Retreatment with anti-EGFR based therapies in metastatic colorectal cancer: impact of intervening time interval and prior anti-EGFR response

BACKGROUND

This retrospective study aims to investigate the activity of retreatment with anti-EGFR-based therapies in order to explore the concept of clonal evolution by evaluating the impact of prior activity and intervening time interval.

METHODS

Eighty-nine KRAS exon 2-wild-type metastatic colorectal patients were retreated on phase I/II clinical trials containing anti-EGFR therapies after progressing on prior cetuximab or panitumumab. Response on prior anti-EGFR therapy was defined retrospectively per physician-records as response or stable disease ≥6 months. Multivariable statistical methods included a multiple logistic regression model for response, and Cox proportional hazards model for progression-free survival.

RESULTS

Retreatment anti-EGFR agents were cetuximab (n = 76) or cetuximab plus erlotinib (n = 13). The median interval time between prior and retreatment regimens was 4.57 months (range: 0.46-58.7). Patients who responded to the prior cetuximab or panitumumab were more likely to obtain clinical benefit to the retreatment compared to the non-responders in both univariate (p = 0.007) and multivariate analyses (OR: 3.38, 95 % CI: 1.27, 9.31, p = 0.019). The clinical benefit rate on retreatment also showed a marginally significant association with interval time between the two anti-EGFR based therapies (p = 0.053). Median progression-free survival on retreatment was increased in prior responders (4.9 months, 95 % CI: 3.6, 6.2) compared to prior non-responders (2.5 months, 95 % CI, 1.58, 3.42) in univariate (p = 0.064) and multivariate analysis (HR: 0.70, 95 % CI: 0.43-1.15, p = 0.156).

CONCLUSION

Our data lends support to the concept of clonal evolution, though the clinical impact appears less robust than previously reported. Further work to determine which patients benefit from retreatment post progression is needed.

A phase 1 study of intermittently administered pazopanib in combination with continuous daily dosing of lapatinib in patients with solid tumors

PURPOSE

Preclinically, pazopanib/lapatinib combination acted synergistically to suppress the activity of multiple tyrosine kinases, including VEGFR-1, 2, 3, PDGFR and c-kit (pazopanib), HER1/EGFR and HER2 (lapatinib), and several other tyrosine kinases including c-Met through, plausibly, network inhibition effects. Clinically, continuous dosing of pazopanib/lapatinib combination was associated with a higher response rate than with lapatinib monotherapy, with poor tolerance. We explored multiple intermittent dose levels of pazopanib combined with continuous daily dosing of lapatinib in patients with solid tumors.

METHODS

The present study used a phase 1, modified 3 + 3, dose-escalation design to evaluate the safety and tolerability of the combination of orally received pazopanib once every other day with continuous daily dosing of lapatinib for 28 days. In the expansion phase, tumor response was evaluated in patients with specific genetic alterations (HER2 amplification, HER2 mutation, c-Met amplification, c-Met mutation, and EGFR mutation).

RESULTS

Twenty-four patients were treated. The most common drug-related adverse events were fatigue 7/24 (29%), skin rash 5/21 (21%), and diarrhea 3/24 (17%), with 4/24 (16%) patients experiencing grade ≥3 drug-related adverse events. Escalation to the FDA-approved dose (800 mg daily for pazopanib and 1500 mg every day for lapatinib) was not feasible due to toxicities. Pazopanib 200 mg every other day + lapatinib 500 mg daily was considered the maximum tolerated dose (MTD). No tumor response was observed, including in patients with the specific molecular genetic alterations tested.

CONCLUSION

Every other day dosing of pazopanib combined with daily lapatinib was tolerated at the established MTD, but no complete or partial tumor responses were observed at these dose levels.

Phase I study of pazopanib and vorinostat: a therapeutic approach for inhibiting mutant p53-mediated angiogenesis and facilitating mutant p53 degradation

BACKGROUND

We carried out a phase I trial of the vascular endothelial growth factor inhibitor pazopanib and the histone deacetylase inhibitor vorinostat to determine the safety and efficacy. Because these agents are known to target factors activated by TP53 mutation and facilitate mutant p53 degradation, a subgroup analysis may be interesting in patients with TP53 mutant malignancies.

PATIENTS AND METHODS

Patients with advanced solid tumors (n = 78) were enrolled following a 3 + 3 design, with dose expansion for those with responsive tumors. Hotspot TP53 mutations were tested when tumor specimens were available.

RESULTS

Adverse events of ≥grade 3 included thrombocytopenia, neutropenia, fatigue, hypertension, diarrhea and vomiting. Overall, the treatment produced stable disease for at least 6 months or partial response (SD ≥6 months/PR) in 19% of the patients, median progression-free survival (PFS) of 2.2 months, and median overall survival (OS) of 8.9 months. In patients with detected hotspot TP53 mutant advanced solid tumors (n = 11), the treatment led to a 45% rate of SD ≥6 months/PR (1 PR and 3 SD ≥6 months), median PFS of 3.5 months, and median OS of 12.7 months, compared favorably with the results for patients with undetected hotspot TP53 mutations (n = 25): 16% (1 PR and 3 SD ≥6 months, P = 0.096), 2.0 months (P = 0.042), and 7.4 months (P = 0.1), respectively.

CONCLUSION

The recommended phase II dosage was oral pazopanib at 600 mg daily plus oral vorinostat at 300 mg daily. The preliminary evidence supports further evaluation of the combination in cancer patients with mutated TP53, especially in those with metastatic sarcoma or metastatic colorectal cancer.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov, NCT01339871.

Predicting high-throughput screening results with scalable literature-based discovery methods

The identification of new therapeutic uses for existing agents has been proposed as a means to mitigate the escalating cost of drug development. A common approach to such repurposing involves screening libraries of agents for activities against cell lines. In silico methods using knowledge from the biomedical literature have been proposed to constrain the costs of screening by identifying agents that are likely to be effective a priori. However, results obtained with these methods are seldom evaluated empirically. Conversely, screening experiments have been criticized for their inability to reveal the biological basis of their results. In this paper, we evaluate the ability of a scalable literature-based approach, discovery-by-analogy, to identify a small number of active agents within a large library screened for activity against prostate cancer cells. The methods used permit retrieval of the knowledge used to infer their predictions, providing a plausible biological basis for predicted activity.

Results from short-term CT assessments in patients (pts) with advanced poor performance status non-small cell lung cancer (NSCLC) receiving pemetrexed in a phase II trial

e19069

Background: Early determination of therapeutic failure can potentially spare a pt ineffective and toxic treatment. We previously reported in a retrospective study the use of CT within 4 weeks of initiation of chemotherapy in advanced NSCLC to assess response and progression by RECIST (Bruzzi et al. JTO 2006). Here, we prospectively assess whether CT imaging after the first cycle of pemetrexed in advanced NSCLC has a role in evaluating response and management. Methods: We accrued pts with PS 2 or 3 advanced NSCLC receiving at least one dose of 1st or 2nd line pemetrexed. A repeat CT prior to a 2nd course was required. Pts with progression by RECIST were to come off study. CT scans were done using multislice CT technology (GE Lightspeed Plus), and images were reconstructed with slice thicknesses of 3.75mm or less. All images were reviewed using a PACs workstation (Stentor iSite) and measurements were done with electronic calipers. RECIST criteria: progression, an increase in the tumor's longest dimension by 20%, response, a decrease by 30%. Results: Thirty pts had a median age of 68 years (45 - 81). PS 2/3, 1st/2nd line, and F/M were 16/14, 17/13, and 12/18 respectively. Pts received 1–8 cycles (median 2). Twelve pts received only 1 course of whom 7 pts had f/u CTs at a median of 20 days (12–25) after 1st chemo dose. Of these pts, 5/7 had progression by RECIST and the other 2/7 pts had stable disease with 1 pt who came off due to serial PEs and 1 pt who opted off for reasons of travel. Two of the 5 pts who had progression by CT had no detectable change by CXR. Of 5/12 pts treated with only 1 course without f/u CT, 2 pts died, 2 pts had progression by CXR, and 1 pt stopped after treatment for pneumonia. All 18 pts receiving ≥2 cycles had a repeat CT prior to their 2nd course. Conclusions: The results of this prospective trial support earlier retrospective findings that short-term follow-up using CT in pts with advanced NSCLC can detect tumor progression and impact patient management. We will also present f/u CTs in pts who received ≥ 1course to determine whether early signs of progression predict later RECIST determined progression.

[Table: see text]

A phase II trial of pemetrexed (P) in patients (pts) with performance status (PS) 2 and 3 as first- and second-line treatment for advanced non-small cell lung cancer (NSCLC)

18149

P (Alimta) is approved as second-line therapy in pts with advanced NSCLC. In a phase III trial comparing P with docetaxel (D), median survival was 8.3 mos (P) vs 7.9 mos (D); P had a more favorable safety profile than D (Hanna, 2004). There are few data on pts with PS 3, and ASCO 2003 guidelines recommend that chemotherapy be reserved for pts with PS 0, 1 and possibly 2. Since P is well tolerated, PS3 pts may tolerate and benefit from it. In this trial, we treated 20 pts with stage IIIb/IV NSCLC and PS 2–3 who were chemo-naive or had received 1 prior regimen. Pts received P 500 mg/m2 IV D1 Q 3 wks. All pts received folic acid, vitamin B12 and dexamethasone prophylaxis. Serial blood samples were obtained to monitor inflammatory cytokines, and symptoms were monitored using the validated MDASI instrument. All pts were assessable for toxicity-symptoms, and 17 pts were evaluable for response (assessed after first cycle). Pt characteristics: 8 pts were PS 3 (4/8 first line) and 12 pts were PS 2 (6/12 first line). Median age was 69 for PS3 and 68 for PS2. 5/8 PS3 pts and 6/12 PS2 pts were men. 2/8 PS3 pts and 4/12 PS2 pts had stage IIIb. 4/8 PS3 pts and 6/12 PS2 pts were chemo-naive. Grade 3–4 toxicities for PS3/PS2 cohorts were: neutropenia 0/1 pt, anemia 1/2, fatigue 2/0, pneumonia 1/1, hypotension 1/1, neutropenic fever 0/1, atrial fibrillation 1/1. Response rates (RR) in PS3 pts were minor response (MR) 1/8, stable disease (SD) 5/8, progressive disease (PD) 2/8; RR in PS2 pts were partial response (PR) 1/12, MR 2/12, SD 3/12, PD 3/12, inevaluable 3/12. RR by line of therapy: first-line 6/10 SD, 2/10 PD, 2/10 inevaluable, and second-line, 1/10 PR, 2/10 MR, 3/10 SD, 3/10 PD, and 1/10 inevaluable. Reasons for PS3 pts coming off study were progression (4/8), constitutional toxicity (3/8), fatal pulmonary emboli (1/8); PS2 pts came off study due to progression (5/12), constitutional toxicity (2/12), and pneumonia (1/12). 4/12 PS2 pts are still on study. These preliminary data suggest that single-agent P is well-tolerated and has a promising RR in poor PS pts. Total planned accrual is 30 PS3 and 45 PS2 pts. Survival, symptom, cytokine data will be presented.

[Table: see text]

Three dimensional analysis of histone methylation patterns in normal and tumor cell nuclei

Histone modifications represent an important epigenetic mechanism for the organization of higher order chromatin structure and gene regulation. Methylation of position-specific lysine residues in the histone H3 and H4 amino termini has linked with the formation of constitutive and facultative heterochromatin as well as with specifically repressed single gene loci. Using an antibody, directed against dimethylated lysine 9 of histone H3 and several other lysine methylation sites, we visualized the nuclear distribution pattern of chromatin flagged by these methylated lysines in 3D preserved nuclei of normal and malignant cell types. Optical confocal serial sections were used for a quantitative evaluation. We demonstrate distinct differences of these histone methylation patterns among nuclei of different cell types after exit of the cell cycle. Changes in the pattern formation were also observed during the cell cycle. Our data suggest an important role of methylated histones in the reestablishment of higher order chromatin arrangements during telophase/early G1. Cell type specific histone methylation patterns are possibly casually involved in the formation of cell type specific heterochromatin compartments, composed of (peri)centromeric regions and chromosomal subregions from neighboring chromosomes territories, which contain silent genes.

Randomized phase III study of chemoradiation with or without amifostine for patients with favorable performance status inoperable stage II-III non-small cell lung cancer: preliminary results

A prospective randomized study was conducted to determine whether amifostine (Ethyol) reduces the rate of severe esophagitis and hematologic and pulmonary toxicity associated with chemoradiation or improves control of non-small cell lung cancer (NSCLC). Sixty patients with inoperable stage II or III NSCLC were treated with concurrent chemoradiotherapy. Both groups received thoracic radiation therapy (TRT) with 1.2 Gy/fraction, 2 fraction per day, 5 days per week for a total dose 69.6 Gy. All patients received oral etoposide (VP-16), 50 mg Bid, 30 minutes before TRT beginning day 1 for 10 days, repeated on day 29, and cisplatin 50 mg/m(2) intravenously on days 1, 8, 29, and 36. Patients in the study group received amifostine, 500 mg intravenously, twice weekly before chemoradiation (arm 1); patients in the control group received chemoradiation without amifostine (arm 2). Patient and tumor characteristics were distributed equally in both groups. Of the 60 patients enrolled, 53 were evaluable (27 in arm 1, 26 in arm 2) with a median follow-up of 6 months. Median survival times were 26 months for arm 1 and 15 months for arm 2, not statistically significantly different. Morphine intake to reduce severe esophagitis was significantly lower in arm 1 (2 of 27, 7.4%) than arm 2 (8 of 26, 31%; P =.03). Acute pneumonitis was significantly lower in arm 1 (1 of 27, 3.7%) than in arm 2 (6 of 26, 23%; P =.037). Hypotension (20 mm Hg decrease from baseline blood pressure) was significantly more frequent in arm 1 (19 of 27, 70%) than arm 2 (1 of 26, 3.8%; P =.0001). Only 1 patient discontinued treatment because of hypotension. These preliminary results showed that amifostine significantly reduced acute severe esophagitis and pneumonitis. Further observation is required to assess long-term efficacy.

The PTEN/MMAC1/TEP tumor suppressor gene decreases cell growth and induces apoptosis and anoikis in breast cancer cells

The PTEN/MMAC1/TEP (PTEN) tumor suppressor gene at 10q23.3 is mutated in multiple types of sporadic tumors including breast cancers and also in the germline of patients with the Cowden's breast cancer predisposition syndrome. The PTEN gene encodes a multifunctional phosphatase capable of dephosphorylating the same sites in membrane phosphatidylinositols phosphorylated by phosphatidylinositol 3'-kinase (PI3K). We demonstrate herein that loss of PTEN function in breast cancer cells results in an increase in basal levels of phosphorylation of multiple components of the P13K signaling cascade as well as an increase in duration of ligand-induced signaling through the P13K cascade. These alterations are reversed by wild-type but not phosphatase inactive PTEN. In the presence of high concentrations of serum, enforced expression of PTEN induces a predominant G1 arrest consistent with the capacity of PTEN to evoke increases in the expression of the p27Kip1 cyclin dependent kinase inhibitor. In the presence of low concentrations of serum, enforced PTEN expression results in a marked increase in cellular apoptosis, a finding which is consistent with the capacity of PTEN to alter the phosphorylation, and presumably function, of the AKT, BAD, p70S6 kinase and GSK3 alpha apoptosis regulators. Under anchorage-independent conditions, PTEN also induces anoikis, a form of apoptosis that occurs when cells are dissociated from the extracellular matrix, which is enhanced in conjunction with low serum culture conditions. Together, these data suggest that PTEN effects on the PI3K signaling cascade are influenced by the cell stimulatory context, and that depending on the exposure to growth factors and other exogenous stimuli such as integrin ligation, PTEN can induce cell cycle arrest, apoptosis or anoikis in breast cancer cells.

Effect of nucleotide on the binding of peptides to 70-kDa heat shock protein

In previous work we found that bovine brain hsp70 has a single binding site for nucleotide, and that, with ATP at this site, the rates of association and dissociation of clathrin from hsp70 are fast, whereas with ADP at this site, these rates are unmeasurably slow. In the present study we show, first, that peptide C, cytochrome c peptide, and RNase S peptide bind competitively with clathrin, suggesting that they bind to the same site on hsp70, although RNase S peptide binds an order of magnitude more weakly than peptide C and cytochrome c peptide. Second, we show that, with ADP bound to hsp70, as occurs with clathrin, the rate constant for dissociation of peptide markedly decreases compared to the rate constant observed in ATP. In contrast, ADP only slightly decreases the rate of association of peptide. Based on these data we propose a model in which substrates of hsp70 bind to and dissociate from the ATP form of the enzyme, while, following ATP hydrolysis, they are locked onto the ATP form of the enzyme, unable to dissociate until ADP is released and ATP rebinds.

[A cortico-cancellous graft with a periosteal pedicle for the treatment of deep single-walled bone pockets]

The treatment of single-walled bone pockets involves a number of problems. Conventional treatment methods fail to bring about permanent success, particularly in the more advanced stages. A new method has been developed and described using a cortico-cancellous graft harvested from the apical region of the teeth with a periosteal pedicle that can be inserted into the highly infection-prone area of a bone pocket. The advantage of this procedure is that the transplant is perfused and thus not subjected to necrosis but highly resistant to infections. Indications, practical procedure and success rates are discussed and illustrated in one example.

[Treatment of one-walled periodontal osseous defect by Periost-inserted bone transplant]

A method is described to treat deep isolated periodontal osseous defects in maxillary incisor and canine region with periost-inserted bonetransplant. Indication, procedure and results are demonstrated by a case.

[Sealer-free surgical filling of root canal by means of Gutta-percha]

The author demonstrates a procedure which is aimed at the insertion of fitting, conically pressed Guttapercha pins for filling of standardized, prepared dental root canals in the apectomy. The renunciation of a sealer is the advantages of the procedure. Indication and performance are explained, the advantages of the procedure discussed.

[Organisation of the dispensary care of the maxillary and facial surgery using mini-computers]

The presented hardware and software solution enables to realize an effective and complete patients' recall and thus the comprehensive dispensary care in an average special department for maxillary and facial surgery.