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Introduction Neutropenia and diarrhoea are common and potentially serious adverse events associated with abemaciclib in advanced breast cancer (ABC), and the risk factors have been minimally explored. The study aimed to develop clinical prediction tools that allow personalized predictions of neutropenia and diarrhoea following abemaciclib initiation. Materials and methods Data was pooled from MONARCH 1, 2 and 3 trials investigating abemaciclib. Cox proportional hazard analysis was used to assess the association between pre-treatment clinicopathological data and grade ≥3 diarrhoea and neutropenia occurring within the first 365 days of abemaciclib use. Results Older age was associated with increased risk of grade ≥3 diarrhoea [HR [95%CI] for age > 70: 1.72 [1.14–2.58]; P = 0.009]. A clinical prediction tool for abemaciclib induced grade ≥3 neutropenia was optimally defined by race, ECOGPS and white blood cell count. Large discrimination between subgroups was observed; the highest risk subgroup had a 64% probability of grade ≥3 neutropenia within the first 365 days of abemaciclib (150 mg twice daily) + fulvestrant/NSAI, compared to 5% for the lowest risk subgroup. Conclusion The study identified advanced age as significantly associated with an increased risk of abemaciclib induced grade ≥ 3 diarrhoea. A clinical prediction tool, defined by race, ECOGPS and pre-treatment white blood cell count, was able to discriminate subgroups with significantly different risks of grade ≥3 neutropenia following abemaciclib initiation. The tool may enable improved interpretation of personalized risks and the risk-benefit ratio of abemaciclib., Highlights • Neutropenia and diarrhoea are common adverse effects of abemaciclib. • Higher age was associated with abemaciclib induced diarrhoea. • White blood cell count, Race, and performance status were linked with neutropenia. • A prediction tool was developed to provide personalized risks of neutropenia.

While many studies have evaluated the relationship between BMI and breast cancer outcomes, it is unclear whether this relationship is consistent between early breast cancer (BC) and advanced BC. The study included 5099 patients with HER2 positive early BC (EBC) and 3496 with HER2 positive advanced BC (ABC). In the EBC cohort, higher BMI was associated with worse overall survival (OS) (HR [95% CI]: overweight = 1.30 [1.13–1.51]; obese = 1.37 [1.14–1.64], P = P = 0.061). In contrast, for the ABC cohort, higher BMI was significantly associated with improved OS (overweight = 0.85 [0.76–0.96]; obese = 0.82 [0.72–0.95], P = 0.014), and progression-free survival (overweight = 0.91 [0.83–1.01]; obese = 0.87 [0.77–0.98], P = 0.034). In this large high-quality dataset, higher BMI was independently associated with worse survival in EBC, paradoxically in ABC higher BMI was independently associated with improved survival.

Introduction: Thrombocytopenia is a common and potentially serious adverse event of ado-trastuzumab emtansine (T-DM1) use in patients with advanced breast cancer. However, the risk factors have been minimally explored. Our aim was to develop a clinical prediction model from the clinicopathologic data that would allow for quantification of the personalized risks of thrombocytopenia from T-DM1 usage. Materials and Methods: Data from 3 clinical trials, EMILIA (a study of trastuzumab emtansine versus capecitabine + lapatinib in participants with HER2 [human epidermal growth factor receptor 2]-positive locally advanced or metastatic breast cancer), TH3RESA (a study of trastuzumab emtansine in comparison with treatment of physician's choice in participants with HER2-positive breast cancer who have received at least two prior regimens of HER2-directed therapy), and MARIANNE [a study of trastuzumab emtansine (T-DM1) plus pertuzumab/pertuzumab placebo versus trastuzumab (Herceptin) plus a taxane in participants with metastatic breast cancer], were pooled. Cox proportional hazard analysis was used to assess the association between the pretreatment clinicopathologic data and grade ≥ 3 thrombocytopenia occurring within the first 365 days of T-DM1 use. A multivariable clinical prediction model was developed using a backward elimination process. Results: Of the 1620 participants, 141 (9%) had experienced grade ≥ 3 thrombocytopenia. On univariable analysis, the body mass index, race, presence of brain metastasis, platelet count, white blood cell count, and concomitant corticosteroid use were significantly associated with the occurrence of grade ≥ 3 thrombocytopenia (P < .05). The multivariable prediction model was optimally defined by race (Asian vs. non-Asian) and platelet count (100-220 vs. 220-300 vs. >300 × 109/L). A large discrimination between the prognostic subgroups was observed. The highest risk subgroup (Asian and platelet count of 100-220 cells ×109/L) had a 40% probability of grade ≥ 3 thrombocytopenia within the first 365 days of T-DM1 therapy compared with 2% for the lowest risk subgroup (non-Asian and platelet count > 300 × 109/L). Conclusion: A clinical prediction model, defined by race and pretreatment platelet count, was able to discriminate subgroups with a significantly different risk of grade ≥ 3 thrombocytopenia after T-DM1 initiation. The model allows for improved interpretation of the personalized risks and risk/benefit ratio of T-DM1. Refereed/Peer-reviewed

Introduction : The discrimination performance of Bellmunt risk score for immune checkpoint inhibitor (ICI) therapy is largely unknown. This study aimed to validate and enhance discrimination of the Bellmunt score in patients with urothelial carcinoma treated with ICIs. Patients and methods : Cox proportional hazard analysis was used to validate overall survival (OS) discrimination performance of Bellmunt score in patients with urothelial carcinoma treated with atezolizumab in IMvigor210. The c-statistic (c) was used to evaluate the ability of C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), lactate dehydrogenase (LDH), PD-L1 gene expression level on immune cells (PD-L1 ICs), albumin, time from prior chemotherapy, and tumor site count to enhance Bellmunt score. External validation of an enhanced Bellmunt score utilized independent atezolizumab arm of IMvigor211. Results : In IMvigor210, Bellmunt score displayed moderate OS discrimination (c=0.66). Addition of CRP (one point for CRP>30mg/L) to Bellmunt score resulted in greatest improvement in performance (c=0.70), followed by NLR (c=0.69). On external validation, CRP-Bellmunt score had superior performance (OS c=0.67, PFS c=0.60) than original Bellmunt score (OS c=0.64, PFS c=0.59) with 30% of patients reclassified into a higher risk group. Patients with CRP-Bellmunt score of 0, 1, 2, or 3-plus had 1-year OS probabilities of 63%, 44%, 21%, and 15%, respectively. Conclusions : CRP inclusion within Bellmunt score enhanced the ability to discriminate high risk patients misclassified using the original Bellmunt model. We propose that the CRP-Bellmunt score may enable improved patient stratification in ICI clinical trials and provide more accurate prognostic information for patients with urothelial carcinoma initiating ICIs. Micro Abstract The Bellmunt risk score is a well-recognized prognostic model in second-line urothelial carcinoma. However, its discrimination performance for immune checkpoint inhibitor (ICI) therapy is unclear. The present analysis indicates addition of one point for C-reactive protein (CRP>30mg/L) to Bellmunt score resulted in superior survival discrimination. The CRP-Bellmunt score will enable more accurate patient stratification in clinical trials and enhanced prognostic information for patients with urothelial carcinoma initiating ICIs.

Background: Proton pump inhibitors (PPIs) are commonly used concomitant to cancer treatment and they induce gut microbiota changes. It is increasingly apparent that gut dysbiosis can reduce the effectiveness of immune checkpoint inhibitors(ICI). However, little is known about PPI effects on outcomes with ICIs, particularly in combination, ICI approaches. Methods: Post hoc, Cox proportional hazard analysis of phase III trial, IMpower150 was conducted to assess the association between PPI use and overall survival (OS) and progression-free survival (PFS) in chemotherapy-naive, metastatic non-squamous non-small cell lung cancer participants randomised atezolizumab plus carboplatin plus paclitaxel (ACP), bevacizumab plus carboplatin plus paclitaxel (BCP), or atezolizumab plus BCP (ABCP). PPI use was defined as any PPI administration between 30 days prior and 30 days after treatment initiation. Results: Of 1202 participants, 441 (37%) received a PPI. PPI use was independently associated with worse OS (n = 748; hazard ratio (HR) [95% confidence interval (CI)] = 1.53 [1.21–1.95], P < 0.001) and PFS (1.34 [1.12–1.61], P = 0.002) in the pooled atezolizumab arms (ACP plus ABCP). This association was not apparent for BCP (n = 368; OS 1.01 [0.73–1.39], P = 0.969; PFS 0.97[0.76–1.25], P = 0.827). The observed OS treatment effect (HR 95% CI) of the atezolizumab (ACP plus ABCP) arms vs BCP was 1.03(0.77–1.36) for PPI users compared to 0.68 (0.54–0.86) for non-users (P [interaction] = 0.028). A similar association was noted for ABCP vs BCP (PPI users 0.96 [0.68–1.35]; PPI non-users 0.66 [0.50–0.87]; P [interaction] = 0.095). Conclusions: PPI use was a negative prognostic marker in patients treated with ACP or ABCP, but not BCP. The analysis suggests that PPIs negatively influence the magnitude of ICI efficacy. Refereed/Peer-reviewed

Machine learning (ML) may enhance the efficiency of developing accurate prediction models for survival, which is critical in informing disease prognosis and care planning. This study aimed to develop an ML prediction model for survival outcomes in patients with urothelial cancer-initiating atezolizumab and to compare model performances when built using an expert-selected (curated) versus an all-in list (uncurated) of variables. Gradient-boosted machine (GBM), random forest, Cox-boosted, and penalised, generalised linear models (GLM) were evaluated for predicting overall survival (OS) and progression-free survival (PFS) outcomes. C-statistic (c) was utilised to evaluate model performance. The atezolizumab cohort in IMvigor210 was used for model training, and IMvigor211 was used for external model validation. The curated list consisted of 23 pretreatment factors, while the all-in list consisted of 75. Using the best-performing model, patients were stratified into risk tertiles. Kaplan–Meier analysis was used to estimate survival probabilities. On external validation, the curated list GBM model provided slightly higher OS discrimination (c = 0.71) than that of the random forest (c = 0.70), CoxBoost (c = 0.70), and GLM (c = 0.69) models. All models were equivalent in predicting PFS (c = 0.62). Expansion to the uncurated list was associated with worse OS discrimination (GBM c = 0.70, random forest c= 0.69, CoxBoost c= 0.69, and GLM c = 0.69). In the atezolizumab IMvigor211 cohort, the curated list GBM model discriminated 1-year OS probabilities for the low-, intermediate-, and high-risk groups at 66%, 40%, and 12%, respectively. The ML model discriminated urothelial-cancer patients with distinctly different survival risks, with the GBM applied to a curated list attaining the highest performance. Expansion to an all-in approach may harm model performance.

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Introduction. Afatinib is a first-line treatment option for patients with an advanced nonsmall cell lung cancer (NSCLC) expressing an epidermal growth factor receptor (EGFR) activating mutation. This study aimed to evaluate the association between early adverse events induced by afatinib and overall survival (OS) and progression free survival (PFS) in patients with advanced NSCLC. Methods. The study was a pooled post hoc analysis of the randomized trials LUX-Lung 3 and LUX-Lung 6 which evaluated afatinib versus pemetrexed-cisplatin or gemcitabine-cisplatin, respectively. Cox proportional hazard analysis was used to assess the impact of adverse events occurring within the first 28 days of afatinib therapy on the PFS and OS outcomes in treatment-naïve advanced NSCLC patients harbouring an EGFR activating mutation. Results. There were 468 patients who initiated first-line afatinib therapy within LUX-Lung 3 and LUX-Lung 6. A significant association between early rash and improved OS (hazard ratio (HR 95% CI); grade 1 = 0.74 [0.56–0.97]; grade 2+ = 0.64 [0.46–0.89]) ( P = 0.018) was observed, although no significant association with PFS was present ( P = 0.732). A significant association was identified between early diarrhoea and improved PFS (grade 1 = 0.83 [0.62–1.12]; grade 2+ = 0.62 [0.44–0.88]) ( P = 0. 015), although no significant association with OS was present ( P = 0.605). No associations between early stomatitis or paronychia and OS or PFS were identified. Conclusion. Rash occurring early after the initiation of afatinib was significantly associated with improved OS, an indicator that rash may be a surrogate of patients likely to achieve long-term survival. Consideration of using rash as a dose adjustment target may be warranted for future prospective trials aiming to optimise outcomes with afatinib therapy.

Simple Summary The lung immune prognostic index (LIPI) is proposed as a simple risk scoring tool to differentiate differences in survival from immune checkpoint inhibitors (ICIs) in advanced non-small cell lung cancer (NSCLC). The tool has not been evaluated for performance in a NSCLC cohort initiating first-line, combination ICI approaches. In a large cohort of participants with chemotherapy-naïve, metastatic non-squamous NSCLC, we independently validated, for the first time, that LIPI discriminates a clear subgroup of patients likely to achieve reduced survival following the initiation of combination therapies including the ICI atezolizumab. Abstract The lung immune prognostic index (LIPI) is proposed to differentiate prognosis and treatment benefit from immune checkpoint inhibitors (ICIs) in advanced non-small cell lung cancer (NSCLC). There is minimal information on the predictive importance with first-line, combination ICI approaches. In post-hoc analysis of IMpower150, Cox-proportional hazard analysis assessed the association between LIPI groups and overall survival (OS)/progression free survival (PFS). IMpower150 involved chemotherapy-naïve, metastatic non-squamous NSCLC participants randomized atezolizumab-carboplatin-paclitaxel (ACP), bevacizumab-carboplatin-paclitaxel (BCP), or atezolizumab-BCP (ABCP). Good (0 factors), intermediate (1 factor), and poor LIPI (2 factors) were defined via derived neutrophil-to-lymphocyte ratio >3, and lactate dehydrogenase >upper limit of normal. Of 1148 participants, 548 had good, 479 intermediate, and 121 poor LIPI. In 385 participants randomised ABCP, a significant association between LIPI and OS (HR (95%CI): intermediate LIPI = 2.16 (1.47–3.18), poor LIPI = 5.28 (3.20–8.69), p < 0.001) and PFS (HR (95%CI): intermediate LIPI = 1.47 (1.11–1.95), poor LIPI = 3.02 (2.03–4.50), p < 0.001) was identified. Median OS was 24, 16, and 7 months for good, intermediate, and poor LIPI, respectively. ACP associations were similar. Relative OS treatment effect (HR 95%CI) of ABCP vs. BCP was 0.78 (0.53–1.15), 0.67 (0.49–0.91), and 0.87 (0.51–1.47) for the good, intermediate, and poor LIPI groups, respectively (P(interaction) = 0.66), with no benefit in median OS observed in the poor LIPI group. LIPI identified subgroups with significantly different survival following ABCP and ACP initiation for chemotherapy-naïve, metastatic non-squamous NSCLC. There was insufficient evidence that LIPI identifies patients unlikely to benefit from ABCP treatment.

Introduction: Beta-blockers (BB) are commonly used to manage cardiovascular disease and may have benefits in controlling complications of anti-HER2 therapies. This study aimed to evaluate the association of pre-existing BB use with survival outcomes inpatients initiating anti-HER2 therapy for advanced breast cancer (ABC). Materials and Methods: Data from clinical trials EMILIA, TH3RESA, MARIANNE, and CLEOPATRA was pooled. Cox proportional analysis was used to assess the association between pre-existing BB use with survival outcomes in patients initiating anti-HER2 therapies Results: Of the 2,777 patients with HER2 positive ABC, 266 were using a BB at the time of anti-HER2 therapy initiation. BB use was associated with worse overall survival (OS) (adjusted HR = 1.27, 95% CI: 1.04–1.55). Sensitivity analysis in patients with pre-existing cardiovascular disease (CVD) also indicated that BB use was associated with worse OS (1.29, 1.02–1.63). Conclusion: In large high-quality data, BB use at the time of anti-HER2 therapy initiation for ABC was independently associated with worse OS, regardless of CVD status. The finding is contrary to pre-study hypotheses and findings in other BC subtypes. Future research should aim to gain a deeper understanding of the effects of BBs on specific BC subtypes, cancer types, and cancer treatments. Refereed/Peer-reviewed

Purpose Sorafenib is an oral tyrosine kinase inhibitor (TKI) and first-line treatment option for advanced hepatocellular carcinoma (HCC). Preliminary evidence indicates proton pump inhibitors (PPI) may affect the absorption of TKIs through decreased gut dissolution. This study aims to evaluate the impact of PPI use on the survival outcomes of advanced HCC patients treated with sorafenib. Methods The study was a secondary analysis of individual-participant data from the phase III clinical trial NCT00699374. Cox proportional hazard analysis was used to evaluate the association between baseline PPI use and survival outcomes. Overall survival (OS) was the primary outcome with progression-free survival (PFS) secondary. Results In a cohort of 542 advanced HCC patients initiating sorafenib treatment, 122 were concomitantly using a PPI at baseline. No significant associations between baseline PPI use and OS were identified on univariable (HR [95% CI]; 1.01 [0.80-1.28], P = 0.93) and adjusted (1.10 [0.82-1.41], P = 0.62) analysis. Furthermore, no significant associations between baseline PPI use and PFS were identified on univariable (0.96 [0.76-1.21], P = 0.73) and adjusted (1.11 [0.86-1.44], P = 0.41) analysis. Conclusion In a large high-quality dataset, PPI use was not observed to compromise the survival outcomes of advanced HCC patients initiated on sorafenib. Refereed/Peer-reviewed

Selecting the dose of a targeted cancer medicine that is most appropriate for a specific individual is a rational approach to maximize therapeutic outcomes and minimize toxicity. There are many different options for optimizing the dose of targeted cancer medicines and the purpose of this review is to provide a comprehensive comparison of the main options explored in prospective studies. Precision initial dose selection of targeted cancer therapies has been minimally explored to date; however, concentration, toxicity, and therapeutic outcome markers are used to guide on-therapy dose adaption of targeted cancer therapies across several medicines and cancers. While a specific concentration, toxicity, or therapeutic outcome marker commonly dominates an investigated precision on-therapy dose adaption strategy, greater attention to simultaneously account for exposure, toxicity, therapeutic outcomes, disease status, time since treatment initiation and patient preferences are required for optimal patient outcomes. To enable successful implementation of precision dosing strategies for targeted cancer medicines into clinical practice, future prospective studies aiming to develop strategies should consider these elements in their design. Refereed/Peer-reviewed

Purpose To validate a plasma vemurafenib steady-state trough concentration (Css,min) threshold that predicts survival outcomes of patients with BrafV600 mutated melanoma. Methods: A pooled analysis of individual patient data from two advanced melanoma trials involving vemurafenib ± cobimetinib therapy was performed. Day 23 was chosen as the landmark time when steady-state concentration reached. Optimal Css,min threshold was determined via assessment of discriminative performance and model fitting. Association between vemurafenib Css,min and survival was modelled using Cox proportional hazards regression. Results: Vemurafenib plasma concentration data were available for 402 patients who were on stable dose for the first 3 weeks. When compared to a previously described plasma vemurafenib Css,min threshold of 42 mg/L, we identified that a cutoff concentration of 50 mg/L by day 23 was strongly associated with progression-free survival and overall survival. The association remained statistically significant after adjusting for important clinical confounding variables. Sub-group analysis showed that while the addition of cobimetinib resulted in a lower day 23 plasma vemurafenib Css,min, the threshold was still associated with overall survival and not in the monotherapy cohort. Conclusion: A plasma vemurafenib Css,min threshold of 50 mg/L is strongly associated with survival outcomes in patients with advanced melanoma. This new threshold needs to be validated prospectively in future studies. Refereed/Peer-reviewed

We thank Auclin et al. [...]

Objectives: Common therapies for HER2-positive advanced breast cancer (ABC) are associated with heterogeneity in prognosis and treatment benefit. Prognostic models of survival outcomes with ado-trastuzumab-emtansine (T-DM1) have not been evaluated.Material and methods: A pre-treatment prognostic model for overall survival (OS) and progression-free survival (PFS) based on clinicopathological factors was developed for HER2-positive ABC patients initiating second-line and later T-DM1 using data from the randomised clinical trials EMILIA and TH3RESA(n ¼ 893). Pre-treatment prognostic groups were identified via recursive partitioning analysis.Results: The most significant OS/PFS pre-treatment risk predictors were metastatic sites count (( ≤ 2versus > 2) and ECOG performance-status (0 versus ≥ 1) (P < 0.05). Based on these two factors, patient scan be characterised as one of three prognostic groups (good ¼ 0 factors; intermediate ¼ 1 factor;poor ¼ 2 factors). The prognostic groups were identified as significantly associated with OS (P < 0.001)and PFS (P < 0.001). Median OS for the good, intermediate and poor prognostic groups were 40 (95%CI:36e48), 25 (23e30) and 16 (14e19) months, respectively, and median PFS was 12 (10e15), 8 (7e9) and 6(4e7) months.Conclusion: Pre-treatment prognostic groups with significant differences in OS and PFS for HER2-positive ABC patients initiating second-line and later T-DM1 were identified. For HER2-positive ABC patients considering initiating second-line and later T-DM1, the prognostic groups enable more personalized expectations of disease control, survival and absolute treatment benefit. Refereed/Peer-reviewed

Background: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease associated with increased risk of cardiovascular disease (CVD). Treatment for CVD may involve pharmacological agents that antagonise beta adrenergic receptors. These receptors may play an important role in immunology, and the effects of beta-blockers (BB) in RA is unknown. The aim of this study was to investigate the association between BB use and remission in patients with RA initiating tocilizumab +/− conventional synthetic (cs-) DMARD therapy. Methods: Data was pooled from five randomised trials investigating tocilizumab and/or csDMARD treatment in RA (primarily methotrexate). The association between BB use and remission according to the Simplified Disease Activity Index (SDAI) and Clinical Disease Activity Index (CDAI) was assessed by Cox proportional hazard analysis. Sensitivity analysis in patients with pre-existing CVD and an exploratory analysis of the impact of other CVD drugs were conducted. Results: Data were available from 5502 participants, 594 (10.8%) of whom were using systemic BB. BB use was associated with less frequent SDAI remission in the total [adjusted hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.57–0.87, p = 0.001] and CVD cohort [adjusted HR 0.72 (0.57–0.90, p = 0.005)]. The association was consistent between trials (interaction p = 0.44) and treatment arms (interaction p = 0.06). No significant association between remission and β1-receptor selectivity was identified ( p = 0.16), and the association was independent from other cardiovascular drug use. Similar associations between BB use and CDAI remission were observed. Conclusion: In a large, pooled cohort of RA patients initiating csDMARDs and/or tocilizumab, BB use was independently associated with less frequent remission.

Despite advances in the breast cancer treatment, significant variability in patient outcomes remain. This results in significant stress to patients and clinicians. Treatment-specific clinical prediction models allow patients to be matched against historical outcomes of patients with similar characteristics; thereby reducing uncertainty by providing personalised estimates of benefits, harms, and prognosis. To achieve this objective, models need to be clinical-grade with evidence of accuracy, reproducibility, generalizability, and be user-friendly. A structured search was undertaken to identify treatment-specific clinical prediction models for therapeutic or adverse outcomes in breast cancer using clinicopathological data. Significant gaps in the presence of validated models for available treatments was identified, along with gaps in prediction of therapeutic and adverse outcomes. Most models did not have user-friendly tools available. With the aim being to facilitate the selection of the best medicine for a specific patient and shared-decision making, future research will need to address these gaps. Refereed/Peer-reviewed

Immune checkpoint inhibitors (ICI) are an important development in the treatment of advanced cancer. A substantial proportion of patients treated with ICI do not respond, and additionally patients discontinue treatment due to adverse effects. While many novel biological markers related to the specific mechanisms of ICI actions have been investigated, there has also been considerable research to identify routinely available blood and clinical markers that may predict response to ICI therapy. If validated, these markers have the advantage of being easily integrated into clinical use for nominal expense. Several markers have shown promise, including baseline and post-treatment changes in leucocyte counts, lactate dehydrogenase and C-reactive protein. While promising, the results between studies have been inconsistent due to small sample sizes, follow-up time and variability in the assessed markers. To date, research on routinely available blood and clinical markers has focussed primarily on ICI use in melanoma, the use of ipilimumab and on univariate associations, but preliminary evidence is emerging for other cancer types, other ICIs and for combining markers in multivariable clinical prediction models. Refereed/Peer-reviewed

Leflunomide is the most recently introduced conventional disease-modifying anti-rheumatic drugs in Australia. It has several unique methods for initiation, unique monitoring recommendations and a distinctive cessation protocol in the event of serious toxicity. The aim of this study was to evaluate initiation and monitoring practices of Australian rheumatologists using leflunomide. A survey was emailed twice, approximately 3 months apart to 332 rheumatologist members of the Australian Rheumatology Association. Wave analysis was used to assess evidence of non-response bias. The response rate to the survey was 20% and there was no difference between the responses of waves 1 and 2. Fifty percent of the respondents indicated that 20 mg once daily was the initial dose of leflunomide that they most commonly prescribed, 45% indicated 10 mg once daily, whilst only 3% preferred to initiate leflunomide at 100 mg daily for 2–3 days followed by 10 mg once a day as recommended when first marketed. Of the responders, 12% had used doses above 20 mg daily and 70% had used alternate daily dosing with leflunomide. In a patient taking leflunomide with an ALT or AST >3 times the ULN on two or more blood tests, 75% of responders indicated they would stop leflunomide immediately and 20% would follow cessation by administering a cholestyramine washout. The choice of initial leflunomide dose among responding Australian rheumatologists varied considerably, although most preferred not to use the loading dose. Despite the recommendation of clinical guidelines, the use of a cholestyramine washout procedure for hepatic toxicity is not universal. Refereed/Peer-reviewed

The literature presently lacks a population pharmacokinetic analysis of doxycycline. This study aimed to develop a population pharmacokinetic model of doxycycline plasma concentrations that could be used to assess the power of bioequivalence between Doryx delayed-release tablets and Doryx MPC. Doxycycline pharmacokinetic data were available from eight phase 1 clinical trials following single/multiple doses of conventional-release doxycycline capsules, Doryx delayed-release tablets, and Doryx MPC under fed and fasted conditions. A population pharmacokinetic model was developed in a stepwise manner using NONMEM, version 7.3. The final covariate model was developed according to a forward inclusion ( P < 0.01) and then backward deletion ( P < 0.001) procedure. The final model was a two-compartment model with two-transit absorption compartments. Structural covariates in the base model included formulation effects on relative bioavailability ( F ), absorption lag (ALAG), and the transit absorption rate (KTR) under the fed status. An absorption delay (lag) for the fed status (FTLAG2 = 0.203 h) was also included in the model as a structural covariate. The fed status was observed to decrease F by 10.5%, and the effect of female sex was a 14.4% increase in clearance. The manuscript presents the first population pharmacokinetic model of doxycycline plasma concentrations following oral doxycycline administration. The model was used to assess the power of bioequivalence between Doryx delayed-release tablets and Doryx MPC, and it could potentially be used to critically examine and optimize doxycycline dose regimens.

Introduction Methotrexate is the ‘anchor’ of rheumatoid arthritis (RA) treatment and leflunomide is commonly added in resistant disease, or where methotrexate is contraindicated.[1] In Australia, biological disease-modifying anti-rheumatic drugs (bDMARDs) are considered when response to conventional DMARD therapy is inadequate.[1, 2] They are expensive and criteria have been developed to restrict their use on the Australian Commonwealth Government subsidised Pharmaceutical Benefits Scheme (PBS). Prior to 2010, to qualify for bDMARDs, a patient must have been treated for at least 12 weeks with: (i) weekly methotrexate; (ii) combination therapy with methotrexate and at least two other DMARDs; and (iii) received treatment with leflunomide or cyclosporine.[2] In August 2010, these restrictions were modified so they could be accessed by patients who failed to respond to 6 months of therapy, which must include at least 3 months of methotrexate (unless contraindicated) and 3 months of hydroxychloroquine, leflunomide or sulfasalazine.[2] We aimed to assess the influence of these changes on the use and expenditure on leflunomide and bDMARDs.

Biological disease-modifying antirheumatic drugs (bDMARDs) for rheumatoid arthritis (RA) treatment were among the first high-cost medicines to be subsidised in Australia. High-cost medicines pose several challenges to the Australian National Medicines Policy, which aims to provide timely access to effective medicines at a cost individuals and the community can afford. Thus, novel restriction criteria were developed to encourage cost-effective use of bDMARDs. Government expenditure on bDMARD subsidies for RA treatment grew to about $383 million in 2014. Evidence that initiation and continuation criteria for bDMARDs meet usually applied cost–benefit criteria is lacking. The combined expenditure on tocilizumab, certolizumab pegol and golimumab (added to the Australian Government’s Pharmaceutical Benefits Scheme in 2010) was $93 million in 2014, which is 210% over the initial estimate. Present and future challenges with regard to bDMARDs for RA and other high-cost drugs include improved expenditure predictions, monitoring of cost-effectiveness in relation to actual use and strategic development, regulation and use of biosimilars. Ten years of documentation on clinical and laboratory findings indicating eligibility to initiate and continue on bDMARDs remains un-used. These data represent an untapped opportunity to promote quality of use of bDMARDs and biosimilars and to improve cost predictions for high-cost drugs. Refereed/Peer-reviewed

Leflunomide is largely considered to be a second-line treatment option for rheumatoid arthritis (RA). Those who fail to respond, tend to progress to treatment with expensive biological agents, which can also be associated with serious toxicities. Optimizing leflunomide treatment to meet the needs of individuals would hence be beneficial in terms of patient outcomes and health care expenditure. In this respect, therapeutic drug monitoring (TDM) may be useful, as plasma concentrations of leflunomide's active metabolite, teriflunomide, correlate with response to treatment, but are highly variable between patients. A number of pharmacogenetic markers have also been identified that influence response and toxicity. Incorporation of these findings into clinical practice could facilitate more efficient use of leflunomide. Refereed/Peer-reviewed