Wild-Type KRAS Is Required for Panitumumab Efficacy in Patients With Metastatic Colorectal Cancer.

PURPOSE: Panitumumab, a fully human antibody against the epidermal growth factor receptor (EGFR), has activity in a subset of patients with metastatic colorectal cancer (mCRC). Although activating mutations in KRAS, a small G-protein downstream of EGFR, correlate with poor response to anti-EGFR antibodies in mCRC, their role as a selection marker has not been established in randomized trials. PATIENTS AND METHODS: KRAS mutations were detected using polymerase chain reaction on DNA from tumor sections collected in a phase III mCRC trial comparing panitumumab monotherapy to best supportive care (BSC). We tested whether the effect of panitumumab on progression-free survival (PFS) differed by KRAS status. RESULTS: KRAS status was ascertained in 427 (92%) of 463 patients (208 panitumumab, 219 BSC). KRAS mutations were found in 43% of patients. The treatment effect on PFS in the wild-type (WT) KRAS group (hazard ratio [HR], 0.45; 95% CI: 0.34 to 0.59) was significantly greater (P < .0001) than in the mutant group (HR, 0.99; 95% CI, 0.73 to 1.36). Median PFS in the WT KRAS group was 12.3 weeks for panitumumab and 7.3 weeks for BSC. Response rates to panitumumab were 17% and 0%, for the WT and mutant groups, respectively. WT KRAS patients had longer overall survival (HR, 0.67; 95% CI, 0.55 to 0.82; treatment arms combined). Consistent with longer exposure, more grade III treatment-related toxicities occurred in the WT KRAS group. No significant differences in toxicity were observed between the WT KRAS group and the overall population. CONCLUSION: Panitumumab monotherapy efficacy in mCRC is confined to patients with WT KRAS tumors. KRAS status should be considered in selecting patients with mCRC as candidates for panitumumab monotherapy.

Detection of chromosomal alteration after infusion of gene-edited allogeneic CAR T cells.

A chromosome 14 inversion was found in a patient who developed bone marrow aplasia following treatment with allogeneic chimeric antigen receptor (CAR) Tcells containing gene edits made with transcription activator-like effector nucleases (TALEN). TALEN editing sites were not involved at either breakpoint. Recombination signal sequences (RSSs) were found suggesting recombination-activating gene (RAG)-mediated activity. The inversion represented a dominant clone detected in the context of decreasing absolute CAR Tcell and overall lymphocyte counts. The inversion was not associated with clinical consequences and wasnot detected in the drug product administered to this patient or in any drug product used in this or other trials using the same manufacturing processes. Neither was the inversion detected in this patient at earlier time points or in any other patient enrolled in this or other trials treated with this or other product lots. This case illustrates that spontaneous, possibly RAG-mediated, recombination events unrelated to gene editing can occur in adoptive cell therapy studies, emphasizes the need for ruling out off-target gene editing sites, and illustrates that other processes, such as spontaneous V(D)J recombination, can lead to chromosomal alterations in infused cells independent of gene editing.

Prognostic or predictive plasma cytokines and angiogenic factors for patients treated with pazopanib for metastatic renal-cell cancer: a retrospective analysis of phase 2 and phase 3 trials.

BACKGROUND: Several targeted drugs are approved for treatment of patients with metastatic renal-cell cancer, but no validated biomarkers are available for prediction of clinical outcome. We aimed to assess the prognostic and predictive associations of pretreatment plasma concentrations of cytokine and angiogenic factors (CAFs) with data from a phase 2 and a phase 3 trial of pazopanib treatment. METHODS: We used a three-step approach for screening, confirmation, and validation of prospective CAF biomarkers. We screened 17 CAFs in 129 patients who had the greatest or least tumour shrinkage in a phase 2 trial of 215 patients treated with pazopanib. We confirmed associations of candidate CAFs (those identified in the screening and from previous studies) with tumour response and progression-free survival (PFS) in 215 patients from this phase 2 trial with an independent analytical platform. We validated confirmed markers in 344 patients from a randomised, placebo-controlled, phase 3 clinical study of pazopanib. FINDINGS: Five candidate markers emerged from initial screening-interleukin 6, interleukin 8, hepatocyte growth factor (HGF), tissue inhibitor of metalloproteinases (TIMP)-1, and E-selectin. Confirmatory analyses identified associations of interleukin 6, interleukin 8, VEGF, osteopontin, E-selectin, and HGF with continuous tumour shrinkage or PFS in patients treated with pazopanib. In the validation set of samples from the phase 3 trial, patients treated with pazopanib who had high concentrations (relative to median) of interleukin 8 (p=0·006), osteopontin (p=0·0004), HGF (p=0·010), and TIMP-1 (p=0·006) had shorter PFS than did those with low concentrations. In the placebo group, high concentrations of interleukin 6 (p<0·0001), interleukin 8 (p=0·002), and osteopontin (p<0·0001) were all prognostically associated with shorter PFS. These factors were stronger prognostic markers than were standard clinical classifications (Eastern Cooperative Oncology Group, Memorial Sloan-Kettering Cancer Center, and Heng criteria). High concentrations of interleukin 6 were predictive of improved relative PFS benefit from pazopanib compared with placebo (p(interaction)=0·009); standard clinical classifications were not predictive of PFS benefit. INTERPRETATION: CAF profiles could provide prognostic information beyond that of standard clinical classification and identify markers predictive of pazopanib benefit in patients with metastatic renal-cell carcinoma. Further studies of the predictive effects of these markers in different populations and with different drugs (eg, mTOR inhibitors) are warranted. FUNDING: GlaxoSmithKline.

Predictive genomic biomarkers.

Advances in the biological characterization of tumors has led to the design and development of anticancer agents targeting specific molecular alterations. The majority of these agents are designed to silence phosphorylation signals that are required for the development and maintenance of the cancer phenotype in specific tumor types. Prospective identification of cancer subsets containing particular target alterations is a requirement for these development programs, which in theory, should include smaller trials and result in larger therapeutic benefits. In this review, we will examine relevant examples of selection markers effectively utilized in oncology, and discuss important considerations pertaining to the co-development of drugs and diagnostics, including current regulatory paths, the incorporation of selection markers emerging late in development, and future directions in the area of personalized oncology.

Triple-drug transcatheter arterial chemoembolization in unresectable hepatocellular carcinoma: assessment of survival in 124 consecutive patients.

OBJECTIVE: The objective of our study was to describe survival outcome in 124 patients with unresectable hepatocellular carcinoma treated with triple-drug transcatheter arterial chemoembolization (TACE) using doxorubicin, cisplatin, and mitomycin C using a standardized regimen. MATERIALS AND METHODS: One hundred twenty-four patients underwent TACE using a standardized triple-drug regimen. Embolization was performed using subselective coaxial embolization technique. Fifty-six patients (group 1) received triple-drug TACE in conjunction with a nonpermanent embolic agent, microfibrillar collagen (Avitene), and 68 patients (group 2) had triple-drug TACE with a permanent embolic agent, Embosphere Microspheres. RESULTS: Twenty-eight patients underwent liver transplantation after TACE, and survival in these patients was significantly longer than those who did not receive a transplant (p < or = 0.001). The mean survival for the no-transplant group (n = 96) was longer in patients with Child-Pugh class A cirrhosis than in those with Child-Pugh class B cirrhosis (30.3 +/- 2.92 [standard error] vs 11.6 +/- 2.84 months, respectively; p < 0.001), in those with Okuda stage I versus stage II disease (31.4 +/- 3.03 vs 17.4 +/- 3.16 months; p = 0.002), and in those with a pre-TACE bilirubin level of less than 2.5 mg/dL (42.75 micromol/L; 28.3 +/- 2.75 vs 13.2 +/- 3.83 months; p = 0.007). Improved survival was seen in the no-transplant patients receiving TACE with the permanent embolic agent (group 2) than in those receiving TACE with the nonpermanent agent (group 1) out to 30 months (p = 0.002). Complications occurred in 16 patients (12.9%). The 30-day mortality was 2.4%. CONCLUSION: Patients with hepatocellular carcinoma who underwent triple-drug TACE followed by liver transplantation showed the longest survival. Patients who did not receive a transplant and were treated with triple-drug TACE with a permanent embolic agent showed longer survival to 30 months after TACE than those receiving a nonpermanent embolic agent.

An open-label clinical trial evaluating safety and pharmacokinetics of two dosing schedules of panitumumab in patients with solid tumors.

PURPOSE: This study evaluated safety, pharmacokinetics, and efficacy of 2 dose schedules and 2 infusion times of panitumumab in patients with advanced solid malignancies. PATIENTS AND METHODS: This phase I multicenter, open-label study sequentially enrolled patients with advanced solid tumors refractory to standard therapy, or for which no standard therapy exists, to receive panitumumab 6 mg/kg every 2 weeks or 9 mg/kg every 3 weeks. Patients receiving panitumumab every 2 weeks received either all infusions over 60 minutes or a 60-minute infusion for the first dose followed by 30-minute infusions if the first infusion was well tolerated. Patients in the every-3-week cohort received 60-minute infusions. Safety outcomes included the incidence of adverse events and antipanitumumab antibody formation. Pharmacokinetic properties were determined. Efficacy endpoints included response rate and duration of response. RESULTS: Eighty-six patients were enrolled; 84 (98%) received panitumumab. Treatment-related adverse events occurred in 90% of patients. Safety profiles were similar between patients receiving 30-minute (n = 20) and 60-minute (n = 43) infusions every 2 weeks and patients receiving panitumumab every 3 weeks (n = 21). Panitumumab exposure at steady state increased dose proportionally, and peak serum concentrations were similar in patients receiving either 30- or 60-minute infusions every 2 weeks. Objective responses were seen in 4 patients (5%) with colon, rectal, esophageal, and bladder cancers. CONCLUSION: Similar drug exposures and safety profiles were observed in patients receiving panitumumab 6 mg/kg every 2 weeks with either 30- or 60-minute infusions and antitumor activity was seen in some patients. Exposure increased approximately dose proportionally at steady state.

Association of progression-free survival, overall survival, and patient-reported outcomes by skin toxicity and KRAS status in patients receiving panitumumab monotherapy.

BACKGROUND: The authors explored the association of skin toxicity (ST) severity as measured by patient-reported ST and Common Terminology Criteria for Adverse Events (CTCAE) grading with efficacy of panitumumab, a fully human antiepidermal growth factor receptor antibody, from a phase 3 metastatic colorectal cancer (CRC) trial. METHODS: Patients were randomized to panitumumab plus best supportive care (BSC) vs BSC alone. ST by modified National Cancer Institute CTCAE v3.0 and modified Dermatology Life Quality Index (mDLQI), health-related quality of life (HRQOL), and CRC symptoms were measured. ST was analyzed using a landmark approach. Associations by KRAS mutational status were also assessed. RESULTS: Of 463 patients, 208 of 231 (90%) panitumumab patients and 184 of 232 (79%) BSC patients had > or = 1 postbaseline patient-reported outcome (PRO) assessment. Panitumumab patients with more severe ST had significantly longer overall survival (OS) (grade 2-4:grade 1; hazard ratio, 0.60; P = .0033). Lower mDLQI scores (< 67; more bothersome ST) were associated with longer OS (Cox model, P < .0001). Similar results were observed with progression-free survival (PFS). An inverse relation between mDLQI and HRQOL scores was observed, suggesting that ST bother correlated with better HRQOL. KRAS and PRO data were available in 363 patients (188 panitumumab; 175 BSC). Longer OS was associated with lower mDLQI scores, regardless of KRAS status. Longer PFS was associated with more severe ST (lower mDLQI scores and higher CTCAE grade ST) in patients with wild-type (WT) KRAS tumors, but not in patients with mutant KRAS tumors. CONCLUSIONS: More severe ST, by both clinical grading and PRO, is associated with better CRC symptoms and HRQOL and with longer OS and PFS among panitumumab-treated patients. The associations for PFS were more pronounced in patients with WT KRAS tumors.

A randomized phase IIIB trial of chemotherapy, bevacizumab, and panitumumab compared with chemotherapy and bevacizumab alone for metastatic colorectal cancer.

PURPOSE: Panitumumab, a fully human antibody targeting the epidermal growth factor receptor, is active in patients with metastatic colorectal cancer (mCRC). This trial evaluated panitumumab added to bevacizumab and chemotherapy (oxaliplatin- and irinotecan-based) as first-line treatment for mCRC. PATIENTS AND METHODS: Patients were randomly assigned within each chemotherapy cohort to bevacizumab and chemotherapy with or without panitumumab 6 mg/kg every 2 weeks. The primary end point was progression-free survival (PFS) within the oxaliplatin cohort. Tumor assessments were performed every 12 weeks and reviewed centrally. RESULTS: A total of 823 and 230 patients were randomly assigned to the oxaliplatin and irinotecan cohorts, respectively. Panitumumab was discontinued after a planned interim analysis of 812 oxaliplatin patients showed worse efficacy in the panitumumab arm. In the final analysis, median PFS was 10.0 and 11.4 months for the panitumumab and control arms, respectively (HR, 1.27; 95% CI, 1.06 to 1.52); median survival was 19.4 months and 24.5 months for the panitumumab and control arms, respectively. Grade 3/4 adverse events in the oxaliplatin cohort (panitumumab v control) included skin toxicity (36% v 1%), diarrhea (24% v 13%), infections (19% v 10%), and pulmonary embolism (6% v 4%). Increased toxicity without evidence of improved efficacy was observed in the panitumumab arm of the irinotecan cohort. KRAS analyses showed adverse outcomes for the panitumumab arm in both wild-type and mutant groups. CONCLUSION: The addition of panitumumab to bevacizumab and oxaliplatin- or irinotecan-based chemotherapy results in increased toxicity and decreased PFS. These combinations are not recommended for the treatment of mCRC in clinical practice.

Association of K-ras mutational status and clinical outcomes in patients with metastatic colorectal cancer receiving panitumumab alone.

BACKGROUND: Identifying predictive biomarkers is important to optimally treat patients. This analysis evaluated the association of K-ras, BRAF, and PIK3CA gene mutations with tumor resistance to panitumumab alone. PATIENTS AND METHODS: From 3 phase II panitumumab metastatic colorectal cancer (mCRC) studies, 62 of 533 patient samples were available. Mutations were identified from genomic DNA by sequencing. RESULTS: Of the 62 samples, 24 (38.7%) harbored a K-ras mutation, and 38 (61.3%) were wild type. In the wild-type K-ras group, 11% of patients had a partial response (PR), 53% had stable disease (SD), and 37% had progressive disease (PD). In the mutant K-ras group, 21% of patients had SD, and 79% of patients had PD; there were no responses. The absence of a K-ras mutation was associated with response to panitumumab (PR vs. SD vs. PD; P = .0028). The hazard ratio for wild-type versus mutant K-ras was 0.4 (95% CI, 0.2-0.7) for progression-free survival and 0.5 (95% CI, 0.3-0.9) for overall survival. Four patients had a V600E BRAF mutation, and 2 patients had a PIK3CA mutation. CONCLUSION: These data suggest that patients with mCRC with activating K-ras mutations are less likely to respond to panitumumab alone. The small sample size limits us from defining a predictive role of PIK3CA and BRAF mutations for panitumumab treatment.

Wild-type KRAS is required for panitumumab efficacy in patients with metastatic colorectal cancer.

PURPOSE: Panitumumab, a fully human antibody against the epidermal growth factor receptor (EGFR), has activity in a subset of patients with metastatic colorectal cancer (mCRC). Although activating mutations in KRAS, a small G-protein downstream of EGFR, correlate with poor response to anti-EGFR antibodies in mCRC, their role as a selection marker has not been established in randomized trials. PATIENTS AND METHODS: KRAS mutations were detected using polymerase chain reaction on DNA from tumor sections collected in a phase III mCRC trial comparing panitumumab monotherapy to best supportive care (BSC). We tested whether the effect of panitumumab on progression-free survival (PFS) differed by KRAS status. RESULTS: KRAS status was ascertained in 427 (92%) of 463 patients (208 panitumumab, 219 BSC). KRAS mutations were found in 43% of patients. The treatment effect on PFS in the wild-type (WT) KRAS group (hazard ratio [HR], 0.45; 95% CI: 0.34 to 0.59) was significantly greater (P < .0001) than in the mutant group (HR, 0.99; 95% CI, 0.73 to 1.36). Median PFS in the WT KRAS group was 12.3 weeks for panitumumab and 7.3 weeks for BSC. Response rates to panitumumab were 17% and 0%, for the WT and mutant groups, respectively. WT KRAS patients had longer overall survival (HR, 0.67; 95% CI, 0.55 to 0.82; treatment arms combined). Consistent with longer exposure, more grade III treatment-related toxicities occurred in the WT KRAS group. No significant differences in toxicity were observed between the WT KRAS group and the overall population. CONCLUSION: Panitumumab monotherapy efficacy in mCRC is confined to patients with WT KRAS tumors. KRAS status should be considered in selecting patients with mCRC as candidates for panitumumab monotherapy.

Dose and schedule study of panitumumab monotherapy in patients with advanced solid malignancies.

PURPOSE: This phase 1 study evaluated the safety, pharmacokinetics, and activity of panitumumab, a fully human, IgG2 monoclonal antibody that targets the epidermal growth factor receptor in patients with previously treated epidermal growth factor receptor-expressing advanced solid tumors. EXPERIMENTAL DESIGN: Sequential cohorts were enrolled to receive four i.v. infusions of panitumumab monotherapy at various doses and schedules. Safety was continuously monitored. Serum samples for pharmacokinetic, immunogenicity, and chemistry assessments were drawn at preset intervals. Tumor response was assessed at week 8. RESULTS: Ninety-six patients received panitumumab. Median (range) age was 61 years (32-79 years), and 72 (75%) patients were male. Tumor types were 41% colorectal cancer, 22% prostate, 16% renal, 15% non-small cell lung, 3% pancreatic, 3% esophageal/gastroesophageal, and 1% anal. The overall incidence of grade 3 or 4 adverse events was 32% and 7%, respectively. The incidence of skin-related toxicities was dose dependent. No maximum tolerated dose was reached. No human anti-panitumumab antibodies were detected. No investigator-determined panitumumab infusion-related reactions were reported. Serum panitumumab concentrations were similar in the 2.5 mg/kg weekly, 6.0 mg/kg every 2 weeks, and 9.0 mg/kg every 3 weeks dose cohorts. Five of 39 patients (13%) with colorectal cancer had a confirmed partial response, and 9 of 39 patients (23%) with colorectal cancer had stable disease. CONCLUSIONS: Panitumumab was well tolerated with comparable exposure and safety profiles for the weekly, every 2 weeks, and every 3 weeks administration schedules. Rash and dry skin occurred more frequently in the dose cohorts receiving > or =2.5 mg/kg weekly dose. Panitumumab has single-agent antitumor activity, most notably in patients with advanced colorectal cancer.

From XenoMouse technology to panitumumab, the first fully human antibody product from transgenic mice.

Therapeutic monoclonal antibodies have shown limited efficacy and safety owing to immunogenicity of mouse sequences in humans. Among the approaches developed to overcome these hurdles were transgenic mice genetically engineered with a 'humanized' humoral immune system. One such transgenic system, the XenoMouse, has succeeded in recapitulating the human antibody response in mice, by introducing nearly the entire human immunoglobulin loci into the germ line of mice with inactivated mouse antibody machinery. XenoMouse strains have been used to generate numerous high-affinity, fully human antibodies to targets in multiple disease indications, many of which are progressing in clinical development. However, validation of the technology has awaited the recent regulatory approval of panitumumab (Vectibix), a fully human antibody directed against epidermal growth factor receptor (EGFR), as treatment for people with advanced colorectal cancer. The successful development of panitumumab represents a milestone for mice engineered with a human humoral immune system and their future applications.

Panitumumab monotherapy in patients with previously treated metastatic colorectal cancer.

BACKGROUND: The safety and efficacy of the fully human antibody panitumumab was evaluated in patients with metastatic colorectal cancer refractory to available therapies. METHODS: This phase 2 open-label, multicenter study of panitumumab enrolled patients with metastatic colorectal cancer who had progressed on chemotherapy that included a fluoropyrimidine and irinotecan or oxaliplatin, or both. All patients had tumors with > or =10% 1+ epidermal growth factor receptor (EGFr) staining by immunohistochemistry. Patients were stratified into 2 strata (high or low staining intensity) and received intravenous panitumumab 2.5 mg/kg weekly 8 of every 9 weeks until disease progression or unacceptable toxicity. RESULTS: In all, 148 patients received panitumumab, 105 in the high EGFr stratum, 43 in the low EGFr stratum. Overall response by central review was 9% (95% confidence interval [CI], 5%-15%) and was similar between strata. An additional 29% of patients had stable disease. Median progression-free survival was 14 weeks (95% CI, 8-16) and median overall survival was 9 months (95% CI, 6-10). Toxicities were manageable, with skin toxicity reported in 95% of patients (5% grade 3 or 4). Four patients discontinued therapy because of toxicity. No antipanitumumab antibodies were detected. One patient had an infusion reaction but was able to continue therapy. CONCLUSIONS: Panitumumab given weekly was well tolerated and had single-agent activity in previously treated patients with colorectal cancer. Dermatologic toxicity was common but rarely severe. Ongoing studies will determine panitumumab activity earlier in the course of treatment for colorectal cancer and in combination with other antineoplastic agents.

Panitumumab with irinotecan/leucovorin/5-fluorouracil for first-line treatment of metastatic colorectal cancer.

PURPOSE: Panitumumab is a fully human monoclonal antibody directed against the epidermal growth factor receptor and is indicated for patients with metastatic colorectal cancer (mCRC) who have experienced disease progression after standard chemotherapy. We conducted this phase II study to assess the ability of panitumumab to be administered with first-line irinotecan-containing regimens in patients with mCRC. PATIENTS AND METHODS: This was a 2-part multicenter study of panitumumab 2.5 mg/kg weekly with irinotecan, 5-fluorouracil (5-FU), and leucovorin. Part 1 used bolus 5-FU (IFL), and part 2 used infusional 5-FU (FOLFIRI). Tolerability (measured by grade 3/4 diarrhea) was the primary endpoint. Objective response, progression-free survival, overall survival, and safety were also examined. RESULTS: Nineteen patients in part 1 and 24 patients in part 2 received panitumumab plus chemotherapy. Grade 3/4 diarrhea occurred in 11 patients (58%) in part 1 and 6 patients (25%) in part 2. All patients had a skin-related toxicity (no grade 4 events). Objective response rates were 46% in part 1 and 42% in part 2. Disease control rates were 74% in part 1 and 79% in part 2. Median progression-free survival (95% confidence interval) was 5.6 months (4.4-8.3 months) for part 1 and 10.9 months (7.7-22.5 months) for part 2. Median overall survival (95% confidence interval) was 17 months (13.7 months to not estimable) for part 1 and 22.5 months (14.4 months to not estimable) for part 2. CONCLUSION: In patients with mCRC, panitumumab/IFL was not well tolerated. Panitumumab/FOLFIRI was well tolerated, showed promising activity, and is undergoing further investigation.

Open-label phase III trial of panitumumab plus best supportive care compared with best supportive care alone in patients with chemotherapy-refractory metastatic colorectal cancer.

PURPOSE: Panitumumab is a fully human monoclonal antibody directed against the epidermal growth factor receptor (EGFR). We compared the activity of panitumumab plus best supportive care (BSC) to that of BSC alone in patients with metastatic colorectal cancer who had progressed after standard chemotherapy. PATIENTS AND METHODS: We randomly assigned 463 patients with 1% or more EGFR tumor cell membrane staining, measurable disease, and radiologic documentation of disease progression during or within 6 months of most recent chemotherapy to panitumumab 6 mg/kg every 2 weeks plus BSC (n = 231) or BSC alone (n = 232). Tumor assessments by blinded central review were scheduled from week 8 until disease progression. The primary end point was progression-free survival (PFS). Secondary end points included objective response, overall survival (OS), and safety. BSC patients who progressed could receive panitumumab in a cross-over study. RESULTS: Panitumumab significantly prolonged PFS (hazard ratio [HR], 0.54; 95% CI, 0.44 to 0.66, [P < .0001]). Median PFS time was 8 weeks (95% CI, 7.9 to 8.4) for panitumumab and 7.3 weeks (95% CI, 7.1 to 7.7) for BSC. Mean (standard error) PFS time was 13.8 (0.8) weeks for panitumumab and 8.5 (0.5) weeks for BSC. Objective response rates also favored panitumumab over BSC; after a 12-month minimum follow-up, response rates were 10% for panitumumab and 0% for BSC (P < .0001). No difference was observed in OS (HR, 1.00; 95% CI, 0.82 to 1.22), which was confounded by similar activity of panitumumab after 76% of BSC patients entered the cross-over study. Panitumumab was well tolerated. Skin toxicities, hypomagnesaemia, and diarrhea were the most common toxicities observed. No patients had grade 3/4 infusion reactions. CONCLUSION: Panitumumab significantly improved PFS with manageable toxicity in patients with chemorefractory colorectal cancer.

Randomized, double-blind, active-controlled trial of every-3-week darbepoetin alfa for the treatment of chemotherapy-induced anemia.

BACKGROUND: In the United States, darbepoetin alfa (Aranesp) is often used to treat patients with chemotherapy-induced anemia using weekly or every-2-week administration schedules. In Europe, darbepoetin alfa is used either weekly or in every-3-week dosing. The every-3-week schedule can be synchronized with many chemotherapy regimens, resulting in fewer visits and reducing burden to patients, but the safety and efficacy of this regimen have not been clear. METHODS: A randomized, double-blind, double-dummy, active-controlled phase 3 trial was performed in 110 European centers. Eligible patients (age > or = 18 years) were anemic (hemoglobin level < 11 g/dL), had a nonmyeloid malignancy, and were to receive at least 12 weeks of chemotherapy. Patients were randomly assigned 1:1 to darbepoetin alfa treatment every 3 weeks (500-microg dose) or weekly (2.25-microg/kg) for 15 weeks. We compared red blood cell transfusion incidence among the two arms from week 5 to the end of the treatment phase using a noninferiority study design. Noninferiority was determined if the upper limit of the 95% confidence interval (CI) for the difference in blood transfusions between groups, calculated using Kaplan-Meier methods, did not exceed 12.5%, a margin based on previous placebo-controlled studies. RESULTS: A total of 705 patients were randomly assigned, and 672 remained in the study at week 5. Fewer patients in the every-3-week arm than in the weekly arm received blood transfusions from week 5 to the end of the treatment phase (unadjusted Kaplan-Meier estimates = 23% versus 30%, difference = -6.8%; 95% CI = -13.6 to 0.1). Percentages of patients achieving the target hemoglobin level (> or = 11 g/dL, consistent with evidence-based practice guidelines) were 84% (every 3 weeks) and 77% (weekly). The frequency of cardiovascular/thromboembolic adverse events was 8% in both groups, and safety was comparable. CONCLUSIONS: Patients with chemotherapy-induced anemia can safely and effectively be treated with 500 microg of darbepoetin alfa every 3 weeks.

Darbepoetin alfa for the treatment of chemotherapy-induced anemia: disease progression and survival analysis from four randomized, double-blind, placebo-controlled trials.

PURPOSE: To determine the effect of darbepoetin alfa (DA) on progression-free survival (PFS) and overall survival (OS) in patients with chemotherapy-induced anemia (CIA). PATIENTS AND METHODS: Two 16-week randomized, double-blind, placebo-controlled phase III studies of weekly DA in anemic patients with lung cancer (n = 314) or lymphoproliferative malignancies (LPMs; n = 344) undergoing chemotherapy were analyzed with prospectively defined long-term PFS and OS end points. Short-term effects of DA on PFS and OS were analyzed by including two additional 16-week dose-finding, double-blind, placebo-controlled studies in anemic patients with multiple tumor types (n = 405) and LPMs (n = 66). RESULTS: Median follow-up is 15.8 months (lung cancer) and 32.6 months (LPM). Median duration of PFS was comparable between DA and placebo: 5.1 months (95% CI, 4.1 to 6.9 months) versus 4.4 months (95% CI, 3.7 to 5.3 months) for lung cancer and 14.2 months (95% CI, 12.2 to 17.5 months) versus 15.9 months (95% CI, 13.1 to 19.0 months) for LPMs. The estimated hazard ratio (HR) of death related to DA use for lung cancer was 0.77 (95% CI, 0.59 to 1.01) and 1.26 (95% CI, 0.92 to 1.71) for LPMs. In the pooled analyses of all four studies (n = 1,129), no differences in PFS or OS were observed between DA and placebo (HR = 0.92; 95% CI, 0.78 to 1.07; and HR = 0.95; 95% CI, 0.78 to 1.16, respectively). CONCLUSION: Treatment with DA does not seem to influence PFS or OS in patients with CIA. Prospective, randomized clinical trials will provide additional insights into the effects of DA on PFS and OS in specific tumor types.

Radiofrequency ablation of hepatocellular carcinoma: treatment success as defined by histologic examination of the explanted liver.

PURPOSE: To retrospectively evaluate the effectiveness of radiofrequency (RF) ablation of hepatocellular carcinoma (HCC) by using histologic examination of the explanted liver. MATERIALS AND METHODS: The study was approved by the medical center Institutional Review Board, with waiver of informed consent. Forty-seven HCC nodules in 24 patients (18 men, six women; age range, 33-71 years; mean age, 56 years) were treated with single or double RF ablation sessions prior to liver transplantation. Histologic data from hematoxylin-eosin staining of explanted liver specimens were retrospectively reviewed to determine treatment success, which was defined as the absence of residual or recurrent viable carcinoma cells at treatment site. Tumor size and the presence of large (> or =3 mm) abutting vessels that were observed during imaging were tested as potential predictors of treatment success or failure (Fisher exact test). In patients who underwent postablation computed tomographic (CT) or magnetic resonance (MR) imaging within 3 months prior to transplantation (21 patients with 44 tumors), imaging results were analyzed for sensitivity and specificity of residual or recurrent tumor by using histologic data as the reference standard. RESULTS: Thirty-five (74%) of 47 ablated tumors, including 29 (83%) of 35 tumors less than 3 cm, were found to be successfully treated on the basis of histologic findings after a mean interval of 7.5 months between RF ablation and transplantation. Nodules that were successfully treated had mean maximal diameter of 2.0 cm, and nodules that were unsuccessfully treated had mean maximal diameter of 3.1 cm (P=.014). Seven (47%) of 15 perivascular lesions were successfully treated whereas 28 (88%) of 32 nonperivascular lesions were successfully treated (P <.01). Imaging correlation showed 100% (33 of 33) specificity and 36% (four of 11) sensitivity of postablation CT and MR imaging for the depiction of residual or recurrent tumor. CONCLUSION: Histologic evidence directly validates RF ablation as an effective treatment of small (<3 cm) HCC.

Clinical gene therapy research utilizing ribozymes: application to the treatment of HIV/AIDS.

Antiretroviral drug therapy can effectively reduce the viral load, and is associated with a degree of immune reconstitution in human immunodeficiency virus (HIV)-infected patients. However, the presence of a latent viral reservoir, the development of drug resistance, drug toxicity, and compliance problems are obstacles that impede full eradication of HIV through drug therapy. The cellular introduction of genetic elements that are capable of inhibiting HIV replication is conceptually appealing as a potential new treatment paradigm for acquired immunodeficiency syndrome (AIDS). In theory, this approach can lead to the development of regenerated hematopoiesis with cells that inhibit viral replication and are protected from the pathogenic effects of HIV. Ribozymes are catalytic RNA molecules that can efficiently and selectively cleave target RNA. By ex vivo retroviral transduction, we have introduced a HIV-1 tat gene-targeted ribozyme (RRz2) and a control construct (LNL6) into granulocyte-colony-stimulating factor (G-CSF) mobilized CD34+ hematopoietic progenitor cells (HPC). Transduced autologous CD34+ cells (an approximately equal mix of RRz2 and LNL6) were infused in 10 patients in this Phase I study. After a median follow-up of 2.5 yr, gene presence and expression were detected by a sensitive polymerase chain reaction (PCR) assay in a transduced-CD34+ cell dose-dependent manner. In this chapter, we describe general considerations related to HIV hematopoietic progenitor-cell gene therapy trial design, implementation, and safety, with an emphasis on the critical steps of this process, namely vector production and characterization, target-cell selection, transduction, final product release testing, and evaluation of vector presence.

Critical steps in the implementation of hematopoietic progenitor-cell gene therapy using ribozyme vectors: a laboratory protocol.

The implementation of a hematopoietic progenitor-cell gene-therapy program involves the performance of laboratory procedures and compliance with the current code of Good Manufacturing Practices. This chapter explains the multiple laboratory steps used in our recent Phase I gene transfer study for HIV. This study employed a retroviral vector to deliver an anti-HIV ribozyme to CD34+ hematopoietic progenitor cells.