A study of pre-operative (neoadjuvant) letrozole in combination with bevacizumab in post-menopausal women with newly diagnosed operable breast cancer: A preliminary safety report

11020

Background: Our preclinical studies suggest that up-regulation of tumor cell VEGF is a mechanism to subvert estrogen dependence in hormone responsive breast cancer resulting in reduced efficacy or acquired resistance; we hypothesized that the combination of Bevacizumab (an anti-VEGF MoAb) and hormonal therapy would be more effective than hormonal therapy alone for breast cancer. Methods: Post-menopausal patients with ER and/or PR positive and Her-2-neu negative operable (T2–4a-c/N 0–2/M0) breast cancer were enrolled. Patients received letrozole (2.5 mg po daily) and Bevacizumab (15 mg/kg IV q 3 wks). Patients were reevaluated every 6 wks for a total of 24 wks; patients with CR/PR/SD in the first evaluation continued in the trial; after an additional 6 weeks of therapy patients with PD or SD were taken off-study and only patients with PR/CR completed 24 weeks of therapy. Definitive surgery was performed at the discretion of the surgeon no sooner than 4 wks after the last dose of bevacizumab. Patients continued letrozole while waiting for surgery. Up to December 2006, 27 patients have been enrolled with 13 patients too early to evaluate. Results: The 14 patients off-study had a median age of 63 years (range; 56 to 79) and an ECOG score of 0 for all patients. None of the patients received therapy for breast cancer before enrollment in the trial. 11 patients were stage II and 3 patients stage III. No treatment-related severe adverse events were seen. Treatment related toxicities were: grade 3 hypertension (n=1), grade 2 hypertension (n=7), grade 2 fatigue (n=2), grade 2 joint pain (n=3), grade 2 hot flashes (n=2), grade 1 proteinuria (n=1); 2 patients were taken off-study because of uncontrolled hypertension occurring on initial infusion of bevacizumab (not evaluable for efficacy). Of the 12 patients evaluable for response, 2 patients had pCR, 8 PR and 2 PD (at 9 weeks and 16 weeks). There have been no problems with wound healing or bleeding related to surgery or progressive disease while awaiting surgery. Conclusions: Combination letrozole and bevacizumab has substantial clinical efficacy and is well tolerated. The combination therapy will be evaluated in a randomized Breast Cancer Research Consortium Trial.

[Table: see text]

Cost comparison of XELOX compared to FOLFOX4 with or without bevacizumab (bev) in metastatic colorectal cancer

4074

Background: A recent randomized 2x2 phase III trial compared oral capecitabine + IV oxaliplatin (XELOX); IV 5FU/LV/oxaliplatin (FOLFOX4), XELOX+bev, and FOLFOX4+bev. FOLFOX4 was the regulatory control. XELOX was non-inferior to FOLFOX4 for progression-free survival, and bev-containing regimens were superior to comparison arms. This economic analysis compared expected costs in XELOX vs. FOLFOX4 arms in a US setting from a payer and societal perspective. Methods: Direct medical and indirect cost estimates (for patient time and travel) were compared. Resource use and patient time were estimated based on trial data and protocols. Data collected during the trial and used in the analysis were as follows: no. of visits / duration of drug administration, central venous access management, treatment of adverse events (AE), including hospital days for treatment-related AEs and total hours of ambulatory encounters. Unit costs were based on government fee schedules (i.e. Medicare reimbursements) and other published sources. Results: Total direct medical cost estimates were similar for bi-weekly FOLFOX4 and 3-weekly XELOX: $45,800 vs. $44,500. XELOX had higher drug costs while FOLFOX had higher drug administration costs, with about 15 more visits. Costs for hospitalization and ambulatory encounters were slightly lower for FOLFOX4; other medications and venous access were slightly higher for FOLFOX4. Similar patterns held for FOLFOX4+bev vs. XELOX+bev (total direct medical cost estimates $76,100 vs. $79,200). Indirect time cost estimates were lower with XELOX due to fewer cycles and visits: estimated savings range from $1000-$5000 depending on assumptions used. Conclusion: XELOX is estimated to have similar total direct medical costs and lower indirect costs compared with FOLFOX4.

[Table: see text]

No significant financial relationships to disclose.

Extended phase I trial of the oral pan-Bcl-2 inhibitor AT-101 by multiple dosing schedules in patients with advanced cancers

3583

Background: Over-expression of Bcl-2 family proteins is common in human cancers. Initial trials of the oral pan-Bcl-2 inhibitor AT-101 showed acute dose limiting toxicity of Gr 3–4 AST/ALT (MTD 40 mg/d), and ileus with prolonged dosing daily (QD) for 21/28 days per cycle (Saleh, NCI_EORTC, 2005; James, ASCO, 2006). Our ongoing Phase 1 study tests different dosing schedules of AT-101 in adults with advanced cancers. Methods: Serial patient (pt) cohorts received AT-101 at escalating doses twice a day for three days every other week (BIDx3dEOW) or once weekly (QW). Adverse events (AEs) were graded by the NCI CTCAE v. 3.0. Results: 24 pts have received pulse dosing; safety data are available for 20 pts (30–70 mg BIDx3dEOW, N=13; 80–160 mg QW, N=7). For comparison, 38 pts received 5–60 mg QD. Median number of cycles (range): BIDx3dEOW_2(1–9); QW_3(1–3), QD_2(1–12). AST/ALT is not yet dose limiting, nor the MTD reached, at 70 mg BIDx3dEOW or 160 mg QW. Ileus occurred in 4/38 pts dosed daily but in no pts on either pulse schedule. Other potentially related Gr 3–4 AEs were: BIDx3dEOW (6 pts)–AST (1 pt), abdominal pain (2 pts), elevated CK/right ventricular dysfunction (1 pt w/history of COPD/doxil therapy), hypokalemia (1 pt);QW: none; QD: AST/ALT (5 pts), nausea/vomiting/diarrhea (3 pts each) fatigue (2 pts), hypocalcemia (2 pts), hypokalaemia/anorexia/dehydration/hypophosphatemia (1 pt), elevated GGT (1 pt). The most common Gr 1–2 AEs_nausea/vomiting/fatigue_occurred in over 50% of QD and BIDx3dEOW pts but only 1/7 QW pts. Plasma Cmax (mean ± SD, μM): 70 mg BIDx3d EOW, 2.4 ± 0.9; 160 mg QW, 3.5 ± 1.3; 40 mg/d (MTD, 21/28 d), 2.6 ± 2.0. T ½ was approx. 3 hours on all schedules. Conclusions: Pulse dosing of AT-101 appears associated with reduced toxicity than more continuous daily dosing, and may be preferable in combination regimens.

No significant financial relationships to disclose.

Phase 2 study of MKC-1 in patients (pts) with metastatic breast cancer (MBC) who have failed prior therapy with an anthracycline (A) and taxane (T)

11508

Background: MKC-1 (previously Ro 31–7453) is a novel cell cycle inhibitor with significant in vitro and in vivo activity against a wide range of tumor cell lines, including multi-drug resistant cell lines. Proteins identified as binding targets of MKC-1 include microtubules (colchicine binding site) and members of the importin-β family (proteins that play a critical role in nuclear transport and spindle formation). Objective responses (ORs) were observed in heavily pre-treated breast and NSCLC pts (Trigo Perez ASCO’03 A62; Kurup ASCO’03 A2725) treated at a dose of 95 mg/m2 BID given 14 days every 4 weeks with little toxicity. Salazar et al (2004 CCR 10:4374) recommended a higher oral dose (125 mg/m2 BID) on this schedule for further studies. This phase 2 trial is exploring the higher dose to maximize potential anticancer activity. Methods: Pts with MBC who had failed prior A and T and met eligibility criteria received MKC-1 at 125mg/m2 BID x 14d every 4 weeks. Pts with known treated and stable CNS metastases could enroll. Primary objective: OR by RECIST. Should 2 or more of the first 23 evaluable pts have an OR, enrollment will continue to 53 pts. Dose escalation/reductions are required based on toxicity (primarily neutropenia). Results: To date, a total of 20 pts have been enrolled (4 active in Cycles 1–5+). All female; median age/KPS of 60/90. 19% / 13% had received A / T in the neo/adjuvant setting; others had received A / T for metastatic disease. To date, a total of 48 cycles (median 2, range 1–8) were administered; of pts proceeding into Cycle 2, 40% and 20% had the dose increased or reduced, respectively. Severe drug-related toxicity (n=17) was observed in 3 pts (18%): ↑AST/ALT in 2 pts and parathesias in 1 pt. Drug related toxicity: nausea (47%), ↑ALT, diarrhea (both 24%), anemia, ↑AST, cough, fatigue, neutropenia and vomiting (all 18%). Two pts discontinued due to toxicity. One pt had complete resolution of measurable disease (1st observed after Cycle 4, confirmed after Cycle 6 with withdrawal for a new lesion at Cycle 8). An additional 2 pts had stable disease for 5 cycles (1 pt remains active). Conclusions: MKC-1 is well tolerated at the initial recommended dose for this schedule. Activity is observed in pts previously treated with A/T for MBC.

No significant financial relationships to disclose.

The effect of tibial lengthening on immature articular cartilage of the knee joint

OBJECTIVE

To investigate the acute response of immature articular cartilage, in the distraction and consolidation phases, to 30% tibial lengthening.

DESIGN

Sixteen immature New Zealand white rabbits underwent diaphyseal lengthening of the left tibia by callotasis at a distraction rate of 0.4mm twice daily. A sham control group of 12 rabbits underwent fixation and osteotomy without lengthening. In each group, half of the rabbits were killed at the end of the distraction phase or at an equivalent time period and the rest were killed after an additional 5 weeks (consolidation phase). The tibial condyles and synovial fluid in the knee joint cavity were taken for laboratory examination. Sulfated glycosaminoglycan in synovial fluid was estimated using a colorimetric method. Sections along the mid-coronal plane of the whole of the tibial condyles were examined histologically and by scanning electron microscopy. A grading system was used to make a semiquantitative assessment of the histopathological changes in articular cartilage.

RESULTS

Damage to the immature articular cartilage had occurred by the end of the distraction period and the cartilage continued to deteriorate in the consolidation phase of 5 weeks. However, when compared with a similar study in a mature rabbit model, damage to immature cartilage appeared less severe.

CONCLUSION

This model of 30% lengthening caused acute cartilage damage which did not recover in the short term. The result may have implications for longer lengthening in children; the effects may be disadvantageous and lead to degenerative diseases later in life.

The inflammatory caspases: guardians against infections and sepsis

Innate immunity is the primary host defense against invading microorganisms. Pathogen recognition, mediated through an elaborate 'microbial sensing' system comprising the Toll-like and Nod-like receptor families results in the activation of caspase-1, which is a prerequisite for pathogen clearance. Tight regulation of caspase-1 is necessary to control the magnitude of the innate immune response and protect the organism from possible damaging effects such as sepsis. Recent findings from population studies and animal models of infectious diseases and sepsis have uncovered a role for full-length caspase-12 in blocking the inflammatory response initiated by caspase-1, thus predisposing the organism to severe sepsis and sepsis-related lethality. In this review, we re-examine the relationship among the Group I caspases, their known substrates and their proposed role in apoptosis. We further discuss their function in inflammation and bacterial clearance, with an emphasis on their regulatory mechanisms during the innate immune response.

Bexarotene improves median survival (MS) in untreated, advanced NSCLC, when given in combination with carboplatin/paclitaxel

17070

Background: Bexarotene (bex) is a subclass specific, synthetic rexinoid analogue, that preferentially binds and modulates the expression of RXR subclass of receptors α, β, and γ. It induces concentration-dependent repression of multiple genes (cyclin D1/D3, total EGFR, pEGFR) inhibiting cell growth, angiogenesis, invasion and metastasis, inducing differentiation, and apoptosis in tumor cells. Several phase-I/II trials suggested increased survival in patients with advanced NSCLC. Methods: Stage-IIIB with pleural effusion & Stage-IV chemo-naïve patients, ECOG 0–2, were enrolled and treated with carboplatin IV AUC-6 d-1 and paclitaxel IV 100 mg/m2 d-1, 8, 15, every 28-d for 4 cycles. Pts were randomized using a 1:1 design to bex PO 400 mg/m2/d either concurrent (C) from Day 1 or sequential (S) at the completion of chemo, for up to a year. Results: 56 patients were enrolled; median age 62.3 (range 41–86), 48 TNM Stage IV, 38 males, 50 ECOG PS 0–1. Of 51 pts evaluable for response, 30 (58%) achieved PR (C: 15 and S: 15); 16 (31%) showed SD (C: 8 and S: 8), and 5 (9.5%) had PD (C: 3 and S: 2). Thirty-two (63%) patients have expired as of 12/31/05. Based on ITT, 40 evaluable pts showed a median TTP of 169 days (C: 166.5 and S 172); The MS for the entire group is 342 days (11.42 mo (C: 12.8 and S: 10.53). Currently, 10 pts are still alive between 407 to 1036 days from registration on the trial. The treatment was well tolerated; overall, AEs were reported in 48% of pts in the S arm and 51% in the C arm. The incidence of Gr 3–4 AEs, regardless of the treatment arm, was < 5%. There were no treatment-associated deaths. Conclusions: Our data suggests a better ORR, TTP, and improvement in MS, when bex is added to carboplatin/ paclitaxel, regardless of concurrent or sequential administration, compared with chemo alone. ORR was not compromised by bex administration and in fact it was above average reported for similar phase-II & -III studies. Toxicity is easily managed.

[Table: see text]

Eltrombopag, a novel, oral platelet growth factor, increases platelet counts in thrombocytopenic patients and healthy subjects

8602

Background: Eltrombopag (SB-497115) is a novel, first in class, orally bioavailable, thrombopoietin receptor agonist that induces differentiation and proliferation of megakaryocyte progenitors and has been shown to increase platelet counts in preclinical and clinical studies. Methods: In two randomized, placebo-controlled trials, eltrombopag was administered as oral tablets, once daily for 10 days to 73 healthy male subjects at doses of 5–75mg in an ascending dose cohort study, and to 103 (64 female/39 male) adult chronic immune thrombocytopenic purpura (ITP) patients, with a platelet count of <30×109/L, once daily for 6 weeks at doses of 30–75mg in a parallel dose cohort study. The primary efficacy endpoint in the Phase II ITP trial was the proportion of subjects with a platelet count >50×109/L after 6 weeks of dosing. Results: In healthy subjects, eltrombopag induced a dose dependent increase in the platelet counts. Mean maximal platelet count increases were 24.1 % at 30mg, 42.9 % at 50mg, and 50.4 % at 75mg. In 95 eligible ITP patients, platelet counts increased from <30 to >50×109/L in 16% (4/25) of subjects on placebo, and in the eltrombopag groups in 28% (7/25, p=ns) on 30mg, 67% (16/24, p<0.001) on 50mg and 86% (18/21, p<0.001) on 75mg eltrombopag. The median platelet counts in each treatment arm after 6 weeks of dosing were 16×109/L on placebo, 29×109/L on 30mg, 132×109L on 50mg, and 202×109/L on 75mg. The dose dependent effect was not significantly affected by the splenectomy status, background immunosuppressant use, or baseline platelet count (greater than or less than 15×109/L). Conclusions: The platelet count data from these clinical studies suggests that eltrombopag could be an effective therapy for the treatment of thrombocytopenia. Eltrombopag is being tested in further studies involving patients with ITP and chronic liver disease, and cancer patients receiving thrombocytopenic chemotherapy.

[Table: see text]

The safety profile of eltrombopag, a novel oral platelet growth factor, in thrombocytopenic patients and healthy subjects

18596

Background: Eltrombopag (SB-497115) is an oral, non-peptide, small molecule, thrombopoietin receptor agonist being tested as a potential treatment for thrombocytopenia. Eltrombopag has been shown to increase platelet counts in both healthy subjects and thrombocytopenic patients. Methods: Safety and tolerability data for eltrombopag (3–75 mg for up to 6 weeks) is presented from randomized, placebo-controlled, parallel group clinical trials involving 115 healthy subjects and 104 immune thrombocytopenic purpura (ITP) patients. Safety and tolerability endpoints involved assessment of adverse events (AE) and clinical laboratory parameters, including ECGs and platelet function. Results: In 3 Phase I trials, 98 healthy males received active eltrombopag QD for up to 10 days at 3–75 mg. In the Phase II dose ranging study, 78 chronic ITP patients (28 male/50 female) received active eltrombopag QD for 6 weeks at doses of 30–75 mg. There was no apparent relationship between active and control arms, the dose of eltrombopag and the incidence or severity of AEs, changes in laboratory values, platelet function or cardiac parameters in any of the studies. There were no serious adverse events (SAEs) reported by subjects in the 3 Phase I studies. 5 SAEs were reported in 1 patient in the ITP study that were considered by the investigator as possibly associated with administration of 50 mg eltrombopag. No SAEs were related to 30 mg or 75 mg eltrombopag, and 2 SAEs in 2 patients were related to placebo. Conclusions: There was no apparent relationship between eltrombopag dose and safety endpoints in these studies. These encouraging safety and tolerability data support the further testing of eltrombopag in phase II and III studies involving patients with ITP and chronic liver disease, and cancer patients receiving thrombocytopenic chemotherapy.

[Table: see text]

Why fine-wire fixators work: an analysis of pressure distribution at the wire-bone interface

Tensioned fine-wire external fixator systems have been used successfully for the treatment of fractures, mal-unions and for limb lengthening for many years. When used in metaphyseal bone, this type of fixator has a lower loosening rate than half-pin fixators. The differing mechanical properties of these fixator systems have been investigated extensively; however, most studies have centered on the mechanical properties of the fixator as a whole. Our knowledge of the interactions occurring at the interface between implant and bone remains sparse. In order to investigate this interaction, we devised a simple experimental model to characterise the distribution of pressure in cancellous bone surrounding a tensioned wire under loading conditions. Comparison was then made to a similar model of a half-pin fixator. Pressure was measured using pressure sensitive film at various distances away from the implant-bone interface. Static, single cycle loading of the model was performed with a Universal Testing Machine. Pressure distribution in the fine-wire model was found to occur in three regions: polar, beam loading and uniform. Polar patterns were seen closest to the wire with pressure concentrated at the entry and exit points of the wire. Beam loading was seen at a distance of 1.5 mm from the wire and pressure reached a uniform distribution at 4.0 mm. Most of the pressure measured was less than 2 MPa, which is less than the yield strength of cancellous bone (2-7 MPa). Higher loads produced higher stresses but the distribution pattern was similar. In contrast, the half-pin model showed far higher pressures (20 MPa), which were present deeper in the bone specimen. These results further our understanding of the biomechanics of fine-wire fixators and may explain the lower loosening rate of this type of fixator when compared to half-pin fixators used in metaphyseal bone.

Outcome after foot and ankle deformity correction using circular external fixation

BACKGROUND

External fixation is the method of choice for correction of chronic severe foot and ankle deformities. We report our experience and outcomes of circular external fixation.

METHODS

Fifty-five patients (60 feet) were treated with circular external fixation. The mean age at surgery was 36 (range 16 to 65) years. The mean followup was 4.4 (range 1 to 10) years. The mean time spent in external fixation was 2.1 (range 1 to 12) months.

RESULTS

There were six excellent, 35 good, eight fair, and six poor results, five of which had below knee amputations. All the patients who had an amputation were treated for infected nonunion of the ankle.

CONCLUSION

Circular external fixation was found to be an effective method for treating a variety of complex foot and ankle problems. The complications were more common in patients with infected nonunions.

Techniques for improving stability in oblique fractures treated by circular fixation with particular reference to the sagittal plane

Biomechanical studies involving all-wire and hybrid types of circular frame have shown that oblique tibial fractures remain unstable when they are loaded. We have assessed a range of techniques for enhancing the fixation of these fractures. Eight models were constructed using Sawbones tibiae and standard Sheffield ring fixators, to which six additional fixation techniques were applied sequentially. The major component of displacement was shear along the obliquity of the fracture. This was the most sensitive to any change in the method of fixation. All additional fixation systems were found to reduce shear movement significantly, the most effective being push-pull wires and arched wires with a three-hole bend. Less effective systems included an additional half pin and arched wires with a shallower arc. Angled pins were more effective at reducing shear than transverse pins. The choice of additional fixation should be made after consideration of both the amount of stability required and the practicalities of applying the method to a particular fracture.

Endothelin-like action of Pausinystalia yohimbe aqueous extract on vascular and renal regional hemodynamics in Sprague Dawley rats

The bark of the African tree Pausinystalia yohimbe has been used as a food additive with aphrodisiac and penile erection enhancing properties. The effect of an aqueous extract of P. yohimbe (CCD-X) on renal circulation was assessed in order to test the hypothesis that it possesses additional effects on nitric oxide production and/or endothelin-1 (ET-1)-like actions. In vivo studies with CCD-X in Sprague Dawley rats demonstrated a dose-dependent (1-1000 ng/kg) increase in mean blood pressure (p < 0.001) and an increase in medullary blood flow (MBF) (p < 0.001). Both the pressor action and renal medullary vasodilation were blocked by endothelinA (ETA) receptor antagonist BMS182874 and endothelinB (ETB) receptor antagonist BQ788 in combination. L-Nomega-nitro-l-arginine methyl ester (L-NAME; 10 mg/kg) also inhibited the increase in MBF induced by CCD-X. In vitro studies in isolated perfused kidney and in pressurized renal microvessels confirmed the dose-dependent vasoconstrictor action of this extract. ETA receptor antagonist BQ610 and ETB receptor antagonist BQ788 separately and significantly attenuated the renal vasoconstrictor actions of the extract (p < 0.001 ANOVA). These preliminary observations indicate that, in addition to the alpha-adrenergic antagonist actions that characterize yohimbine, CCD-X possesses endothelin-like actions and affects nitric oxide (NO) production in renal circulation. These findings suggest a strong possibility of post-receptor cross-talk between alpha2-adrenoceptors and endothelin, as well as a direct effect of alpha2-adrenoceptors on renal NO production.

Limb lengthening and correction of deformity in the lower limbs of children with osteogenesis imperfecta

We performed limb lengthening and correction of deformity of nine long bones of the lower limb in six children (mean age, 14.7 years) with osteogenesis imperfecta (OI). All had femoral lengthening and three also had ipsilateral tibial lengthening. Angular deformities were corrected simultaneously. Five limb segments were treated using a monolateral external fixator and four with the Ilizarov frame. In three children, lengthening was done over previously inserted femoral intramedullary rods.

The mean lengthening achieved was 6.26 cm (mean healing index, 33.25 days/cm). Significant complications included one deep infection, one fracture of the femur and one anterior angulation deformity of the tibia. The abnormal bone of OI tolerated the external fixators throughout the period of lengthening without any episodes of migration of wires or pins through the soft bone. The regenerate bone formed within the time which is normally expected in limb-lengthening procedures performed for other conditions.

We conclude that despite the abnormal bone characteristics, distraction osteogenesis to correct limb-length discrepancy and angular deformity can be performed safely in children with OI.

The management of chronic osteomyelitis using the Lautenbach method

We describe our medium-term results for the management of chronic osteomyelitis in long bones using the Lautenbach procedure. Seventeen consecutive patients (18 segments) were treated prospectively. Osteomyelitis had been present for a mean of 12.5 years (1 to 31). A discharging sinus was present in all cases. Nine of the associated fractures had failed to unite and a further two needed correction of malunion. The Lautenbach procedure involves debridement, intramedullary reaming and the insertion of double-lumen tubes to establish both a local antibiotic delivery system and cavity analysis for volume and culture. The end-point of treatment is when the irrigate produces three consecutive clear cultures with improvement in the blood indices and obliteration of the cavity volume.

The mean length of treatment was 27 days (14 to 48). One patient required a second procedure and another local debridement for recurrence of the infection. Two patients had Papineau grafting because of cortical defects. All the patients have subsequently remained free from infection. After treatment 11 had internal or external fixation for treatment of non- or malunion or a joint replacement, including two successful limb-lengthening procedures. Two further patients, while cured of infection, underwent amputation for other reasons. The mean length of follow-up was 75 months.

This procedure allows precise control over the osteomyelitis until objective assessment suggests that infection has been cleared and the cavity obliterated.

We recommend this procedure for long-standing complex cases in which basic techniques using debridement and antibiotics have failed.