A Single-institution Comparison of Cetuximab, Carboplatin, and Paclitaxel Induction Chemotherapy Followed by Chemoradiation (CRT) Versus CRT for Locally Advanced Squamous Cell Carcinoma of the Head and Neck (LA-SCCHN).

OBJECTIVES: Comparisons of induction chemotherapy (IC) against upfront chemoradiation (CRT) for locally advanced head and neck cancer (LA-HNSCC) have demonstrated no differences except greater toxicity with IC. Effective induction regimens that are less toxic are therefore warranted. To inform future efforts with IC, we present our institutional experience comparing a less toxic IC regimen to CRT. METHODS: We included patients with LA-HNSCC treated with organ-preservation CRT (+/-induction) between 2008 and 2011. Patients were of age above 18 years, ECOG performance status 0-1, and had minimum 6 months follow-up. IC consisted of 8 weekly cycles of cetuximab, carboplatin, and paclitaxel followed by CRT. The CRT regimen was platinum based, with cetuximab reserved for patients contraindicated to receive platinum. RESULTS: Of 118 patients, 24 (20%) received IC and 94 (80%) received CRT. Median follow-up was 17 (IC) and 19 (CRT) months (P=0.05). There were no differences in toxicity between the groups. IC patients were more likely male, with more advanced tumor and nodal stage. Even when controlling for these factors, IC was still associated with worse locoregional control (HR=3.6, P=0.02), distant metastasis-free survival (HR=5.3, P=0.02), and overall survival (HR=5.1, P<0.01). CONCLUSIONS: IC patients had greater disease burden than those receiving CRT. IC was well tolerated, but with significant rates of locoregional and systemic failures. Given the retrospective nature of the study, our findings are not meant to be definitive or conclusive, but rather suggestive in directing future efforts with IC. For now, we favor CRT as the standard option for treatment of inoperable LA-HNSCC.

Combined MTOR and autophagy inhibition: phase I trial of hydroxychloroquine and temsirolimus in patients with advanced solid tumors and melanoma.

The combination of temsirolimus (TEM), an MTOR inhibitor, and hydroxychloroquine (HCQ), an autophagy inhibitor, augments cell death in preclinical models. This phase 1 dose-escalation study evaluated the maximum tolerated dose (MTD), safety, preliminary activity, pharmacokinetics, and pharmacodynamics of HCQ in combination with TEM in cancer patients. In the dose escalation portion, 27 patients with advanced solid malignancies were enrolled, followed by a cohort expansion at the top dose level in 12 patients with metastatic melanoma. The combination of HCQ and TEM was well tolerated, and grade 3 or 4 toxicity was limited to anorexia (7%), fatigue (7%), and nausea (7%). An MTD was not reached for HCQ, and the recommended phase II dose was HCQ 600 mg twice daily in combination with TEM 25 mg weekly. Other common grade 1 or 2 toxicities included fatigue, anorexia, nausea, stomatitis, rash, and weight loss. No responses were observed; however, 14/21 (67%) patients in the dose escalation and 14/19 (74%) patients with melanoma achieved stable disease. The median progression-free survival in 13 melanoma patients treated with HCQ 1200mg/d in combination with TEM was 3.5 mo. Novel 18-fluorodeoxyglucose positron emission tomography (FDG-PET) measurements predicted clinical outcome and provided further evidence that the addition of HCQ to TEM produced metabolic stress on tumors in patients that experienced clinical benefit. Pharmacodynamic evidence of autophagy inhibition was evident in serial PBMC and tumor biopsies only in patients treated with 1200 mg daily HCQ. This study indicates that TEM and HCQ is safe and tolerable, modulates autophagy in patients, and has significant antitumor activity. Further studies combining MTOR and autophagy inhibitors in cancer patients are warranted.

Induction chemotherapy with cetuximab, carboplatin and paclitaxel for the treatment of locally advanced squamous cell carcinoma of the head and neck.

Although controversy exists in the management of locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN), clinicians often use induction chemotherapy for treatment of the most advanced cases. One promising regimen combines weekly cetuximab (400 mg/m2 loading dose followed by 250 mg/m2) with carboplatin (AUC of 2) and paclitaxel (90 mg/m2). We retrospectively evaluated patients treated with this regimen prior to definitive chemoradiation or surgery between May 2008 and December 2011. The primary endpoint used for this retrospective analysis was feasibility. Thirty consecutive, unselected patients were included. Median follow-up was 13.7 months (range, 5.0-38.7 months). All but one patient had stage IV SCCHN. Dose intensity was high for carboplatin (92%), paclitaxel (93%) and cetuximab (85%). Grade 3-4 toxicities occurred in <7% of the study population and were limited to rash, neutropenia and infusion reactions. Response rate (RR) to induction chemotherapy was 97% (30% complete response, 67% partial response). All patients completed subsequent chemoradiotherapy or surgery. Nineteen patients (63%) demonstrated a complete response and 11 patients (37%) demonstrated a partial response. Median overall survival and progression-free survival data are not yet mature. The RR to therapy in our off-protocol experience is at least comparable to that observed in the two phase II studies of this regimen and appears superior to that observed with docetaxel, cisplatin and fluorouracil (TPF).

A randomized phase II study of cetuximab every 2 weeks at either 500 or 750 mg/m2 for patients with recurrent or metastatic head and neck squamous cell cancer.

Cetuximab is typically administered on a weekly schedule for patients with recurrent or metastatic head and neck squamous cell cancer (HNSCC). This study explores cetuximab administered every 2 weeks (q2w). In this multicenter randomized prospective phase II study, eligible patients (≤2 prior cytotoxic chemotherapy regimens for recurrent or metastatic disease; ECOG performance status ≤2) were randomized to receive cetuximab q2w at 500 mg/m(2) (Group A) or 750 mg/m(2) (Group B). The primary end point was response rate (RECIST 1.0). Sixty-one patients were enrolled: 35 in Group A and 26 in Group B, which was closed early for lack of efficacy. Confirmed partial response rates were 11% for Group A (4/35) and 8% for Group B (2/26) according to intention to treat analysis. Partial responses occurred only among patients whose primary tumors were in the oral cavity or larynx. Median progression-free survival (PFS) and median overall survival (OS) were similar for both groups (PFS, 2.2 and 2.0 months; OS, 7.0 and 9.4 months; Groups A and B, respectively). The most common cetuximab-related adverse events (all grades) among treated subjects included rash, fatigue, and hypomagnesemia. Cetuximab, 500 mg/m(2), q2w achieves similar efficacy as conventional dosing for patients with recurrent or metastatic HNSCC. Escalating the dose to 750 mg/m(2) q2w offers no obvious therapeutic advantage.

Spontaneous smoking cessation before lung cancer diagnosis.

INTRODUCTION: We have observed that many patients with lung cancer stop smoking before diagnosis, usually before clinical symptoms, and often without difficulty. This led us to speculate that spontaneous smoking cessation may be a presenting symptom of lung cancer. METHODS: Patients from the Philadelphia Veterans Affairs Medical Center with lung cancer and for comparison, prostate cancer and myocardial infarction underwent a structured interview about their smoking habits preceding diagnosis. Severity of nicotine addiction was graded using the Fagerström Test for Nicotine Dependence. Among former smokers, dates of cessation, onset of symptoms, and diagnosis were recorded. Difficulty quitting was rated on a scale of 0 to 10. Distributions of intervals from cessation to diagnosis were compared between groups. RESULTS: All 115 patients with lung cancer had been smokers. Fifty-five (48%) quit before diagnosis, and only six of these (11%) were symptomatic at quitting. Patients with lung cancer who quit were as dependent on nicotine, when smoking the most, as those who continued to smoke, unlike the other groups. Despite this, 31% quit with no difficulty. The median interval from cessation to diagnosis was 2.7 years for lung cancer, 24.3 years for prostate cancer, and 10.0 years for patients with myocardial infarction. CONCLUSIONS: These results challenge the notion that patients with lung cancer usually quit smoking because of disease symptoms. The hypothesis that spontaneous smoking cessation may be a presenting symptom of lung cancer warrants further investigation.

Phase I study of Paclitaxel given by seven-week continuous infusion concurrent with radiation therapy for locally advanced non-small cell lung cancer.

BACKGROUND: Paclitaxel is active in non-small-cell lung cancer (NSCLC) and is a radiosensitizer with a dose-response relationship that depends more on duration of exposure than peak concentration. A continuous infusion prolongs exposure and may maximize the drug-radiation interaction. The goal of this National Cancer Institute-sponsored phase I study was to determine the feasibility and toxicity of a continuous infusion paclitaxel (24 hours/day, 7 days/week, 7 weeks total) concurrent with standard radiation therapy (RT) for locally advanced NSCLC. METHODS: Eligible patients had locally advanced (T4, N1-3, M0 or Tany, N2-3, M0) NSCLC, performance status less than or equal to 2, and adequate hematological, hepatic, renal, and pulmonary function. RT was given to a total dose of 64.8 Gy at 1.8 Gy/day. Paclitaxel was delivered by infusion beginning 48 hours before and then continuously throughout the 7 weeks of RT. The paclitaxel concentration was escalated in sequential dose cohorts ranging from 0.5 to 17 mg/m/d, and each contained at least three patients in a standard phase I design. RESULTS: Twenty-nine patients were enrolled. Significant grade 3+ toxicity was observed in one patient, who experienced grade 3 pneumonitis at the 6.5-mg/m/day dose level. This cohort was expanded, but none of four additional patients experienced significant toxicity. Three patients completed the 15-mg/m/day dose level without serious or dose-limiting toxicity. The two patients entered at the 17-mg/m/day dose level had grade 4 neutropenia requiring a delay in therapy of more than 1 week. The median survival of all patients was 12 months; however, 4 of 27 patients (15%) survived longer than 60 months (mean 63.4 months). CONCLUSION: The maximally tolerated and recommended phase II paclitaxel dose delivered by protracted continuous infusion is 15 mg/m/day when combined with thoracic RT. This schedule allows for the delivery of more total paclitaxel than other published regimens and may have less esophagitis than weekly paclitaxel regimens. This regimen has the potential to achieve a radiosensitizing serum concentration of paclitaxel continuously for 7 weeks without exceeding levels associated with neutropenia or neurotoxicity. There were four long-term survivors in this phase I study. These data suggest that continuous paclitaxel infusion with concurrent RT is safe and should be of interest to explore in combination with other cytotoxic or targeted therapies.

Gefitinib in patients with advanced non-small cell lung cancer (NSCLC): the expanded access protocol experience at the University of Pennsylvania.

Gefitinib (Iressa; AstraZeneca Pharmaceuticals, Wilmington, DE) is an oral epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) with favorable toxicity and antitumor activity in pretreated patients with non-small cell lung cancer (NSCLC). The purpose of this study was to evaluate the toxicity and efficacy of gefitinib in patients with advanced NSCLC treated at our institution as part of an expanded access protocol; 112 patients with advanced NSCLC were entered. All patients had failed at least one previous chemotherapy regimen, or were not suitable for any systemic chemotherapy because of poor performance status (PS), or were ineligible for other clinical trials. Therapy consisted of gefitinib 250 mg orally once daily; 10.5% (95% CI 5.3-17.9%) of patients achieved partial/minimal response (PR/MR) and 29.5% (95% CI 21.0-39.2%) had stable disease (SD), resulting in a disease control rate (PR/MR+SD) of 40% (95% CI 31-50%). The median duration of treatment for all patients was 12 weeks (range 2-116 weeks) and for patients achieving disease control 28 weeks (range 8-116). Nine patients received gefitinib for more than 1 year. Median survival was 30 weeks. Symptoms were improved in 36% of evaluable patients, and 64% of patients who achieved disease control experienced improvement of their disease related symptoms. Adverse events were generally mild and consisted mostly of skin rash (48%) and diarrhea (38%). A statistically significant association was observed between disease control and skin rash (p = < 0.001), nonsmoking status (p = 0.048), and symptom improvement (p = 0.001). The disease control rate was not statistically associated with histology, PS, gender, or number of prior treatments. In addition, longer survival was significantly associated with skin rash (p = < 0.001) and symptom improvement (p = < 0.001). Gefitinib demonstrated relevant clinical activity and a favorable toxicity profile in pretreated patients with advanced NSCLC. The development of toxicity was associated with a favorable response. In addition, a history of never having smoked seems to predict a higher efficacy of gefitinib.

A population-based study of lung carcinoma in Pennsylvania: comparison of Veterans Administration and civilian populations.

BACKGROUND: Lung carcinoma remains the major cause of cancer death in North America and is even more common among military veterans. The objective of this study was to determine whether there were differences in the characteristics and survival of Pennsylvania patients with lung carcinoma in the Veterans Administration (VA) hospital system compared with patients in the rest of the state. METHODS: The Pennsylvania Cancer Registry was used to identify all patients who were diagnosed with lung carcinoma in the State of Pennsylvania from 1995 to 1999. Patients who were treated within the Veterans Administration Health Care Network were identified by hospital code. Survival from the date of diagnosis of lung carcinoma was determined by using the Pennsylvania state mortality files from 1995 to 2001. RESULTS: From 1995 to 1999, 48,994 patients were newly diagnosed with lung carcinoma in Pennsylvania (41.2% women), including 856 patients in the VA system (6 women). The current analysis was restricted to male patients (n = 28,798 men). There was no major difference in age of VA patients compared with non-VA patients, and the proportions of patients who had localized or regional stage disease were similar (49% of VA patients vs. 48% of non-VA patients). The proportion of black patients was much higher in the VA population (23%) compared with the non-VA population (9%). The median survival was 6.3 months for VA patients compared with 7.9 months for patients in the rest of the state, and the 5-year overall survival rate was 12% for VA patients compared with 15% for patients in the rest of the state. When survival was analyzed according to race, there was a significant difference in the age-adjusted survival of white patients in the VA system compared with patients in the rest of the state (P = 0.0007), but no significant difference was observed among black patients (P = 0.92). CONCLUSIONS: The overall survival of VA patients with lung carcinoma in Pennsylvania was inferior to that of patients in the remainder of the state and this was due primarily to differences in survival among the white patients. Further investigation will be necessary to determine whether this disparity was caused by differences in socioeconomic status or comorbidities or whether there are systematic differences in the diagnosis, staging, or treatment of lung carcinoma between VA patients and civilian patients.

A phase I, dose escalation trial of ZD0473, a novel platinum analogue, in combination with gemcitabine.

PURPOSE: To develop a combination regimen for clinical testing, we performed a dose escalation study of ZD0473 in combination with gemcitabine. ZD0473 is a novel platinum analogue with an aliphatic cyclic carrier ligand. In vitro and in vivo studies suggest that it possesses a different spectrum of antitumor activity from cisplatin and carboplatin. In single-agent studies of ZD0473, myelosuppression was the predominant toxicity and responses wer observed. METHODS: In this combination phase I trial, 36 patients with advanced cancer were accrued to four dose levels, with doses of ZD0473 and gemcitabine ranging from 60 to 120 mg/m2 and 600 to 750 mg/m2, respectively ZD0473 was administered on day 1 and gemcitabine was given on days 1 and 8 of a 21-day cycle. RESULTS: Hematologic toxicity was dose-limiting. Grade 3 and 4 thrombocytopenia and neutropenia occurred during 60% and 41% of all cycles. Nonhematologic toxicities were mild and reversible. Two partial responses and 19 patients with stable disease were observed. CONCLUSIONS: The recommended phase II doses are 90 mg/m2 of ZD0473 and 750 mg/m2 of gemcitabine for lightly pretreated patients and 600 mg/m2 for heavily pretreated patients. The combination of ZD0473 and gemcitabine is associated with dose-dependent thrombocytopenia and neutropenia as well as having promising clinical activity.

Phase I trial of the antifolate ZD9331 in combination with cisplatin in patients with refractory solid malignancies.

PURPOSE: To determine the maximum tolerated dose and dose-limiting toxicities (DLTs) of ZD9331 in combination with cisplatin in patients with refractory solid tumors and to describe any preliminary antitumor activity associated with this regimen. MATERIALS AND METHODS: Patients received combination therapy with ZD9331 as a 30-min infusion on days 1 and 8 of a 21-day cycle at doses of 100 or 130 mg/m(2), followed by cisplatin at 50 or 75 mg/m(2) as a 30- to 60-min infusion on day 1 only. RESULTS: A total of 16 patients received 59 cycles of ZD9331 and cisplatin. Patients were enrolled at three dose levels: ZD9331/cisplatin 100/50 ( n=3), 130/50 ( n=9), 130/75 ( n=4). DLTs at 130/75 included thrombocytopenia, neutropenia, fatigue, nausea, vomiting and stomatitis. Among 15 evaluable patients, 2 showed a partial response (patients with mesothelioma and head and neck cancer) and 6 showed stable disease (for a median of 5.5 cycles). CONCLUSIONS: ZD9331 in combination with cisplatin was well tolerated at a dose of 130/50 mg/m(2) after establishing the principal DLTs of neutropenia and thrombocytopenia. The combination shows evidence of antitumor activity in a pretreated population.

Two commonly used neoadjuvant chemoradiotherapy regimens for locally advanced stage III non-small cell lung carcinoma: long-term results and associations with pathologic response.

BACKGROUND: We performed this study to determine the outcomes (pathologic response, survival, local-regional control, and toxicity) in patients treated with neoadjuvant chemoradiotherapy and planned operation for stage IIIA non-small cell lung carcinoma. METHODS: Patients treated from 1993 to 2000 with neoadjuvant chemoradiotherapy and a predetermined plan for subsequent surgical resection for stage III non-small cell lung carcinoma were analyzed. All patients underwent pretreatment evaluation at the university's Multidisciplinary Lung Cancer Center. Most patients (87%) had complete mediastinoscopy staging, and all were believed to be poor candidates for up-front operation because of bulky extent of disease. The radiotherapy program used conventional, 2-dimensionally planned treatment to 45 to 54 Gy in 1.8- to 2-Gy fraction size. Concurrent chemotherapy consisted of etoposide/cisplatin or carboplatin/paclitaxel. Study end points included resectability, pathologic response, local-regional control, survival, and toxicity. An exploratory comparison between pathologic response and long-term survival was performed. An exploratory comparison between older chemotherapy (etoposide/cisplatin) and third-generation chemotherapy (carboplatin/paclitaxel) was also performed. RESULTS: Of 53 patients, 45 (85%) were deemed surgical candidates after induction therapy. Twenty-two (42% of the initial cohort) patients had a major pathologic response to stage 0, I, or II disease. The 5-year actuarial survival was 31%. Major pathologic response was associated with improved survival (48% vs 24%; P =.027). The overall rate of early death potentially related to therapy in this series was 9%; this mostly occurred in patients who underwent right pneumonectomy. There was no difference in efficacy or mortality between etoposide/cisplatin and radiotherapy versus carboplatin/paclitaxel and radiotherapy, although the latter regimen was associated with less grade 3 or higher acute toxicity necessitating interruption or hospitalization during neoadjuvant treatment (P =.02). In-field local control was achieved in 83% of all patients (90% of the patients who underwent resection). Brain metastases as the first site of treatment failure occurred in 23% of all patients. CONCLUSIONS: Neoadjuvant concurrent chemoradiation delivers high resectability, major pathologic response rate, and excellent local-regional control, with encouraging long-term survival considering the patient population studied. Major pathologic response correlates with long-term survival. Neoadjuvant carboplatin/paclitaxel and radiotherapy is an appropriate framework on which to add new therapies.

Dose escalation study of tezacitabine in combination with cisplatin in patients with advanced cancer.

BACKGROUND: The authors performed a dose escalation study of cisplatin and the novel deoxycytidine analog, tezacitabine, to determine the maximum tolerated dose of the combination. METHODS: Twenty-three patients with advanced cancer and good performance status were accrued to 3 dose levels of tezacitabine (150-270 mg/m(2)) and cisplatin (50 mg/m(2)). Using a 28-day treatment cycle, both drugs were administered on Days 1 and 15. RESULTS: Hematologic toxicity was the most frequently observed side effect and was dose limiting. Grade 3 or 4 neutropenia and thrombocytopenia complicated 75% and 31% of all cycles, respectively. Nonhematologic toxicities were mild. Among 18 evaluable patients, 2 with upper gastrointestinal tract tumors achieved partial responses and 4 had stable disease. CONCLUSIONS: Based on dose-limiting neutropenia and thrombocytopenia at the highest dose level, the recommended Phase II doses are 200 mg/m(2) of tezacitabine and 50 mg/m(2) of cisplatin.

Phase I and pharmacokinetic trial of the proapoptotic sulindac analog CP-461 in patients with advanced cancer.

CP-461 is a member of a class of novel proapoptotic drugs that specifically inhibit cyclic GMP phosphodiesterases but not cyclooxygenase-1 or -2. CP-461 inhibits the growth of a broad range of human tumor cell lines in vitro at micromolar concentrations and selectively induces apoptosis in cancer cell lines but not normal cells. Preclinical studies revealed good oral bioavailability and no toxicity in dogs and rats at single doses up to 500 mg/kg. In a Phase I trial, 21 patients with a range of solid tumors and good performance status received CP-461 p.o. twice daily for 28 consecutive days. Cycles were repeated without a treatment-free interval. CP-461 doses ranged from 100 to 800 mg/day. Therapy was well tolerated overall, and a maximum tolerated dose was not reached. Grade 3 asymptomatic aspartate aminotransferase/alanine aminotransferase elevation in 1 patient treated at 800 mg/day was the only dose-limiting toxicity. No hematologic toxicity was noted. Peak plasma concentrations occurred between 1 and 2 h after dosing, and doses above 200 mg/day exceeded the known in vitro EC(50) (1-2 micro M) for apoptosis in cancer cells. No drug was detectable after 24 h of administration, and the terminal half-life was 6.7 h. The area under the plasma concentration-time curve was dose-proportional from 200 to 800 mg/day. Four patients exhibited disease stability after two cycles of treatment. CP-461 is minimally toxic at doses up to 800 mg/day when administered p.o. on a twice-daily schedule.

A phase I study of SPI-077 (Stealth liposomal cisplatin) concurrent with radiation therapy for locally advanced head and neck cancer.

BACKGROUND: Liposomal cisplatin preparations have two potential advantages over the free drug when combined with radiation therapy (RT): 1) selective tumor localization, improving the therapeutic ratio, and 2) prolonged half-life, allowing more radiosensitization. We performed a Phase I study of Stealth liposomal cisplatin (SPI-077) concurrent with RT for head and neck squamous cell carcinoma (HNSCC). METHODS: Patients with Stage IVa/b HNSCC were treated with SPI-077, given intravenously twice two weeks apart, concurrent with RT (60-72 Gy in 6-7 weeks). The SPI-077 dose was escalated in standard phase I design. RESULTS: Twenty patients received 38 doses of SPI-077, escalated from 20-200 mg/m2 in six dose levels. Two of these patients received one dose because of reversible Grade 3 liver toxicity or rash. Three patients had a Grade 1, and one had a Grade 2 infusion reaction. Four patients had transiently elevated transaminases: Grade I (n = 1), Grade 2 (n = 1), and Grade 3 (n = 2). Grade 3 neutropenia occurred in one patient. There was no ototoxicity, neurotoxicity, or nephrotoxicity. In-field radiation skin and mucosal toxicities did not appear to be intensified. Ten of 17 patients (59%) finishing treatment achieved initial complete response. CONCLUSIONS: Systemic and in-field radiation toxicities of SPI-077 were minimal. Infusion reactions were minimized with a slower and more dilute initial infusion. Further dose escalation was stopped in the absence of dose-limiting toxicity to address the reformulation of the liposomally bound cisplatin. Nonetheless, this study shows that high doses of SPI-077 can be given safely. The potentially beneficial therapeutic ratio suggests that liposomal radiosensitizer preparations warrant further investigation.

Clinical and molecular features of small cell lung cancer.

Small cell lung cancer is a common malignancy found in smokers. It has a poor long-term prognosis despite initial sensitivity to chemotherapy and radiation. The clinical features of small cell lung cancer are unique among lung cancers and other neuroendocrine tumors. In order to better understand the pathogenesis of small cell lung cancer, there has been a great effort to identify the genetic alterations involved in the development and progression of the disease, and to translate these to novel molecular strategies for treatment.

Phase I trial of the cryptophycin analogue LY355703 administered as an intravenous infusion on a day 1 and 8 schedule every 21 days.

The cryptophycin analogue LY355703 is a potent inhibitor of microtubule polymerization that displays in vitro and in vivo activity in cell lines and tumor xenografts displaying the multidrug-resistant phenotype. In a Phase I trial, 25 patients received LY355703 as a 2-h i.v. infusion on day 1 and day 8 repeated every 3 weeks. Doses were escalated from 0.1 to 2.22 mg/m2 using a modified continual reassessment method. Neurological toxicity was found to be dose-limiting at 1.84 and 2.22 mg/m2. Among four patients treated at these doses, two had grade 4 constipation/ileus, one with severe myalgias, and one had grade 3 motor neuropathy. These findings were reversible. The 1.5 mg/m2 dose level was well tolerated. An amended twice-weekly schedule was pursued in 11 patients in an attempt to improve dose intensity and avoid dose-limiting neurotoxicity. Doses of >0.75 mg/m2 on a day 1, 4, 8, and 11 schedule every 21 days were not tolerated as a result of nausea/constipation, suggesting that LY335703 toxicity is not schedule dependent and is related to cumulative dose. LY355703 plasma concentrations measured by liquid chromatography with tandem mass spectrometry were evaluated using a population pharmacokinetic model. LY355703 was eliminated rapidly with a short terminal half-life that ranged from 0.8 to 3.9 h. Interpatient variability with respect to plasma clearance and volume of distribution, including covariates, was moderate at 32% and 39%, respectively. Maximum plasma concentration and area under the plasma concentration-time curve were linear over the dose range studied. A patient with non-small cell lung cancer previously treated with taxanes experienced a partial response lasting 4 months, and five patients had stable disease lasting > or =3 months. LY355703 at a dose of 1.5 mg/m2 is recommended for Phase II evaluation on a days 1 and 8 schedule. Twice-weekly dosing did not allow improvement in dose intensity or tolerability.