Preclinical evaluation of the effects on the gastrointestinal tract of the antineoplastic drug vincristine repeatedly administered to rats

BACKGROUND

Vincristine is a commonly used chemotherapeutic agent. It is associated with undesirable digestive side effects. However, the impact of vincristine on gastrointestinal structure and motility or its long-term effects have not been deeply studied in animal models. This could be useful in order to develop therapeutic or preventive strategies for cancer patients. The aim of this study was to analyze such effects.

METHODS

Rats received saline or vincristine (0.1 mg kg^-1 , ip) daily for 10 days. Evaluations were performed during treatment and 2-6 weeks after. Somatic mechano-sensitivity was assessed using von Frey hairs. Gastrointestinal motor function was studied by means of radiographic still images and colonic propulsion of fecal pellets using fluoroscopy videos. Histological assessment of the gut morphology and immunohistochemistry for HuC/D and nNOS were performed in whole-mount myenteric plexus preparations.

KEY RESULTS

Peripheral sensitivity was increased in animals treated with vincristine and did not subside 2 weeks after treatment finalization. Vincristine treatment inhibited gastrointestinal motility although this was recovered to normal values with time. Damage in the digestive wall after vincristine treatment was greater in the ileum than in the colon. Villi shortening (in ileum) and large inflammatory nodules still remained 2 weeks after treatment finalization. Finally, the proportion of nNOS-immunoreactive neurons was increased with vincristine and continued to be increased 2 weeks after treatment finalization.

CONCLUSIONS AND INFERENCES

Vincristine alters gastrointestinal motility, peripheral sensitivity and mucosal architecture. Vincristine-induced neuropathy (somatic and enteric), intestinal mucosa damage and inflammatory infiltrations are relatively long-lasting.

Phase II study of a fixed dose-rate infusion of gemcitabine associated with erlotinib in advanced pancreatic cancer

PURPOSE

To evaluate the feasibility, toxicity and efficacy of the combination regimen consisting of gemcitabine-FDR infusion plus erlotinib, in ACP patients.

METHODS

Forty-two patients with histologically confirmed, locally advanced or metastatic pancreatic cancer were included in this phase II trial. Main objectives were to assess the efficacy and safety of this regimen. Therapeutic regimen consisted of gemcitabine 1,200 mg/m(2) in 120-min infusion on days 1, 8 and 15, plus erlotinib 100 mg orally once daily. Cycles were repeated every 28 days.

RESULTS

A total of 160 courses of gemcitabine-FDR erlotinib were administered (median 3.8 courses per patient). The most common grade 3-4 AEs were neutropenia (21%), thrombocytopenia (10%), skin rash (10%) and asthenia (10%). Complete response was achieved in one patient (2%) and 11 (26%) achieved a partial response. Stable disease and progression disease were observed in 11 patients (26%) and 19 (45%), respectively. Median time to progression was 5 months (95%CI: 3.9-5.8 months) and median overall survival was 8 months (95% CI: 5.1-10.8). One-year survival rate was 35%.

CONCLUSIONS

A regimen consisting of gemcitabine-FDR infusion plus erlotinib is active and well tolerated in APC patients. However, the results do not justify the conduct of a Phase III trial.

Phase II randomised trial of raltitrexed-oxaliplatin vs raltitrexed-irinotecan as first-line treatment in advanced colorectal cancer

The purpose of this phase II randomised trial was to determine which of two schemes, raltitrexed-irinotecan or raltitrexed-oxaliplatin, offered better activity and less toxicity in patients with advanced colorectal cancer (CRC). A total of 94 patients with previously untreated metastatic CRC were included and randomised to receive raltitrexed 3 mg m⁻² followed by oxaliplatin 130 mg m⁻² on day 1 (arm A), or CPT-11 350 mg m⁻² followed by raltitrexed 3 mg m⁻² (arm B). In both arms treatment was repeated every 3 weeks. Intent-to-treat (ITT) analysis showed an overall response rate of 46% (95% CI, 29.5–57.7%) for arm A, and 34% (95% CI, 19.8–48.4%) for arm B. Median time to progression was 8.2 months for arm A and 8.8 months for arm B. After a median follow-up of 14 months, 69% of patients included in arm A were still alive, compared to 59% of those included in arm B. Overall, 31 patients (65%) experienced some episode of toxicity in arm A and 32 patients (70%) in arm B, usually grade 1–2. The most common toxicity was hepatic, with 29 patients (60%) in arm A and 24 patients (62%) in arm B, and was grade 3–4 in four (8%) and four (9%) patients, respectively. In all, 14 patients (29%) from arm A and 24 patients (52%) from arm B had some grade of diarrhoea (P<0.03). Neurologic toxicity was observed in 31 patients (64%) in arm A, and was grade 3–4 in five patients (10%), while a cholinergic syndrome was detected in nine patients (19%) in arm B. There were no differences in haematologic toxicity. One toxic death (2%) occurred in arm A and three (6.5%) in arm B. In conclusion, both schemes have high efficacy as first-line treatment in metastatic CRC and their total toxicity levels are similar. Regimens with raltitrexed seem a reasonable alternative to fluoropyrimidines.

Irinotecan plus raltitrexed as first-line treatment in advanced colorectal cancer: a phase II study

To evaluate the efficacy and toxicity of irinotecan (CPT-11) in combination with raltitrexed as first-line treatment of advanced colorectal cancer (CRC). A total of 91 previously untreated patients with advanced CRC and measurable disease were enrolled in this phase II study. The median age was 62 years (range 31–77); male/female 54/37; ECOG performance status was 0 in 50 patients (55%), one in 39 (43%) and two in two (2%). Treatment consisted of CPT-11 350 mg m⁻² in a 30-min intravenous infusion on day 1, followed after 30 min by a 15-min infusion of raltitrexed 3 mg m⁻². Measurements of efficacy included the following: response rate, time to disease progression and overall survival. Of the 83 evaluable patients valuable to objective response, there were five complete responses (6%) and 23 partial responses (28%), for an overall response rate of 34% (95% CI: 25.9–46.5%). In all, 36 patients (43%) had stable disease, whereas 19 (23%) had a progression. The median time to progression was 11.1 months and the median overall survival was 15.6 months. A total of 487 cycles of chemotherapy were delivered with a median of five per patient. Grade 3–4 WHO toxicities were as follows: diarrhoea in 13 patients (15%), nausea/vomiting in four (4%), transaminase increase in six (7%), stomatitis in two (2%), febrile neutropenia in three (3%), anaemia in five (6%) and asthenia in three (3%). The combination CPT-11–raltitrexed is an effective, well-tolerated and convenient regimen as front-line treatment of advanced CRC.

[Early assessment in perinatal hypoxia. Prognostic markers]

INTRODUCTION

Perinatal asphyxia and its neurological signs are the most important cause of brain damage and neurological sequelae in full term newborn babies. Neuroprotection treatments currently being investigated promise to reduce such sequelae, but these treatments are not without risk and the patients involved should be selected.

OBJECTIVE

To analyze a scale composed of variables recorded from the start of delivery until the fourth hour of life, comparing the neurological evolution of the patients. By means of this scale we aim to establish a criterion for the selection of neonates with acute perinatal asphyxia, who would benefit from neuroprotector treatment.

PATIENTS AND METHODS

A retrospective study was made of 50 patients with the diagnosis of perinatal asphyxia. Our scale was formed of the following variables: intrauterine meconiorrhexis, pathological cardiotocographic recordings, resuscitation at birth, Apgar score at five minutes, pH of the umbilical artery blood, neurological examination, multisystemic involvement, seizures, persistent metabolic acidosis and need for mechanical ventilation during the first hours of life. The patients were followed up for at least one year by means of periodical studies (neurological examination and evaluation of psychomotor development according to the Brunnet Lezinne test). For statistical analysis we used the chi squared test, Fisher's exact test, Kruskal-Wallis test and the area beneath the ROC curve.

RESULTS AND CONCLUSIONS

The scale presented constitutes a rapid, easy method which is statistically significant for the selection of perinatal asphyxia of high neurological risk which would benefit from neuroprotector treatment after the event.

Stereotactic radiosurgery may be effective in the treatment of idiopathic epilepsy: report on the methods and results in a series of eleven cases

Between 1982 and 1991, 11 patients (4 male, 7 female) ranging in age from 16 to 42 years who had been diagnosed with idiopathic focal epilepsy resistant to medication, were treated with stereotactic radiosurgery. The preoperative symptomatic period was 3-24 years. The process of localizing epileptic focus was based on chronic electrocorticography with flexible electrodes introduced into the subarachnoid space through single burr holes, and left in place during a maximum of 7 days until a clinical seizure was recorded. In most cases the procedure had to be repeated until localization was clear. This process was aided by a computer-assisted automatic analysis procedure. Final confirmation of focus location was done with depth electrode recording in most cases. Stereotactic radiosurgery was performed with a 60Co gamma source using 10 mm collimators, except in two cases in which a betatron was used. The estimated dose was 10-20 Gy at the isocenter. Four of the 11 patients (36%) were medication- and seizure-free after a mean follow-up of 102.5 months. Five patients (45%) presented a reduction of seizures of 98, 89, 86, 75 and 75%, respectively. Two patients did not respond to treatment. Seizure reduction began after a delay period of 2-12 months except in 2 patients and in most cases seizure rate decreased progressively during several months (range: 3-48) postoperatively until stabilization. No complications related to irradiation were recorded. Doses effective for epilepsy are much lower than those for producing cerebral lesions, so the mechanism is not destruction of the focus of the pathways spreading the epileptic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiosurgery of epilepsy. Long-term results

Based on experimental research, since 1982 until 1991 a series of 11 patients diagnosed as suffering from idiopathic focal epilepsy have been treated with stereotactic radiosurgery. Focus location was determined with cortical electrodes and confirmed by stereotactically placed deep electrodes. Stereotactic radiosurgery was performed with photons from a cobalt source with a dose of 10 to 20 Gy, except in two cases in whom a betatron was used. The results were: complete cessation of seizures in four cases and a significant reduction in the number of seizures in five additional cases. Seizures began to decrease gradually after a period of three months of one year, except in two cases in whom there was an immediate response after treatment. In two cases there was no change. No complication related to the irradiation was recorded. The gradual and delayed effect, obtained with low doses, may favour the hypothesis that non-descructive permanent structural changes, possibly related to the neuronal plasticity phenomenon, constitute the mechanism underlying these facts. Although the number of cases so far is too small, the absence of side-effects may make this bloodless method the one of choice specially in those cases in whom eloquent areas are involved.

Radiosurgery of epilepsy

Since 1982 a series of 11 epileptic patients have been treated with stereotactic radiosurgery. Patients were intracranially recorded with cortical and deep electrodes until the location of the epileptogenic focus was determined. A deep electrode was stereotactically placed at this point to confirm the accuracy of the location. All patients received radiosurgery with a gamma source and a dose of 10 to 20 Gy, except two of them in which a betatron was used. The results were: Total disappearance of the crises and withdrawal of medication: 4 cases (36%). More than 80% reduction of crises: 3 cases (27%). More than 50% reduction of crises: 2 cases (18%). Less than 50% reduction of crises: 2 cases (18%). No complications were observed, even in those cases in which the focus was located near critical areas of the brain. The efficacy of the low doses used accounts for non-destructive mechanisms, probably mediated by a neuronal plasticity phenomenon, as experimental studies suggest. The lack of complications can make this therapeutic approach an alternative to be considered when critical areas are involved.

Response of experimental epileptic focus to focal ionizing radiation

An experimental model of cobalt-induced epilepsy was performed on 15 cats. 3 months later, they were irradiated by means of a gamma source with a total target dose of 10 Gy. One month after irradiation all EEG recordings returned to normal, while a control group maintained the epileptiform traces. Histological study of the irradiated foci showed neuronal reafferentation. The action mechanism of ionizing radiation over epileptogenic foci in relation to this reafferentation and neuronal plasticity mechanisms is discussed.