A first-in-human phase I study of the PD-1 inhibitor, retifanlimab (INCMGA00012), in patients with advanced solid tumors (POD1UM-101).

BACKGROUND: Retifanlimab is a humanized, hinge-stabilized immunoglobulin G4κ monoclonal antibody against human programmed cell death protein 1 (PD-1). This first-in-human, phase I study assessed the safety and efficacy of retifanlimab in patients with advanced solid tumors and identified optimal dosing. PATIENTS AND METHODS: POD1UM-101 was conducted in two parts: (i) dose escalation-evaluated retifanlimab [1 mg/kg every 2 weeks (q2w), 3 or 10 mg/kg q2w or every 4 weeks (q4w)] in patients with relapsed/refractory, unresectable, locally advanced or metastatic solid tumors; (ii) cohort expansion-biomarker-unselected tumor-specific cohorts [endometrial, cervical, sarcoma, non-small-cell lung cancer (NSCLC)] received retifanlimab 3 mg/kg q2w, and tumor-agnostic cohorts received flat dosing [375 mg every 3 weeks (q3w), or 500 and 750 mg q4w]. Primary objectives were safety and tolerability; secondary objective was efficacy in selected tumor types. RESULTS: Thirty-seven patients were enrolled in dose escalation, 134 in PD-1 therapy-naïve tumor-specific cohort expansion (endometrial, n = 29; cervical, NSCLC, soft tissue sarcoma, each n = 35), and 45 in flat dosing (375 mg q3w, 500 and 750 mg q4w, each n = 15). No dose-limiting toxicities occurred during dose escalation; maximum tolerated dose was not reached and 3-mg/kg q2w expansion dose was selected based on safety and pharmacokinetic data. Immune-related adverse events were experienced by 40 patients (30%) in tumor-specific cohorts (most frequently hypothyroidism, hyperthyroidism, colitis, nephritis) and 6 (13%) in flat dosing (most frequently hypothyroidism, hyperthyroidism). Objective response rate (95% confidence interval) was 14% (4.8 to 30.3), 14% (3.9 to 31.7), 20% (8.4 to 36.9), and 3% (0.1 to 14.9) in advanced NSCLC, endometrial, cervical, and sarcoma tumor-specific cohorts that progressed after multiple prior systemic therapies. CONCLUSIONS: Retifanlimab demonstrated clinical pharmacology, safety, and antitumor activity consistent with the programmed death (ligand)-1 inhibitor class. POD1UM-101 results support further exploration of retifanlimab as monotherapy and backbone immunotherapy in combination treatments, with recommended doses of 500 mg q4w and 375 mg q3w.

The paradox-breaking panRAF plus SRC family kinase inhibitor, CCT3833, is effective in mutant KRAS-driven cancers.

BACKGROUND: KRAS is mutated in ∼90% of pancreatic ductal adenocarcinomas, ∼35% of colorectal cancers and ∼20% of non-small-cell lung cancers. There has been recent progress in targeting G12CKRAS specifically, but therapeutic options for other mutant forms of KRAS are limited, largely because the complexity of downstream signaling and feedback mechanisms mean that targeting individual pathway components is ineffective. DESIGN: The protein kinases RAF and SRC are validated therapeutic targets in KRAS-mutant pancreatic ductal adenocarcinomas, colorectal cancers and non-small-cell lung cancers and we show that both must be inhibited to block growth of these cancers. We describe CCT3833, a new drug that inhibits both RAF and SRC, which may be effective in KRAS-mutant cancers. RESULTS: We show that CCT3833 inhibits RAF and SRC in KRAS-mutant tumors in vitro and in vivo, and that it inhibits tumor growth at well-tolerated doses in mice. CCT3833 has been evaluated in a phase I clinical trial (NCT02437227) and we report here that it significantly prolongs progression-free survival of a patient with a G12VKRAS spindle cell sarcoma who did not respond to a multikinase inhibitor and therefore had limited treatment options. CONCLUSIONS: New drug CCT3833 elicits significant preclinical therapeutic efficacy in KRAS-mutant colorectal, lung and pancreatic tumor xenografts, demonstrating a treatment option for several areas of unmet clinical need. Based on these preclinical data and the phase I clinical unconfirmed response in a patient with KRAS-mutant spindle cell sarcoma, CCT3833 requires further evaluation in patients with other KRAS-mutant cancers.

A phase I dose-escalation study of enzalutamide in combination with the AKT inhibitor AZD5363 (capivasertib) in patients with metastatic castration-resistant prostate cancer.

BACKGROUND: Activation of the PI3K/AKT/mTOR pathway through loss of phosphatase and tensin homolog (PTEN) occurs in approximately 50% of patients with metastatic castration-resistant prostate cancer (mCRPC). Recent evidence suggests that combined inhibition of the androgen receptor (AR) and AKT may be beneficial in mCRPC with PTEN loss. PATIENTS AND METHODS: mCRPC patients who previously failed abiraterone and/or enzalutamide, received escalating doses of AZD5363 (capivasertib) starting at 320 mg twice daily (b.i.d.) given 4 days on and 3 days off, in combination with enzalutamide 160 mg daily. The co-primary endpoints were safety/tolerability and determining the maximum tolerated dose and recommended phase II dose; pharmacokinetics, antitumour activity, and exploratory biomarker analysis were also evaluated. RESULTS: Sixteen patients were enrolled, 15 received study treatment and 13 were assessable for dose-limiting toxicities (DLTs). Patients were treated at 320, 400, and 480 mg b.i.d. dose levels of capivasertib. The recommended phase II dose identified for capivasertib was 400 mg b.i.d. with 1/6 patients experiencing a DLT (maculopapular rash) at this level. The most common grade ≥3 adverse events were hyperglycemia (26.7%) and rash (20%). Concomitant administration of enzalutamide significantly decreased plasma exposure of capivasertib, though this did not appear to impact pharmacodynamics. Three patients met the criteria for response (defined as prostate-specific antigen decline ≥50%, circulating tumour cell conversion, and/or radiological response). Responses were seen in patients with PTEN loss or activating mutations in AKT, low or absent AR-V7 expression, as well as those with an increase in phosphorylated extracellular signal-regulated kinase (pERK) in post-exposure samples. CONCLUSIONS: The combination of capivasertib and enzalutamide is tolerable and has antitumour activity, with all responding patients harbouring aberrations in the PI3K/AKT/mTOR pathway. CLINICAL TRIAL NUMBER: NCT02525068.

PATRIOT: A phase I study to assess the tolerability, safety and biological effects of a specific ataxia telangiectasia and Rad3-related (ATR) inhibitor (AZD6738) as a single agent and in combination with palliative radiation therapy in patients with solid tumours.

PATRIOT is a phase I study of the ATR inhibitor, AZD6738, as monotherapy, and in combination with palliative radiotherapy. Here, we describe the protocol for this study, which opened in 2014 and is currently recruiting and comprises dose escalation of both drug and radiotherapy, and expansion cohorts.

Vistusertib (dual m-TORC1/2 inhibitor) in combination with paclitaxel in patients with high-grade serous ovarian and squamous non-small-cell lung cancer.

Background: We have previously shown that raised p-S6K levels correlate with resistance to chemotherapy in ovarian cancer. We hypothesised that inhibiting p-S6K signalling with the dual m-TORC1/2 inhibitor in patients receiving weekly paclitaxel could improve outcomes in such patients. Patients and methods: In dose escalation, weekly paclitaxel (80 mg/m2) was given 6/7 weeks in combination with two intermittent schedules of vistusertib (dosing starting on the day of paclitaxel): schedule A, vistusertib dosed bd for 3 consecutive days per week (3/7 days) and schedule B, vistusertib dosed bd for 2 consecutive days per week (2/7 days). After establishing a recommended phase II dose (RP2D), expansion cohorts in high-grade serous ovarian cancer (HGSOC) and squamous non-small-cell lung cancer (sqNSCLC) were explored in 25 and 40 patients, respectively. Results: The dose-escalation arms comprised 22 patients with advanced solid tumours. The dose-limiting toxicities were fatigue and mucositis in schedule A and rash in schedule B. On the basis of toxicity and pharmacokinetic (PK) and pharmacodynamic (PD) evaluations, the RP2D was established as 80 mg/m2 paclitaxel with 50 mg vistusertib bd 3/7 days for 6/7 weeks. In the HGSOC expansion, RECIST and GCIG CA125 response rates were 13/25 (52%) and 16/25 (64%), respectively, with median progression-free survival (mPFS) of 5.8 months (95% CI: 3.28-18.54). The RP2D was not well tolerated in the SqNSCLC expansion, but toxicities were manageable after the daily vistusertib dose was reduced to 25 mg bd for the following 23 patients. The RECIST response rate in this group was 8/23 (35%), and the mPFS was 5.8 months (95% CI: 2.76-21.25). Discussion: In this phase I trial, we report a highly active and well-tolerated combination of vistusertib, administered as an intermittent schedule with weekly paclitaxel, in patients with HGSOC and SqNSCLC. Clinical trial registration: ClinicialTrials.gov identifier: CNCT02193633.

Clinical Outcome of Patients with Advanced Biliary Tract Cancer in a Dedicated Phase I Unit.

AIMS: Advanced biliary tract carcinomas (ABC) are malignancies with limited effective therapies for advanced disease. There is little published evidence of outcomes of ABC patients participating in phase I clinical trials. MATERIALS AND METHODS: Patient characteristics, treatment details and outcomes of ABC patients treated at a dedicated phase I unit were captured and analysed from case and trial records. RESULTS: In total, 123 ABC patients were included in the study, of which 48 patients participated in 41 different phase I trials; 75 (61%) did not participate due to rapid disease progression or patient choice. Molecular characterisation of tumours using a targeted panel was conducted in 15 (31%), yielding several potentially actionable mutations, including BRCA, PIK3CA, FGFR, AKT and PTEN loss. Of the 39 evaluable patients there was one exceptional responder. Eighteen (46%) other patients achieved stable disease as their best response, with a clinical benefit rate at 4 months of 10%. Treatment was generally well tolerated with grade 3 or 4 adverse events only observed in eight patients (17 %), of which six were drug related and led to trial discontinuation in one (3%), with no toxicity-related deaths. CONCLUSION: Carefully selected ABC patients have been found to tolerate experimental phase I clinical trials without excess toxicity. The aggressive nature of this disease warrants consideration of early referral to a phase I unit. Future work will require comprehensive molecular profiling in an attempt to understand the biology underlying the exceptional responders and to match patients in real-time to targeted therapies.

A phase I/II trial of AT9283, a selective inhibitor of aurora kinase in children with relapsed or refractory acute leukemia: challenges to run early phase clinical trials for children with leukemia.

Aurora kinases regulate mitosis and are commonly overexpressed in leukemia. This phase I/IIa study of AT9283, a multikinase inhibitor, was designed to identify maximal tolerated doses, safety, pharmacokinetics, and pharmacodynamic activity in children with relapsed/refractory acute leukemia. The trial suffered from poor recruitment and terminated early, therefore failing to identify its primary endpoints. AT9283 caused tolerable toxicity, but failed to show clinical responses. Future trials should be based on robust preclinical data that provide an indication of which patients may benefit from the experimental agent, and recruitment should be improved through international collaborations and early combination with established treatment strategies.

Phase I trial outcomes in older patients with advanced solid tumours.

BACKGROUND: This study had two aims: (a) to test the hypothesis that advanced age is associated with lower levels of tolerability and clinical benefit to experimental Phase I trial agents; (b) to assess the validity of the Royal Marsden Hospital (RMH) prognostic score as a patient selection tool in older patients. METHODS: Clinico-pathological characteristics and treatment outcomes of all patients treated consecutively from 2005 to 2009 in phase I trials at the RMH were recorded. All toxicity and clinical outcome data were compared between patients aged below and above 65 years of age. RESULTS: One thousand and four patients were treated in 30 Phase I trials, with 315 (31%) patients aged 65 years and older. Grade 3-5 toxicities (22.8% vs 24.8% (P=0.52)), trial discontinuation (6% vs 4%; P=0.33), and dose interruptions (8.0% vs 8.0% (P=0.96)) were observed at similar rates in patients below and above 65 years of age, respectively. The overall response rate 5.2% vs 4.1%, progression-free survival (PFS) 1.9 vs 3.5 months and clinical benefit rate (CBR) at 6 months 15.2% vs 14.3% were comparable in both groups. To avoid bias due to the potential therapeutic benefit of abiraterone, comparisons were repeated excluding prostate cancer patients with similar results (ORR 4.6% vs 4%, PFS 1.8 vs 3.0 months, CBR at 6 months 13.5% vs 9.5%). Multivariate analysis indicated that the previously identified RMH score (including albumin and lactate dehydrogenase levels) was an accurate predictor of outcome. CONCLUSIONS: Phase I clinical trials should be considered in patients with advanced cancers regardless of age, as older patients who enter these have similar safety and efficacy outcomes as their younger counterparts. The RMH prognostic score can assist in the selection of suitable older patients.

Complications of hyperglycaemia with PI3K-AKT-mTOR inhibitors in patients with advanced solid tumours on Phase I clinical trials.

BACKGROUND: PI3K-AKT-mTOR inhibitors (PAMi) are promising anticancer treatments. Hyperglycaemia is a mechanism-based toxicity of these agents and is becoming increasingly important with their use in larger numbers of patients. METHODS: Retrospective case-control study comparing incidence and severity of hyperglycaemia (all grades) between a case group of 387 patients treated on 18 phase I clinical trials with PAMi (78 patients with PI3Ki, 138 with mTORi, 144 with AKTi and 27 with PI3K/mTORi) and a control group of 109 patients treated on 10 phase I clinical trials with agents not directly targeting the PAM pathway. Diabetic patients were excluded in both groups. RESULTS: The incidence of hyperglycaemia was not significantly different between cases and controls (86.6% vs 80.7%, respectively, P=0.129). However, high grade (grade 3-4) hyperglycaemia was more frequent in the PAMi group than in controls (6.7% vs 0%, respectively, P=0.005). The incidence of grade 3-4 hyperglycaemia was greater with AKT and multikinase inhibitors compared with other PAMi (P<0.001). All patients with high-grade hyperglycaemia received antihyperglycemic treatment and none developed severe metabolic complications (diabetic ketoacidosis or hyperosmolar hyperglycemic nonketotic state). High-grade hyperglycaemia was the cause of permanent PAMi discontinuation in nine patients. CONCLUSIONS: PI3K-AKT-mTOR inhibitors are associated with small (6.7%) but statistically significant increased risk of high-grade hyperglycaemia compared with non-PAM targeting agents. However, PAMi-induced hyperglycaemia was not found to be associated with severe metabolic complications in this non-diabetic population of patients with advanced cancers.

Titration of signalling output: insights into clinical combinations of MEK and AKT inhibitors.

BACKGROUND: We aimed to understand the relative contributions of inhibiting MEK and AKT on cell growth to guide combinations of these agents. MATERIALS AND METHODS: A panel of 20 cell lines was exposed to either the MEK inhibitor, PD0325901, or AKT inhibitor, AKT 1/2 inhibitor. p-ERK and p-S6 ELISAs were used to define degrees of MEK and AKT inhibition, respectively. Growth inhibition to different degrees of MEK and AKT inhibition, either singly or in combination using 96-h sulphorhodamine assays was then studied. RESULTS: A significantly greater growth inhibition was seen in BRAF(M) and PIK3CA(M) cells upon maximal MEK (P = 0.004) and AKT inhibition (P = 0.038), respectively. KRAS(M) and BRAF/PIK3CA/KRAS(WT) cells were not significantly more likely to be sensitive to MEK or AKT inhibition. Significant incremental growth inhibition of the combination of MEK + AKT over either MEK or AKT inhibition alone was seen when MEK + AKT was inhibited maximally and not when sub-maximal inhibition of both MEK + AKT was used (11/20 cell lines versus 1/20 cell lines; P = 0.0012). CONCLUSIONS: KRAS(M) cells are likely to benefit from combinations of MEK and AKT inhibitors. Sub-maximally inhibiting both MEK and AKT within a combination, in a majority of instances, does not significantly increase growth inhibition compared with maximally inhibiting MEK or AKT alone and alternative phase I trial designs are needed to clinically evaluate such combinations.

AKT inhibition synergistically enhances growth-inhibitory effects of gefitinib and increases apoptosis in non-small cell lung cancer cell lines.

OBJECTIVES: EGFR inhibitors are ineffective against most EGFR wild-type non-small cell lung cancer, for which novel treatment strategies are needed. AKT signalling is essential for mediating EGFR survival signals in NSCLC. We evaluated the combination of gefitinib and two different AKT inhibitors, the allosteric inhibitor AKTi-1/2 and the ATP-competitive pan-AKT inhibitor AZD5363, in EGFR-mutant (HCC-827 and PC-9) and -wild-type (NCI-H522, NCI-H1651), non-small cell lung cancer cell lines. MATERIALS AND METHODS: Drug interaction was studied in two EGFR mutant and two EGFR wild-type non-small cell lung cancer cell lines by calculating combination index (CI) using median effect analysis. The effects on p-EGFR, p-ERK, p-AKT, p-S6 and apoptosis were studied by Western blot analysis. RESULTS: The combination of gefitinib and AKTi-1/2 or AZD5363 showed synergistic growth inhibition in all cell lines. CI values for the combination of gefitinib and AKTi-1/2 were 0.35 (p=0.0048), 0.56 (p=0.036), 0.75 (p=0.13) and 0.64 (p=0.0003) in NCI-H522, NCI-H1651, HCC-827 and PC-9 cell lines, respectively; CI values of 0.45 (p=0.0087) and 0.22 (p<0.0001) were observed in NCI-H522 and PC-9 cells, respectively, when gefitinib was combined with AZD5363. Additive inhibition of signalling output through AKT and key downstream proteins (S6) and increased apoptosis were demonstrated. CONCLUSION: Dual inhibition of EGFR and AKT may be a useful up-front strategy for patients with EGFR-mutant and -wild-type non-small cell lung cancer.

Association of creatine kinase and skin toxicity in phase I trials of anticancer agents.

BACKGROUND: We investigated the association between skin rash and plasma creatine kinase (CK) levels in oncology phase I trials. METHODS: We analysed data from 295 patients treated at our institution within 25 phase I trials which included CK measurements in the protocol. Trials involved drugs targeting EGFR/HER2, m-TOR, VEGFR, SRC/ABL, aurora kinase, BRAF/MEK, PARP, CDK, A5B1 integrin, as well as oncolytic viruses and vascular disrupting agents. RESULTS: Creatine kinase measurements were available for 278 patients. The highest levels of plasma CK during the trial were seen among patients with Grade (G) 2/3 rash (median 249 U l(-1)) compared with G1 (median 81 U l(-1)) and no rash (median 55 U l(-1)) (P<0.001). There was a significant reduction in CK after the rash resolved (mean 264.2 vs 100.1; P=0.012) in 25 patients, where serial CK values were available. In vitro exposure of human keratinocytes to EGFR, MEK and a PI3Kinase/m-TOR inhibitor led to the increased expression of CK-brain and not CK-muscle or mitochondrial-CK. CONCLUSION: Plasma CK elevation is associated with development of skin rash caused by novel anticancer agents. This should be studied further to characterise different isoforms as this will change the way we report adverse events in oncology phase I clinical trials.

Safety, tolerability, pharmacokinetics and pharmacodynamics of AZD8055 in advanced solid tumours and lymphoma.

BACKGROUND: This study assessed the safety, tolerability, pharmacokinetics and pharmacodynamics of the first-in-class dual mammalian target of rapamycin complex (mTORC)1/mTORC2 inhibitor, AZD8055. METHODS: Patients with advanced solid malignancies or lymphomas were recruited into this phase I, open-label, dose-escalation study of AZD8055 starting at 10 mg twice-daily oral dosing (BID). RESULTS: Forty-nine patients received AZD8055. Dose-limiting toxicities were reported at 40 mg (n=1), 90 mg (n=1) and 120 mg (n=3) BID; all were grade 3 rises in transaminases, reversible in all patients, apart from one who had liver metastases. The maximum tolerated dose was defined as 90 mg BID. The most frequent adverse events assessed to be related to AZD8055 were increased alanine aminotransferase (22%), increased aspartate aminotransferase (22%) and fatigue (16%). AZD8055 was rapidly absorbed (median t(max) ∼0.5 h) and exposure increased with increasing doses. Seven patients had stable disease for ≥ 4 months. Partial metabolic responses, assessed by fluorodeoxyglucose positron emission tomography, were observed at ≥ 40 mg BID (n=8 at day 35). CONCLUSION: The maximum tolerated dose for AZD8055 is 90 mg BID. Apart from elevated transaminases, which occurred at most dose levels, the drug had an acceptable toxicity profile; however, no RECIST responses were seen.

Creatinine clearance is associated with toxicity from molecularly targeted agents in phase I trials.

OBJECTIVES: This study aimed to evaluate any correlations between baseline creatinine clearance and the development of grade 3/4 toxicities during treatment within oncology phase I trials of molecularly targeted agents where entry criteria mandate a serum creatinine of ≤ 1.5 × the upper limit of normal. METHODS: Documented toxicity and creatinine clearance (calculated by the Cockcroft-Gault formula) from all patients treated with molecularly targeted agents in the context of phase I trials within our centre over a 5-year period were analyzed. RESULTS: Data from 722 patients were analyzed; 116 (16%) developed at least one episode of grade 3/4 toxicity. Patients who developed a late-onset (>1 cycle) grade 3/4 toxicity had a lower creatinine clearance than those who did not (82.69 ml/min vs. 98.97 ml/min; p = < 0.001). CONCLUSION: Creatinine clearance (even when within normal limits) should be studied as a potential factor influencing late toxicities in the clinical trials of molecularly targeted anti-cancer drugs.

Defining the risk of toxicity in phase I oncology trials of novel molecularly targeted agents: a single centre experience.

BACKGROUND: This study defined the risk of serious toxicity in phase I trials of molecularly targeted agents (MTA). PATIENTS AND METHODS: A retrospective analysis of toxicity data from patients treated in phase I trials of MTAs was carried out to define the rate of treatment-related grade 3/4 toxic effects, deaths and risk factors associated with grade 3 or more toxicity. RESULTS: Data from 687 patients [median age, 59.1 years (range 12.5-85.5)] treated in 36 trials were analysed. Two hundred and eleven patients were of Eastern Cooperative Oncology Group performance status (PS) zero, 432 of PS one, 38 of PS two and 6 unknown. The rate of grade 3 and 4 events was 14.1% (n=97) and 1.9% (n=13), respectively. Twenty-four percent of events were gastrointestinal, 22% constitutional and 20% metabolic. PS two was associated with a higher risk of toxicity [odds ratio (OR), 2.6; 95% confidence interval (CI) 1.1-6.1; P=0.032] as was receiving >100% of maximum tolerated dose or maximum administered dose (OR 2.5; CI 1.6-3.9; P<0.001). Mortality rate was 0.43% (n=3). CONCLUSIONS: Therapy with novel MTAs in phase I trials is associated with a moderate risk of significant toxicity. This appears less than in phase I studies involving cytotoxic agents, particularly in relation to grade 4 toxicity. The risk of death is low.

A phase I/II trial of sorafenib and infliximab in advanced renal cell carcinoma.

BACKGROUND: There is clinical evidence to suggest that tumour necrosis factor-α (TNF-α) may be a therapeutic target in renal cell carcinoma (RCC). Multi-targeted kinase inhibitors, such as sorafenib and sunitinib, have become standard of care in advanced RCC. The anti-TNF-α monoclonal antibody infliximab and sorafenib have differing cellular mechanisms of action. We conducted a phase I/II trial to determine the safety and efficacy of infliximab in combination with sorafenib in patients with advanced RCC. METHODS: Eligible patients were systemic treatment-naive or had received previous cytokine therapy only. Sorafenib and infliximab were administered according to standard schedules. The study had two phases: in phase I, the safety and toxicity of the combination of full-dose sorafenib and two dose levels of infliximab were evaluated in three and three patients, respectively, and in phase II, further safety, toxicity and efficacy data were collected in an expanded patient population. RESULTS: Acceptable safety was reported for the first three patients (infliximab 5 mg kg⁻¹) in phase 1. Sorafenib 400 mg twice daily and infliximab 10 mg kg⁻¹ were administered to a total of 13 patients (three in phase 1 and 10 in phase 2). Adverse events included grade 3 hand-foot syndrome (31%), rash (25%), fatigue (19%) and infection (19%). Although manageable, toxicity resulted in 75% of the patients requiring at least one dose reduction and 81% requiring at least one dose delay of sorafenib. Four patients were progression-free at 6 months (PFS6 31%); median PFS and overall survival were 6 and 14 months, respectively. CONCLUSION: Sorafenib and infliximab can be administered in combination, but a significant increase in the numbers of adverse events requiring dose adjustments of sorafenib was observed. There was no evidence of increased efficacy compared with sorafenib alone in advanced RCC. The combination of sorafenib and infliximab does not warrant further evaluation in patients with advanced RCC.

Clinical benefit in Phase-I trials of novel molecularly targeted agents: does dose matter?

Phase-I trials traditionally involve dose-escalation to determine the maximal tolerated dose (MTD). With conventional chemotherapy, efficacy is generally deemed to be dose-dependent, but the same may not be applicable to molecularly targeted agents (MTAs). We analysed consecutive patients included in Phase-I trials at the Royal Marsden Hospital from 5 January 2005 to 6 June 2006. We considered only trials of monotherapy MTAs in which the MTD was defined. Three patient cohorts (A, B, and C) were identified according to the dose received as a percentage of the final trial MTD (0-33%, 34-65%, >66%). Potential efficacy was assessed using the non-progression rate (NPR), that is, complete/partial response or stable disease for at least 3 months by RECIST. A total of 135 patients having progressive disease before enrolment were analysed from 15 eligible trials. Median age was 57 years (20-86); male : female ratio was 1.8 : 1. Cohort A, B, and C included 28 (21%), 22 (16%), and 85 (63%) patients; NPR at 3 and 6 months was 21% and 11% (A), 50% and 27% (B), 31% and 14% (C), respectively, P=0.9. Median duration of non-progression (17 weeks; 95% CI=13-22) was not correlated with the MTD level, P=0.9. Our analysis suggests that the potential for clinical benefit is not confined to patients treated at doses close to the MTD in Phase-I trials of MTAs.

From darkness to light with biomarkers in early clinical trials of cancer drugs.

Compared with conventional chemotherapy, rationally designed molecularly targeted agents may be more likely to have antitumor activity in selected tumor subgroups driven by the oncogenic signals targeted by these compounds and a different side-effect profile. The use of biomarkers in the early clinical trials of these new anticancer agents has the potential to increase study participants' benefit from early clinical trials, accelerate the drug development process, maximize the ability to generate important biological information about human cancer, and decrease the risk of late and costly drug attrition.

Clinical efficacy of capecitabine as first-line chemotherapy in metastatic breast cancer--how low can you go?

Sixty-three patients received capecitabine at 1000 mg/m2 twice daily every 2 out of 3 weeks as first-line treatment for advanced disease at our institution. Forty-five patients (71%) had previously received adjuvant or neoadjuvant chemotherapy. The median number of capecitabine cycles administered was 5(1-40). Forty-eight patients had measurable disease with response rate (RR) of 29%. The median time to progression (TTP) was 18(2-122) weeks. Seven patients (11%) had TTP of >1 yr, four of whom received more than 10(24-40) cycles of capecitabine. Thirty-seven percent of patients still needed dose reductions. Our retrospective audit is consistent with a previously published study which used a higher starting dose of capecitabine as first-line chemotherapy. For a subgroup of patients, capecitabine can result in a long TTP with minimal toxicity. The benefit of continuing capecitabine beyond a fixed number of cycles should be investigated further. Schedules using even lower doses of capecitabine for longer periods may also be of interest.

Hsp90 inhibitors in the clinic.

Specific inhibitors of Hsp90 have recently entered human clinical trials. At the time of writing, trials have been initiated only in metastatic cancer, although a rationale exists for using these agents in a variety of human diseases where protein (mis)folding is involved in the disease pathophysiology. Hsp90 inhibitors offer a unique anti-cancer opportunity because they provide simultaneous combinatorial blockade of multiple oncogenic pathways. The first compound in this class, 17-AAG, has completed phase I trials and phase II trials are in progress. The toxicity has been manageable and evidence of possible clinical activity has been seen in metastatic melanoma, prostate cancer and multiple myeloma. Other inhibitors with improved properties are approaching clinical trials. This chapter presents an update of the current clinical trials using Hsp90 inhibitors, focussing on the areas that will be increasingly relevant in the next 5 years.