Docetaxel in the treatment of ovarian cancer

Docetaxel (Taxotere) has extended the armamentarium of agents with significant activity in the treatment of ovarian cancer. As a single agent in advanced ovarian cancer patients previously treated with a platinum agent, docetaxel at 100 mg/m2 every 3 weeks yields a 30% overall response rate and a 6-month duration of response. In vitro data demonstrate a lack of complete cross-resistance between docetaxel and paclitaxel. As a result, antitumor activity has also been demonstrated in patients refractory to a paclitaxel-containing regimen. In both platinum- and paclitaxel-pretreated patients, the highest response rates were obtained in patients with the longest interval of time since receipt of prior chemotherapy. Docetaxel has been successfully combined with the platinum salts for the first-line treatment of ovarian cancer patients. In combination with cisplatin, response rates of 69% were reported. In an effort to minimize hematologic toxicities and asthenia associated with the cisplatin/docetaxel combination, investigators have substituted carboplatin (Paraplatin) for cisplatin. Several phase II studies and the Scottish Randomized Trial in Ovarian Cancer (SCOTROC), a large phase III randomized trial, of the docetaxel/ carboplatin combination have been completed. The most frequent toxicity noted is neutropenia, which is generally of brief duration, predictable, and manageable. The docetaxel/carboplatin combination has a notably low rate of neurotoxicity. Therefore, the SCOTROC comparative trial, demonstrating equivalent overall response rates and progression-free survival rates, suggests that the docetaxel/carboplatin combination may represent a new alternative to paclitaxel/carboplatin as first-line chemotherapy for advanced ovarian cancer.

Docetaxel for gastric and esophageal carcinomas

Docetaxel (Taxotere) has been successfully investigated in the therapy for advanced gastroesophageal tumors as both a single agent and in combination regimens. As a single agent, phase II study results demonstrate an overall response rate of 17% to 24%, with occasional complete responses in a disease in which complete responses are rare. These figures classify docetaxel among the most active agents for the disease. Further research initiatives in gastric cancer have evaluated the combined use of docetaxel with traditionally established agents, such as cisplatin and fluorouracil (5-FU). The rationales for the combined use of docetaxel with these agents include the in vitro demonstration of a lack of complete cross-resistance and nonoverlap-ping side-effect profiles. Phase II study results of docetaxel-based combinations demonstrate high overall response rates and progression-free survival, comparable with results obtained with established three- and four-drug regimens. Therapy is generally well tolerated, with a predominant toxicity of hematologic neutropenia. Docetaxel-based combination regimens are currently undergoing evaluation in randomized phase III trials in comparison with established standard regimens. While previous combination chemotherapy regimens have failed to improve survival over single-agent therapy, the aim for incorporation of docetaxel with other active agents is to improve palliation and possibly survival of patients with gastric cancer.

Perspectives and opportunities: Docetaxel in the current and future treatment of non-small cell lung cancer

Docetaxel is active as monotherapy in patients with advanced or metastatic non-small cell lung cancer. In addition to the conventional 3-weekly regimen, docetaxel delivered in smaller, weekly doses to patients who are elderly or have comorbidities maintains activity while minimizing myelosuppression. Randomized phase III trials show that docetaxel monotherapy improves survival when compared with best supportive care in both first- and second-line settings. More recently, the combination of docetaxel with cisplatin in chemotherapy-naive patients has been shown to be significantly superior to the vinorelbine/cisplatin combination in terms of both increased survival and reduced toxicity. Docetaxel can be combined with nonplatinum agents such as gemcitabine to produce regimens that have substantial activity and a favorable therapeutic index. In multimodality therapy, following platinum/etoposide chemoradiation with docetaxel may have played an important role in the encouraging outcome of the recent Southwest Oncology Group 9504 study. If this can be confirmed, docetaxel appears suitable for inclusion in a range of sequential chemoradiotherapy approaches. Docetaxel can safely be combined with a platinum in patients receiving thoracic radiotherapy; and the combination is a candidate for induction therapy in patients with stage IB-IIIA disease. There is also considerable promise in combining docetaxel with any of the large number of molecularly targeted therapies now becoming available.

Docetaxel in the integrated management of prostate cancer. Current applications and future promise

Docetaxel (Taxotere)-based regimens can be included among the most effective treatment options for the management of patients with advanced, androgen-independent prostate cancer. Results with docetaxel as a single agent and in combination regimens with estramustine (Emcyt) have consistently achieved a palliative response, reduced serum PSA levels by > or = 50%, and produced objective responses in patients with measurable disease. In addition, encouraging survival data have been demonstrated in several phase II trials. The ability to administer docetaxel on a weekly basis has substantially enhanced research efforts for treatment in prostate cancer patients. The results of ongoing phase III randomized trials evaluating docetaxel regimens in androgen-independent prostate cancer are eagerly awaited for their potential to definitively demonstrate a beneficial impact on overall patient survival. Docetaxel-containing regimens are likely to demonstrate a substantial role in the management of early-stage prostate cancer patients in the adjuvant and neoadjuvant settings, where clinical investigations are under way. In addition, study results from ongoing trials that integrate docetaxel with hormonal therapies for patients with biochemical recurrence following definitive local treatments will be important in refining the future role of chemotherapy for prostate cancer in general. The preliminary findings from studies conducted with docetaxel are encouraging and await final analysis. Finally, preliminary results from studies exploring combination regimens of docetaxel and novel agents that possess completely different mechanisms of action (eg, proapoptotic agents, angiogenesis inhibitors, and vitamin D analogs) have demonstrated the regimens to be feasible and safe, with promising early response data. These types of investigational studies will likely occupy a dominant position in future research initiatives for patients with advanced prostate cancer.

Paclitaxel in cancer therapy

The last decade witnessed the introduction of exciting new chemotherapeutic agents. Among these, paclitaxel emerged as one of the most powerful compounds. Paclitaxel promotes the polymerisation of tubulin, thereby causing cell death by disrupting the normal microtubule dynamics required for cell division and vital interphase processes. Mechanisms of acquired resistance to paclitaxel include alterations of tubulin structure and the amplification of membrane phosphoglycoproteins that function as drug-efflux pumps. Toxicities associated with paclitaxel include hypersensitivity reaction, neurotoxicity and haematological toxicities. Toxicities may be both dose- and schedule-dependent. Paclitaxel has activity against a broad band of tumour types, including breast, ovarian, lung, head and neck cancers. Paclitaxel also has activity in other malignancies that are refractory to conventional chemotherapy, including previously-treated lymphoma and small cell lung cancers and oesophageal, gastric endometrial, bladder and germ cell tumours. Paclitaxel is also active against AIDS-associated Kaposi's sarcoma.

Docetaxel in the management of advanced or metastatic urothelial tract cancer

Phase II studies of single-agent docetaxel (Taxotere) yielded promising results in advanced or metastatic transitional cell carcinoma (TCC) of the urothelium. Antitumor responses have been demonstrated in previously treated and chemotherapy-naive TCC patients, as well as in a subgroup of patients with renal impairment unable to receive traditional cisplatin-based regimens. Investigations of docetaxel-containing doublet and triplet drug combinations in the first-line setting have been pursued. When combined with cisplatin in previously untreated patients, response rates of 52% to 60% have been achieved, with median overall survival of 8 to 13.6 months. Triplet drug combinations of the docetaxel/platinum base have been investigated, when the addition of an anthracycline (doxorubicin or epirubicin [Ellence]) or of gemcitabine (Gemzar) has proven feasible, and has resulted in favorable efficacy findings. Non-platinum-containing regimens such as docetaxel/gemcitabine are also being studied. Randomizedphase III trials of a docetaxel-containing regimen in comparison with established regimens are ongoing, and additional studies are warranted to determine if overall long-term survival of TCCpatients can be improved.

Randomised, phase II trial comparing oral capecitabine (Xeloda) with paclitaxel in patients with metastatic/advanced breast cancer pretreated with anthracyclines

Capecitabine, an oral fluoropyrimidine carbamate, was designed to generate 5-fluorouracil preferentially at the tumour site. This randomised, phase II trial evaluated the efficacy and safety of capecitabine or paclitaxel in patients with anthracycline-pretreated metastatic breast cancer. Outpatients with locally advanced and/or metastatic breast cancer whose disease was unresponsive or resistant to anthracycline therapy were randomised to 3-week cycles of intermittent oral capecitabine (1255 mg m(-2) twice daily, days 1-14, (22 patients)) or a reference arm of i.v. paclitaxel (175 mg m(-2), (20 patients)). Two additional patients were initially randomised to continuous capecitabine 666 mg m(-2) twice daily, but this arm was closed following selection of the intermittent schedule for further development. Overall response rate was 36% (95% CI 17-59%) with capecitabine (including three complete responses) and 26% (95% CI 9-51%) with paclitaxel (no complete responses). Median time to disease progression was similar in the two treatment groups (3.0 months with capecitabine, 3.1 months with paclitaxel), as was overall survival (7.6 and 9.4 months, respectively). Paclitaxel was associated with more alopecia, peripheral neuropathy, myalgia and neutropenia, whereas typical capecitabine-related adverse events were diarrhoea, vomiting and hand-foot syndrome. Twenty-three per cent of capecitabine-treated patients and 16% of paclitaxel-treated patients achieved a > or =10% improvement in Karnofsky Performance Status. Oral capecitabine is active in anthracycline-pretreated advanced/metastatic breast cancer and has a favourable safety profile. Furthermore, capecitabine provides a convenient, patient-orientated therapy.

Phase I study of vinorelbine and carboplatin combination in patients with taxane and anthracycline pretreated advanced breast cancer

AIM

To define the maximum tolerated dose (MTD) and the dose-limiting toxicities (DLTs) of the carboplatin-vinorelbine combination in pretreated patients with advanced breast cancer.

PATIENTS AND METHODS

Patients with histologically confirmed metastatic breast cancer relapsing or progressing after prior taxane and anthracycline containing chemotherapy were enrolled. Cohorts of 3-6 patients were treated at successive dose levels (DLs) with escalated doses of carboplatin [range, area under the curve (AUC) 4-6] on day 1 and vinorelbine (range, 20-35 mg/m(2)) on days 1 + 8 recycled every 28 days.

RESULTS

Twenty-seven patients with a median age of 58 years and performance status (WHO) of 0-2 were treated at 6 DLs. All patients were assessable for toxicity and 20 for response. DLT was reached at carboplatin 6 AUC and vinorelbine 35 mg/m(2), and therefore, this was considered as the MTD. Prophylactic G-CSF administration could not allow further dose escalation. The recommended dose for further phase II testing was defined at carboplatin 6 AUC on day 1 and vinorelbine 30 mg/m(2) on days 1 and 8. Among 98 administered treatment cycles 41 (42%) and 7 (7%) were complicated with grades 3 and 4 neutropenia and thrombocytopenia, respectively. Nonhematologic toxicities included grade 2 peripheral neuropathy in 3 cycles and grades 2 and 3 fatigue in 32 (32%).

CONCLUSION

The present study determined the feasibility of the combination of carboplatin at AUC 6 (day 1) and vinorelbine at 30 mg/m(2) (days 1 and 8 ) without G-CSF support in patients with taxane and anthracycline pretreated advanced breast cancer. Phase II studies at these doses should follow in order to determine the activity of the regimen.

The antineoplastic treatment in the elderly

More than 550,000 American people died for cancer only in 1998 and more than third of them were over 65 years of age. According to recent data in next decade more than 70% of all the deaths for tumour will be verified in the population over 65 years. The cancers mostly frequently associated with the deaths in the elderly population are the tumour of the lung, colon, prostate and breast. Therefore the geriatrics oncology is progressively assuming a central and essential role within the medical oncology. One of the aspects of great interest in the treatment of the cancers of the elderly patient (> 65 years) is the study about some pharmacokinetic modifications of the antitumour medicines in such band of age, and the study about some pattern of toxicity characteristics in the elderly patients. In this ambit there are a few studies in literature devoted specifically to such aspect. This study represents an attempt of revision of the literature finalized to analyse the toxicological and pharmacokinetic characteristics of the principal chemotherapeutic agents used in the therapy of elderly patients affected with cancer. In the last part of the review we have tried to synthesize the state of the art of the achieved results about the medicines that have shown a better therapeutic index and a better impact on the clinical benefit in such population of patients.

Phase II and pharmacokinetic study of GL331 in previously treated Chinese gastric cancer patients

PURPOSE

A phase II and pharmacokinetic study was designed to assess the efficacy and toxicity profile of an epidophyllotoxin analogue, GL331, in previously treated Chinese gastric cancer patients, with concurrent pharmacokinetic evaluation of the drug's metabolism.

MATERIAL AND METHODS

GL331 was given at 200 mg/m(2) as a daily 3-h infusion for 5 days every 4 weeks.

RESULTS

Enrolled in the study were 15 patients. One patient died from neutropenic sepsis before evaluation, one patient did not receive the full dose for reasons unrelated to GL331, nine patients had progressive disease with a median survival of 80 days, and five had stable disease with a median survival of 240 days. Grade 3 and 4 myelosuppression occurred in 10 of the 15 patients, with one death from neutropenic sepsis. This patient's peak GL331 concentration was 16.8 microg/ml, which was high compared to the mean peak drug concentration of 6+/-4.1 microg/ml. The mean systemic GL331 clearance was 12.1+/-7.2 l/h per m(2), much lower than 23.3+/-8.2 l/h per m(2) found in the phase I trial. Topoisomerase IIalpha was determined by immunohistochemistry and overexpression was detected in 3 of 11 specimens.

CONCLUSIONS

GL331 was ineffective at this dose and schedule in this group of patients in spite of adequate blood levels of the drug.

Taxol reactions

Paclitaxel (Taxol) a taxane antineoplastic agent causing irreversible microtubule aggregation with activity against breast, ovarian, lung, head and neck, bladder, testicular, esophageal, endometrial and other less common tumors was derived from the bark of the Pacific yew (Taxus brevifolia). Phase I trials conducted in the late 1980s were almost halted because of the high frequency of hypersensitivity-like reactions. Respiratory distress (dyspnea and/or bronchospasm), hypotension, and angioedema were the major manifestations, but flushing, urticaria, chest, abdomen, and extremity pains were described also. Reactions occurred on first exposure in the majority of cases raising etiologic questions. The vehicle for paclitaxel Cremophor EL (polyoxyethylated castor oil in 50% ethanol) was strongly suspect as a direct (non-immunoglobulin E dependent) histamine releaser. Premedication regimens and longer infusion times lowered the incidence of reactivity allowing phase II and III trials to progress through the early 1990s. The mechanism(s) underlying paclitaxel hypersensitivity-like reactions is still unknown, and clinical data on probable complement and mast cell activation are lacking. The original clinical trial protocols for paclitaxel required discontinuation of therapy for patients who experienced hypersensitivity-like reactions. Here, we review the current etiologic knowledge of these reactions and describe our clinical approach to allow completion of chemotherapy with this powerful plant-derived agent.

Phase I and pharmacological study of single paclitaxel administered weekly for heavily pre-treated patients with epithelial ovarian cancer

We have reported that paclitaxel results in cisplatin sensitization in cisplatin-resistant ovarian cancer cell lines in vitro and in nude mice. The purpose of this trial was to determine the maximum tolerated dose and recommend phase II dose of weekly single agent paclitaxel for outpatients with recurrent or persistent epithelial ovarian carcinoma (REOC), with standard chemotherapy containing platinum in the initial setting. Patients with REOC were eligible for this protocol regardless of the number and kind of previous chemotherapy regimens. The starting dose was paclitaxel 70 mg/m2/week in 1-hour infusion, 3 weeks on, 1 off and repeated at least twice. This dose was increased by 10 mg per step to 100 mg/m2/week. Three patients were accrued to each dose cohort. Three new patients were to be entered at escalation doses unless dose-limiting toxicities (DLT) occurred, defined as grade 4 hematological or grade 3/4 non-hematological toxicities. If 1 out of 3 patients developed DLT, 3 additional patients were entered at the same dose level. Sixteen patients were accrued. All the patients had received at least one prior platinum-containing regimen (1 regimen 14 cases, 2 regimens 1 case, 3 regimens 1 case). At the level I dose of 70 mg/m2/week no hematological or non-hematological toxicity more than grade 2 was observed. At the level II dose of 80 mg/m2/week, 1 patient had grade 4 non-hematological toxicity, showing difficulty-walking. Three new additional patients were treated with the same dose. Except for this patient, 1 had grade 3 leukopenia and grade 4 neutropenia, but these toxicities were overcome within 3 days without support of granulocyte-colony stimulating factor (G-CSF). At the level III dose, 90 mg/m2/week, 1 of 3 patients showed grade 4 leukopenia and 2 had grade 4 neutropenia, requiring support by G-CSF. Similarly, when using 100 mg/m2/week of paclitaxel, 2 out of 4 patients had more than grade 3 hematological toxicity. However, at levels II or IV, no non-hematological toxicity exceeding grade 2 was observed. Even if the weekly single paclitaxel was repeated, the toxicity did not seem to accumulate. According to dose-escalation, use of G-CSF and treatment delay were increased. The use of G-CSF was significantly (p<0.05) increased between levels I, II, III and IV. Although treatment with 90 or 100 mg/m2/week, at 3 weeks on, 1 off was tolerable and safe with support of G-CSF, these doses cannot be recommended for out-patients because of treatment delay. In this phase I trial, 80 mg/m2/week of paclitaxel was recommended as the phase II dose for outpatients.

Phase I and pharmacokinetic study of ABI-007, a Cremophor-free, protein-stabilized, nanoparticle formulation of paclitaxel

PURPOSE

ABI-007 is a novel Cremophor-free, protein-stabilized, nanoparticle formulation of paclitaxel. The absence of Cremophor EL may permit ABI-007 to be administered without the premedications used routinely for the prevention of hypersensitivity reactions. Furthermore, this novel formulation permits a higher paclitaxel concentration in solution and, thus, a decreased infusion volume and time. This Phase I study examines the toxicity profile, maximum tolerated dose (MTD), and pharmacokinetics of ABI-007.

EXPERIMENTAL DESIGN

ABI-007 was administered in the outpatient setting, as a 30-min infusion without premedications. Doses of ABI-007 ranged from 135 (level 0) to 375 mg/m2 (level 3). Sixteen patients participated in pharmacokinetic studies.

RESULTS

Nineteen patients were treated. No acute hypersensitivity reactions were observed during the infusion period. Hematological toxicity was mild and not cumulative. Dose-limiting toxicity, which occurred in 3 of 6 patients treated at level 3 (375 mg/m2), consisted of sensory neuropathy (3 patients), stomatitis (2 patients), and superficial keratopathy (2 patients). The MTD was thus determined to be 300 mg/m2 (level 2). Pharmacokinetic analyses revealed paclitaxel C(max) and area under the curve(inf) values to increase linearly over the ABI-007 dose range of 135-300 mg/m2. C(max) and area under the curve(inf) values for individual patients correlated well with toxicity.

CONCLUSIONS

ABI-007 offers several features of clinical interest, including rapid infusion rate, absence of requirement for premedication, and a high paclitaxel MTD. Our results provide support for Phase II trials to determine the antitumor activity of this drug.

Acute and subacute toxicity associated with concurrent adjuvant radiation therapy and paclitaxel in primary breast cancer therapy

The purpose of this study was to describe the toxicity of concurrent standard dose adjuvant radiation therapy (RT) and paclitaxel in a series of patients receiving primary breast cancer therapy. From June 1998 to April 1999, 20 patients with breast cancer received concurrent adjuvant radiation and paclitaxel. There were 16 patients (80%) with American Joint Committee on Cancer (AJCC) stage II disease and 4 with stage III disease. Eighteen patients, 12 postmastectomy and 6 breast conservation, were treated with definitive surgery followed by concurrent RT and paclitaxel. Two received concurrent neoadjuvant radiation and paclitaxel. All patients received a doxorubicin-containing combination prior to radiation and paclitaxel. RT was delivered concurrently with paclitaxel after the completion of all doxorubicin therapy, with all patients receiving at least two cycles of paclitaxel (175 mg/m2) every 3 weeks during RT. Toxicity was graded weekly according to Radiation Therapy Oncology Group criteria. Thirteen patients (65%) developed grade 2 or higher cutaneous toxicity. In the postmastectomy group, 6 of 12 patients (50%) developed grade 2 cutaneous toxicity, and 4 of 12 patients (33%) developed grade 3. RT was discontinued in 1 and placed on hold in 3 of these patients. In the breast-conservation group, 2 of 6 patients (33%) developed grade 3 toxicity. In the neoadjuvant group, 1 of 2 patients (50%) developed grade 3 toxicity. Four patients (20%) developed radiation pneumonitis, 2 of 12 (17%) in the postmastectomy group and 2 of 6 (33%) in the breast conservation group, with 2 requiring hospitalization and 1 a diagnostic open-lung biopsy. In this group of patients, standard dose concurrent radiation and paclitaxel resulted in a high incidence of cutaneous and pulmonary toxicity. Concurrent radiation and paclitaxel with these doses and schedule should be approached cautiously until further studies documenting its safety are completed.

Weekly paclitaxel in women age 65 and above with metastatic breast cancer

We evaluated therapy with weekly paclitaxel 80 mg/m2 in metastatic breast cancer patients age > or =65. There was a low incidence of serious toxicities, with similar tolerability profiles in younger and older patients. Response rates and overall survival times were comparable in the two age groups (<65 and > or =65). Weekly paclitaxel therapy is a reasonable option for older patients with metastatic breast cancer.

Herbal supplement PC-Spes for prostate cancer

OBJECTIVE

To determine the efficacy and toxicity of the herbal supplement PC-Spes in prostate cancer patients.

METHODS

Literature search through MEDLINE (1966-October 2001), PubMed, and abstracts from the Annual Meeting of the American Society of Clinical Oncology (1995-2001).

RESULTS

PC-Spes was associated with biochemical and clinical response in some prostate cancer patients. The mechanisms of action of PC-Spes appeared to be related to its estrogenic activity.

CONCLUSIONS

PC-Spes is associated with some efficacy in prostate cancer patients. Due to the limited data available, it should not be used to replace standard androgen suppression therapy in androgen-dependent patients. PC-Spes may have a role for patients who have failed standard treatments for androgen-independent disease and have no history of thromboembolism or abnormal bleeding. PC-Spes has a toxicity profile similar to those of androgen suppression and estrogen therapy.

Evaluation of paclitaxel in adjuvant chemotherapy for patients with operable breast cancer: preliminary data of a prospective randomized trial

PURPOSE

Paclitaxel has significant antitumor activity in patients with metastaticbreast cancer who have been previously treated with or exposed to anthracycline-containing chemotherapy. In this prospective randomized trial, the role of paclitaxel was evaluated in an adjuvant setting to determine its impact on reducing the risk of recurrence in patients with operable breast cancer.

EXPERIMENTAL DESIGN

Five hundred twenty-four patients were randomized to be treated either with 4 cycles of paclitaxel followed by 4 cycles of combination therapy with 5-fluorouracil, Adriamycin, and cyclophosphamide (Pac/FAC) or with 8 cycles of FAC alone. Patients with intact primary breast cancer received the initial 4 cycles of paclitaxel or 4 cycles of FAC in a neoadjuvant setting. Planned duration of therapy was the same in all patients. After completion of 8 cycles of chemotherapy, those patients who were > or =50 years and whose tumors were positive for estrogen receptors received tamoxifen for 5 years.

RESULTS

Ninety-two patients have had a recurrence after a median follow-up of 60 months with a range of 5-89 months. Estimated disease-free survival at 48 months was 0.83 for FAC and 0.86 for Pac/FAC group. The difference between the two groups was not statistically significant (P = 0.09). The overall estimated hazard ratio for Pac/FAC compared with FAC derived by fitting the Cox regression model and incorporating terms for prognostic factors was 0.66.

CONCLUSION

Preliminary results suggest that the addition of paclitaxel to a FAC regimen of adjuvant or neoadjuvant therapy may further reduce the risk of disease recurrence; however, differences were not statistically significant. At the time of this analysis, there have been 47 deaths. The survival data are too preliminary to permit meaningful evaluation of the impact of paclitaxel on mortality.

Olfactory epithelium as a novel toxic target following an intravenous administration of vincristine to mice

To delineate morphological characteristics of olfactory lesions induced by vincristine (VCR), a vinca alkaloid derivative with antitumor activity, male BALB/c mice were given a single intravenous injection of 1.95 mg/kg, an estimated 10% lethal dose (designated as day 1). The animals were serially sacrificed on days 2, 3, 5, 10, 15 and 60, and the nasal mucosa was examined histopathologically. Cell death was noted in the olfactory epithelia adjacent to the respiratory epithelia from days 2 to 5. Inflammatory responses were not detected throughout the observation periods. Cell death was identified as apoptotic by the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling (TUNEL) assay and electron microscopy. Mitotic figures and proliferating cell nuclear antigen (PCNA)-positive reactions were diffusely scattered in both the basal and sensory cells. On days 10 or after, no prominent histological abnormalities were noted in the olfactory epithelia, which suggests the aforementioned lesions were completely recovered. These results demonstrate that it is essential to perform histopathological evaluation of the nasal mucosa during an early preclinical stage for novel antitumor drugs, since olfactory lesions due to the certain compounds like VCR may not be detected by any other procedure.