Ascending Flaccid Paralysis Secondary to Hypokalemia in A Cancer Patient using Abiraterone - A Case Report.

BACKGROUND: Prostate cancer (PC) is the most common type of neoplasm in men and the fourth leading cause of mortality in Brazil. The prostate cancer refractory metastatic castration can be treated with abiraterone acetate (AA). CASE PRESENTATION: Its use has been associated with increased survival. However, there are also side effects associated with the use of this drug, such as severe electrolyte disturbances. CONCLUSION: The objective is to report the clinical case of a patient with castration-resistant metastatic prostate cancer who developed ascending flaccid paralysis secondary to severe hypokalemia, probably due to hyperaldosteronism secondary to the use of Abiraterone Acetate, despite the use of Prednisone.

Syncope due to non-sustained episodes of Torsade de Pointes associated to androgen-deprivation therapy use: a case presentation.

BACKGROUND: Abiraterone is a medication frequently used for metastatic castrate-resistant prostate cancer. We report a case of non-sustained episodes of TdP associated with severe hypokalemia due to androgen-deprivation therapy. Few case presentations describe this association; the novelty lies in the potentially lethal cardiovascular events among cancer patients receiving hormonal therapy. CASE PRESENTATION: A 70-year-old male presented with recurrent syncope without prodrome. ECG revealed frequent ventricular ectopy, non-sustained episodes of TdP, and severe hypomagnesemia and hypokalemia. During potassium and magnesium infusion for repletion, the patient underwent temporary transvenous atrial pacing. As part of the work-up, coronary angiography revealed a mild coronary artery disease, and transthoracic echocardiogram showed a moderately depressed ejection fraction. After electrolyte disturbances were corrected, the QT interval normalized, and transvenous pacing was no longer necessary. Abiraterone was discontinued during the admission, and the patient returned to baseline. CONCLUSIONS: Cancer treatment is complex and requires a multidisciplinary approach. We presented a case of non-sustained TdP associated with androgen-deprivation therapy in an elderly patient with mild coronary artery disease and moderately reduced ejection fraction. Close follow-up and increased awareness are required in patients with hormonal treatment, especially in the setting of other cardiovascular risk factors.

Effectiveness, safety and cost of abiraterone acetate in patients with metastatic castration-resistant prostate cancer: a real-world data analysis.

PURPOSE: New therapies with diverse mechanisms of action are available for metastatic castration-resistant prostate cancer (mCRPC). This study aims to evaluate the effectiveness, safety and cost of abiraterone acetate (AA) in patients with mCRPC. MATERIALS AND METHODS: Observational retrospective cohort study in which mCRPC patients who initiated AA between January 1, 2012 and December 31, 2017, were included. The patients were followed-up until death or March 31, 2018. Demographic, clinical and economic data were collected from the corporate electronic information systems. Survival distributions were estimated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: A total of 69 mCRPC patients were started on AA, of whom 18 (26.1%) received prior chemotherapy (post-CT) and 51 (73.9%) did not receive it (CT-naïve). A PSA decline of ≥ 50% was achieved in five (27.8%) post-CT and 32 (62.7%) CT-naïve patients (p = 0.011). Median time to PSA progression, progression-free survival (PFS) and overall survival (OS) were 4.4/7.9 months (p = 0.003), 5.1/7.5 months (p = 0.034) and 12.1/21.3 months (p = 0.119), respectively, for post-CT/CT-naïve patients. Treatment-related adverse events (AEs) occurred in 10 (55.6%) post-CT and 11 (21.6%) CT-naïve patients (p = 0.007). The most common AEs were hypokalaemia (11.6%), hypertension (8.7%) and fatigue (5.8%). The cost per median PFS month and per median OS month was €2818.4/€2784.3 and €1187.9/€980.4 for post-CT/CT-naïve patients, respectively. CONCLUSIONS: CT-naïve patients treated with AA obtained a better clinical benefit in terms of effectiveness, safety and cost-effectiveness ratio than post-CT patients. The effectiveness outcomes were poorer than those reported previously in the clinical trial setting.

Análise de custo-efetividade da abiraterona para câncer de próstata metastático resistente à castração em pacientes com uso prévio de quimioterapia / Cost-effectiveness analysis of abiraterone for metastatic, castrateresistant prostate cancer following previous chemotherapy

Objetivo: Avaliar a custo-utilidade e o impacto orçamentário (IO) da abiraterona para o tratamento de câncer de próstata resistente à castração, em pacientes previamente tratados com docetaxel. Métodos: Foi construído um modelo de Markov com ciclos mensais sob a perspectiva do Sistema Único de Saúde (SUS), em um horizonte temporal de cinco anos e taxa de desconto de 5%. A estimativa de efetividade foi oriunda do principal ensaio clínico dessa condição de saúde. Para dados de utilidade, aplicaram-se estimativas internacionais, enquanto para custos se utilizaram tabelas de remuneração do SUS. Para o IO, a população-alvo foi estimada com base em dados do Departamento de Informática do SUS (DATASUS). Resultados: A abiraterona ocasionou ganho de 1,045 ano de vida ajustado para qualidade (QALY) e 1,609 ano de vida ganho (AVG), enquanto para o placebo esses valores foram de 0,763 e 1,299, respectivamente. O custo total na estratégia abiraterona foi de R$ 83.295 e para o placebo, de R$ 2.895. A relação de custo-efetividade incremental (RCEI) foi de R$ 284.416 por QALY ganho. Em nenhuma das análises de sensibilidade os valores ficaram abaixo de R$ 100.000 por QALY. Mesmo quando variados simultaneamente seis parâmetros, todos no seu limite mais favorável à abiraterona, os resultados seguiram elevados, com RCEI de R$ 98.330 por QALY. O IO foi de R$ 270 milhões em cinco anos no cenário mais conservador (tempo médio de tratamento de 7,4 meses e 10% de novos casos/ano). Conclusão: A abiraterona se mostrou pouco custo-efetiva nesta situação clínica, com RCEI superior a nove vezes o PIB per capita por QALY, sendo os resultados robustos em análise de sensibilidade.

Objective: To evaluate the cost-utility and the budget impact (BI) of abiraterone in patients with castration-resistant prostate cancer previously treated with docetaxel. Methods: A Markov model was constructed, with monthly cycles, under the perspective of the Brazilian Public Healthcare System (SUS), in a 5-year time horizon, and with a 5% discount rate. The effectiveness estimate was obtained from the pivotal clinical trial for abiraterone in this health condition. For utility data, international estimates were applied; while for costs, SUS reimbursement information were used. In the BI analysis, the target population was estimated with claims data from DATASUS. Results: Abiraterone resulted in a gain of 1.045 quality-adjusted life years (QALY) and 1.609 life years gained (LYG), while for placebo these values were 0.763 and 1.299, respectively. The total cost for the abiraterone strategy was BRL 83,295, and for placebo, BRL 2,895. The incremental cost-effectiveness ratio (ICER) was BRL 284,416 per QALY gained. None of the estimates from the sensitivity analysis was below BRL 100,000 per QALY. Even when six parameters were variated simultaneously in the range more favorable to abiraterone, the results were still elevated, with an ICER of BRL 98,330 per QALY. The BI was BRL 270 million in 5 years in the most conservative scenario (average time of the treatment of 7.4 months and 10% of the new cases/year). Conclusion: Abiraterone shows unfavorable cost-effective results for this clinical condition in Brazil, with an ICER above 9 times the per capita per QALY. Results were robust in sensitivity analysis.

Platelet-lymphocyte and neutrophil-lymphocyte ratios are prognostic but not predictive of response to abiraterone acetate in metastatic castration-resistant prostate cancer.

PURPOSE: Recently neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) have been reported to be inflammatory parameters that confer poorer outcome in metastatic castration-resistant prostate cancer (mCPRPC). However, these ratios have not been analyzed in patients treated with abiraterone acetate. We explored the relationship between different values of PLR and NLR and survival in mCPRCP treated with abiraterone and their possible relation with a prostate specific antigen (PSA) response. METHODS: We retrospectively analyzed 101 patients with mCRPC treated with abiraterone from January of 2012 to November of 2015 in two different hospitals. A cut-off value of 5 for NLR and 150 for PLR were used to compare survival by Kaplan-Meier method. Moreover, an association between these cut-off values and the PSA response was analyzed by a χ 2 test. RESULTS: In the case of NLR, the median DFS were 12, 1 months for NLR <5 and 7 months for NLR ≥5, p = 0.061. The median OS were 23.9 months for NLR <5 and 16.3 months for NLR ≥5, p = 0.046. In the case of PLR, the median DFS were 11.8 months for PLR <150 and 10.6 months for PLR ≥150, p = 0.549. The median OS were 27.4 months for PLR <150 and 15.9 months for PLR ≥150, p = 0.005. It was not observed a correlation between the different cut-off values of PLR or NLR and a PSA response ≥25% (p = 0.31). CONCLUSIONS: It is shown a better prognostic relationship between PLR and NLR low values and OS that is statistically significant in mCPRC patients treated with abiraterone. Furthermore, it was not shown a relation between PLR and NLR values and PSA response.

Supervivencia del cáncer de próstata resistente a la castración en la práctica clínica y el papel del tratamiento / Survival of Castration-Resistant Prostate Cancer in Clinical Practice and the Role of Treatment

Resumen Objetivo: Evaluar en un contexto de práctica clínica la ventaja de supervivencia para pacientes con cáncer de próstata resistente a castración (CPRC) tratado activamente con diversos tratamientos que incluyen acetato de abiraterona (AA) y prednisona con o sin docetaxel. Material y método: Se analiza la supervivencia de pacientes con CPRC y se compara un grupo tratado con AA y prednisona (n = 33) con un control histórico formado por pacientes consecutivos tratados una década antes en la misma institución exclusivamente con retirada de antiandrógeno y medidas paliativas (n = 31). Se analizan variables clínico-patológicas predictivas de pronóstico en la población activamente tratada. Se evalúa la respuesta global a AA y el intervalo libre de progresión radiológica. Resultados: La supervivencia cáncer específica a 2 años fue 79% para pacientes tratados activamente y 17,2% para control (log-rank, p < 0,0001). Cinco de 13 pacientes con AA post-docetaxel (38,5%) recibieron después de AA quimioterapia de segunda línea (4 cabazitaxel y 1 vinorelbina) y 1 (7,7%) hormonoterapia con enzalutamida. Tres de 20 pacientes tratados con AA sin quimioterapia (15%) recibieron enzalutamida y solo 1 (5%) fue tratado con docetaxel. Los pacientes de menor edad (<65años; p = 0,02) y sin metástasis al diagnóstico (p = 0,04) tuvieron mejor pronóstico. Aquellos de PSA más alto (>45ng/ml; p = 0,09) y patrón de Gleason 5 en la biopsia se comportaron de manera más desfavorable. Globalmente el 75,8% tuvieron respuesta a AA (80% pre- y 69,2% post-quimioterapia; p = 0,1) y el 52,4% estuvieron libre de progresión radiológica al año (47,9% pre y 49,8% post-quimioterapia; log-rank, p = 0,3). Conclusión: El tratamiento de pacientes con CPRC prolonga la expectativa de supervivencia en un entorno de práctica clínica y es posible identificar factores predictivos de pronóstico en estos pacientes.

Abstract Purpose: To assess, in a clinical practice context, the survival advantages of patients with castration-resistant prostate cancer (CRPC) actively treated with several treatments that include abiraterone acetate (AA) and prednisone, with or without docetaxel. Material and Methods: An analysis was performed on patient survival with CRPC, and was compared to a group treated with AA and prednisone (n = 33), with a historical control treated exclusively with anti-androgen withdrawal and palliative measures (n = 31). In the population actively treated, variables predictive of prognosis were analysed, as well as an evaluation of the overall response to AA and radiographic progression-free survival. Results: Cancer-specific survival at 2 years was 79% for patients actively treated and 17.2% for control group (P<.0001). Five (38.5%) of 13 patients treated with AA post-docetaxel received second-line chemotherapy after AA (4 cabazitaxel, 1 vinorelbine), and one (7.7%) enzalutamide. Three (15%) of 20 patients treated with AA without chemotherapy received enzalutamide and 1(5%) docetaxel. The younger patients (<65yrs; P=.02) without metastases at diagnosis (P=.04) had better prognoses. Patients with higher PSA levels (>45 ng/ml; P=.09) and a Gleason pattern 5 in the biopsy had less favourable outcomes. There was a 75.8% over response to AA (80% preand 69.2%post-chemotherapy; P=.1), and 69.2%post-chemotherapy; P=.1), and 52.4% were radiographic progression-free at 1 year of treatment (47.9% pre- and 49.8% post-chemotherapy; P=.3). Conclusion: Treatment of CRPC patients extends survival expectations in a clinical practice setting and prognostic predictors can be identified in these patients.

Análise de custo-efetividade do acetato de abiraterona associado à prednisona pós-terapia de privação androgênica, seguido de enzalutamida pós-quimioterapia versus a sequência oposta para o tratamento de pacientes com câncer de próstata metastático resistentes à castração sob a perspectiva do Sistema de Saúde Suplementar brasileiro / Cost-effectiveness analysis of abiraterone acetate plus prednisone in the post-androgen deprivation therapy setting followed by enzalutamide in the post-chemotherapy setting versus the opposite treatment sequence in metastatic castration resistant prostate cancer patients under the Brazilian Private Healthcare System perspective

Objetivo: O acetato de abiraterona e a enzalutamida são utilizados no tratamento de câncer de próstata metastático pós-terapia de privação androgênica, em pacientes resistentes à castração. O objetivo deste estudo foi comparar o custo-efetividade de abiraterona mais prednisona pós-terapia de privação androgênica, seguidos de docetaxel e enzalutamida pós-quimioterapia com a sequência oposta de tratamento no Sistema de Saúde Suplementar brasileiro. Métodos: Um modelo de Markov foi desenvolvido para comparar o custo-efetividade das duas sequências em um tempo horizonte lifetime. Os parâmetros de eficácia e probabilidades de transição foram derivados de estudos clínicos. Foram considerados os custos diretos dos medicamentos, administração, monitoramento e eventos adversos. A medida de efetividade foram anos de vida ganhos, estimados pela extrapolação de dados dos estudos clínicos. Os resultados foram apresentados em custos e anos de vida ganho a cada sequência. Resultados: O estado pós-terapia de privação androgênica representou a maior parte dos custos de tratamento, e os eventos adversos tiveram pequeno impacto nos custos totais. O uso de abiraterona nesse estado reduziu 7,3% dos custos. A sequência abiraterona mais prednisona pós-terapia de privação androgênica, seguida de enzalutamida pós-quimioterapia, foi dominante em relação à oposta; apresentou menor custo (R$ 262.801 versus R$ 274.165) e efetividade levemente maior, com estimados 3,367 anos de vida ganhos versus 3,282. Conclusão: O uso da abiraterona mais prednisona pós-terapia de privação androgênica e enzalutamida pós-quimioterapia demonstrou-se dominante em relação à sequência oposta no tratamento de pacientes com câncer de próstata metastático resistentes à castração, no Sistema de Saúde Suplementar brasileiro.

Objective: Abiraterone acetate and enzalutamide are important options in the treatment of metastatic castration resistant prostate cancer. The objective of this study is to compare the cost-effectiveness of the use of abiraterone plus prednisone post-ADT, followed by docetaxel and enzalutamide post-chemotherapy (Abi+Doce+Enza) with the opposite treatment sequence (Enza+Doce+Abi) under the perspective of the Brazilian private healthcare system. Methods: A Markov model was developed to assess the cost-effectiveness of both sequences in a lifetime time horizon. Transition probabilities and efficacy data were drawn from clinical studies. Cost parameters included drug acquisition and administration, disease monitoring and adverse events were considered. Effectiveness was measured as life years gained, derived from clinical trials. Results were presented as total costs and life years gained in each sequence. Results: Post-ADT state represented the majority of the treatment costs, and adverse events had little impact in total costs. The sequence Enza+Doce+Abi was dominated by Abi+Doce+Enza. The sequence Abi+Doce+Enza generated a reduction of 7,3% in total treatment costs compared to Enza+Doce+Abi (R$ 262,801 vs R$ 274,165). Effectiveness was slightly higher, with an estimated 3.367 life-years gained in the Abi+Doce+Enza sequence compared with 3.282 life-years gained in the Enza+Doce+Abi sequence. Conclusion: The use of abiraterone plus prednisone post-ADT and enzalutamide in post-chemo had lower treatment costs and higher effectiveness when compared to the opposite sequence in the treatment of metastatic castration resistant prostate cancer, under the Brazilian Private Health System perspective.

Treatment Sequences and Pharmacy Costs of 2 New Therapies for Metastatic Castration-Resistant Prostate Cancer.

BACKGROUND: The approval of new therapies for metastatic castration-resistant prostate cancer (mCRPC), including the oral agents abiraterone acetate and enzalutamide, has altered the standard of care for patients with mCRPC. Little information exists regarding the sequences in which new therapies for mCRPC with evidence of survival benefits are used. OBJECTIVE: To describe the sequence of medication use for patients with mCRPC as observed in 3 healthcare data sets. METHODS: Three healthcare claims data sets were used to identify patients with mCRPC who had no previous use of and were newly initiating 1 of the 2 oral study drugs (ie, abiraterone acetate or enzalutamide). The index date was the first study drug claim after September 1, 2012. Patients were followed until the data cutoff or until being lost to follow-up. Descriptive statistics summarized the proportion of patients receiving 1 line of therapy versus ≥2 lines of therapy. The use of a corticosteroid and the mean monthly pharmacy costs of abiraterone acetate or enzalutamide during the follow-up period were compared between the cohorts. RESULTS: A total of 3525 patients with mCRPC were identified from data set 1, 499 patients from data set 2, and 1949 patients from data set 3. The first-line use of abiraterone acetate was observed in 74%, 82%, and 80% of data sets 1, 2, and 3, respectively, and the first-line use of enzalutamide was seen in 26%, 18%, and 20%, respectively, of these same populations. The concomitant use of corticosteroids was observed in patients receiving first-line abiraterone acetate and in patients receiving first-line enzalutamide in all 3 data sets. After September 2012, abiraterone acetate was the most frequently administered therapy for mCRPC among the 2 oral agents, abiraterone acetate and enzalutamide. The monthly pharmacy costs associated with abiraterone acetate were significantly lower than those associated with enzalutamide in all 3 data sets. CONCLUSIONS: Based on the data used in this study, abiraterone acetate was more frequently administered for patients with mCRPC than enzalutamide. The concomitant use of corticosteroids was common in patients receiving first-line abiraterone acetate or first-line enzalutamide therapy. Patients receiving abiraterone acetate had significantly lower monthly pharmacy costs than patients receiving enzalutamide. These findings may facilitate the estimation of the budgetary impact of a treatment mix for population health and for managed care stakeholders.