A phase II trial of gefitinib in patients (pts) with progressive metastatic neuroendocrine tumors (NET): A Phase II Consortium (P2C) study

4043

Background: Systemic treatment options for progressive metastatic NET, including islet cell carcinoma (ICC) and carcinoid tumor (CT), are limited. These tumors frequently express the epidermal growth factor receptor (EGFR). Gefitinib, a small-molecule inhibitor of the EGFR tyrosine kinase, has been shown to inhibit the growth of NET cell lines. Methods: Eligibility criteria included: radiographic progression by RECIST criteria, ECOG PS ≤ 2, ≤ 1 prior chemotherapy, and good organ function. Prior interferon and prior or concurrent octreotide (if disease progression documented on stable dose) were allowed. Pts received gefitinib 250 mg po daily. We evaluated 6 month (mos) progression-free survival (PFS) in two cohorts (ie, CT and ICC) using separate 2-stage phase II designs. 6 mos PFS rates of 30% (CT) and 10% (ICC) were considered promising. Results: 96 pts were enrolled: (57 CT, 39 ICC). For pts evaluable for the primary endpoint, 23 of 38 (61%) CT pts and 9 of 29 (31%) pts with ICC were progression-free at 6 mos. 1 PR and one minor response (MR = 20–29% decrease in sum of target lesion diameters) were observed in 40 CT pts; 2 PR and 1 MR in 31 ICC pts. In addition, 32% (12/38) of CT and 14% (4/29) of ICC pts had stable disease on study for a duration that exceeded by at least 4 months the time to progression documented prior to study entry. Grade 3–4 toxicity was infrequent with fatigue (6%), diarrhea (5%) and rash (3%) most common. Evaluation of markers of the EGFR pathway on tumor tissue will be presented. Conclusions: Gefitinib is well-tolerated and results in prolonged disease stabilization in pts with prior documented objective progression of CT and ICC, with rare objective responses. Supported by NOI CM17104.

No significant financial relationships to disclose.

Sunitinib for patients (pts) with advanced imatinib (IM)-refractory GIST: Early results from a “treatment-use” trial

9540

Background: Pts with advanced or metastatic GIST are typically treated first with IM, but many GISTs develop resistance to IM over time or are initially resistant this agent, and a small fraction of GIST pts are intolerant of IM therapy. Sunitinib malate (previously known as SU11248) is an oral, multitargeted tyrosine kinase inhibitor of KIT, PDGFR, VEGFR, FLT3, and RET that has demonstrated efficacy in extensive prior trials involving IM-refractory GIST pts. Since GIST pts who were ineligible for participation in sunitinib clinical trials might derive significant benefit from this therapy, a treatment-use program was implemented for this purpose. Methods: This on-going, multicenter, open-label trial was designed to grant access to sunitinib for treatment use in pts who were ineligible for other sunitinib trials and who had advanced IM-resistant GIST or documented intolerance to IM. Pts on sunitinib are monitored closely to assess clinical benefit as judged by the investigator. Sunitinib is administered at a starting dose of 50 mg/day on a 4/2 schedule (4 consecutive weeks on, 2 weeks off treatment). Clinical endpoints include safety and tolerability, as well as disease control (TTP), response rates, and survival. Results: Of 268 GIST pts enrolled in this treatment-use trial at the time of this analysis, 247 had received at least one dose of sunitinib. The median number of cycles completed was 2 (range, 0–9), and the median number of days on treatment was 83 (range, 1–385). The most frequently reported treatment-related AEs were fatigue (36%), diarrhea (31%), nausea (27%), and hand-foot syndrome (15%), which were generally grade 1/2. At the time of analysis, preliminary efficacy data were available for 152 pts. Of these, 123 pts remain on therapy and have received a median of 3 (range, 2–7) cycles of sunitinib. Based on initial investigator assessments, one pt achieved a CR, 14% achieved PR and 63% have noted SD as best response. Conclusions: Sunitinib was associated with acceptable tolerability in this population of IM-refractory GIST pts enrolled in this treatment-use trial. Consistent with previous results, promising clinical activity was seen, and expanded tolerability and efficacy data will be presented.

[Table: see text]

Phase 1 and pharmacokinetic study of weekly docosahexaenoic acid-paclitaxel (Taxoprexin) in resistant solid tumor malignancies

2036

Background: Docosahexaenoic acid-paclitaxel (DHAP) is a covalent conjugate of paclitaxel and the essential fatty acid, docosahexaenoic acid. Preclinical studies have demonstrated increased activity relative to paclitaxel with the potential for an improved therapeutic ratio. We performed a phase 1 and pharmacokinetics (PK) study of DHAP in patients with resistant solid tumor malignancies. Methods: Patients were treated with DHAP administered by 2-hour intravenous infusion weekly for three out of four weeks. Dose escalation started at DHAP 200 mg/m2 and was increased by 100 mg/m2 per dose level ending at 600 mg/m2. Blood samples for PK of DHAP and paclitaxel derived from DHAP were collected in cycle 1 at 0 (prior to the start of the infusion), 2 (prior to the end of the infusion), 3, 4, 9, 26 hours and just prior to the next weekly treatment on days 8, 15 and 29. Results: Twenty-one patients enrolled and received 39 cycles of treatment (mean = 2). Three patients received DHAP at 200 mg/m2 (dose level 1), four at 300 mg/m2 (dose level 2), three at 400 mg/m2 (dose level 3) and 500 mg/m2 (dose level 4) each, and eight at 600 mg/m2 (dose level 5). In cycle 1, grade 2/3 neutropenia resulted in treatment delays for 8 patients, 6 of whom received treatment at dose level 4 and 5. Two of the 8 patients, treated with DHAP 600 mg/m2, went on to experience grade 4 neutropenia lasting < five days on later cycles. Only one patient had grade 2 sensory neuropathy, which occurred after 3 cycles of treatment. Preliminary PK analyses on all patients demonstrated that there is not a substantial accumulation of DHAP or paclitaxel with weekly treatment. Detailed PK analyses will be presented. Eighteen of the 21 patients were evaluable for response. Three patients, one each with esophageal and lung carcinoma and melanoma, had stable disease for 11, 16, and 17 weeks, respectively. Conclusions: DHAP administered weekly at 600 mg/m2 was well-tolerated and the maximum dose administered in this study. The slow release of paclitaxel from DHAP and the weekly schedule approximates continuous infusion paclitaxel which should be more active than every 3 week or weekly taxanes. Further studies with DHAP in non-small cell lung carcinoma and melanoma are on-going.

[Table: see text]

Phase I study of pegylated liposomal doxorubicin and the multidrug-resistance modulator, valspodar

Valspodar, a P-glycoprotein modulator, affects pharmacokinetics of doxorubicin when administered in combination, resulting in doxorubicin dose reduction. In animal models, valspodar has minimal interaction with pegylated liposomal doxorubicin (PEG-LD). To determine any pharmacokinetic interaction in humans, we designed a study to determine maximum tolerated dose, dose-limiting toxicity (DLT), and pharmacokinetics of total doxorubicin, in PEG-LD and valspodar combination therapy in patients with advanced malignancies. Patients received PEG-LD 20–25 mg m⁻² intravenously over 1 h for cycle one. In subsequent 2-week cycles, valspodar was administered as 72 h continuous intravenous infusion with PEG-LD beginning at 8 mg m⁻² and escalated in an accelerated titration design to 25 mg m⁻². Pharmacokinetic data were collected with and without valspodar. A total of 14 patients completed at least two cycles of therapy. No DLTs were observed in six patients treated at the highest level of PEG-LD 25 mg m⁻². The most common toxicities were fatigue, nausea, vomiting, mucositis, palmar plantar erythrodysesthesia, diarrhoea, and ataxia. Partial responses were observed in patients with breast and ovarian carcinoma. The mean (range) total doxorubicin clearance decreased from 27 (10–73) ml h⁻¹ m⁻² in cycle 1 to 18 (3–37) ml h⁻¹ m⁻² with the addition of valspodar in cycle 2 (P=0.009). Treatment with PEG-LD 25 mg m⁻² in combination with valspodar results in a moderate prolongation of total doxorubicin clearance and half-life but did not increase the toxicity of this agent.

Phase I study of rubitecan and gemcitabine in patients with advanced malignancies

BACKGROUND

Rubitecan (9-nitrocamptothecin, 9-NC, Orathecin) and gemcitabine have single-agent activity in pancreatic and ovarian carcinoma. We conducted a phase I trial to evaluate the maximum tolerated dose (MTD) and toxicities of this combination in advanced malignancies.

PATIENTS AND METHODS

Twenty-one patients with refractory or recurrent malignancies were enrolled in this dose escalation trial. Dose escalation proceeded from a starting level of rubitecan at 0.75 mg/m(2)/day administered orally on days 1-5 and 8-12 in combination with gemcitabine 1000 mg/m(2) administered intravenously on days 1 and 8 of a 21-day cycle.

RESULTS

The MTD was defined as rubitecan 1 mg/m(2) administered orally days 1-5 and 8-12, and gemcitabine 1000 mg/m(2) administered intravenously over 30 min days 1 and 8, given every 21 days. Dose-limiting toxicity was myelosuppression including neutropenia and thrombocytopenia. Other side effects included diarrhea, nausea, vomiting and fatigue. Five patients with stable disease were observed among 18 evaluable patients.

CONCLUSIONS

The recommended phase II dose is rubitecan 1 mg/m(2) given orally on days 1-5 and 8-12 in combination with gemcitabine 1000 mg/m(2) as a 30-min intravenous infusion on days 1 and 8 of a 21-day cycle.

A phase II Hoosier Oncology Group study of vinorelbine and estramustine phosphate in hormone-refractory prostate cancer

BACKGROUND

The purpose was to evaluate the combined anti-microtubular regimen of vinorelbine and estramustine phosphate (EMP) in hormone refractory prostate cancer.

PATIENTS AND METHODS

Weekly vinorelbine 20 mg/m2 (or 15 mg/m2 if a history of prior pelvic radiotherapy) was combined with EMP at 280 mg orally tds for 3 days (the day before, the day of and the day after vinorelbine infusion). After 8 weeks of therapy the combination was given every other week.

RESULTS

From February 1998 to February 1999, 23 men were enrolled with a median age of 69 years (range 50-83 years). The median prostate-specific antigen (PSA) at entry was 160 ng/ml (range 0-802 ng/ml). A median of 13 weeks of therapy was administered and the median follow-up was 14.8 months. Eleven patients (48%) had lower extremity edema requiring diuretic therapy, two (9%) had grade 2 granulocytopenia and four patients [17%; 95% confidence interval (CI) 5% to 39%] had a thromboembolic episode. There was no treatment-related mortality. Fifteen of 21 patients (71%; 95% CI 49% to 89%) had at least a 50% decrease in the PSA for at least 2 months with a median time to serologic progression of 3.5 months (range 0.75-10.5 months). One of eight patients (12.5%; 95% CI 0% to 53%) with measurable disease had a confirmed partial response. The estimated median survival was 15.1 months and the actual one year overall survival was 71% (95% CI 51% to 88%).

CONCLUSIONS

Weekly vinorelbine with short course oral EMP is an active regimen as evaluated by rate of PSA response, time to progression and median survival. However, the toxicities of EMP, even when given as a short course, are still problematic.

Altretamine for the treatment of metastatic renal cell carcinoma. A Hoosier Oncology Group trial

Thirty patients with advanced renal cell carcinoma were treated on a phase 11 trial with altretamine. Altretamine was administered orally at a dosage of 260 mg/m2 days 1 through 14 with cycles repeated every 28 days. Nausea and vomiting were the most common toxicities. Ten percent (3 of 30) experienced Grade 3 gait abnormalities. None of the thirty evaluable patients achieved a complete or partial response. In summary, altretamine did not show antitumor activity in the treatment of advanced renal cell carcinoma.

Radiation therapy for epidermoid carcinoma of the anal canal, clinical and treatment factors associated with outcome

BACKGROUND AND PURPOSE

In recent years, treatment with combined chemotherapy and radiation has become the standard of care for epidermoid carcinoma of the anus. However, optimal radiotherapy techniques and doses are not well established.

MATERIALS AND METHODS

During the period 1975-1997, 106 patients with epidermoid carcinoma of the anal canal underwent radiation therapy. Treatment policies evolved from radiation therapy alone or with surgery, to combined chemotherapy and radiation followed by surgery, to combined chemotherapy and radiation.

RESULTS

Overall 74% of patients were NED (no evidence of disease) at last follow-up. The most important clinical correlate with ultimate freedom from disease (includes the contribution of salvage surgery) was extent of disease. The 5-year ultimate freedom from disease was 87+/-5% for T1/T2N0, 78+/-10% for T3N0 (15% salvaged by surgery), and 43+/-10% for either T4N0 or any N+ lesions (P<0.001, Tarone-Ware). There was no difference between planned vs. expectant surgery (5-year ultimate NED: 67+/-11% planned surgery vs. 73+/-5% expectant surgery). The most important correlate with late toxicity was a history of major pelvic surgery (surgical vs. non-surgical group: P=0.013, Fisher's exact test, two-tailed summation). Thirty-three additional malignancies have been seen in 26 patients. The most common additional malignancies were gynecologic (nine cases), head and neck (six cases), and lung cancer (five cases).

CONCLUSIONS

For T1/T2N0 disease, moderate doses of radiation combined with chemotherapy provided adequate treatment. T4N0 and N+ lesions are the most appropriate candidates for investigational protocols evaluating dose intensification. T3N0 tumors may also be appropriate for investigation; however, dose intensification may ultimately prove counterproductive if the cure rate is not improved and salvage surgery is rendered more difficult. The volume of irradiated small bowel should be minimized for patients who have a past history of major pelvic surgery or who (because of locally advanced tumors) may need salvage surgery in the future. Because of the occurrence of additional malignancy, patients with anal cancer should receive general oncologic screening in long-term follow-up.

A phase I/II trial of three-dimensionally planned concurrent boost radiotherapy and protracted venous infusion of 5-FU chemotherapy for locally advanced rectal carcinoma

BACKGROUND

Improving the response to preoperative therapy may increase the likelihood of successful resection of locally advanced rectal cancers. Historically, the pathologic complete response (pCR) rate has been < approximately 10% with preoperative radiation therapy alone and < approximately 20% with concurrent chemotherapy and radiation therapy.

METHODS AND MATERIALS

Thirty-seven patients were enrolled on a prospective Phase I/II protocol conducted jointly at Washington University, St. Louis and the Catholic University of the Sacred Heart, Rome evaluating a three-dimensionally (3D) planned boost as part of the preoperative treatment of patients with unresectable or recurrent rectal cancer. Preoperative treatment consisted of 4500 cGy in 25 fractions over 5 weeks to the pelvis, with a 3D planned 90 cGy per fraction boost delivered once or twice a week concurrently (no time delay) with the pelvic radiation. Thus, on days when the boost was treated, the tumor received a dose of 270 cGy in one fraction while the remainder of the pelvis received 180 cGy. When indicated, nonaxial beams were used for the boost. The boost treatment was twice a week (total boost dose 900 cGy) if small bowel could be excluded from the boost volume, otherwise the boost was delivered once a week (total boost dose 450 cGy). Patients also received continuous infusion of 5-fluorouracil (1500 mg/m(2)-week) concurrently with the radiation as well as postoperative 5-FU/leucovorin.

RESULTS

All 37 patients completed preoperative radiotherapy as planned within 32--39 elapsed days. Twenty-seven underwent proctectomy; reasons for unresectability included persistent locally advanced disease (6 cases) and progressive distant metastatic disease with stable or smaller local disease (4 cases). Actuarial 3-year survival was 82% for the group as a whole. Among resected cases the 3-year local control and freedom from disease relapse were 86% and 69%, respectively.Twenty-four of the lesions (65%) achieved an objective clinical response by size criteria, including 9 (24%) with pCR at the primary site (documented T0 at surgery). The most important factor for pCR was tumor volume: small lesions with planning target volume (PTV) < 200 cc showed a 50% pCR rate (p = 0.02). There were no treatment associated fatalities. Nine of the 37 patients (24%) experienced Grade 3 or 4 toxicities (usually proctitis) during preoperative treatment. There were an additional 7 perioperative and 2 late toxicities. The most important factors for small bowel toxicity (acute or late) were small bowel volume (> or = 150 cc at doses exceeding 4000 cGy) and large tumor (PTV > or = 800 cc). For rectal toxicity the threshold is PTV > or = 500 cc.

CONCLUSION

3D planned boost therapy is feasible. In addition to permitting the use of nonaxial beams for improved dose distributions, 3D planning provides tumor and normal tissue dose-volume information that is important in interpreting outcome. Every effort should be made to limit the treated small bowel to less than 150 cc. Tumor size is the most important predictor of response, with small lesions of PTV < 200 cc most likely to develop complete responses.

Pretreatment clinical findings predict outcome for patients receiving preoperative radiation for rectal cancer

BACKGROUND

As a sole modality, preoperative radiation for rectal carcinoma achieves a local control comparable to that of postoperative radiation plus chemotherapy. Although the addition of chemotherapy to preoperative treatment improves the pathologic complete response rate, there is also a substantial increase in acute and perioperative morbidity. Identification of subsets of patients who are at low or high risk for recurrence can help to optimize treatment.

METHODS

During the period 1977-95, 384 patients received preoperative radiation therapy for localized adenocarcinoma of the rectum. Ages ranged from 19 to 97 years (mean 64.4), and there were 171 females. Preoperative treatment consisted of conventionally fractionated radiation to 3600-5040 cGy (median 4500 cGy) 6-8 weeks before surgery in 293 cases or low doses of <3000 cGy (median 2000 cGy) immediately before surgery in 91 cases. Concurrent preoperative chemotherapy was given to only 14 cases in this study period. Postoperative chemotherapy was delivered to 55 cases.

RESULTS

Overall 93 patients have experienced recurrence (including 36 local failures). Local failures were scored if they occurred at any time, not just as first site of failure. For the group as a whole, the actuarial (Kaplan-Meier) freedom from relapse (FFR) and local control (LC) were 74% and 90% respectively at 5 years. Univariate analysis of clinical characteristics demonstrated a significant (p < 0.05) adverse effect on both LC and FFR for the following four clinical factors: (1) location <5 cm from the verge, (2) circumferential lesion, (3) near obstruction, (4) tethered or fixed tumor. Size, grade, age, gender, ultrasound stage, CEA, radiation dose, and the use of chemotherapy were not associated with outcome. Background of the surgeon was significantly associated with outcome, colorectal specialists achieving better results than nonspecialist surgeons. We assigned a clinical score of 0 to 2 on the basis of how many of the above four adverse clinical factors were present: 0 for none, 1 for one or two, 2 for three or four. This sorted outcome highly significantly (p < or = 0.002, Tarone Ware), with 5-year LC/FFR of 98%/85% (score 0), 90%/72% (score 1), and 74%/58% (score 2). The scoring system sorts the data for both subgroups of surgeons; however, there are substantial differences in LC on the basis of the surgeon's experience. For colorectal specialists (251 cases), the 5-year LC is 100%, 94%, and 78% for scores of 0, 1, and 2, respectively (p = 0.004). For the more mixed group of nonspecialist surgeons (133 cases), LC is 98%, 80%, and 65% for scores of 0, 1, and 2 (p = 0.008). In multivariate analysis, the clinical score and surgeon's background retained independent predictive value, even when pathologic stage was included.

CONCLUSIONS

For many patients with rectal cancer, adjuvant treatment can be administered in a well-tolerated sequential fashion-moderate doses of preoperative radiation followed by surgery followed by postoperative chemotherapy to address the risk of occult metastatic disease. A clinical scoring system has been presented here that would suggest that the local control is excellent for lesions with a score of 0 or (if the surgeon is experienced) 1, and therefore sequential treatment could be considered. Cases with a clinical score of 2 should be strongly considered for protocols evaluating more aggressive preoperative treatment, such as combined modality preoperative treatment.

Scatter factor-hepatocyte growth factor elevation in the serum of patients with prostate cancer

PURPOSE

Scatter factor (SF), also known as hepatocyte growth factor (HGF), has been shown to induce proliferation, scattering and invasiveness in human prostate cancer cell lines. In this study we determined the serum level of SF-HGF in men with metastatic prostate cancer compared to those with localized prostate cancer and without prostate cancer.

MATERIALS AND METHODS

Serum samples were obtained from men with biopsy proved adenocarcinoma of the prostate and radiographic evidence of metastatic disease, those with biopsy proved adenocarcinoma of the prostate and clinically localized disease, and those with negative sextant prostate biopsies. Serum SF-HGF was determined using a commercially available enzyme-linked immunosorbent assay kit.

RESULTS

Of the 108 men enrolled in our study 52 had negative sextant biopsies, 36 had clinically localized cancer and 20 had metastatic disease. The serum level in men with metastatic disease was significantly elevated (mean 2,117 pg./ml., range 820 to 6,403) compared to that in men with localized cancer and without prostate cancer (mean 974 pg./ml., range 437 to 2,132 and 700, range 272 to 1,875, respectively, p = 9.5 x 10(-15)). Logistic regression analysis demonstrated that the association of ln (SF-HGF) with prostate cancer persisted after controlling for patient age and ln (prostate specific antigen) (p = 3.1 x 10(-4)).

CONCLUSIONS

Serum SF-HGF is increased in men with metastatic prostate cancer. SF-HGF levels are associated with metastatic prostate cancer independent of the prostate specific antigen level and patient age. These data imply that SF-HGF may be an important serum marker for prostate cancer.

Neoadjuvant therapy for adenocarcinoma of the rectum: tumor response and acute toxicity

PURPOSE

This study was designed to evaluate the down-staging effect and acute toxicity of preoperative radiation and chemoradiation for primary adenocarcinoma of the rectum.

METHODS

The results of pretreatment staging with transrectal ultrasound and computed tomography were compared with final histologic stage in 260 consecutive patients who underwent neoadjuvant therapy and proctectomy for primary adenocarcinoma of the rectum. Patients underwent short-course radiation (2,000 cGy in five fractions), long-course radiation (4,500 cGy in 25 fractions), or chemoradiation (4,500 cGy in 25 fractions with concurrent chemotherapy).

RESULTS

Down-staging of one or more T stages occurred in 116 of 260 (45 percent) patients overall (short-course radiation 34/82 (42 percent), long-course radiation 55/122 (45 percent), chemoradiation 27/56 (48 percent), P = not significant). Down-staging of one or more N stages occurred in 85 of 178 (48 percent) patients overall (short-course radiation 12/45 (27 percent), long-course radiation 49/86 (57 percent), chemoradiation 24/47 (51 percent), P = 0.003). Complete pathologic response was observed in 16 of 260 (6 percent) patients overall (short-course radiation 4/82 (5 percent), long-course radiation 5/122 (4 percent), chemoradiation 7/56 (13 percent), P = 0.08). Resection with negative margins (distal, proximal, and radial) was achieved in 211 of 227 patients (93 percent) in whom complete radial margin data were available. Permanent stomas were created in 35 percent of patients; temporary stomas were created in 15 percent. Thirty-three Grade 3 or 4 toxicities occurred in 22 of 260 (8 percent) patients overall during neoadjuvant therapy. Toxicity was more frequent in patients receiving chemoradiation (14/56; 25 percent) and long-course radiation (8/122; 7 percent) than in those receiving short-course radiation (0/82; 0 percent), P < 0.0001. Perioperative complications occurred in 93 patients overall (36 percent). The postoperative mortality rate was 0.4 percent (1/260). There was no significant difference in the complication rate between patients treated with short-course radiation (26/82; 32 percent), long-course radiation (46/122; 36 percent), and chemoradiation (21/56; 38 percent).

CONCLUSION

Neoadjuvant therapy for adenocarcinoma of the rectum is well tolerated and can produce substantial down-staging and a high curative resection rate. Chemoradiation can achieve high complete pathologic response rates, although toxicity during neoadjuvant therapy is greater than for radiation alone. Short-course radiation can achieve down-staging of both T stage and N stage.

Activity of multitargeted antifolate (pemetrexed disodium, LY231514) in patients with advanced colorectal carcinoma: results from a phase II study

BACKGROUND

The aim of this study was to confirm the activity and assess the safety profile of multitargeted antifolate (MTA) for patients with metastatic colorectal adenocarcinoma.

METHODS

Forty-six patients were enrolled in the study, 35 with colon and 11 with rectal carcinoma. Adjuvant therapy was allowed if completed 1 year previously. Patients received MTA 600 mg/m(2) as a 10-minute intravenous infusion once every 21 days. Blood samples were taken every cycle for pharmacokinetic and vitamin metabolite assays.

RESULTS

Among 39 patients eligible for efficacy analysis, 1 complete response and 5 partial responses were identified, for an overall response rate of 15.4% (95% confidence interval [CI], 4.1-26. 7%) for all patients. Fifteen patients had stable disease, with 9 living longer than 1 year. The median survival was 16.2 months (95% CI, 10.5-17.0%); 65% of patients were alive at 1 year, and the median time to progression was 4.4 months (range, 3.2-5.7 months). The main toxicities were hematologic, with common toxicity criteria (CTC) Grades 3 or 4 noted as follows: thrombocytopenia (18%), neutropenia (55%), and anemia (18%). Nonhematologic toxicities included Grade 2 or 3 skin reaction (53%), ameliorated by dexamethasone, and Grade 3 transaminases (23%). Dose omissions were not required and 21% of doses were reduced.

CONCLUSIONS

MTA has clear activity in patients with colorectal carcinoma, and encouraging survival times were noted. MTA was well tolerated in this patient group, but myelosuppression was frequent. Toxicity may be increased with folate deficiency.