A phase I study of AT9283, an aurora kinase inhibitor, in patients with refractory solid tumors

2566

Background: AT9283, a multitargeted kinase inhibitor, inhibits several closely related tyrosine and serine/threonine kinases with an IC50 of <10 nM including Aurora A and B, JAK and ABL. Exposure of solid tumour cell lines to AT9283 in vitro induces an “aurora inhibitory” phenotype. Cell survival decreases with increased duration of exposure. Methods: A phase I dose escalation study was performed using a 72 hour continuous intravenous (iv) infusion schedule repeated three weekly according to a stand ard “3+3” design. Results: Thirty-three patients have been treated with a median age of 61 (range 33 to 76 years). The maximum tolerated dose (MTD) was 9 mg/m2/day. Treatment was well tolerated with febrile neutropenia the only dose limiting toxicity. Other adverse events considered possibly related to AT9283 were reversible and included gastrointestinal disturbance and fatigue. Biological evidence of aurora B inhibition manifest as a reduction in histone H3 phosphorylation in skin biopsies during the infusion was observed at all dose levels. A plateau steady state plasma concentration of AT9283 was achieved within 24 hours of initiating drug infusion at all dose levels and exposure increased linearly with dose. Seven patients received an initial oral dose of AT9283 as an aqueous solution in a fasting state at a dose of 0.9 mg mg/m2 one week prior to starting iv treatment. Interim pharmacokinetic analysis indicated that the median oral bioavailability was 27% (range 17 to 45%) The best response to treatment was a partial response in one patient with NSCLC (ongoing). An additional 4 patients received at least six cycles of therapy (squamous cell carcinoma of the lung, adenocarcinoma of the esophagus and colorectal carcinoma [2]) with a best response of stable disease. Conclusions: The MTD of AT9283 when administered as a 72 hour continuous iv infusion was 9mg/m2/day. Febrile neutropenia is the dose limiting toxicity and evidence of anticancer activity was seen in heavily pre-treated patients.

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Advances in the treatment of gastrointestinal stromal tumours

Imatinib, a selective tyrosine kinase inhibitor, is currently the standard of care first-line treatment for unresectable or metastatic gastrointestinal stromal tumour (GIST), improving survival time and delaying disease progression in many patients. Nevertheless, primary and secondary (acquired) resistance to imatinib is a substantial problem in routine clinical practice. Sunitinib is an oral, multitargeted tyrosine kinase inhibitor that was approved for the treatment of imatinib-resistant or -intolerant GIST. In the pivotal phase III study, sunitinib provided substantial clinical benefits including disease control and superior survival versus placebo as second-line treatment. Treatment with sunitinib was reasonably well tolerated. The availability of sunitinib represents an important clinical advance in GIST management, providing physicians and patients with an effective therapy when resistance to imatinib develops.

Molecularly targeted therapy and cancer surgery

May reduce micrometastases

A phase I trial of the heat shock protein 90 (HSP90) inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17- DMAG, alvespimycin) administered weekly

3568

Background: The geldanamycin analogue 17-DMAG inhibits the ATPase activity of HSP90, thus altering client protein & chaperone interactions and targeting client proteins for degradation. The plethora of oncogenic HSP90 client proteins offers the potential of combinatorial blockade across multiple, cancer causing signalling pathways in cancer. Methods: 17-DMAG was administered weekly to patients with advanced, solid tumours using a dose-doubling 3 + 3 Phase I design. The pharmacokinetic (PK) and pharmacodynamic (PD) analyses undertaken were validated to comply with U.K clinical trial legislation. Results: 10 patients, 7 male and 3 female with a mean age of 60 years (range 38 - 78) have received 107 infusions (mean 10.7 weeks, range 2 - 30) at dose levels of 2.5mg/m2, 5mg/m2 & 20mg/m2. No dose-limiting or drug related grade 3 or 4 toxicity has occurred in 9 patients eligible for toxicity assessment. A linear relationship exists between dose and AUC and Cmax (see table ). Hsp72 induction and CDK4 depletion (consistent with HSP90 inhibition) have been detected at doses of 20mg/m2 in peripheral blood mononuclear cells. A confirmed partial response (by PSA and RECIST) has occurred in a patient with hormone refractory prostate cancer (HRPC). Conclusions: We have shown linear PK for 17-DMAG up to 20mg/m2. No dose-limiting toxicity has been encountered. A robust biologically active dose has not been reached but evidence of the pharmacological signature of HSP90 inhibition has been detected in surrogate tissue and a confirmed PR seen in a patient with HRPC. These data support dose escalation to 40mg/m2 and paired tumor biopsies will be taken to further define the PK-PD-clinical relationships.

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Effect of smoking on imatinib pharmacokinetics

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Background: Smoking is a potent inducer of the cytochrome P450 1A2 isoenzyme (CYP1A2) and may therefore effect the pharmacokinetics (PK) of drugs metabolized by CYP1A2. Indeed, clinical studies with erlotinib (metabolized by CYP3A4 and also partly by CYP1A2) have shown a major increase in erlotinib clearance in smokers versus non-smokers. The effect of smoking on the PK of imatinib, which is also metabolized by CYP3A4 and partly by CYP1A2, is unknown. We aimed to study the effect of smoking on imatinib PK in order to explain a part of the interpatient variation. Methods: The effect of smoking on the PK parameters was analyzed in 34 patients with gastro-intestinal stromal tumors or soft tissue sarcoma included in the EORTC-STBSG phase I and phase II trials. This cohort included 9 smokers and 25 non-smokers. The daily smoking habits of the study patients were retrieved retrospectively from the patient’s record. PK parameters assessed with NONMEM, version V were clearance (Cl), distribution volume (V), elimination half life (T1/2) and the dose standardized area under the concentration curve (AUC). We considered a 40% reduction in imatinib exposure clinically relevant and this study is adequately powered to detect this difference. Results: The mean PK parameters in the smokers versus the non-smokers group ± SD were: Cl; 9.6 ± 5.5 L/h vs 9.2 ± 4.6 L/h, V; 216.5 ± 114.3 L vs 207.0 ± 116.9 L, T1/2; 16.1 ± 6.0 h vs 16.5 ± 6.0 h, AUC; 133.6 ± 71.0 ng.h/ml.mg vs 142.3 ± 84.0 ng.h/ml.mg. There was no significant difference in PK parameters observed between the smokers and the non- smokers. Conclusion: This retrospective study suggest that the PK of imatinib was not affected by smoking and therefore does not explain the large variation in imatinib PK.

No significant financial relationships to disclose.

Paclitaxel in patients (pts) with advanced angiosarcomas

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Background: Angiosarcomas represent a heterogenous group of rare sarcomas with specific clinical behaviour and risk factors. Paclitaxel has been suggested to induce tumor control in a proportion of pts with angiosarcoma while being inactive in other soft tissue sarcomas subtypes. The objective of this retrospective study was to investigate the antitumor activity of this compound in a larger series and a multicenter setting. Patients and Methods: Data from pts with angiosarcoma treated with paclitaxel in centers of the EORTC Soft Tissue and Bone Sarcoma Group were collected using a standardized data collection form. Results: Data from 32 pts were collected from 10 centers. There were 17 males and 15 females with a median age of 60.4 years (range 24–91). Eight pts (25%) had angiosarcomas of the face and scalp, 24 pts (75%) at other primary sites. Ten (31 %) pts had a previous cancer history, 7 of whom had been irradiated for breast cancer. Ten (31 %) pts had received 1st line chemotherapy (ctx) and 3 pts 2nd line ctx prior to treatment with paclitaxel. All 13 (40%) pretreated pts had doxorubicin, 5 pts in combination with ifosfamide as 1st line and 3 pts ifosfamide as 2nd line ctx. 21 (66 %) pts received paclitaxel 175 mg/m2 every 3 weeks, and 11 (34 %) received 75–100 mg/m2weekly. The overall response rate (RR) was 62.5 % [including 1 CR (3%) and 19 PR (59%)]; in pts with face and scalp primary sites the RR was 75% (1CR, 5 PR), whereas pts with angiosarcoma at other sites achieved a response in 58% (14 PR). PFS was 7.6 months for all 32 pts. Conclusion: Paclitaxel was an active agent in angiosarcoma in this retrospective multicenter study, also in angiosarcoma originating at other sites than scalp and face. These results need to be confirmed in a controlled, prospective phase II study.

No significant financial relationships to disclose.

A phase I trial of the selective oral cyclin-dependent kinase inhibitor seliciclib (CYC202; R-Roscovitine), administered twice daily for 7 days every 21 days

Seliciclib (CYC202; R-roscovitine) is the first selective, orally bioavailable inhibitor of cyclin-dependent kinases 1, 2, 7 and 9 to enter clinical trial. Preclinical studies showed antitumour activity in a broad range of human tumour xenografts. A phase I trial was performed with a 7-day b.i.d. p.o. schedule. Twenty-one patients (median age 62 years, range: 39-73 years) were treated with doses of 100, 200 and 800 b.i.d. Dose-limiting toxicities were seen at 800 mg b.i.d.; grade 3 fatigue, grade 3 skin rash, grade 3 hyponatraemia and grade 4 hypokalaemia. Other toxicities included reversible raised creatinine (grade 2), reversible grade 3 abnormal liver function and grade 2 emesis. An 800 mg portion was investigated further in 12 patients, three of whom had MAG3 renograms. One patient with a rapid increase in creatinine on day 3 had a reversible fall in renal perfusion, with full recovery by day 14, and no changes suggestive of renal tubular damage. Further dose escalation was precluded by hypokalaemia. Seliciclib reached peak plasma concentrations between 1 and 4 h and elimination half-life was 2-5 h. Inhibition of retinoblastoma protein phosphorylation was not demonstrated in peripheral blood mononuclear cells. No objective tumour responses were noted, but disease stabilisation was recorded in eight patients; this lasted for a total of six courses (18 weeks) in a patient with ovarian cancer.

Participation of patients with gynecological cancer in phase I clinical trials: two years experience in a major cancer center

OBJECTIVES

This study aims at analyzing the clinico-demographic features that influence the recruitment of gynecological cancer (GC) patients to phase I trials. The possible clinical benefit to patients resulting from the participation in these trials has been also investigated.

METHODS

We performed a retrospective analysis of GC patients referred to the Phase I Unit of the Royal Marsden Hospital in Sutton (Surrey, UK), over 2 years.

RESULTS

Overall 68 GC patients were referred, and subsequently 32 (47.1%) enrolled. The percentage of patients enrolled increased as the distance to travel between the patient's residence and the hospital shortened (8.3% through 47.8% to 60.8%, for travel time >2, 1-2 or < or =1 h, respectively; p=0.008). Better performance status (PS) was found to be associated with higher enrollment rate with percentages increasing from 0 through 51.2 to 58.8 in cases with PS> or =2, PS=1, PS=0, respectively (p=0.015). Among the biochemical parameters, only hepatobiliary dysfunction was found to be associated with lower enrollment (p=0.012). Minimal response/disease stabilization was observed in 11 patients (34.4%). An increased median survival following the first visit was observed in patients enrolled compared to those not enrolled (8 versus 4 months, respectively, p=0.0055). In the multivariate analysis, only PS and enrollment in trials retained an independent prognostic role (p=0.031 and p=0.040, respectively).

CONCLUSIONS

This study, suggesting liver function and PS as important factors influencing the recruitment of GC patients to phase I trials could guide referral of patients to phase I Units. Moreover, the practical limitations imposed by long distance travel, together with the potential clinical benefit due to the participation to these trials, should encourage more investigators to develop phase I units in major cancer centers.

Phase 1 European Organisation for Research and Treatment of Cancer study determining safety of pegylated liposomal doxorubicin (Caelyx®) in combination with ifosfamide in previously untreated adult patients with advanced or metastatic soft tissue sarcomas

This phase I study evaluated the toxicity of first-line combined pegylated liposomal doxorubicin (Caelyx) and ifosfamide in patients with advanced and/or metastatic soft tissue sarcomas. Five dose levels (L) were studied: Caelyx 30 mg/m2 (L1-4) or 40 mg/m2 (L5) 1-h infusion d 1 q 3 weeks + ifosfamide and mesna at X g/m2/4 h d 1-3 q 3 weeks at five doses: L1: X = 1.7 g; L2: X = 2 g; L3: X = 2.5 g; L4 and L5: X = 3 g. Cohorts of 3 patients were entered at each level unless a dose-limiting toxicity (DLT) occurred. In case of DLT in 1 of 3 patients a new cohort was added. Toxicity was evaluated by Common Toxicity Criteria (CTC). A total of 28 patients was included: 4 at dose L1, 8 at L2, 3 at L3, 6 at L4, and 7 at L5. Median age was 60 years (range 29-69 years). Male/female ratio was 12/16. Seventy-five percent of patients had a performance status of 1.0 and 36% had leiomyosarcomas. No DLT was observed at dose L1-4. Six patients developed a DLT at dose L5, and thus the recommended dose is level 4 (i.e. Caelyx 30 mg/m2/1 h d 1+ifosfamide at 3 g/m2/4 h d 1-3 q 3 weeks). Few haematological and biochemical events were observed and the principal toxicities were granulocytopaenia and leucopaenia. Five patients discontinued therapy because of toxicity, 4 of them at dose level 5. Non-haematological toxicities > grade 2 were also few. Palmar-plantar erythrodysesthesia (PPE) > grade 1 was not seen. Two patients obtained partial response (PR) and 13 stable disease (SD). Median overall survival (OS) was 333 d and median progression-free survival (PFS) 174 d. In conclusion, this seems to be a feasible combination in patients with advanced soft tissue sarcomas, allowing ifosfamide to be given in a dosage similar to that used when given alone. The recommended dose for future studies is Caelyx 30 mg/m2/1 h d 1+ifosfamide 3 g/m2/4 h d 1-3 q 3 weeks.

Summary of results in patients with metastatic renal cell cancer (RCC) from phase I studies of RAD001 (everolimus)

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Background: Activation of mammalian target of rapamycin (mTOR) is implicated in the pathogenesis of RCC. Hereditary RCC in tuberous sclerosis pts is associated with loss of function of TS complex genes and resultant activation of mTOR. In non-hereditary RCC, mutation of VHL reduces opposition to mTOR-dependant upregulation of HIF. HIF-1α stimulates growth-factor-mediated activities (VEGF, PDGF, TGFα) supporting tumor-growth and proliferation. RAD001, an orally bioavailable inhibitor of mTOR, could have a role in the treatment of pts with RCC. Methods: All pts with metastatic RCC treated in two phase 1 studies of RAD001 in advanced solid cancer were reviewed. Changes in tumor were assessed using RECIST. Results: There were 12 pts (8.2% of total study population) with histology of clear cell (10 pts), papillary (1 pt), sarcomatoid (1 pt). Dosing was either weekly (20 mg:1 pt, 50 mg:2 pts, 70 mg:4 pts) or daily (10 mg:5 pts). 8 pts were male, 4 female. Median age 60 yrs (range: 44–76). Baseline performance status (WHO) was 0 (2 pts) or 1 (10 pts). Metastatic sites included lung (9 pts), bone (7 pts), liver (2 pts). 10 pts had failed prior drug therapy including IL-2 (2 pts), bevacizumab & erlotinib (7 pts), others (5 pts). Most frequent suspected drug reactions (3 pts or more) were: fatigue, diarrhea, rash, anorexia, mucositis, nausea, abdominal distension, vomiting, headache. Gr.3 events in single pts comprised: hypertriglyceridemia, hyperglycemia, epistaxis with prolonged bleeding time. 6 pts were progression-free at 6 months, 4 pts beyond 12 months (max. 20 months ongoing). Partial response apparent in 1 pt (papillary) on D334 is ongoing at D502. Conclusions: Advanced RCC pts can benefit from RAD001 as indicated by prolonged stable disease in half the cohort. Tumor shrinkaqe may appear only after several months of treatment. Toxicity is mostly mild and similar to patients with other tumor types. Further studies of RAD001 in pts with RCC are planned.

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Updated results from a phase III trial of sunitinib in GIST patients (pts) for whom imatinib (IM) therapy has failed due to resistance or intolerance

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Background: Sunitinib malate (previously known as SU11248) is an oral multitargeted tyrosine kinase inhibitor with both antitumor and antiangiogenic effects due to blockade of KIT, PDGFRs, VEGFRs, FLT3, and RET. Initial results from this phase III trial showed sunitinib was associated with significantly longer TTP than placebo in IM-resistant GIST pts. Methods: This double-blind, placebo-controlled, phase III trial compared sunitinib 50 mg/day (N=207) to placebo (N=105) in IM-resistant or -intolerant GIST pts. Treatment was administered in 6-week cycles (4 weeks on, 2 weeks off treatment). The primary endpoint was TTP. Secondary endpoints included PFS, OS, ORR, and pain and health status (HS) measures. Pain relief response rate (PRRR) was defined as the proportion of pts who had ≥1 pain relief response event (based on weekly changes in present pain index of MPQ and analgesic consumption). HS was measured using the EQ-5D questionnaire. Results: A planned interim analysis showed significantly longer median TTP with sunitinib versus placebo (27.3 vs 6.4 weeks; HR, 0.33; P<0.001), which led to unblinding of the study and crossover of all placebo pts to open-label sunitinib. OS was also significantly longer with sunitinib (median OS will be presented). Sunitinib therapy induced PRs in 14 pts (6.8%) and durable SD (≥22 weeks) in 36 (17.4%) vs. 0% PR and SD ≥22 weeks in 2 (1.9%) pts on placebo. Four of 9 IM-intolerant pts achieved PR with sunitinib therapy versus 0 of 4 IM-intolerant pts treated with placebo. There was a trend for higher PRRR with sunitinib versus placebo in the ITT population (17.4% vs 9.5%, P=0.064) and in 174 pts who reported pain or analgesic use at baseline (31.0% vs 17.2%, P=0.052). The most common treatment-related AEs were fatigue, diarrhea, skin discoloration, and nausea, which were usually grade 1/2 and easily managed. Updated survival and tumor-control efficacy measures, tolerability, and HS results will be available for presentation. Conclusions: Sunitinib significantly prolonged TTP and OS in GIST pts for whom IM therapy had failed due to resistance or intolerance. This trial demonstrated major clinical benefit from a multitargeted tyrosine kinase inhibitor in pts resistant to a different kinase inhibitor.

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Patterns of tumor response to trabectedin (ET743) in myxoid liposarcomas

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Background: Trabectedin (T) is a marine-derived agent found to be active in ovarian cancer and sarcomas. Among sarcomas, activity has been notable in leiomyosarcomas and liposarcomas. Since liposarcomas are a heterogeneous group, including well/de-differentiated, pleomorphic, and myxoid/round cell subtypes, we have noted particularly interesting patterns of responsiveness to T in myxoid liposarcomas, which are associated with t(12;16)(q13;p11) or t(12;22)(q13;q12) chromosomal translocations, resulting in CHOP-TLS or CHOP-EWS fusion products. Methods: 15 cases of myxoid liposarcomas treated with T at the Istituto Nazionale Tumori, Milan, were retrospectively reviewed. In most cases, T was given as a 24-hr continuous infusion every 21 days, at dose levels from 1.0 to 1.5 mg/sqm. 108 courses were delivered, with a median of 5 courses per patient (range 2–20). Observations made in this series were shared with five other institutions having treated myxoid liposarcoma cases with T, all of which also report a significant response rate, for a total of 44 pts. A centralized radiological review of all pts is ongoing. Results: In the Milan series, early tissue alterations in tumors were observed in 14 patients, mainly with a decrease in tumor density on CT scan and/or decrease in contrast enhancement on MRI. These changes were followed by tumor shrinkage amounting to a conventional PR/CR in 8 (pending final review), while 3 others have responses which continue to evolve. Progression followed treatment interruption in one patient, with a minor response occurring at treatment restart. Treatment is continuing in 12 pts (median duration of therapy in excess of 5 months). Further results of the central radiological review from all centres will be reported. Conclusions: Tumor response to T seen in myxoid liposarcoma appears to be marked by early radiological alterations in tumor tissue, often preceding tumor shrinkage, which may be delayed. A selective mechanism of action for this chromosomal translocation-related sarcoma is suggested, and is being actively investigated at the moment.

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Role of palliative chemotherapy in advanced soft tissue sarcoma: Retrospective analysis of 488 patients

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Background: Advanced soft tissue sarcomas (aSTS) represent an incurable clinical entity of poor prognosis, in which chemotherapy is frequently viewed as relatively ineffective. We aimed to review the efficacy of palliative chemotherapy and investigate prognostic factors in a large group of patients treated on routine palliative protocols. Methods: Patients with STS who had first line chemotherapy for advanced and/or metastatic disease between 1991 and 2005 were identified from the Royal Marsden Hospital’s sarcoma database. Patients with Ewing’s sarcoma, rhabdomyosarcoma, desmoplastic small round cell tumour and GIST were excluded from the study. Patients who were treated elsewhere more than 1 year before they come to our hospital were also excluded. Results: 488 patients (242M/286F) fulfilled the criteria. Median age at the time of treatment was 50 years (range 19–79). The main tumour types were leiomyosarcomas (35%) synovial sarcoma (13%), liposarcoma (10%) and malignant fibrous histiocytoma (10%). The majority of patients (83%) received chemotherapy for metastatic disease. 71% of patients had single organ involvement and 29% had multiple disease sites. Lung was the most common site of metastasis (56%). 54% were treated with single agent chemotherapy. Response rate to chemotherapy was 33% (53% for synovial sarcoma); 22% achieved stable disease for a median duration of 8 months; 45% progressed through chemotherapy. Median time to progression was 3 months, duration of response 9 months and post treatment survival (OS) 12 months. In multivariate analysis, age <60, liposarcoma and synovial histology were found as positive and bone involvement as negative independent prognostic factors. Patients treated with combination chemotherapy experienced longer survival (11 vs 14 months OS; p=0.001). Conclusions: This retrospective study of standard palliative chemotherapy in unselected patients with aSTS shows that more than half of patients benefit from treatment, indicating that this is a worthwhile treatment option. Synovial sarcoma and liposarcoma represent the most chemosensitive sarcoma subtypes. Nevertheless, continuing search for new agents is strongly warranted to improve the survival of these patients.

No significant financial relationships to disclose.