Order of patient entry and outcomes in phase II clinical trials: A meta-analysis of individual patient data

BACKGROUND

Prior meta-analysis of stem-cell transplantation trials for renal-cell carcinoma observed that clinical outcomes vary by subjects' order of entry, specifically their quartile of accrual. We test this hypothesis using meta-analysis of individual patient data from diverse Phase II trials conducted by an oncology consortium.

METHODS

Eligible were all Phase II trials in hematologic or solid tumors opened and closed by California Cancer Consortium during 2005-2020. Excluded were trials closed in first quartile or currently embargoed pending publication and subjects ineligible per protocol or untreated on study. The primary risk factor was entry by quartile of planned sample size. As a cross-protocol endpoint, primary outcome was time to discontinuation of intervention. One-stage meta-analysis used a shared frailty model with trial as random effect. As covariates, stepwise selection retained tumor type, obesity, their interaction, calendar year, entry at least 3 years post-diagnosis, and performance status but rejected age, sex, randomized design, and class of drug.

RESULTS

Twenty trials (including 8 terminated early, 2 not published) included n = 923 subjects. Most (90.6%) subjects discontinued intervention, usually for disease progression or toxicity. Independently of covariates, risk of discontinuation increased (p < 0.0001) with each quartile of entry (Hazards Ratio 1.13, 95% CI 1.06-1.22), culminating at Quartile 4 (HR 1.46, 1.36-1.57). The 95% prediction interval for the Hazards Ratio in future trials was (1.04-1.24). Progression-free survival similarly worsened by quartile of entry.

CONCLUSION

In Phase II trials, clinical outcome worsens with quartile of entry. This finding merits independent replication, and the cause of this phenomenon merits investigation.

Osimertinib plus necitumumab in EGFR-mutant NSCLC: Final results from an ETCTN California Cancer Consortium phase I study

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Background: Osimertinib (Osi) is standard of care in 1st line (1L) EGFR mut NSCLC and TKI resistant T790Mpos NSCLC but acquired resistance emerges; outcomes are less robust in T790Mneg, C797Xpos and EGFR exon 20 insertion (ex20ins) disease. We examined Osi with the EGFR monoclonal antibody Necitumumab (Neci) in select settings of EGFR TKI resistance. Methods: Pts were accrued to 5 expansion cohorts (ExC) at recommended phase 2 dose (RP2D) of Osi 80 mg daily and Neci 800 mg D1 + D8 of q21d cycle. ExC (18 pts/cohort): A) T790Mneg progressive disease (PD) on 1st/2nd gen TKI as last therapy, B) T790Mneg PD on 1st/2nd gen TKI and PD on 3rd gen TKI, C) T790Mpos PD on 1st/2nd gen TKI and PD on 3rd gen TKI, D) EGFR ex20ins PD on chemotherapy, E) PD on 1L osi. In ExC A-C, T790M was confirmed centrally (tissue) by ddPCR. Additional correlative studies include: tissue NGS (> 400 gene panel), EGFR FISH, plasma for PK and serial EGFR ctDNA by ddPCR. Adverse events were graded (Gr) by CTCAEv5; ORR, PFS by RECIST 1.1. Primary pre-specified efficacy endpoint ≥3/18 pts responding per cohort. Results: 101 patients accrued (100 evaluable). Efficacy is summarized in the Table. Drug related Gr 3 AEs were seen in 38% of pts, mainly rash (21%). ORR among all pts was 19% (95% CI 12-28%) that varied across cohorts (Table). In ExC A-C, 69% pts had detectable EGFR activating mutations in ctDNA, with decline in mutant allele frequency (AF) on treatment in 80% and ctDNA clearance in 33%. Conclusions: Osi/Neci is feasible and tolerable at the RP2D. EGFR ctDNA was detectable at baseline in the majority of pts with decrease in AF on treatment. Osi/Neci was active in select settings of EGFR-TKI resistance, meeting its prespecified efficacy endpoint in T790Mneg PD on 1st/2nd gen TKI as last therapy (ExC A), EGFR ex20ins post-chemo (ExC D) and PD on 1L osimertinib (ExC E). mPFS in the EGFR ex20ins cohort was within the range of current EGFR Exon 20 ins agents in development. EGFR monoclonal antibodies with osimertinib warrant further study in settings of de novo and acquired EGFR dependent resistance to EGFR-TKI. Clinical trial information: NCT02496663. [Table: see text]

Erlotinib and Onalespib Lactate Focused on EGFR Exon 20 Insertion Non-Small Cell Lung Cancer (NSCLC): A California Cancer Consortium Phase I/II Trial (NCI 9878)

This study examined the safety and tolerability of erlotinib and the heat shock protein 90 inhibitor onalespib in EGFR-mutant non–small cell lung cancer (NSCLC). The phase II component examined preliminary efficacy in epidermal growth factor receptor exon 20 insertion (EGFRex20ins) NSCLC. Overlapping toxicities, mainly diarrhea, limited the tolerability of the combination. EGFRex20ins circulating tumor DNA (ctDNA) was detected in the majority of patients; failure to clear ctDNA was consistent with lack of tumor response.

A phase I study of intravenous fenretinide (4-HPR) for patients with malignant solid tumors

BACKGROUND

Fenretinide is a synthetic retinoid that can induce cytotoxicity by several mechanisms. Achieving effective systemic exposure with oral formulations has been challenging. An intravenous lipid emulsion fenretinide formulation was developed to overcome this barrier. We conducted a study to establish the maximum tolerated dose (MTD), preliminary efficacy, and pharmacokinetics of intravenous lipid emulsion fenretinide in patients with advanced solid tumors.

METHODS

Twenty-three patients with advanced solid tumors refractory to standard treatments received fenretinide as a continuous infusion for five consecutive days in 21-day cycles. Five different dose cohorts were evaluated between doses of 905 mg/m² and 1414 mg/m² per day using a 3 + 3 dose escalation design. A priming dose of 600 mg/m² on day 1 was introduced in an attempt to address the asymptomatic serum triglyceride elevations related to the lipid emulsion.

RESULTS

The treatment-related adverse events occurring in ≥ 20% of patients were anemia, hypertriglyceridemia, fatigue, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) increase, thrombocytopenia, bilirubin increase, and dry skin. Five evaluable patients had stable disease as best response, and no patients had objective responses. Plasma steady-state concentrations of the active metabolite were significantly higher than with previous capsule formulations.

CONCLUSION

Fenretinide emulsion intravenous infusion had a manageable safety profile and achieved higher plasma steady-state concentrations of the active metabolite compared to previous capsule formulations. Single-agent activity was minimal but combinatorial approaches are under evaluation.

Untenable dosing: A common pitfall of modern DLT-targeting Phase I designs in oncology

BACKGROUND

There is increasing use of Phase I statistical designs to find a dose that causes rapidly emerging and particularly concerning severe or life-threatening toxicities (dose-limiting toxicities, DLTs) in a specified percent of patients most commonly 25%. While a convenient statistical framework, the foundation for selecting any specified target DLT rate, and its relevance to the recommended Phase II dose is generally lacking.

METHOD

We surveyed 78 medical oncologists, most (69%) with experience as a principal investigator on a Phase I study, to ascertain their opinions related to this approach to Phase I studies and the targets often chosen.

RESULTS

Eighty-seven percent of respondents preferred severe toxicities in only 5%-10% of patients, consistent with 58% of respondents noting that 10% or fewer patients experience severe toxicities in the first cycle with standard outpatient treatments. The survey also documented in an example that the majority (62%) of physicians modify their patient selection during the conduct of the study based on observed toxicity and 78% note that higher toxicity is acceptable in patients where a cure is more likely.

CONCLUSION

DLT-target rate designs search for a single target that is rarely well-supported in a patient population that is not stable. The most common target used is inconsistent with the toxicity of most clinically used drugs and investigator preference and can lead to the pursuit of unacceptable doses. Use of Phase I trial designs with a target DLT rate should be limited to settings with a well-justified target and should specify how the target relates to the recommended Phase II dose.

Phase I study of TRC102 in combination with cisplatin and pemetrexed in patients with advanced solid tumors/Phase II study of TRC102 with pemetrexed in patients with mesothelioma refractory to pemetrexed and cisplatin or carboplatin

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Background: Treatment options remain limited in malignant pleural mesothelioma refractory to pemetrexed +/- platinum. TRC102 (methoxyamine hydrochloride) is a novel biochemical inhibitor of the BER pathway. Available data support the hypothesis that TRC102 bound DNA is a substrate for topoisomerase II, which cleaves TRC102-bound DNA sites to produce strand breaks in cancer cells that cause cellular apoptosis and enhance the cytotoxic effects of chemotherapy. Methods: This was a parallel cohort trial of a Phase I of TRC102 in combination with cisplatin (CDDP) and pemetrexed in patients with advanced solid tumors (Arm A) and a Phase II of TRC102 with pemetrexed in patients with mesothelioma refractory to platinum and pemetrexed (Arm B). Results: In Arm A dose escalation, 16 pts (11M/5F) were treated; 9 evaluable through 3 TRC102 dose levels (50, 75, and 100 mg/day, PO), with CDDP 60 mg/m2 and pemetrexed 500 mg/m2 (levels 1- 3); and 5 evaluable at TRC102 100 mg/day PO, CDDP 75 mg/m2, pemetrexed 500 mg/m2 (level 4). Cycles were every 21 days. There were no DLT’s, establishing level 4 as the RP2D. The only grade 4 treatment-related AE was thrombocytopenia on cycle 22 (level 2). Cycle 1 grade 3 AEs were 1 hypophosphatemia (level 1) and 1 leukopenia (level 2). There were 3 PRs (all parotid salivary gland tumors). Median PFS (95%CI) = 7.1% (1.4 – 15.5) mos. Arm B was designed as the first stage of a two stage Gehan design trial of patients with mesothelioma who had progressed on or recurred within 6 months of pemetrexed + platinum frontline treatment. 14 pts were treated with TRC102 50 mg/day D1-4 and pemetrexed 500 mg/m2 every 21 days. There were 2 PRs (both in epithelioid cancer of which 1 was confirmed), meeting the pre-specified criteria for continued interest ( > 0/14). mPFS (95% CI) was 4.3 (1.4 - 6.8) mos. 8 pts had stable disease for at least 1 cycle (4 stable at cycles 6, 9, 10 and 12). There were 1 grade 4 neutropenia and 5 grade 3 AE’s (1 each – anemia, neutropenia, leukopenia, fatigue, hyponatremia). Conclusions: TRC102 in combination with CDDP and pemetrexed exhibited antitumor activity, particularly in salivary gland tumors, and a tolerable safety profile at the doses tested. The combination of TRC102 and pemetrexed demonstrated activity in malignant mesothelioma that progressed on prior pemetrexed. Additional studies are warranted to confirm preliminary signals of activity. Clinical trial information: NCT02535312.

Model of a Queuing Approach for Patient Accrual in Phase 1 Oncology Studies

IMPORTANCE

Phase 1 cancer studies, which guide dose selection for subsequent studies, are almost 3 times more prevalent than phase 3 studies and have a median study duration considerably longer than 2 years, which constitutes a major component of drug development time.

OBJECTIVE

To discern a method to reduce the duration of phase 1 studies in adult and pediatric cancer studies without violating risk limits by better accommodating the accrual and evaluation process (or queue).

DESIGN

The process modeled, the phase 1 queue (IQ), includes patient interarrival time, screening, and dose-limiting toxicity evaluation. For this proof of principle, the rules of the 3 + 3 and rolling 6 phase 1 designs were modified to improve patient flow through the queue without exceeding the maximum risk permitted in the parent designs. The resulting designs, the IQ 3 + 3 and the IQ rolling 6, were each compared with their parent design by simulations in 12 different scenarios.

MAIN OUTCOMES AND MEASURES

(1) The time from study opening to determination of the maximum tolerated dose (MTD), (2) the number of patients treated to determine the MTD, and (3) the association of the design with the dose selected as the MTD.

RESULTS

Based on 800 simulations, for all 12 scenarios considered, the IQ 3 + 3 and the IQ rolling 6 designs were associated with reduced expected study durations compared with the parent design. The expected IQ 3 + 3 reduction ranged from 1.6 to 10.4 months (with 3.7 months for the standard scenario), and the expected reduction associated with IQ rolling 6 ranged from 0.4 to 10.5 months (with 3.4 months for the standard scenario). The increase in the mean number of patients treated in the IQ 3 + 3 compared with the 3 + 3 ranged from 0.6 to 3.2 patients. No increase in the number of patients was associated with the IQ rolling 6 compared with the rolling 6 design. The probability of selecting a dose level as the MTD changed by less than 3% for all dose levels and scenarios in both parent designs.

CONCLUSIONS AND RELEVANCE

This study found that IQ designs were associated with reduced mean duration of phase 1 studies compared with their parent designs without changing the risk limits or MTD selection operating characteristics. These approaches have been successfully implemented in both hematology and solid tumor phase 1 studies.

Intravenous 5-fluoro-2'-deoxycytidine administered with tetrahydrouridine increases the proportion of p16-expressing circulating tumor cells in patients with advanced solid tumors

PURPOSE

Following promising responses to the DNA methyltransferase (DNMT) inhibitor 5-fluoro-2'-deoxycytidine (FdCyd) combined with tetrahydrouridine (THU) in phase 1 testing, we initiated a non-randomized phase 2 study to assess response to this combination in patients with advanced solid tumor types for which tumor suppressor gene methylation is potentially prognostic. To obtain pharmacodynamic evidence for DNMT inhibition by FdCyd, we developed a novel method for detecting expression of tumor suppressor protein p16/INK4A in circulating tumor cells (CTCs).

METHODS

Patients in histology-specific strata (breast, head and neck [H&N], or non-small cell lung cancers [NSCLC] or urothelial transitional cell carcinoma) were administered FdCyd (100 mg/m2) and THU (350 mg/m2) intravenously 5 days/week for 2 weeks, in 28-day cycles, and progression-free survival (PFS) rate and objective response rate (ORR) were evaluated. Blood specimens were collected for CTC analysis.

RESULTS

Ninety-three eligible patients were enrolled (29 breast, 21 H&N, 25 NSCLC, and 18 urothelial). There were three partial responses. All strata were terminated early due to insufficient responses (H&N, NSCLC) or slow accrual (breast, urothelial). However, the preliminary 4-month PFS rate (42%) in the urothelial stratum exceeded the predefined goal-though the ORR (5.6%) did not. An increase in the proportion of p16-expressing cytokeratin-positive CTCs was detected in 69% of patients evaluable for clinical and CTC response, but was not significantly associated with clinical response.

CONCLUSION

Further study of FdCyd + THU is potentially warranted in urothelial carcinoma but not NSCLC or breast or H&N cancer. Increase in the proportion of p16-expressing cytokeratin-positive CTCs is a pharmacodynamic marker of FdCyd target engagement.

Phase 1 study of the Aurora kinase A inhibitor alisertib (MLN8237) combined with the histone deacetylase inhibitor vorinostat in lymphoid malignancies

Alisertib, an Aurora kinase A inhibitor, was evaluated in a Phase 1 study in combination with the histone deacetylase inhibitor vorinostat, in patients with relapsed/refractory lymphoid malignancies (N = 34; NCT01567709). Patients received alisertib plus vorinostat in 21-day treatment cycles with escalating doses of alisertib following a continuous or an intermittent schedule. All dose-limiting toxicities (DLTs) were hematologic and there were no study-related deaths. The recommended phase 2 dose (RP2D) of the combination was 20 mg bid of alisertib and 200 mg bid of vorinostat on the intermittent schedule. A 13-patient expansion cohort was treated for a total of 18 patients at the RP2D. There were no DLTs at the RP2D, and toxicities were mainly hematologic. Two patients with DLBCL achieved a durable complete response, and two patients with HL achieved partial response. Alisertib plus vorinostat showed encouraging clinical activity with a manageable safety profile in heavily pretreated patients with advanced disease.

Inhibition of MDR1 Overcomes Resistance to Brentuximab Vedotin in Hodgkin Lymphoma

PURPOSE

In classical Hodgkin lymphoma, the malignant Reed-Sternberg cells express the cell surface marker CD30. Brentuximab vedotin is an antibody-drug conjugate (ADC) that selectively delivers a potent cytotoxic agent, monomethyl auristatin E (MMAE), to CD30-positive cells. Although brentuximab vedotin elicits a high response rate (75%) in relapsed/refractory Hodgkin lymphoma, most patients who respond to brentuximab vedotin eventually develop resistance.

PATIENTS AND METHODS

We developed two brentuximab vedotin-resistant Hodgkin lymphoma cell line models using a pulsatile approach and observed that resistance to brentuximab vedotin is associated with an upregulation of multidrug resistance-1 (MDR1). We then conducted a phase I trial combining brentuximab vedotin and cyclosporine A (CsA) in patients with relapsed/refractory Hodgkin lymphoma.

RESULTS

Here, we show that competitive inhibition of MDR1 restored sensitivity to brentuximab vedotin in our brentuximab vedotin-resistant cell lines by increasing intracellular MMAE levels, and potentiated brentuximab vedotin activity in brentuximab vedotin-resistant Hodgkin lymphoma tumors in a human xenograft mouse model. In our phase I trial, the combination of brentuximab vedotin and CsA was tolerable and produced an overall and complete response rate of 75% and 42% in a population of patients who were nearly all refractory to brentuximab vedotin.

CONCLUSIONS

This study may provide a new therapeutic strategy to combat brentuximab vedotin resistance in Hodgkin lymphoma. This is the first study reporting an effect of multidrug resistance modulation on the therapeutic activity of an ADC in humans. The expansion phase of the trial is ongoing and enrolling patients who are refractory to brentuximab vedotin to confirm clinical activity in this population with unmet need.

Abstract B018: Restoration of p16INK4A expression in circulating tumor cells in patients with advanced solid tumors treated with deoxycytidine analogs and associated dynamic EMT phenotypic changes

Background. In vitro experiments from multiple laboratories have shown that the methylation-induced silencing of the p16INK4A gene, a tumor suppressor gene, can be reversed by DNA methyltransferase (DNMT1) inhibitor-based epigenetic modulation. However, it remains unclear whether DNMT1 inhibitors induce re-expression of p16INK4A in patients treated with demethylation promoting agents. Here we report p16INK4A expression status in human circulating tumor cells (CTCs) and its dynamic changes during DNMT1 inhibitor therapy in patients with advanced solid tumors, by using a novel CTC-based p16INK4A immunofluorescence assay. Methods. We demonstrated in vitro re-expression of p16 by Western blot and whole cell immunofluorescence in EJ-6 cells treated with decitabine, 4-thio-2’-deoxycytidine (TdCyd) and 5-fluoro-2’-deoxyctidine (FdC) but not in the p16-deleted line A549. We analyzed p16 re-expression in epithelial /mesenchymal CTC subpopulations as a clinical pharmacodynamic (PD) marker to assess the effects of DNMT1 inhibitors (analyzed using CellSearch® and fluorescence microscopy). Results. Over 300 specimens from 70 patients were analyzed from patients enrolled in both Phase 1 and Phase 2 clinical trials of the DNMT1 inhibitors TdCyd or FdC in combination with tetrahydrouridine (THU). Circulating tumor cells were characterized as DAPI+/CD45-/CEA or MUC1 positive, then classified as epithelial or mesenchymal based on expression of (pan-)cytokeratin (CK) or vimentin (VIM), respectively. The p16INK4A-positive CTC baseline level ranged from 0 to 15% in 57 of 58 patients with assessable CK+CTC numbers and in 46 of 53 patients with assessable VIM+CTC numbers. There were no patient specimens with CTCs that were positive for only VIM, but most specimens had higher numbers of VIM+ CTC compared to CK+ CTC, and not all patients had both CTC phenotypes present at baseline. During treatment with DNMT1 inhibitors, p16INK4A-positive CTCs increased in 46 of 58 patients with assessable CK+ CTCs (epithelial phenotype), but only 6 patients with VIM+ CTCs (mesenchymal phenotype) had p16 re-expression, and these patients had both CTC phenotypes present. The restoration of p16INK4A expression in CTC, not the CTC number, was correlated with evidence of drug clinical activity in patients. Drug treatment longer than 2 cycles was associated with both EMT phenotypic conversion and obvious morphological changes in CTCs that accompanied increased p16INK4A expression. Conclusions. Our studies indicate that monitoring dynamic changes of CTC-based p16INK4A expression is a sensitive PD biomarker for assessing DNMT1-targeted epigenetic anticancer therapeutics in clinical development. CTCs were predominantly mesenchymal phenotype. In addition, the CTC phenotype (epithelial vs mesenchymal) appeared to be quite dynamic in treated patients. Funded by NCI Contract No. HHSN261200800001E, and Cooperative Agreements U01CA062505 and UM1CA186717.

Citation Format: Lihua Wang, Brandon Miller, Sonny Khin, Geraldine O’Sullivan-Coyne, Alice P. Chen, Shivaani Kummar, Naoko Takebe, Kate Ferry-Galow, Ralph E. Parchment, Larry Rubinstein, Richard Piekarz, Edward M. Newman, James H. Doroshow, Robert J. Kinders. Restoration of p16INK4A expression in circulating tumor cells in patients with advanced solid tumors treated with deoxycytidine analogs and associated dynamic EMT phenotypic changes [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B018. doi:10.1158/1535-7163.TARG-19-B018

Phase I trial of belinostat in combination with 13-cis-retinoic acid in advanced solid tumor malignancies: a California Cancer Consortium NCI/CTEP sponsored trial

PURPOSE

The reported maximum tolerated dose (MTD) of single-agent belinostat is 1000 mg/m² given days 1-5, every 21 days. Pre-clinical evidence suggests histone deacetylase inhibitors enhance retinoic acid signaling in a variety of solid tumors. We conducted a phase I study of belinostat combined with 50-100 mg/m²/day 13-cis-retinoic acid (13-cRA) in patients with advanced solid tumors.

METHODS

Belinostat was administered days 1-5 and 13-cRA days 1-14, every 21 days. Dose-limiting toxicity (DLT) was defined as cycle 1 hematologic toxicity grade ≥ 3 not resolving to grade ≤ 1 within 1 week or non-hematologic toxicity grade ≥ 3 (except controlled nausea and vomiting and transient liver function abnormalities) attributable to belinostat.

RESULTS

Among 51 patients, two DLTs were observed: grade 3 hypersensitivity with dizziness and hypoxia at 1700 mg/m²/day belinostat with 100 mg/m²/day 13-cRA, and grade 3 allergic reaction at 2000 mg/m²/day belinostat with 100 mg/m²/day 13-cRA. The MTD was not reached. Pharmacokinetics of belinostat may be non-linear at high doses. Ten patients had stable disease, including one with neuroendocrine pancreatic cancer for 56 cycles, one with breast cancer for 12 cycles, and one with lung cancer for 8 cycles. Partial responses included a patient with keratinizing squamous cell carcinoma of the tonsils, and a patient with lung cancer.

CONCLUSIONS

The combination of belinostat 2000 mg/m² days 1-5 and 13-cRA 100 mg/m² days 1-14, every 21 days, was well-tolerated and an MTD was not reached despite doubling the established single-agent MTD of belinostat.

A Phase I Study of the Combination of Rituximab and Ipilimumab in Patients with Relapsed/Refractory B-Cell Lymphoma

PURPOSE

Based on the potential for ipilimumab (I) to augment T-cell activation, we hypothesize that ipilimumab would augment the efficacy of rituximab (R) in patients with relapsed/refractory (R/R) CD20⁺non-Hodgkin's lymphoma (NHL). This phase I study aimed to identify a recommended phase 2 dose, document toxicities, and preliminarily assess efficacy and potential predictive biomarkers.

PATIENTS AND METHODS

Thirty-three patients with R/R CD20⁺B-cell lymphoma received R at 375 mg/m²weekly for 4 weeks and I at 3 mg/kg on day 1 and every 3 weeks for four doses. Responding patients went on to maintenance with each agent given every 12 weeks. To facilitate correlative analysis, the expansion phase randomized patients to simultaneous R+I versus R with I delayed 2 weeks.

RESULTS

Toxicity was manageable; no dose-limiting toxicity was observed at the doses studied. When considering the entire cohort, efficacy was modest, with an objective response rate (ORR) of 24% and median progression-free survival (PFS) of 2.6 months. However, in follicular lymphoma patients, the ORR was 58% with a median PFS of 5.6 months. The randomized comparison of R with R+I demonstrated that R+I resulted in more effective B-cell depletion (BCD). Both B-cell depletion and the ratio of CD45RA^-regulatory T cell (Treg) to Treg were associated with response at all time points.

CONCLUSIONS

The combination of R+I has manageable toxicity and encouraging efficacy in R/R follicular lymphoma. The ratio of CD45RA^-Tregs to total Tregs, and peripheral BCD should be studied further as potential predictors of response.

Osimertinib (Osi) plus necitumumab (Neci) in EGFR-mutant NSCLC: An ETCTN California cancer consortium phase I study

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Background: Osi (3rd gen EGFR TKI) has robust activity in 1st line EGFR mutant NSCLC and TKI resistant T790Mpos NSCLC but progressive disease (PD) occurs and outcomes with Osi alone are poor in T790Mneg, C797Xpos and EGFR exon 20 insertion (ins20) disease. This study examined the EGFR monoclonal antibody Neci with Osi in select settings of EGFR TKI resistance. Methods: Using a 3+3 design, Neci was examined in advanced EGFR mutant NSCLC at dose levels (DL) of 600 mg (DL1) & 800 mg (DL2) D1, D8 IV q21 days + Osi 80 mg qd. Four expansion cohorts (ExC; 18 each) included: A) T790Mneg PD on 1st/2nd gen TKI as last therapy, B) T790Mneg PD on 3rd gen TKI, C) T790Mpos PD on 3rd gen TKI, D) EGFR ex20ins PD on chemotherapy. Central T790M testing by ddPCR in ExC A-C. Additional studies performed include: NGS panel of > 400 genes, EGFR FISH, plasma for PK and serial EGFR ctDNA by ddPCR as exploratory analyses. Adverse events (AEs) graded (Gr) by CTCAEv5 with ORR and PFS by RECIST 1.1. Results: Dose escalation and ExC B completed accrual. In total 55 pts were evaluable (Table). 1 pt had DLT at DL2, Gr 3 sinus bradycardia. Drug related Gr 3 AEs were seen in 27% (15) of pts, mainly rash (7;13%). ctDNA showed decreased mutant allele frequency with therapy in all pts studied with detected EGFR at baseline, with complete plasma clearance in a pt with detectable C797S. Conclusions: The RP2D (Osi 80 mg qd and Neci 800 mg D1, D8 IV on q21d cycle) is feasible and tolerable. In ExC A,T790Mneg pts with 1st/2nd gen EGFR TKI as last treatment, using curtailed sampling, the pre-specified efficacy signal was reached for Osi + Neci comparing favorably to Osi alone in analogous pts from the AURA trial. Clinical activity was also seen in EGFR-dependent resistance (T790Mpos C797Spos) after PD on 3rd gen TKI and in EGFR ins 20. Clinical trial information: NCT02496663. [Table: see text]

Phase II Trial of Cabozantinib Plus Erlotinib in Patients With Advanced Epidermal Growth Factor Receptor (EGFR)-Mutant Non-small Cell Lung Cancer With Progressive Disease on Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Therapy: A California Cancer Consortium Phase II Trial (NCI 9303)

Introduction: Mesenchymal epidermal transition and vascular endothelial growth factor pathways are important in mediating non-small cell lung cancer (NSCLC) tumorigenesis and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) resistance. We hypothesized that treatment with cabozantinib plus erlotinib in EGFR mutation-positive NSCLC following progression on EGFR TKI therapy may allow tumors to overcome this resistance or restore sensitivity to therapy regardless of T790M status. Methods: Patients with advanced NSCLC, known EGFR mutation and progressive disease on an EGFR TKI immediately prior to enrollment without intervening therapy were enrolled. Patients received erlotinib 150 mg and cabozantinib 40 mg daily. The primary endpoint was evaluation of efficacy by objective response rate. Secondary endpoints included assessment of progression free survival (PFS), overall survival, change in tumor growth rate, safety and toxicity, and the evaluation of specific EGFR mutations and MET amplification in pre-treatment tissue and plasma. Results: Thirty-seven patients were enrolled at 4 centers. Four patients had partial response (10.8%) and 21 had stable disease (59.5%). A greater than 30% increase in tumor doubling time was observed in 79% of assessable patients (27/34). Median PFS was 3.6 months for all patients. Diarrhea (32%) was the most common grade 3 adverse event; 3 patients had asymptomatic grade 4 elevation of amylase and lipase. Conclusions: Combination erlotinib and cabozantinib demonstrates activity in a highly pretreated population of patients with EGFR mutation and progression on EGFR TKI. Further elucidation of beneficial patient subsets is warranted. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT01866410.

A phase I trial of topotecan plus tivantinib in patients with advanced solid tumors

PURPOSE

Tyrosine kinase inhibitors (TKI) that target MET signaling have shown promise in various types of cancer, including lung cancer. Combination strategies have been proposed and developed to increase their therapeutic index. Based on preclinical synergy between inhibition of MET and topoisomerase I, a phase I study was designed to explore the combination of topotecan with the MET TKI tivantinib.

METHODS

Eligible patients with advanced solid malignancies for which there was no known effective treatment received topotecan at doses of 1.0-1.5 mg/m²/day for five consecutive days in 21-day cycles with continuous, oral tivantinib given at escalating doses of 120-360 mg orally twice daily. Pharmacokinetic analyses of tivantinib were included. Circulating tumor cells (CTC) were collected serially to identify peripheral changes in MET phosphorylation.

RESULTS

The trial included 18 patients, 17 of whom received treatment. At the planned doses, the combination of topotecan and tivantinib was not tolerable due to thrombocytopenia and neutropenia. The addition of G-CSF to attenuate neutropenia did not improve tolerability. Greater tivantinib exposure, assessed through pharmacokinetic analysis, was associated with greater toxicity. No responses were seen. MET phosphorylation was feasible in CTC, but no changes were seen with therapy.

CONCLUSIONS

The combination of topotecan and oral tivantinib was not tolerable in this patient population.

BCL2 Inhibition by Venetoclax: Targeting the Achilles' Heel of the Acute Myeloid Leukemia Stem Cell?

Venetoclax is an oral drug with an excellent side-effect profile that has the potential to revolutionize acute myeloid leukemia (AML) therapy in two areas. Venetoclax-based combination therapies could be a bridge to hematopoietic cell transplant with curative intent for patients with refractory/relapsed AML, and venetoclax-based therapy could provide meaningful survival prolongation for older patients with AML who are not candidates for more aggressive therapies. Cancer Discov; 6(10); 1082-3. ©2016 AACR.See related article by Konopleva and colleagues, p. 1106.

Phase I Study of Fenretinide Delivered Intravenously in Patients with Relapsed or Refractory Hematologic Malignancies: A California Cancer Consortium Trial

Purpose: A phase I study was conducted to determine the MTD, dose-limiting toxicities (DLT), and pharmacokinetics of fenretinide delivered as an intravenous emulsion in relapsed/refractory hematologic malignancies.Experimental Design: Fenretinide (80-1,810 mg/m²/day) was administered by continuous infusion on days 1 to 5, in 21-day cycles, using an accelerated titration design.Results: Twenty-nine patients, treated with a median of three prior regimens (range, 1-7), were enrolled and received the test drug. Ninety-seven courses were completed. An MTD was reached at 1,280 mg/m²/day for 5 days. Course 1 DLTs included 6 patients with hypertriglyceridemia, 4 of whom were asymptomatic; 2 patients experienced DLT thrombocytopenia (asymptomatic). Of 11 patients with response-evaluable peripheral T-cell lymphomas, two had complete responses [CR, progression-free survival (PFS) 68+ months; unconfirmed CR, PFS 14+ months], two had unconfirmed partial responses (unconfirmed PR, PFS 5 months; unconfirmed PR, PFS 6 months), and five had stable disease (2-12 cycles). One patient with mature B-cell lymphoma had an unconfirmed PR sustained for two cycles. Steady-state plasma levels were approximately 10 mcg/mL (mid-20s μmol/L) at 640 mg/m²/day, approximately 14 mcg/mL (mid-30s μmol/L) at 905 mg/m²/day, and approximately 22 mcg/mL (mid-50s μmol/L) at 1,280 mg/m²/day.Conclusions: Intravenous fenretinide obtained significantly higher plasma levels than a previous capsule formulation, had acceptable toxicities, and evidenced antitumor activity in peripheral T-cell lymphomas. A recommended phase II dosing is 600 mg/m² on day 1, followed by 1,200 mg/m² on days 2 to 5, every 21 days. A registration-enabling phase II study in relapsed/refractory PTCL (ClinicalTrials.gov identifier: NCT02495415) is ongoing. Clin Cancer Res; 23(16); 4550-5. ©2017 AACR.

Efficacy of the PARP Inhibitor Veliparib with Carboplatin or as a Single Agent in Patients with Germline BRCA1- or BRCA2-Associated Metastatic Breast Cancer: California Cancer Consortium Trial NCT01149083

Purpose: We aimed to establish the MTD of the poly (ADP-ribose) (PAR) polymerase inhibitor, veliparib, in combination with carboplatin in germline BRCA1- and BRCA2- (BRCA)-associated metastatic breast cancer (MBC), to assess the efficacy of single-agent veliparib, and of the combination treatment after progression, and to correlate PAR levels with clinical outcome.Experimental Design: Phase I patients received carboplatin (AUC of 5-6, every 21 days), with escalating doses (50-20 mg) of oral twice-daily (BID) veliparib. In a companion phase II trial, patients received single-agent veliparib (400 mg BID), and upon progression, received the combination at MTD. Peripheral blood mononuclear cell PAR and serum veliparib levels were assessed and correlated with outcome.Results: Twenty-seven phase I trial patients were evaluable. Dose-limiting toxicities were nausea, dehydration, and thrombocytopenia [MTD: veliparib 150 mg po BID and carboplatin (AUC of 5)]. Response rate (RR) was 56%; 3 patients remain in complete response (CR) beyond 3 years. Progression-free survival (PFS) and overall survival (OS) were 8.7 and 18.8 months. The PFS and OS were 5.2 and 14.5 months in the 44 patients in the phase II trial, with a 14% RR in BRCA1 (n = 22) and 36% in BRCA2 (n = 22). One of 30 patients responded to the combination therapy after progression on veliparib. Higher baseline PAR was associated with clinical benefit.Conclusions: Safety and efficacy are encouraging with veliparib alone and in combination with carboplatin in BRCA-associated MBC. Lasting CRs were observed when the combination was administered first in the phase I trial. Further investigation of PAR level association with clinical outcomes is warranted. Clin Cancer Res; 23(15); 4066-76. ©2017 AACR.

A phase I pharmacodynamic study of GTI-2040, an antisense oligonucleotide against ribonuclotide reductase, in acute leukemias: a California Cancer Consortium study

We performed a phase I study of GTI-2040, an antisense oligonucleotide against ribonucleotide reductase mRNA, on a novel dosing schedule of days 1-4 and 15-18 by continuous infusion to examine efficacy and tolerability in patients with leukemia. A dose of 11 mg/kg/d was safely reached. Dose-limiting toxicities (DLTs) at the higher levels included elevated troponin I and liver function enzymes. There were no objective responses to GTI-2040 in this study; 7/24 patients were able to complete the predetermined three infusion cycles. Pharmacokinetic and pharmacodynamic studies were performed, indicating a trend towards increasing intracellular drug levels and decreasing RRM2 gene expression with increasing doses. This dose schedule may be considered if appropriate combinations are identified in preclinical studies.

Pharmacodynamics (PD) and pharmacokinetics (PK) of E7389 (eribulin, halichondrin B analog) during a phase I trial in patients with advanced solid tumors: a California Cancer Consortium trial

BACKGROUND

The California Cancer Consortium completed a phase I trial of E7389 (eribulin mesylate), an analog of the marine natural product halichondrin B. This trial was to determine the pharmacodynamics, pharmacokinetics, and MTD of E7389 administered by bolus injection weekly for 3 weeks out of four.

METHODS

This trial included a rapid titration design. Real-time pharmacokinetics were utilized to guide dose escalation. Initially, single-patient cohorts were enrolled with intra- and inter-patient dose doubling. The second phase was a standard 3 + 3 dose escalation schedule. At the MTD, a cohort of patients was enrolled for target validation studies (separate manuscript). The starting dose was 0.125 mg/m(2), and doses were doubled within and between patients in the first phase. Blood and urine sampling for E7389 pharmacokinetics was performed on doses 1 and 3 of cycle 1. Levels were determined using a LC/MS/MS assay.

RESULTS

Forty patients were entered. Thirty-eight were evaluable for toxicity and 35 for response. The rapid escalation ended with a grade 3 elevation of alkaline phosphatase at 0.5 mg/m(2)/week. The second phase ended at 2.0 mg/m(2)/week with dose-limiting toxicities of grades 3 and 4 febrile neutropenia. Other toxicities included hypoglycemia, hypophosphatemia, and fatigue. The MTD was 1.4 mg/m(2)/week. Responses included four partial responses (lung cancer [2], urothelial [1], and melanoma [1]).

CONCLUSIONS

E7389 was well tolerated in this trial with the major toxicity being myelosuppression. PD shows that E7389 induces significant morphologic changes (bundle formation) in the microtubules of peripheral blood mononuclear cells and tumor cells in vivo. The data suggest that lower intra-tumoral levels of β-tubulin III or higher intra-tumoral levels of MAP4 may correlate with response to E7389, while lower intra-tumoral levels of stathmin may be associated with progression. PK data reveal that E7389 exhibits a tri-exponential elimination from the plasma of patients receiving a rapid i.v. infusion. At sub-toxic doses, plasma concentrations of E7389 are maintained well above the levels required for activity in vitro for >72 h.

Oral and intravenous pharmacokinetics of 5-fluoro-2'-deoxycytidine and THU in cynomolgus monkeys and humans

INTRODUCTION

5-Fluoro-2'-deoxycytidine (FdCyd; NSC48006), a fluoropyrimidine nucleoside inhibitor of DNA methylation, is degraded by cytidine deaminase (CD). Pharmacokinetic evaluation was carried out in cynomolgus monkeys in support of an ongoing phase I study of the PO combination of FdCyd and the CD inhibitor tetrahydrouridine (THU; NSC112907).

METHODS

Animals were dosed intravenously (IV) or per os (PO). Plasma samples were analyzed by LC-MS/MS for FdCyd, metabolites, and THU. Clinical chemistry and hematology were performed at various times after dosing. A pilot pharmacokinetic study was performed in humans to assess FdCyd bioavailability.

RESULTS

After IV FdCyd and THU administration, FdCyd C(max) and AUC increased with dose. FdCyd half-life ranged between 22 and 56 min, and clearance was approximately 15 mL/min/kg. FdCyd PO bioavailability after THU ranged between 9 and 25 % and increased with increasing THU dose. PO bioavailability of THU was less than 5 %, but did result in plasma concentrations associated with inhibition of its target CD. Human pilot studies showed comparable bioavailability for FdCyd (10 %) and THU (4.1 %).

CONCLUSION

Administration of THU with FdCyd increased the exposure to FdCyd and improved PO FdCyd bioavailability from <1 to 24 %. Concentrations of THU and FdCyd achieved after PO administration are associated with CD inhibition and hypomethylation, respectively. The schedule currently studied in phase I studies of PO FdCyd and THU is daily times three at the beginning of the first and second weeks of a 28-day cycle.

A phase I, pharmacokinetic, and pharmacodynamic evaluation of the DNA methyltransferase inhibitor 5-fluoro-2'-deoxycytidine, administered with tetrahydrouridine

PURPOSE

Inhibitors of DNA (cytosine-5)-methyltransferases (DNMT) are active antineoplastic agents. We conducted the first-in-human phase I trial of 5-fluoro-2'-deoxycytidine (FdCyd), a DNMT inhibitor stable in aqueous solution, in patients with advanced solid tumors. Objectives were to establish the safety, maximum tolerated dose (MTD), pharmacokinetics, and pharmacodynamics of FdCyd + tetrahydrouridine (THU).

METHODS

FdCyd + THU were administered by 3 h IV infusion on days 1-5 every 3 weeks, or days 1-5 and 8-12 every 4 weeks. FdCyd was administered IV with a fixed 350 mg/m(2)/day dose of THU to inhibit deamination of FdCyd. Pharmacokinetics of FdCyd, downstream metabolites and THU were assessed by LC-MS/MS. RBC γ-globin expression was evaluated as a pharmacodynamics biomarker.

RESULTS

Patients were enrolled on the 3-week schedule at doses up to 80 mg/m(2)/day without dose-limiting toxicity (DLT) prior to transitioning to the 4-week schedule, which resulted in an MTD of 134 mg/m(2)/day; one of six patients had a first-cycle DLT (grade 3 colitis). FdCyd ≥40 mg/m(2)/day produced peak plasma concentrations >1 µM. Although there was inter-patient variability, γ-globin mRNA increased during the first two treatment cycles. One refractory breast cancer patient experienced a partial response (PR) of >90 % decrease in tumor size, lasting over a year.

CONCLUSIONS

The MTD was established at 134 mg/m(2) FdCyd + 350 mg/m(2) THU days 1-5 and 8-12 every 4 weeks. Based on toxicities observed over multiple cycles, good plasma exposures, and the sustained PR observed at 67 mg/m(2)/day, the phase II dose for our ongoing multi-histology trial is 100 mg/m(2)/day FdCyd with 350 mg/m(2)/day THU.

Phase I study of the halichondrin B analogue eribulin mesylate in combination with cisplatin in advanced solid tumors

BACKGROUND

Eribulin mesylate is a synthetic macrocyclic ketone analogue of Halichondrin B that has demonstrated high antitumor activity in preclinical and clinical settings. This phase I study aimed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetics in combination with cisplatin (CP) in patients with advanced solid tumours.

METHODS

Thirty-six patients with advanced solid tumours received eribulin mesylate 0.7-1.4 mg m(-2) and CP 60-75 mg m(-2). Eribulin mesylate was administered on days 1, 8, and 15 in combination with CP day 1 every 28-day cycle. The protocol was amended after dose level 4 (eribulin mesylate 1.4 mg m(-2), CP 60 mg m(-2)) when it was not feasible to administer eribulin mesylate on day 15 because of neutropenia; the treatment schedule was changed to eribulin mesylate on days 1 and 8 and CP on day 1 every 21 days.

RESULTS

On the 28-day schedule, three patients had DLT during the first cycle: grade (G) 4 febrile neutropenia (1.0 mg m(-2), 60 mg m(-2)); G 3 anorexia/fatigue/hypokalemia (1.2 mg m(-2), 60 mg m(-2)); and G 3 stomatitis/nausea/vomiting/fatigue (1.4 mg m(-2), 60 mg m(-2)). On the 21-day schedule, three patients had DLT during the first cycle: G 3 hypokalemia/hyponatremia (1.4 mg m(-2), 60 mg m(-2)); G 4 mucositis (1.4 mg m(-2), 60 mg m(-2)); and G 3 hypokalemia (1.2 mg m(-2), 75 mg m(-2)). The MTD and recommended phase II dose was determined as eribulin mesylate 1.2 mg m(-2) (days 1, 8) and CP 75 mg m(-2) (day 1), on a 21-day cycle. Two patients had unconfirmed partial responses (PR) (pancreatic and breast cancers) and two had PR (oesophageal and bladder cancers).

CONCLUSIONS

On the 21-day cycle, eribulin mesylate 1.2 mg m(-2), administered on days 1 and 8, in combination with CP 75 mg m(-2), administered on day 1 is well tolerated and showed preliminary anticancer activity.

A phase 2 study of belinostat (PXD101) in patients with relapsed or refractory acute myeloid leukemia or patients over the age of 60 with newly diagnosed acute myeloid leukemia: a California Cancer Consortium Study

We performed a phase II study of belinostat in patients with acute myeloid leukemia (AML). In this open label phase II study (NCT00357032), patients with relapsed/refractory AML, or newly diagnosed patients with AML over the age of 60, were eligible. Belinostat was administered intravenously (IV) at a dose of 1000 mg/m(2) daily on days 1-5 of a 21-day cycle until progression or unacceptable toxicity. The primary endpoint was complete response (CR) rate, with secondary endpoints of overall response rate (CR + partial response [PR]), time to treatment failure (TTF), overall survival and safety. Twelve eligible patients with AML were enrolled, of whom six had received at least one prior line of therapy. No CR or PR was seen. Four patients had stable disease for at least five cycles. Grade 3 non-hematological toxicities occurred in four patients. Belinostat as monotherapy has minimal single-agent effect in AML on this dosing schedule.

A phase I trial of oxaliplatin in combination with docetaxel in patients with advanced solid tumors

The primary objective of this trial was to establish the maximum tolerated dose (MTD) of oxaliplatin 130 mg/m² preceded by escalating doses of docetaxel 60 mg/m² (75, 90, 100 mg/m²) administered every 3 weeks. A total of 11 patients were entered; 10 evaluable for response: 4 stable disease (liver, ovary and esophagus) and 1 partial remission (esophagus). At dose level 1, there was 1 dose-limiting toxicity (DLT) (grade 3 allergic reaction). At dose level 2, there were 3 DLTs (3 grade 4 neutropenia, grade 3 gastritis, diarrhea, hypophosphatemia, neuro-mood). The MTD is docetaxel 60 mg/m² with oxaliplatin 130 mg/m².

PHI-55: (NCI#7427): A phase I study of halichondrin B analog (E7389) in combination with cisplatin (CDDP) in advanced solid tumors: A CCC, NCI/CTEP-sponsored trial (grant U01 CA 062505)

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Background: E7389 is a structurally simplified synthetic macrocyclic ketone analog of the marine sponge natural product Halichondrin B, which inhibits microtubule dynamics via a novel mechanism characterized by suppression of microtubule growth, lack of effect on microtubule depolymerization, and sequestration of tubulin into nonfunctional aggregates. Methods: The goals of this trial were to determine the DLT, the MTD, and PK of E7389 (administered on days 1, 8 and 15 every 28 days) in combination with CDDP (administered on day 1 every 28 days) in patients (pts) with advanced solid tumors. The protocol was amended after dose level 4 (E7389 1.4 mg/m2, CDDP 60 mg/m2) when it was not feasible to administer E7389 on day 15 due to neutropenia; the treatment schedule was changed to E7389 days 1 and 8 and CDDP day 1 every 21 days. Eligibility criteria included normal organ function and < 2 prior chemotherapy regimens. Results: To date, 36 pts have been treated (E7389 0.7-1.4 mg/m2 and CDDP 60-75 mg/m2). Median age 61 years; 19 males; the most common tumor types were lung (8), pancreatic (5), head and neck (6). 36% ECOG 0, 56% ECOG 1, 8% ECOG 2; Median number of cycles was 3 (1 – 8). There were 3 pts with DLT’s on the 28-day cycle: gr 4 febrile neutropenia (1.0/60); gr 3 anorexia/fatigue/hypokalemia (1.2/60); and gr 3 stomatitis/fatigue (1.4/60). There were 3 pts with DLTs treated on the 21-day schedule: gr 3 hypokalemia/hyponatremia (1.4/60); gr 4 mucositis (1.4/60); and gr 3 hypokalemia (1.2/75). With 2 DLTs out of 6 pts at E7389 1.4 mg/m2 and CDDP 60 mg/m2, E7389 was reduced, CDDP was escalated, and the MTD was determined to be E7389 1.2 mg/m2 and CDDP 75 mg/m2(1 patient out of 6 with a DLT). At the MTD, protocol defined dose modifications or delays were required in 2 of the 6 patients by cycle 2. Notably, all DLTs were observed in patients exposed to at least 2 prior lines of chemotherapy. Two pts had an unconfirmed PR (pancreatic, breast) and 2 had a PR (esophagus, transitional bladder). Conclusions: On a 21 day schedule,E7389 in combination with CDDP appears well tolerated and showed preliminary activity. The MTD was determined to be E7389 1.2 mg/m2 and CDDP 75 mg/m2. Clinical trial information: 00400829.

Phi-53: (NCI#7251): Phase I trial of belinostat (PXD101) in combination with 13-cis-retinoic acid (13c-RA) in advanced solid tumor malignancies—A California Cancer Consortium NCI/CTEP sponsored trial

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Background: Belinostat has a reported maximum tolerated dose (MTD) of 1,000 mg/m2 given days 1 to 5 every 21 days as a single agent, although in one study in hepatocellular carcinoma belinostat was given at 1,400 mg/m2on the same schedule. Pre-clinical evidence suggests HDAC inhibitors enhance retinoic acid signaling with a synergistic impact in a variety of solid tumors. We conducted a phase I study of belinostat and 13c-RA in advanced solid tumors. Methods: Dose limiting toxicity (DLT) was defined as cycle 1 hematologic toxicity: ≥grade 3 that not resolved to <grade 1 within 1 week or non-hematologic toxicity: ≥grade 3. We sought the MTD of belinostat days 1-5 with 13-cRA days 1-14, every 21 days, in patients (pt) with advanced solid tumors. Eligibility criteria included normal organ function and QT/QTc interval; 4 weeks from previous therapy. Results: 51 pt were treated: median age 61 (range 40-80); 29 men; 57% ECOG 0, 41% ECOG 1, 2% ECOG 2; 13 lung, 11 breast, 8 colorectal, 3 pancreatic. 11 dose levels (DL) were tested starting from belinostat 600 mg/m2/day and 13c-RA 50 mg/m2/day to belinostat 2000 mg/m2/day and 13c-RA 100 mg/m2/day. Only two DLTs were observed: a grade 3 hypersensitivity reaction with dizziness and hypoxia at DL 8 (belinostat 1700 mg/m2/day, 13c-RA 100 mg/m2/day); and a grade 3 allergic reaction in a patient with an ECOG PS 2 at DL 11 (belinostat 2000 mg/m2/day, 13c-RA 100 mg/m2/day). The MTD was not reached. Pharmacokinetics of belinostat suggests dose proportionality. Median number of cycles: 2 (range 1–56). 10 patients had SD including: 1 neuroendocrine pancreatic stable for 56 cycles; 1 breast pt for 12 cycles; 1 lung pt 8 cycles. 2 pt had PRs: a keratinizing squamous cell carcinoma (tonsil) and a lung cancer pt. Conclusions: Belinostat 2000 mg/m2 days 1-5and 13-cis-Retinoic acid 100 mg/m2days 1-14, every 21 days, was well-tolerated and an MTD was not reached despite doubling the established single agent MTD. Future studies building on this combination to belinostat are warranted. Support: U01CA062505 and P30CA033572 (City of Hope); U01CA099168 and P30CA047904 (University of Pittsburgh).

Phase I study of pazopanib in patients with advanced solid tumors and hepatic dysfunction: a National Cancer Institute Organ Dysfunction Working Group study

PURPOSE

Pazopanib is a potent, multitargeted receptor tyrosine kinase inhibitor; however, there is limited information regarding the effects of liver function on pazopanib metabolism and pharmacokinetics. The objective of this study was to establish the maximum-tolerated dose (MTD) and pharmacokinetic profile of pazopanib in patients with varying degrees of hepatic dysfunction.

EXPERIMENTAL DESIGN

Patients with any solid tumors or lymphoma were stratified into four groups based on the degree of hepatic dysfunction according to the National Cancer Institute Organ Dysfunction Working Group (NCI-ODWG) criteria. Pazopanib was given orally once a day on a 21-day cycle. A modified 3+3 design was used.

RESULTS

Ninety-eight patients were enrolled. Patients in the mild group tolerated 800 mg per day. The moderate and severe groups tolerated 200 mg per day. Pharmacokinetic data in the mild group were similar to the data in the normal group. Comparison of the median Cmax and area under the curve [AUC(0-24)] in the moderate or severe groups at 200 mg per day to the values in the normal and mild groups at 800 mg per day indicated less than dose-proportional systemic exposures in patients with moderate and severe hepatic impairment. This suggests that the lower maximum-tolerated dose in the moderate and severe group is not due to a decrease in drug clearance or alteration in the proportion of metabolites.

CONCLUSIONS

In patients with mild liver dysfunction, pazopanib is well tolerated at the Food and Drug Administration (FDA)-approved dose of 800 mg per day. Patients with moderate and severe liver dysfunction tolerated 200 mg per day.

Phase I trial of fenretinide (4-HPR) intravenous emulsion in hematologic malignancies: A California Cancer Consortium study (PhI-42)

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Background: Fenretinide (4-HPR) is a cytotoxic retinoid with broad anticancer activity in preclinical studies. Due to limited bioavailability of a capsule formulation an intravenous intralipid-like emulsion formulation (4-HPR ILE) was developed to increase systemic exposures. Methods: 4-HPR was administered as a continuous intravenous infusion for 120 hrs every 21 days. Systemic toxicities, responses, and pharmacokinetics were assessed. Accelerated Simon design proceeded until moderate or dose-limiting toxicities (DLT) were scored on Course 1. Doses were 80 mg/m2/day to 1810 mg/m2/day. Patients with asymptomatic hypertriglyceridemia were scored separately. All patients were heavily pretreated. Results: Toxicity-evaluable patients = 25. At 1810 mg/m2/day, two patients experienced DLT hypertriglyceridemia, one with transient Grade 2 pancreatitis; at 1280 mg/m2/day (8 pts), two had asymptomatic Grade 4 hypertriglyceridemia, one experienced DLT pleural effusions; at 905 mg/m2/day (6 pts) 2 experienced asymptomatic Grade 4 hypertriglyceridemia; All 5 pts at 640 mg/m2/day tolerated treatment. Pharmacokinetics showed a dose-to-plasma level relationship with mean steady-state 4-HPR levels of ~mid-20’s μM (640 mg/m2); ~mid-30’s μM (905 mg/m2/day); and ~mid-50’s μM (1280 mg/m2). Responses to date include a 64% CR+PR+SD response rate (36% CR+PR response rate) in 11 relapsed T-cell lymphomas which included histone deacetylase inhibitor-refractory patients, and a PRu response in a NHL B-cell lymphoma. Reversible hypertriglyceridemia related to the intralipid vehicle accounted for 6/7 DLTs. Conclusions: MTD = 1280 mg/m2/day x 5 days, every three weeks. 4-HPR ILE was safely administered and obtained 4-HPR plasma levels 6 -7 times higher than previously obtained using oral capsules. Durable complete responses were observed in T-cell lymphomas from 905 – 1810 mg/m2/day. An expanded cohort is accruing to a dosing schedule modified to decrease asymptomatic hypertriglyceridemia of 600 mg/m2 on Day 1 (to allow for induction of serum lipases) followed by 1200 mg/m2 Days 2-5. Supported by NCI U01 CA062505 and CPRIT RP10072.

A mismatch between methods and objectives in phase I drug development: Statistical limitations and personalized medicine—A California Cancer Consortium (CCC) study

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Background: Patient variation in drug response and toxicity impacts all phases of drug development. While detailed sample-size calculations and analysis based on statistical methodology are critical for addressing variation in late stage trials, phase I studies pose unique and largely unsolved challenges related to variability. Changes in patient selection during the study, small sample-sizes and large patient variation in toxicity are exactly the kind of problems that statistical methods cannot address in small, isolated phase I studies, regardless of apparent mathematical rigor. We have documented these problems via a physician survey. Methods: A 10-question anonymous survey was sent to 670 oncologists at National Comprehensive Cancer Network (NCCN) and CCC institutions via an online survey. 19 % (126/670) of the oncologists polled responded. 78/126 (62%) specialized in Medical Oncology. The number of years in practice varied from 2-45 yrs with a median of 17 yrs. Results: a) 66% of all respondents stated that non-DLT toxicities on one dose level would impact their patient selection on the following dose level, conflicting with the assumption of random patient selection implicit in simulations used in evaluating statistical designs. b) Only 13% stated a desire to target a non-heme toxicity as high as 20% grade 3, while 87% desired a 10% or less grade 3 rate; c) More than half the respondents would prefer not to escalate if 3/3 patients experienced grade 2 LFTs; d) 82% of the respondents thought the appropriate target toxicity differed for patients depending on their potential for becoming a surgical candidate, furthering the need for personalized dosing. Conclusions: Statistical methods in phase I trials are unable to address many of the salient features of phase I study conduct and investigator goals. We will present several approaches we have initiated to address these limitations, and present future plans to help produce a more reliable estimate of a recommended dose. Supported in part by NCI grants U01CA062505, N01-CM-62209, and NCCN data collection assistance.

A phase I study of veliparib in combination with metronomic cyclophosphamide in adults with refractory solid tumors and lymphomas

PURPOSE

Oral administration of the alkylating agent cyclophosphamide at low doses, metronomic dosing, is well tolerated, with efficacy in multiple tumor types. PARP inhibition potentiates effects of cyclophosphamide in preclinical models. We conducted a phase I trial of the PARP inhibitor veliparib and metronomic cyclophosphamide in patients with refractory solid tumors and lymphoid malignancies.

EXPERIMENTAL DESIGN

Objectives were to establish the safety and maximum tolerated dose (MTD) of the combination; characterize veliparib pharmacokinetics (PK); measure poly(ADP-ribose) (PAR), a product of PARP, in tumor biopsies and peripheral blood mononuclear cells (PBMC); and measure the DNA-damage marker γH2AX in PBMCs and circulating tumor cells (CTC). Cyclophosphamide was administered once daily in 21-day cycles in combination with veliparib administered once daily for 7, 14, or 21 days.

RESULTS

Thirty-five patients were enrolled. The study treatment was well tolerated, and the MTD was established as veliparib 60 mg with cyclophosphamide 50 mg given once daily. Seven patients had partial responses; an additional six patients had disease stabilization for at least six cycles. PAR was significantly decreased in PBMCs (by at least 50%) and tumor biopsies (by at least 80%) across dose levels (DL); γH2AX levels were increased in CTCs from seven of nine patients evaluated after drug administration.

CONCLUSIONS

The combination of veliparib with metronomic cyclophosphamide is well tolerated and shows promising activity in a subset of patients with BRCA mutations. A phase II trial of the combination compared with single-agent cyclophosphamide is ongoing in BRCA-positive ovarian cancer, triple-negative breast cancer, and low-grade lymphoma.

A phase I and pharmacokinetic study of oral 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP, NSC #663249) in the treatment of advanced-stage solid cancers: a California Cancer Consortium Study

BACKGROUND

3-Aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP) is a novel small-molecule ribonucleotide reductase inhibitor. This study was designed to estimate the maximum tolerated dose (MTD) and oral bioavailability of 3-AP in patients with advanced-stage solid tumors.

METHODS

Twenty patients received one dose of intravenous and subsequent cycles of oral 3-AP following a 3 + 3 patient dose escalation. Intravenous 3-AP was administered to every patient at a fixed dose of 100 mg over a 2-h infusion 1 week prior to the first oral cycle. Oral 3-AP was administered every 12 h for 5 consecutive doses on days 1-3, days 8-10, and days 15-17 of every 28-day cycle. 3-AP was started at 50 mg with a planned dose escalation to 100, 150, and 200 mg. Dose-limiting toxicities (DLT) and bioavailability were evaluated.

RESULTS

Twenty patients were enrolled. For dose level 1 (50 mg), the second of three treated patients had a DLT of grade 3 hypertension. In the dose level 1 expansion cohort, three patients had no DLTs. No further DLTs were encountered during escalation until the 200-mg dose was reached. At the 200 mg 3-AP dose level, two treated patients had DLTs of grade 3 hypoxia. One additional DLT of grade 4 febrile neutropenia was subsequently observed at the de-escalated 150 mg dose. One DLT in 6 evaluable patients established the MTD as 150 mg per dose on this dosing schedule. Responses in the form of stable disease occurred in 5 (25%) of 20 patients. The oral bioavailability of 3-AP was 67 ± 29% and was consistent with the finding that the MTD by the oral route was 33% higher than by the intravenous route.

CONCLUSIONS

Oral 3-AP is well tolerated and has an MTD similar to its intravenous form after accounting for the oral bioavailability. Oral 3-AP is associated with a modest clinical benefit rate of 25% in our treated patient population with advanced solid tumors.

A phase 1 trial dose-escalation study of tipifarnib on a week-on, week-off schedule in relapsed, refractory or high-risk myeloid leukemia

Inhibition of farnesyltransferase (FT) activity has been associated with in vitro and in vivo anti-leukemia activity. We report the results of a phase 1 dose escalation study of tipifarnib, an oral FT inhibitor, in patients with relapsed, refractory, or newly diagnosed (if over age 70) acute myelogenous leukemia (AML), on a week-on, week-off schedule. Forty-four patients were enrolled, 2 patients were newly diagnosed, the rest were relapsed or refractory to previous treatment, with a median age of 61 (range 33–79). The maximum tolerated dose was determined to be 1200 mg given orally twice-daily (bid) on this schedule. Cycle one dose-limiting toxicities were hepatic and renal. There were 3 complete remissions seen, 2 at the 1200 mg bid dose and one at the 1000 mg bid dose, with minor responses seen at the 1400 mg bid dose level. Pharmacokinetic studies performed at doses of 1400 mg bid showed linear behavior with minimal accumulation between days 1–5. Tipifarnib administered on a week-on week-off schedule shows activity at higher doses, and represents an option for future clinical trials in AML.

Abstract 1283: Phase I and pharmacokinetic evaluation of the DNA methyltransferase inhibitor 5-fluoro-2′-deoxycytidine: A California Cancer Consortium study

Background: The California Cancer Consortium conducted the first-in-human clinical trial of the investigational new drug 5-fluoro-2′-deoxycytidine (FdC), a DNA methyltransferase inhibitor stable in aqueous solution, as a 3-hour infusion concurrent with 350 mg/m2 of the cytidine deaminase inhibitor tetrahydrouridine (THU), included to prolong the half-life of FdC in vivo. Methods: A 3+3 design was used; initial FdC dose doubling ended when two moderate toxicities or one severe toxicity were observed. Pharmacokinetics of FdC and THU were obtained. Results: On the initial schedule, daily (QD) × 5 every 21 days (d), FdC was escalated from 2.5 to 80 mg/m2/d without treatment-related grade 3 toxicity other than anemia and lymphopenia. At FdC doses ≥20 mg/m2/d, peak plasma FdC concentrations were above those that inhibit DNA methylation in vitro (Beumer, et al., Cancer Chemother Pharmacol 62:363-8, 2008). The schedule was amended to QD × 5 for 2 consecutive weeks every 28 d, and patients (pts) were enrolled at 40, 67, 100, 134, and 180 mg/m2/d. Overall, 51 pts were treated [28 M; 23 F; median (range): age 63 (30-85), KPS 80 (60-100)]; 44 pts were evaluable for toxicity (1 cycle). 1/6 pts at 134 mg/m2/d had dose-limiting toxicity (DLT) (grade 3 colitis) and 2/2 pts at 180 mg/m2/d had DLT (1-grade 3 fatigue + LFT; 1-grade 4 mucositis + ANC + platelets). Of the 31 pts on 28-d cycles, 8 had clinical progression prior to the first scheduled evaluation at 8 weeks and 5 did not complete 2 cycles for other reasons; 7 pts had progressive disease at 8 weeks; and 10 pts had stable disease for ≥8 weeks. In addition, 1 heavily-pretreated pt with breast cancer, treated at 67 mg/m2/d, had a partial response lasting 1 year. Conclusions: The Maximum Tolerated Dose was 134 mg/m2/d FdC + 350 mg/m2/d THU QD × 5 for 2 consecutive weeks every 28 d. An expansion cohort is being accrued to determine the pharmacokinetics of oral FdC and THU. Based on the nature of the toxicities and the observed response at 67 mg/m2/d, a multi-histology Phase II trial has been initiated at 100 mg/m2/d QD × 5 for 2 consecutive weeks every 28 d. Supported by U01 CA62505, P30 CA33572, N01-CM-52202, and P30CA47904. The authors acknowledge the invaluable contribution of Dr. M. J. Egorin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1283. doi:10.1158/1538-7445.AM2011-1283

Phase I trial of GTI-2040, oxaliplatin, and capecitabine in the treatment of advanced metastatic solid tumors: a California Cancer Consortium Study

BACKGROUND

GTI-2040 is a 20-mer antisense oligonucleotide targeting the mRNA of ribonucleotide reductase M2. It was combined with oxaliplatin and capecitabine in a phase I trial in patients with advance solid tumors based on previous studies demonstrating potentiation of chemotherapy with ribonucleotide reductase inhibitors.

METHODS

Patients at least 18 years of age with advanced incurable solid tumors and normal organ function as well as a Karnofsky performance status of > or =60% were eligible. One prior chemotherapy regimen for advanced disease or relapse within 12 months of adjuvant chemotherapy was required. Patients could have received prior fluoropyrimidines, including capecitabine, but not oxaliplatin. Treatment cycles were 21 days. In each cycle, GTI-2040 was given as a continuous intravenous infusion over 14 days, oxaliplatin as a 2-h intravenous infusion on day 1, and capecitabine orally twice a day for 14 days. In cycle 1 only, oxaliplatin and capecitabine were started on day 2 to allow ribonucleotide reductase mRNA levels to be measured with and without oxaliplatin and capecitabine. Doses were escalated in cohorts of three patients using a standard 3 + 3 design until the maximum tolerated dose was established, defined as no more than one first-cycle dose-limiting toxicity among six patients treated at a given dose level.

RESULTS

The maximum tolerated dose was estimated to be the combination of GTI-2040 3 mg/kg per day for 14 days, capecitabine 600 mg/m(2) twice daily for 14 days, and oxaliplatin 100 mg/m(2) every 21 days. Dose-limiting toxicities were hematologic. GTI-2040 pharmacokinetics, obtained at steady-state on days 7 and 14, showed the high inter-patient variability previously reported. Two of six patients had stable disease at the maximum tolerated dose and one patient, with heavily pre-treated non-small cell lung cancer, had a partial response at a higher dose level. In samples from a limited number of patients, there was no clear decrease in ribonucleotide reductase expression in peripheral blood mononuclear cells during treatment.

CONCLUSION

A combination of GTI-2040, capecitabine and oxaliplatin is feasible in patients with advanced solid tumors.

Concentrations of the DNA methyltransferase inhibitor 5-fluoro-2'-deoxycytidine (FdCyd) and its cytotoxic metabolites in plasma of patients treated with FdCyd and tetrahydrouridine (THU)

PURPOSE

Although the DNA methyltransferase inhibitor 5-fluoro-2'-deoxycytidine (FdCyd), is being evaluated clinically, it must be combined with the cytidine deaminase inhibitor tetrahydrouridine (THU) to prevent rapid metabolism of FdCyd to the pharmacologically active, yet unwanted, metabolites 5-fluoro-2'-deoxyuridine (FdUrd), 5-fluorouracil (FU), and 5-fluorouridine (FUrd). We assessed plasma concentrations of FdCyd and metabolites in patients receiving FdCyd and THU.

METHODS

We validated an LC-MS/MS assay, developed for a preclinical study, to quantitate FdCyd and metabolites in human plasma. Patients were treated with five daily, 3-h infusions of FdCyd at doses of 5-80 mg/m(2) with 350 mg/m(2) THU. Plasma was obtained during, and before the end of infusions on days 1 and 5.

RESULTS

The lower limits of quantitation for FU, FdUrd, FUrd, FC and FdCyd were 1, 1.5, 10, 3, and 10 ng/ml, respectively. Plasma FdCyd increased with dose, from 19-96 ng/ml at 5 mg/m(2) to 1,600-1,728 ng/ml at 80 mg/m(2). FdUrd was undetectable in patients treated with FdCyd doses <20 mg/m(2), and increased from 2.3 ng/ml at 20 mg/m(2) to 3.5-5.7 ng/ml at 80 mg/m(2). FU increased from 1.2-5.5 ng/ml at 5 mg/m(2) to 6.0-12 ng/ml at 80 mg/m(2).

CONCLUSIONS

By co-administering FdCyd with THU, FdCyd plasma concentrations were achieved that are known to inhibit DNA methylation in vitro. The accompanying plasma FU and FdUrd concentrations are <10% those observed after therapeutic infusions of FU or FdUrd, while FdCyd levels are well above those required to inhibit methylation in vitro. Therefore, inhibition of DNA methylation with FdCyd and THU appears feasible.

Phase I study of cisdiamminedichloroplatinum in combination with azidothymidine in the treatment of patients with advanced malignancies

PURPOSE

Azidothymidine (AZT, zidovudine) has been shown to reverse cisplatin resistance in cell culture. This phase I study was performed to determine the maximally tolerated dose (MTD) and dose-limiting toxicities of AZT when administered by continuous intravenous infusion in combination with cisplatin (CDDP), and to evaluate the pharmacokinetics of AZT in this setting.

PATIENTS AND METHODS

Entered in the study were 61 patients with advanced, histologically confirmed malignancies which were unresponsive to or for which no "standard" chemotherapeutic regimen existed. AZT was administered as a 72-h infusion on days 1-3 and 14-16 of a 28-day cycle at dose levels from 400 through 14,364 mg/m(2) per day. CDDP at dose levels of 30, 45, or 60 mg/m(2) was administered at hour 36 of each AZT infusion. The plasma pharmacokinetics of AZT were determined in patients treated at representative dose levels.

RESULTS

Of the 61 patients who completed 125 courses of therapy, 21 had stable disease for a median of four cycles (range two to eight), 33 progressed on therapy, and 7 were not assessable for response. The major observed toxicity was myelosuppression. The MTD of AZT was 8135 mg/m(2) per day when administered on this schedule. Escalation of CDDP did not result in additive toxicity. The mean steady-state level of AZT at the MTD was 44 microM (range 35-51 microM).

CONCLUSIONS

Steady-state concentrations of AZT increased with dose. The plasma levels achieved at the MTD exceeded those required for drug resistance reversal in vitro. The administration of CDDP had no effect on AZT steady-state levels. The dose-limiting toxicity of this drug combination is myelosuppression. AZT may be useful in further studies utilizing combination therapy to achieve increased chemotherapy effectiveness.

Phase I trial of continuous infusion 5-aza-2'-deoxycytidine

PURPOSE

To identify a dose of the demethylating agent 5-aza-2'-deoxycytidine (DAC) with acceptable side effects, and to study its effect on the methylation patterns of relevant genes in tumor biopsies before and after treatment with a novel methylation assay using real-time PCR.

METHODS

A group of 19 patients with metastatic solid tumors were treated with DAC by continuous intravenous infusion over 72 h, days 1-3 of a 28-day cycle. Tumor biopsies were taken before and 7 days after starting DAC.

RESULTS

The dose levels studied were 20, 30 and 40 mg/m(2). Grade 4 neutropenia was found in two of five patients at 40 mg/m(2) and one of six patients at 30 mg/m(2). No objective responses were seen in this study. Steady-state DAC levels of 0.1 to 0.2 microM were achieved in the 30 and 40 mg/m(2) cohorts. Changes in methylation were observed, but no single gene consistently demonstrated evidence of demethylation.

CONCLUSIONS

DAC was tolerated at a dose of 30 mg/m(2) per day for a 72-h intravenous infusion. Changes in gene methylation were observed.

Quantification of chemotherapeutic target gene mRNA expression in human breast cancer biopsies: comparison of real-time reverse transcription-PCR vs. relative quantification reverse transcription-PCR utilizing DNA sequencer analysis of PCR products

The solid tumor mRNA expression of genes related to the mechanism of action of certain antineoplastic agents is often predictive of clinical efficacy. We report here on the development of a rapid and practical real-time RT-PCR method to quantify genetic expression in solid tumors. The genes examined are related to the intracellular pharmacology of gemcitabine and cisplatin, two drugs that are used in the treatment of several types of advanced cancer. We evaluated target gene mRNA levels from breast tumor samples using two quantitative RT-PCR methods: 1) an improved relative RT-PCR method using fluorescence-labeled primers, automated PCR set up, and GeneScan analysis software; and 2) real-time RT-PCR with redesigned primers using an ABI 7900HT instrument, with additional postprocessing of the data to adjust for efficiency differences across the target genes. Using these methods, we quantified mRNA expression levels of deoxycytidine kinase (dCK), deoxycytidylate deaminase (dCDA), the M1 and M2 subunits of ribonucleotide reductase (RRM1, RRM2), and excision cross complementation group 1 (ERCC1) in 35 human "fresh" frozen breast cancer biopsies. While both assay methods were substantially more rapid than traditional RT-PCR, real-time RT-PCR appeared to be superior to the amplification end-point measurement in terms of precision and high throughput, even when a DNA sequencer was used to assess fluorescence-labeled PCR products. This reproducible, highly sensitive real-time RT-PCR method for the detection and quantification of the mRNAs for dCK, dCDA, RRM1, RRM2, and ERCC1 in human breast cancer biopsies appears to be more informative and less time-consuming than either classical radioisotope-dependent RT-PCR or the technique utilizing GeneScan analysis described herein. By allowing the measurement of intratumoral target gene expression, these new methods may prove useful in predicting the clinical utility of gemcitabine- and platinum-containing chemotherapy programs in patients with solid tumors.

Phase I pharmacodynamic study of time and sequence dependency of hydroxyurea in combination with gemcitabine: a California Cancer Consortium Trial

Preclinical studies in our laboratory have demonstrated that prior exposure to hydroxyurea increases the percentage of cells in S phase, enhancing the cytotoxicity of subsequent gemcitabine treatment in human oropharyngeal KB cells. To evaluate the clinical implications of this time- and sequence-dependent potentiation, we performed a phase I trial of hydroxyurea given over 24 h followed by a 30-min infusion of gemcitabine in weeks 1 and 2 of a 3-week cycle. The dose of hydroxyurea was fixed at 500 mg orally every 6 h for four doses starting 24 h before each dose of gemcitabine. The initial dose level of gemcitabine was 250 mg/m(2) on days 2 and 9, and this was escalated stepwise to 1000 mg/m(2) on days 2 and 9. Gemcitabine pharmacokinetics were determined on days 2 and 9 of the first cycle. Of 27 patients enrolled (12 female, 15 male), 24 were evaluable for response and 23 were evaluable for toxicity. Their median age was 56 years (range 27-76 years). Tumor types included lung, head and neck, pancreas, breast, colon, prostate, stomach, ovary, esophagus, germ cell, thyroid, gallbladder, and unknown primary. A total of 80 cycles of treatment were completed. One patient (unknown primary) had an objective partial response lasting 21 months, and 12 patients had stable disease. All observed dose-limiting toxicities were related to myelosuppression. The gemcitabine maximum tolerated dose was established at 750 mg/m(2) on days 2 and 9. Hydroxyurea had no effect on the plasma pharmacokinetics of gemcitabine. These results suggest that hydroxyurea followed by gemcitabine can be safely administered and has activity on this schedule. We are presently developing a phase II trial of this regimen for patients with platinum-resistant head and neck cancer.

Pharmacokinetics and toxicity of high-dose intravenous methotrexate in the treatment of leptomeningeal carcinomatosis

PURPOSE

To evaluate the pharmacokinetics and toxicity of high-dose intravenous (i.v.) methotrexate (MTX) with leucovorin in patients with meningeal carcinomatosis.

METHODS

Of 16 eligible patients entered on this study, 13 with meningeal carcinomatosis from breast cancer, lung cancer, or osteosarcoma were treated with MTX at loading doses of 200-1500 mg/m2, followed by a 23-h infusion of 800-6000 mg/m2. Three patients without meningeal disease were also treated and the cerebrospinal fluid (CSF) MTX concentrations were compared in patients with and without central nervous system (CNS) disease.

RESULTS

Patients without CNS disease had lower CSF MTX concentrations relative to the plasma MTX levels than those with CNS disease, who all had CSF MTX concentrations above the target cytotoxic concentration (1 microM). The CSF MTX concentrations correlated better with the free and the total plasma MTX concentrations than with the doses. The mean half-life of CSF MTX was 8.7 +/- 3.4 h. The mean plasma clearance of MTX was not significantly different in patients with CNS disease (84 +/- 41 ml/min per m2) versus without CNS disease (59 +/- 38 ml/min per m2). All toxicities were grade 2 or less except grade 3 hematologic toxicity. No patient had an objective response in the CSF.

CONCLUSION

This trial demonstrates that potentially cytotoxic CSF MTX concentrations (> 1 microM) are delivered safely by i.v. infusion, a less invasive and better distributed CSF therapy compared with intrathecal MTX. Because of the excellent pharmacokinetics and toxicity, high-dose i.v. MTX should be evaluated at a loading dose of 700 mg/m2 and a 23-h infusion of 2800 mg/m2 with leucovorin in less heavily pretreated patients with carcinomatous meningitis.

Cellular but not plasma pharmacokinetics of lometrexol correlate with the occurrence of cumulative hematological toxicity

Lometrexol inhibits the first folate-dependent enzyme in de novo purine biosynthesis and is avidly polyglutamated and retained in tissues expressing folylpolyglutamate synthetase. Although clinical studies have been limited by cumulative toxicity, preclinical studies show that pretreatment with folic acid can protect normal tissue while maintaining tumor cytotoxicity. Therefore, a Phase I study of lometrexol every 21 days preceded by i.v. folic acid was initiated. Lometrexol was studied in six patients at 15 mg/m2, in six patients at 20 mg/m2, in three patients at 25 mg/m2, and in nine patients at 30 mg/m2. Patients received either 5 mg of folic acid 1 h before or 25 mg/m2 3 h before lometrexol. Blood samples were obtained around the first course and weekly thereafter for determination of plasma and erythrocyte (RBC) lometrexol concentrations. Bioactive folates in plasma and RBCs were determined in a subset of patients. Lometrexol pharmacokinetics were best described by a three-compartment model. Mean clearance and volume of distribution were 1.6 +/- 0.6 liters/h/m2 and 8.9 +/- 4.1 liters/m2. Mean half-lives were 0.23 +/- 0.1, 2.9 +/- 1.4, and 25.0 +/- 48.7 h. Pharmacokinetics were independent of either lometrexol or folic acid dose. In the weekly blood samples, RBC lometrexol levels rose, long after plasma lometrexol was undetectable. RBC lometrexol levels were independent of folic acid or lometrexol dose. Bioactive folates measured in plasma and RBCs during this same time period did not accumulate. Rising RBC levels were correlated with a fall in hematocrit, hemoglobin, and platelet count. This study indicates that the cumulative toxicity of lometrexol is related to tissue concentration and not plasma pharmacokinetics. RBC lometrexol may be an indicator of cumulative drug exposure and effect.

Phase I trial of intraperitoneal iododeoxyuridine with and without intravenous high-dose folinic acid in the treatment of advanced malignancies primarily confined to the peritoneal cavity: flow cytometric and pharmacokinetic analysis

In this Phase I study, the maximally tolerated doses (MTDs) of i.p. iododeoxyuridine (IdUrd) alone and in combination with i.v. calcium leucovorin (LV) were determined. The pharmacokinetics and pharmacological advantage of IdUrd were evaluated, and flow cytometric analysis allowed examination of the extent of incorporation of IdUrd into tumor cells with and without the addition of i.v. LV. Thirty-nine patients with advanced neoplasms primarily confined to the peritoneal space were enrolled in a dose-escalation trial using 4-h dwells of IdUrd administered i.p. daily for 4 days with and without an i.v. infusion of LV 500 mg/m2/day for 4.5 days. Twenty-three patients received single-agent therapy, and 13 patients received i.p. IdUrd in combination with i.v. LV. The MTD of single-agent IdUrd administered on this schedule was 4125 mg/m2/day for 4 days; and that of the IdUrd in combination was 3438 mg/m2/day. Dose-limiting toxicities were myelosuppression and stomatitis. During the period of the dwell, the peritoneal AUC (area under the curve) of IdUrd exceeded the plasma AUC of IdUrd by one or two orders of magnitude in all patients at all doses tested; there was a possible effect of LV on peritoneal AUC. The geometric mean pharmacological advantage (AUCperitoneal/ AUCplasma) was 181 at 625 mg/m2/day and 90 at 4538 mg/m2/day. Flow cytometric analysis suggests saturation of IdUrd measured in DNA at the 2500-3125 mg/m2 dose level, without an increase after the addition of LV. Twelve patients received 4-12 courses of therapy. One patient with recurrent ovarian cancer who received 16 courses of therapy experienced complete resolution of her ascites, near normalization of CA-125 levels, and improved quality of life; two patients with high-risk tumors receiving "adjuvant" therapy are disease-free at 3 and 6 years after treatment; other patients experienced transient clearing of ascites. The recommended Phase II dose of i.p. IdUrd using a 4-h dwell daily for 4 days is 3750 mg/m2/day alone or 3125 mg/m2/day in combination with continuous i.v. LV at 500 mg/m2/day for 4.5 days. Although flow cytometric data suggest that DNA incorporation of IdUrd is not affected by the addition of LV, the cytotoxicity of the combination regimen may be increased due to LV-enhanced, IdUrd-related inhibition of thymidylate synthase. For this reason, we recommend that efficacy studies of the combination continue in parallel with studies of IdUrd alone.

Pharmacokinetics and toxicity of 120-hour continuous-infusion hydroxyurea in patients with advanced solid tumors

A group of 18 patients with advanced cancer were entered on a phase I study of a 120-h continuous intravenous infusion of hydroxyurea. The dose of hydroxyurea was escalated in cohorts of patients from 1 to 2 to 3.2 g/ m2 per day. The primary dose-limiting toxicity was neutropenia, often accompanied by leukopenia, thrombocytopenia and generalized skin rash. Prophylactic treatment of patients with dexamethasone and diphenhydramine hydrochloride prevented the skin rash, but not the hematopoietic toxicities. The pharmacokinetics of hydroxyurea were studied in all patients. The steady-state concentrations of hydroxyurea were linearly correlated with the dose (R2 = 0.71, n = 18, P < 0.0001). The mean +/- SE concentrations were 93 +/- 16, 230 +/- 6 and 302 +/- 27 microM at 1, 2 and 3.2 g/m2 per day, respectively. The mean +/- SE renal and nonrenal clearances of hydroxyurea were 2.14 +/- 0.18 and 3.39 +/- 0.28 l/h per m2 (n = 16), neither of which correlated with the dose. The concentration of hydroxyurea in plasma decayed monoexponentially with a mean +/- SE half-life of 3.25 +/- 0.18 h (n = 17). The steady-state concentration of hydroxyurea was > 200 microM in all nine patients treated at 2 g/m2 per day, a dose which was well tolerated for 5 days. We recommend this dose for phase II trials in combination with other antineoplastic agents.