A phase I safety, pharmacological and biological study of the farnesyl protein transferase inhibitor, tipifarnib and capecitabine in advanced solid tumors

BACKGROUND

To evaluate the toxicity and pharmacological and biological properties of the farnesyl protein transferase (FPTase) inhibitor, tipifarnib (R115777, ZARNESTRAtrade mark) and capecitabine administered for 14 days every 3 weeks.

PATIENTS AND METHODS

Patients with advanced cancers received twice daily tipifarnib (100-500 mg) and capecitabine (1000-1125 mg/m(2)) for 14 days every 3 weeks. Pharmacokinetics of tipifarnib, capecitabine and 5-fluorouracil (5-FU) were determined. Peripheral blood mononuclear cells were analyzed for farnesylation of the HDJ2 chaperone protein and FPTase activity.

RESULTS

Forty-one patients received 185 courses of treatment. Diarrhea and palmar-plantar erythrodysesthesia were dose limiting at 300 mg tipifarnib/1125 mg/m(2) capecitabine b.i.d. When the capecitabine dose was fixed at 1000 mg/m(2) b.i.d., neutropenia was dose limiting at 400 and 500 mg b.i.d. of tipifarnib. Capecitabine did not affect the pharmacology of tipifarnib at 100-300 mg b.i.d., although tipifarnib significantly increased the C(max) of 5-FU at 400 mg b.i.d. HDJ2 farnesylation and FPTase activity decreased between 200 and 400 mg b.i.d. doses of tipifarnib, without a dose-response relationship. Five patients demonstrated partial remissions and 11 patients maintained prolonged stable disease.

CONCLUSIONS

Tipifarnib and capecitabine are well tolerated at 300 mg/1000 mg/m(2) b.i.d., respectively, resulting in biologically relevant plasma concentrations and antitumor activity. The recommended dose for further disease-focused studies is 300 mg b.i.d. tipifarnib and 1000 mg/m(2) b.i.d. capecitabine, given for 14 days every 3 weeks.

Correlates of patient referral to surgeons for treatment of breast cancer

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Background: Characteristics of surgeons and their practice settings have been associated with cancer treatments and outcomes. Yet, there is little information about factors that are associated with referral pathways to surgeons and treatment settings. Methods: We merged and analyzed tumor registry and survey data from all women with DCIS and a 20% random sample of women with invasive breast cancer diagnosed in 2002 and reported to the Detroit and Los Angeles SEER registries (N = 1,844, response rate 77.4%,) and their surgeons (N = 365, response rate 80.0%). Results: About half of the patients (54.2%) reported that they were referred to their surgeon by another provider or health plan; 20.3% reported that they selected their surgeon; 21.9% reported that they both were referred and were involved in selecting their surgeon; and the remaining patients (4.9%) reported that they had a prior relationship with their surgeon primarily through previous surgery. Selecting their surgeon based on reputation was more frequently reported by white patients (36.5% vs 26.5%, p < .001), and more highly educated patients (40.0% and 21.6%, respectively for highest and lowest education categories, p < .001). Patients who selected their surgeon based on reputation were more likely to have received treatment from a high volume surgeon (adjusted odds ratio 2.3; 95% CI 1.7, 3.2) and more likely to have been treated in an American College of Surgeon approved cancer program or NCI-designated cancer center (adjusted odds ratio 1.8; 95% CI 1.1, 2.8; 3.0 95% CI 1.6, 5.3, respectively). Patients who were referred to their surgeon were less likely to be treated in an NCI-designated cancer center (adjusted OR 0.4; 95% CI 0.2, 0.8). Conclusions: Women with breast cancer who actively participate in the surgeon selection process are more likely to be treated by more experienced surgeons and in hospitals with approved cancer programs. Patients should be aware that provider or health plan-based referral may not connect them with the most experienced surgeon or comprehensive practice setting in their community. An active patient role in the surgeon selection process has important implications for both the type of treatment received and where care is delivered.

No significant financial relationships to disclose.

Patient and surgeon correlates of shared decision making for surgical breast cancer treatment

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Background: The choice of surgical breast cancer treatment represents an opportunity for shared decision making (SDM), since both mastectomy and breast conserving surgery are viable options. Yet women vary in their desire for involvement in this decision. Correlates of SDM and/or the level of involvement in breast cancer surgical treatment decision-making are not known. Methods: Breast cancer patients of Detroit and Los Angeles SEER registries were mailed a questionnaire shortly after diagnosis in 2002 (N = 1,800, RR: 77%). Their responses were merged with a surgeon survey (N = 456, RR: 80%) for a dataset of 1,547 patients of 318 surgeons. Surgical treatment decision making was categorized into: 1) surgeon-based; 2) shared; or 3) patient-based. The concordance between a woman’s self-reported actual and desired decisional involvement was categorized as having more, less, or the right amount of involvement. Decision making and concordance were each analyzed as three-level dependent variables using multinomial logistic regression controlling for clustering within surgeons. Independent variables included patient clinical, treatment and demographic factors, surgeon demographic and practice-related factors, and a measure of surgeon-patient communication. Results: 37% of women reported the surgery decision was shared, 25% that it was surgeon-based, and 38% that it was patient-based. Two-thirds experienced the right amount of involvement, while 13% had less and 19% had more. Compared to women who reported a shared decision, those with surgeon-based decision were significantly (p < 0.05) more likely to have male surgeons, and those reporting a patient-based decision were more likely to have received mastectomy vs. breast conserving surgery. Women who were less involved in the surgery decision than they wanted were younger and had less education, while those with more involvement (vs. the right amount) more often had male surgeons. Patient-surgeon communication was associated with decisional involvement. Conclusions: Correlates of SDM and decisional involvement relating to surgical breast cancer treatment differ. Determining patients’ desired role in decision making may as important as achieving a shared decision for evaluating perceived quality of care.

No significant financial relationships to disclose.

The incidence of BRCA1 and BRCA2 variants of unknown significance varies in different ethnic populations

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Background: BRCA1 and BRCA2 mutations in the general population are rare. Women with these mutations have a significantly increased risk of invasive breast and ovarian cancer (65–85% and 15–65% cumulative lifetime risk, respectively). Variants of unknown significance (VUS), which are of uncertain clinical importance, account for up to 50% of all identified BRCA1 and BRCA2 sequence alterations1. Methods: Pooled data from all patients presenting to Fox Chase Cancer Center for genetic counseling was examined. Patients underwent genetic testing after detailed genetic counseling. Clinical data, including gender, ethnic background, and personal history of cancer, and total number of patients tested were collected. Results: A total of 1,765 women and 236 men underwent genetic testing. The distribution of ethnicity was: <1% Asian, 2.7% African American, <1% Hispanic, 2.4% other or of more than one ethnicity, 83% White, and 11% unknown. Mutations of BRCA1 and BRCA2 were seen in 13% of the women and 2.7% of the men. VUS were seen in 6.2% of the women and .15% of the men. Of the women positive for a VUS, 2.4% were Asian, 18.1% were African American, 5.5% were Hispanic, 4.7% were more than one ethnicity, 66.9% were White, and 2.4% were Unknown ethnicity. Only .15% of the men tested were positive for a VUS, all of whom were White. Of the 51 African American women tested, 45.1% were positive for a VUS while only 5.5% of the 1,503 White women tested were positive (p<0.0001). Of the females testing positive for a VUS, a personal history of breast cancer was seen in 66.7% of Asians, 78.3% of African Americans, 100% of Hispanics, 83.3% of those more than one race, 61% of Whites, and none of the people of unknown ethnic origin. One of three men testing positive for a VUS reported a history of breast cancer. Conclusions: Identification of VUS occurred disproportionately in African Americans, occurring ten times more often in African American women than White women in our study. Studies to improve classification of VUS as deleterious or neutral are needed to enhance the utility of genetic testing for women at risk, particularly those of African American ethnicity. 1Goldman, DE et al. Am. J. Hum. Genet., 2004.

No significant financial relationships to disclose.

ZD6474, an inhibitor of VEGFR and EGFR tyrosine kinases, blocks VEGF-C-induced activation of VEGFR-3 and cell proliferation in human colon cancer cell lines

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Background: Vascular endothelial growth factor receptors 1, 2 and 3 (VEGFR-1, -2 and -3) have a key role in activation and proliferation of endothelial cells, with expression of VEGFR-3 largely restricted to lymphatic endothelial cells. Although high expression of VEGFR-3 and its specific ligands, VEGF-C and VEGF-D, has been associated with an increased incidence of lymph node metastasis and a poor prognosis in different human malignancies, little is known about the role of this signaling pathway in tumor cells. This study investigated VEGFR-3 and its specific ligands in human colon cancer cells, and the antiproliferative activity of ZD6474, an inhibitor of VEGFR, epidermal growth factor receptor (EGFR) and RET tyrosine kinases, and of the EGFR inhibitors gefitinib and cetuximab. Methods: The expression of VEGFRs and EGFR was determined by RT-PCR, immunoblotting, flow cytometry and immunohistochemistry in four human colon cancer cell lines (HCT-116, HT-29, HCT-15 and SW480). Secretion of transforming growth factor-α (TGF-α), VEGF-A and VEGF-C by cancer cells was determined by ELISA. The in vitro antiproliferative effects of ZD6474, gefitinib and cetuximab were determined using an MTT assay. Results: All four human colon cancer cell lines expressed functional EGFR and secreted high levels of TGF-α. All four cell lines expressed VEGFR-1 and VEGFR-3, but not VEGFR-2, and secreted both VEGF-A and VEGF-C. Treatment with ZD6474 resulted in a dose-dependent cell growth inhibition (IC50 3–5 μM), whereas treatment with gefitinib or with cetuximab produced little growth inhibition under the same culture conditions. Addition of VEGF-C induced a 2-fold increase in cell growth in vitro in all four colon cancer cell lines. Treatment with ZD6474 blocked both basal and VEGF-C-induced phosphorylation of VEGFR-3, as well as VEGF-C-induced cell proliferation. Conclusions: Human colon cancer cell lines express VEGFR-1 and VEGFR-3, and secrete VEGF-A and VEGF-C. A potential VEGF-C/VEGFR-3 autocrine loop has been identified in human colon cancer cells, which can be inhibited by ZD6474, suggesting that ZD6474 may have direct antitumor activity through inhibition of VEGFR signaling.

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Prediction of breast cancer size by ultrasound, mammography and core biopsy

Neoadjuvant chemotherapy and non-surgical tumor ablation rely upon imaging studies to determine tumor size. In this study the accuracy of ultrasound (US) mammography and core biopsy in determining tumor size was examined in 202 patients with Stages I and II breast cancer. The most accurate single modality for determining tumor size was mammography with a correlation coefficient of 0.66, followed by US (r = 0.48) and core biopsy (r = 0.28). Size measurements were less accurate in lobular than ductal cancers. The combination of the three modalities understaged 25% of the tumors > 1cm in size, and overstaged 10% of those < 1cm. The inability to accurately determine tumor size has important implications for the use of non-surgical ablation.

Sentinel lymph node biopsy: benefits and limitations

Multiple studies have demonstrated that a sentinel node can be identified in most women with breast cancer, and that it reliably predicts the status of the remaining axillary nodes. Contraindications to the procedure are decreasing with experience but further long term follow up is needed.

Elevated protein kinase C alpha expression may be predictive of tamoxifen treatment failure

We previously reported that stable transfection of protein kinase C alpha (PKCalpha) into T47D human breast cancer cells results in tamoxifen (TAM)-resistant tumour growth. Relevance of PKCalpha expression in clinical specimens was determined by comparing PKCalpha expression in tumours from patients exhibiting disease recurrence with patients remaining disease-free following TAM treatment. Our results suggest that PKCalpha expression may predict TAM treatment failure.

Low incidence of CMV viremia and disease after allogeneic peripheral blood stem cell transplantation. Role of pretransplant ganciclovir and post-transplant acyclovir

To establish the incidence of CMV viremia after allogeneic blood stem cell transplantation, we studied 51 consecutive allogeneic peripheral blood stem cell (PBSC) transplant recipients. A total of 12 recipients were at moderate risk for CMV disease and 39 were at high risk. Conditioning regimens varied, but GvHD prophylaxis consisted of tacrolimus and mini-methotrexate in all patients. All patients received prophylactic ganciclovir from admission until day -2 and prophylactic acyclovir from day -1 until day 180 after transplantation. CMV viremia was treated with ganciclovir. Using a PCR-based technique, the cumulative incidence of CMV viremia was 31+/-14% by day 100 and 35+/-14% by day 150. Donor type, CMV risk group, underlying disorder, conditioning regimen, GvHD, and steroid use were not associated with the risk for CMV viremia. No cases of CMV disease occurred. We hypothesize that the low rate of CMV viremia and the absence of CMV disease in this cohort of PBSCT transplant recipients, which contrasts with other reports, may be related to the prophylactic use of high-dose acyclovir and possibly to pretransplant use of ganciclovir.

Who should not receive chemotherapy? Data from American databases and trials

The demonstration of the effectiveness of chemotherapy in both premenopausal and postmenopausal women, regardless of estrogen receptor (ER) status, raises the question of whether all breast cancer patients should receive chemotherapy. Several patient groups with such a favorable long-term prognosis that they will obtain an extremely small benefit from chemotherapy can be identified. They include patients with lymph node-negative tumors of 1 cm or less in size, those with grade 1 tumors between 1.1 and 2.0 cm in size, and those with tumors of favorable histologic type (tubular and mucinous) up to 3 cm in size. A patient subgroup in which it is not clear that the benefits of chemotherapy routinely exceed the risks is postmenopausal women with ER-positive, lymph node-negative cancers receiving tamoxifen. There is a wide variation in prognosis in this group, and chemotherapy should be reserved for those at high risk of recurrence. Finally, no benefit for chemotherapy in women aged 70 years and older has been identified. The high rate of death from causes other than breast cancer may negate small survival benefits, and after adjustment for quality of life, the duration of treatment exceeds the gain in life expectancy.

Selective estrogen receptor modulation and reduction in risk of breast cancer, osteoporosis, and coronary heart disease

The recognition of selective estrogen receptor modulation in the laboratory has resulted in the development of two selective estrogen receptor modulators (SERMs), tamoxifen and raloxifene, for clinical application in healthy women. SERMs are antiestrogenic in the breast but estrogen-like in the bones and reduce circulating cholesterol levels. SERMs also have different degrees of estrogenicity in the uterus. Tamoxifen is used specifically to reduce the incidence of breast cancer in premenopausal and postmenopausal women at risk for the disease. In contrast, raloxifene is used specifically to reduce the risk of osteoporosis in postmenopausal women at high risk for osteoporosis. The study of tamoxifen and raloxifene (STAR) trial is currently comparing the ability of these SERMs to reduce breast cancer incidence in high-risk postmenopausal women. There is intense interest in understanding the molecular mechanism(s) of action of SERMs at target sites in a woman's body. An understanding of the targeted actions of this novel drug group will potentially result in the introduction of new multifunctional medicines with applications as preventive agents or treatments of breast cancer and endometrial cancer, coronary heart disease, and osteoporosis.