Long-term safety of using local anesthetic injections in professional rugby league

BACKGROUND

Local anesthetic pain-killing injections are commonly used by some professional football teams to allow continued play for certain injuries; however, the long-term safety of this practice has not been studied.

HYPOTHESIS

The majority of local anesthetic injections administered in professional football are helpful and safe, not leading to long-term sequelae.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective survey was conducted of 100 players over 10 seasons who had been injected with local anesthetic on 1023 occasions for 307 injuries (81% follow-up; average follow-up, 5 years; minimum, 1 year). A comparison of match performance statistics was made from 3 seasons between players using and not using local anesthetic.

RESULTS

The majority (98%) of players would repeat the procedure if they had their injury again, although 32% felt that there were side effects associated with the procedure (including 22% who thought that the recovery of the primary injury was delayed and 6% who thought that the injury was worsened by playing with local anesthetic). On long-term follow-up, only 6% of players had significant residual pain in the body part injected. The satisfaction rates for acromioclavicular injuries, finger injuries, rib injuries, and iliac contusions were higher than for sternum injuries, wrist injuries, and ankle injuries. Player performance between those players injected and not injected with local anesthetic was not substantially different and mainly reflected a positional bias for the players who used local anesthetic.

CONCLUSION

The most commonly injected injuries-acromioclavicular joint sprains, finger and rib injuries, and iliac crest contusions-appear to be quite safe (in the context of professional sport) to inject at long-term follow-up. Conversely, ankle, wrist, and sternum injections appear to be less safe. A few injuries may have been substantially worsened by playing after an injection.

Combining hit identification strategies: fragment-based and in silico approaches to orally active 2-aminothieno[2,3-d]pyrimidine inhibitors of the Hsp90 molecular chaperone

Inhibitors of the Hsp90 molecular chaperone are showing considerable promise as potential molecular therapeutic agents for the treatment of cancer. Here we describe novel 2-aminothieno[2,3-d]pyrimidine ATP competitive Hsp90 inhibitors, which were designed by combining structural elements of distinct low affinity hits generated from fragment-based and in silico screening exercises in concert with structural information from X-ray protein crystallography. Examples from this series have high affinity (IC50 = 50-100 nM) for Hsp90 as measured in a fluorescence polarization (FP) competitive binding assay and are active in human cancer cell lines where they inhibit cell proliferation and exhibit a characteristic profile of depletion of oncogenic proteins and concomitant elevation of Hsp72. Several examples (34a, 34d and 34i) caused tumor growth regression at well tolerated doses when administered orally in a human BT474 human breast cancer xenograft model.

Successful management of tendinopathy with injections of the MMP-inhibitor aprotinin

Aprotinin is a broad spectrum proteinase inhibitor (including matrix metalloproteinase [MMP] inhibitor) used for treating patellar and Achilles tendinopathies. One previous randomized control trial demonstrated aprotinin injections superior to both corticosteroid and saline injections in patellar tendinopathy (Level II), whereas results reported for aprotinin treatment in Achilles tendinopathy have been mixed. We performed a case review and followup questionnaire for 430 consecutive patients with tendinopathy treated by 997 aprotinin injections (30,000 KIU). A response rate of 72% was achieved with a minimum followup of 3 months (average, 12.2 months; range, 3-54 months). Seventy-six percent of patients had improved, 22% of patients reported no change, and 2% were worse. Sixty-four percent of patients thought aprotinin injections were helpful, while 36% believed they had neither a positive nor negative effect. Mid-Achilles tendinopathy patients (84% improvement) were more successfully treated than patellar tendinopathy patients (69% improvement). Despite stronger published evidence of benefit in patellar tendinopathy, clinical outcomes appeared better with aprotinin use in Achilles tendinopathies.

LEVEL OF EVIDENCE

Level IV, case series.

NVP-AUY922: a small molecule HSP90 inhibitor with potent antitumor activity in preclinical breast cancer models

Introduction

Heat shock protein 90 (HSP90) is a key component of a multichaperone complex involved in the post-translational folding of a large number of client proteins, many of which play essential roles in tumorigenesis. HSP90 has emerged in recent years as a promising new target for anticancer therapies.

Methods

The concentrations of the HSP90 inhibitor NVP-AUY922 required to reduce cell numbers by 50% (GI₅₀ values) were established in a panel of breast cancer cell lines and patient-derived human breast tumors. To investigate the properties of the compound in vivo, the pharmacokinetic profile, antitumor effect, and dose regimen were established in a BT-474 breast cancer xenograft model. The effect on HSP90-p23 complexes, client protein degradation, and heat shock response was investigated in cell culture and breast cancer xenografts by immunohistochemistry, Western blot analysis, and immunoprecipitation.

Results

We show that the novel small molecule HSP90 inhibitor NVP-AUY922 potently inhibits the proliferation of human breast cancer cell lines with GI₅₀ values in the range of 3 to 126 nM. NVP-AUY922 induced proliferative inhibition concurrent with HSP70 upregulation and client protein depletion – hallmarks of HSP90 inhibition. Intravenous acute administration of NVP-AUY922 to athymic mice (30 mg/kg) bearing subcutaneous BT-474 breast tumors resulted in drug levels in excess of 1,000 times the cellular GI₅₀ value for about 2 days. Significant growth inhibition and good tolerability were observed when the compound was administered once per week. Therapeutic effects were concordant with changes in pharmacodynamic markers, including HSP90-p23 dissociation, decreases in ERBB2 and P-AKT, and increased HSP70 protein levels.

Conclusion

NVP-AUY922 is a potent small molecule HSP90 inhibitor showing significant activity against breast cancer cells in cellular and in vivo settings. On the basis of its mechanism of action, preclinical activity profile, tolerability, and pharmaceutical properties, the compound recently has entered clinical phase I breast cancer trials.

Thiothymidine plus low-dose UVA kills hyperproliferative human skin cells independently of their human papilloma virus status

The thymidine analogue 4-thiothymidine (S(4)TdR) is a photosensitizer for UVA radiation. The UV absorbance spectrum of S(4)TdR and its incorporation into DNA suggests that it might act synergistically with nonlethal doses of UVA to selectively kill hyperproliferative or cancerous skin cells. We show here that nontoxic concentrations of S(4)TdR combine with nonlethal doses of UVA to kill proliferating cultured skin cells. Established cell lines with a high fraction of proliferating cells were more sensitive than primary keratinocytes or fibroblasts to apoptosis induction by S(4)TdR/UVA. Although S(4)TdR plus UVA treatment induces stabilization of p53, cell death, as measured by apoptosis or clonal survival, occurs to a similar extent in both p53 wild-type and p53-null backgrounds. Furthermore, different types of human papilloma virus E6 proteins, which protect against UVB-induced apoptosis, have little effect on killing by S(4)TdR/UVA. S(4)TdR/UVA offers a possible therapeutic intervention strategy that seems to be applicable to human papilloma virus-associated skin lesions.

4,5-diarylisoxazole Hsp90 chaperone inhibitors: potential therapeutic agents for the treatment of cancer

Inhibitors of the Hsp90 molecular chaperone are showing considerable promise as potential chemotherapeutic agents for cancer. Here, we describe the structure-based design, synthesis, structure-activity relationships and pharmacokinetics of potent small-molecule inhibitors of Hsp90 based on the 4,5-diarylisoxazole scaffold. Analogues from this series have high affinity for Hsp90, as measured in a fluorescence polarization (FP) competitive binding assay, and are active in cancer cell lines where they inhibit proliferation and exhibit a characteristic profile of depletion of oncogenic proteins and concomitant elevation of Hsp72. Compound 40f (VER-52296/NVP-AUY922) is potent in the Hsp90 FP binding assay (IC50 = 21 nM) and inhibits proliferation of various human cancer cell lines in vitro, with GI50 averaging 9 nM. Compound 40f is retained in tumors in vivo when administered i.p., as evaluated by cassette dosing in tumor-bearing mice. In a human colon cancer xenograft model, 40f inhibits tumor growth by approximately 50%.

Delay of 6 weeks between aprotinin injections for tendinopathy reduces risk of allergic reaction

Aprotinin is a collagenase inhibitor previously shown to be effective for treating tendinopathies but associated with systemic allergic reactions. This historical cohort study aimed to determine whether or not the injection regime used affected the risk of allergic reaction and outcome. It compared 223 tendinopathy cases (group R) generally treated with a rapid series of aprotinin injections spaced one to two weekly and 158 cases (group D) generally given a single injection or a delay in their repeat injection(s) of over 6 weeks. Side effects and outcome measures were documented by questionnaire with a response rate of 75%. Systemic allergic reactions occurred in 7% of group R cases compared with 2% in group D (NS). Injections given 2-4 weeks after a previous injection were significantly more likely to lead to allergic reactions (6%) than initial injections (0.3%) and injections given >6 weeks after a previous injection (0.9%) (P<0.05). Overall patient rated satisfaction and outcome measures were similar between groups. In summary the current published regime of multiple aprotinin injections over a period of a few weeks has a fairly high rate of systemic allergic reactions. This can be reduced by minimising repeat injections and recommending a delay of at least 6 weeks between injections. Practitioners using aprotinin must have available facilities to treat anaphylaxis.

Gefitinib and irinotecan in patients with fluoropyrimidine-refractory, irinotecan-naive advanced colorectal cancer: a phase I-II study

BACKGROUND

To establish the recommended dose level (RDL) and to evaluate the efficacy and safety of gefitinib plus irinotecan in patients with advanced fluoropyrimidine-refractory colorectal cancer (CRC).

PATIENTS AND METHODS

Patients with advanced CRC progressing on or within 12 weeks of fluoropyrimidine-based chemotherapy, irinotecan naive and performance status of two or less were recruited. During dose-finding phase, dose-limiting toxicity (DLT) was encountered at dose level 1, therefore subsequent dose de-escalation and pharmacokinetic (PK) studies were carried out. The RDL was then expanded in a multicentre setting to further evaluate safety and efficacy.

RESULTS

From June 2002 to February 2005, 39 patients were treated in total with 27 at the RDL. The RDL was established at irinotecan 225 mg/m(2) every 3 weeks and gefitinib 250 mg daily. The DLTs were neutropenia and diarrhoea. For the patients treated at RDL, the objective tumour response rate was 11.1% (95% confidence interval 2.4% to 29.2%) and median survival was 9.3 months. PK studies indicated that the addition of irinotecan to gefitinib resulted in an average of 50% increase in exposure to gefitinib (P < 0.05), but gefitinib did not alter the PK profiles of irinotecan or SN-38. Grade 3-4 toxic effects in all patients included diarrhoea (35.9%), lethargy (15.4%), neutropenia (15.4%), febrile neutropenia (10.3%) and skin rash (7.7%).

CONCLUSIONS

Irinotecan and gefitinib at this dose schedule was tolerable, but gefitinib did not appear to add substantial efficacy to irinotecan.

Targeting Hsp90 for the treatment of cancer

Heat shock protein (Hsp)90 is a molecular chaperone that is responsible for the correct folding of a large number of proteins, which allows these proteins to achieve their functional conformation. Client proteins of Hsp90 include many overexpressed or mutated oncogenes that are known to be critical for the transformed phenotype observed in tumors. The compounds 17-AAG (Kosan Biosciences Inc/National Cancer Institute) and 17-DMAG (Kosan Biosciences Inc/National Cancer Institute) are Hsp90 inhibitors that are derived from the prototypical ansamycin natural product Hsp90 inhibitor geldanamycin. These compounds have demonstrated preclinical efficacy in mouse xenograft models, and are now undergoing phase II and I clinical trials, respectively. Preclinical efficacy studies of these compounds are collated and discussed in this review. More recent disclosures of small-molecule Hsp90 inhibitors include purine and resorcinol analogs, and the first small-molecule Hsp90 compounds showing oral efficacy have been described. Inhibition of Hsp90 not only results in the degradation of client proteins, but also results in the induction of another chaperone, Hsp70. Hsp70 is known to be anti-apoptotic, and therefore the induction of Hsp70 may ultimately limit the efficacy of Hsp90 inhibitors under certain circumstances. Histone deacetylase inhibitors have recently been demonstrated to exert some of their effect through modulation of Hsp90 chaperoning activity, and some mechanistic aspects of this control are also discussed herein.

Gefitinib and irinotecan in patients with fluoropyrimidine-refractory irinotecan-naïve advanced colorectal cancer (CRC): dose-finding, pharmacokinetics, safety and efficacy

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Background: Gefitinib (IRESSA) is an oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has shown supra-additive activity in human CRC xenografts when combined with irinotecan. We have previously established that the recommended dose level (RDL) to be irinotecan 225mg/m2 q3 weeks and gefitinib 250mg daily (Chau et al ASCO 2004). The dose limiting toxicities were neutropenia and diarrhoea. The continuation phase of this study aimed to evaluate the efficacy and safety of this combination. Patients and Methods: Between Jun 2002 and Feb 2005, patients (pts) with advanced CRC progressing on or within 12 weeks of fluoropyrimidines-based chemotherapy, irinotecan-naïve and performance status ≤2 were recruited. Thirty-nine pts were treated with irinotecan and gefitinib in total with 27 treated at the RDL. Results: Median age was 61 years (range: 31–79) and 13 (33.3%) pts were females. All pts were Caucasians (94.9%) and non-oriental Asians (5.1%). Thirteen (33.3%) pts had received (neo)adjuvant chemotherapy and 16 (41.0%) pts had prior oxaliplatin-based chemotherapy for metastatic disease. Grades 3–4 toxicities were anaemia 2.6%, neutropenia 15.4%, febrile neutropenia 10.3%, diarrhoea 35.9%, nausea 2.6%, vomiting 5.1%, lethargy 15.4% and skin rash 7.7%. For the pts treated at RDL, the objective tumour response rate was 11.1% (3 partial responses [PRs]; 95% confidence interval [CI]: 2.4–29.2%) and the disease control rate was 40.7% (3PRs, 8 stable diseases lasting for ≥12 weeks). The median time to progression was 4.2 months and median survival was 9.3 months. Six-month progression free survival was 22.2% (95% CI: 6.5–37.9%) and 6-month overall survival was 73.4% (95% CI: 56.5–90.3%). Preliminary pharmacokinetic data suggested that the addition of irinotecan to gefitinib resulted in an average of 14–33% increase in exposure to gefitinib (p<0.05). Conclusions: Irinotecan and gefitinib at this dose schedule was tolerable. Gefitinib did not appear to add substantial efficacy to irinotecan. The relative low dose of irinotecan at the RDL and the rarity of EGFR somatic mutation in CRC may be contributory to the modest activity of irinotecan and gefitinib combination.

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4-Amino derivatives of the Hsp90 inhibitor CCT018159

Novel piperazinyl, morpholino and piperidyl derivatives of the pyrazole-based Hsp90 inhibitor CCT018159 are described. Structure-activity relationships have been elucidated by X-ray co-crystal analysis of the new compounds bound to the N-terminal domain of human Hsp90. Key features of the binding mode are essentially identical to the recently reported potent analogue VER-49009. The most potent of the new compounds has a methylsulfonylbenzyl substituent appended to the piperazine nitrogen, possesses an IC50 of less than 600 nM binding against the enzyme and demonstrates low micromolar inhibition of tumour cell proliferation.

CA19-9 as a prognostic factor in inoperable pancreatic cancer: the implication for clinical trials

In a multivariate analysis of 154 patients receiving chemotherapy, baseline CA19-9 was an independent prognostic factor for overall survival (OS) (HR 1.8; 95% CI: 1.3–2.5, P=0.0004). The 1-year OS was 19 and 46%, respectively, for patients with a baseline CA19-9 above or below the median value. A fall of 20% in CA19-9 level from baseline was an independent prognostic factor for OS (HR 1.9; 95% CI: 1.1–3.4, P=0.019).

3-(5-Chloro-2,4-dihydroxyphenyl)-pyrazole-4-carboxamides as inhibitors of the Hsp90 molecular chaperone

Information from X-ray crystal structures of Hsp90 inhibitors bound to the human Hsp90 molecular chaperone was used to assist in the design of 3-(5-chloro-2,4-dihydroxyphenyl)-pyrazole-4-carboxamides as novel inhibitors of Hsp90. Accessing an extra interaction with the protein via Phe138 gave a significant increase in binding potency compared to similar analogues that do not make this interaction.

Structure-based discovery of a new class of Hsp90 inhibitors

Docking-based virtual screening identified 1-(2-phenol)-2-naphthol compounds as a new class of Hsp90 inhibitors of low to sub-micromolar potency. Here we report the binding affinities and cellular activities of several members of this class. A high resolution crystal structure of the most potent compound reveals its binding mode in the ATP binding site of Hsp90, providing a rationale for the observed activity of the series and suggesting strategies for developing compounds with improved properties.

Novel, potent small-molecule inhibitors of the molecular chaperone Hsp90 discovered through structure-based design

The crystal structure of a previously reported screening hit 1 (CCT018159) bound to the N terminal domain of molecular chaperone Hsp90 has been used to design 5-amide analogues. These exhibit enhanced potency against the target in binding and functional assays with accompanying appropriate cellular pharmacodynamic changes. Compound 11 (VER-49009) compares favorably with the clinically evaluated 17-AAG.

4-Thio-5-bromo-2′-deoxyuridine: chemical synthesis and therapeutic potential of UVA-induced DNA damage

4-Thio-5-bromo-2'-deoxyuridine (3a) is prepared from 5-bromo-2'-deoxyuridine (BrdU) and its key properties are explored. The thionucleoside (3a) can react readily with monobromobimane and produces high fluorescence. 3a has UV maximum absorption at 340 nm and can be incorporated into cellular DNA. The cells containing 3a become sensitive to UVA light, offering therapeutic potential for UVA-induced cell killing.

Adenine derived inhibitors of the molecular chaperone HSP90—SAR explained through multiple X-ray structures

Multiple co-crystal structures of an adenine-based series of inhibitors bound to the molecular chaperone Hsp90 have been determined. These structures explain the observed SAR for previously described compounds and new compounds, which possess up to 8-fold improved potency against the isolated enzyme. Anti-tumour cell potency and mechanism of action data is also described for the most potent compounds. These data should enable the design of more potent Hsp90 inhibitors.