficacy of the simultaneous docetaxel-doxorubicin combination were assessed as a function of dosing time in experiment 3. Two combinations were tested (A, 16.3 mg/kg/injection of docetaxel and 2.5 mg/kg/injection of doxorubicin; and B, 11.6 and 3.5 mg/kg/injection, respectively) at each of the above six circadian times. Mortality, body weight change, and tumor size were recorded for 60-70 days in each experiment. Single agent docetaxel or doxorubicin was significantly best tolerated near the middle of the rest span (7 HALO) and most toxic in the middle of the activity phase (19 HALO). Docetaxel or doxorubicin as a single drug were also most effective at 7 HALO, irrespective of dose. Treatment at 7 HALO produced highest rates of complete tumor inhibition (81% versus 11% at 3 HALO for docetaxel, p from chi2 <0.001, and 69% versus 44% at 11 HALO for doxorubicin, not significant) and highest day 60 survival rate (100% versus 28% at 3 HALO for docetaxel, p from chi2 <0.001 and 89% versus 69% at 15 HALO for doxorubicin, not significant). Docetaxel-doxorubicin combinations were most effective following dosing in the beginning of the rest span or short after the onset of the activity span, with regard to the rates of both complete tumor inhibitions (45% at 3 HALO versus 15% at 19 HALO) and day 70 survival rates (85% and 80% at 3 and 7 HALO respectively, versus 20% at 19 HALO). The efficacy of single agent docetaxel or doxorubicin and that of their combination varied largely as a function of circadian dosing time. Single agent docetaxel at 7 HALO was the best treatment option in this model with regard to both tolerability and efficacy. This timing may correspond to the middle of the night in cancer patients.

Irinotecan and chronomodulated infusion of 5-fluorouracil and folinic acid in the treatment of patients with advanced colorectal carcinoma: a phase I study.

BACKGROUND: Irinotecan (CPT-11) is an active drug in the treatment of patients with advanced colorectal carcinoma. The infusion of 5-fluorouracil (5-FU) according to circadian rhythms was used previously to decrease toxicity and to increase its therapeutic efficacy. The objective of this study was to establish the maximum tolerated dose (MTD) of CPT-11 together with a chronomodulated infusion of 5-FU and the l-form of folinic acid (FA). Secondary end points were the assessment of activity and quality of life (QoL). METHODS: Twenty-six patients with advanced colorectal carcinoma who had received previous treatment with 5-FU were entered on this Phase I study. At least three patients were recruited at each dose level. The CPT-11 starting dose was 175 mg/m(2) on Day 1 with an increase of 50 mg/m2 per dose level. A daily administration of chronomodulated 5-FU (900 mg/m2; peak delivery rate at 04:00) and FA (175 mg/m2; peak delivery rate at 04:00) for 5 days every 3 weeks was given with CPT-11. After the first three patients, the 5-FU dose was reduced to 700 mg/m2 per day due to toxicity. No intrapatient dose escalation was allowed. RESULTS: One hundred sixty-one courses were delivered. Dose-limiting toxicity was observed during the first course in seven patients (27%). Four patients developed neutropenia, with one patient reporting febrile neutropenia, two patients reporting severe stomatitis, and six patients reporting severe diarrhea. CPT-11 MTD was reached at 350 mg/m2 when a toxic death was observed with a recommended dose of 325 mg/m2. Six partial responses were observed (23%). The median duration of response and the progression free and overall survival rates were 199 days, 175 days, and 359 days, respectively. QoL was not affected by the treatment. CONCLUSIONS: The recommended dose for Phase II trials is 325 mg/m2 CPT-11 on Day 1, which is similar to the dose given as a single agent, together with a 5-day chronomodulated infusion of 700 mg/m2 5-FU and 175 mg/m2 FA. Intensification of this schedule every 2 weeks should be achievable.

Weekly schedule of vinorelbine in pretreated breast cancer patients.

PURPOSE: In this phase II study, we explored tolerability and activity of vinorelbine administered according to a dose-dense weekly schedule with hematopoietic growth factor support in pretreated, advanced breast cancer patients. PATIENTS AND METHODS: From January 1994 to March 1996, 40 patients with metastatic breast cancer, pretreated with at least one prior anthracycline-containing regimen, were entered into the study. PATIENT CHARACTERISTICS: median age 53 years (range 32-70); ECOG performance status 0-1: 34 patients, 2: 6 patients; dominant visceral metastatic disease: 15 patients, dominant non-visceral: 25; anthracycline-refractory/resistant: 2 patients, sensitive: 38 patients. Six patients were treated as first-line therapy for metastatic disease and 34 in second- or subsequent lines. All patients received vinorelbine at the dose of 25 mg/m2/week as a short intravenous infusion, together with routine antiemetic medication. Granulocyte-colony stimulating factor (Lenograstim) at the dose of 150 microg/m2 subcutaneously on day 3 was included in the treatment schedule. RESULTS: The median number of treatment weeks was 23 (range: 4-24), with a delivered dose-intensity (DDI) of 23.8 mg/m2/week (range: 18.7-25, 95.2% of projected dose-intensity). Toxicity was mild, with non-complicated neutropenia being the main toxicity observed (grade 3-4 in 25% of the patients but only 2% of treatment weeks). Overall response rate was 52.5%, with complete responses in 12.5% of patients. Median duration of the response and median time to progression were 10 and 9 months, respectively. Median overall survival was 19 months. CONCLUSION: Dose-dense weekly vinorelbine is safe and effective with minimal toxicity in pretreated advanced breast cancer patients.