Atypical haemolytic uremic syndrome with refractory multiorgan involvement and heterozygous CFHR1/CFHR3 gene deletion.

BACKGROUND: We present this challenging case report of Atypical Haemolytic Uremic Syndrome (aHUS) presenting with multi-organ involvement in a patient and heterozygous CFHR1/CFHR3 gene variant, which was refractory to initial eculizumab therapy. CASE PRESENTATION: A forty-three year old female presented with aHUS and had heterozygous disease-associated deletions in the complement genes CFHR1/CFHR3. She had progressive kidney failure and severe extra-renal manifestations including cardiomyopathy and haemorrhagic cystitis; as well as pulmonary, gastrointestinal and neurological involvement. The initial kidney biopsy revealed thrombotic microangiopathy (TMA) changes involving all glomeruli. Clinical improvement was initially seen during eculizumab initiation with suppressed CH50 level, but a new rhinovirus/enterovirus upper respiratory tract infection triggered further severe multi-organ disease activity. The extra-renal manifestations stabilised, then ultimately improved after a period of eculizumab dose intensification. However, the impact on dose intensification on this improvement is unclear. Despite the extra-renal clinical improvement, she ultimately progressed to end-stage kidney disease (ESKD), commencing peritoneal dialysis for three years before undergoing a successful uncomplicated cadaveric kidney transplant without prophylactic eculizumab. Two years after transplant, she has excellent transplant graft function without any further disease recurrence. CONCLUSIONS: This case highlights the concept of extra-renal manifestations in aHUS initially resistant to eculizumab, which potentially responded to dose intensification. Whilst organ injuries are potentially reversible with timely targeted treatment, it appears that the kidneys are most vulnerable to injury.

Health impact and cost-effectiveness of implementing gender-neutral vaccination with the 9-valent HPV vaccine in Hong Kong.

Human papillomavirus (HPV) can cause several diseases, including cancers, in both sexes. In January 2020, the Hong Kong government launched a school-based vaccination program for girls 10-12 years of age with the 9-valent HPV (9vHPV) vaccine for the prevention of HPV-related diseases; however, boys were not included. The current study estimated the potential health and economic impact of a routine gender-neutral vaccination (GNV) approach compared with the current female-only vaccination (FOV) strategy. We used a dynamic transmission model, adapted to Hong Kong. The model estimates changes in HPV-related disease incidence and mortality, treatment costs (in 2019 Hong Kong dollars), quality-adjusted life years (QALY), and incremental cost-effectiveness ratios (ICERs) over a 100-year time horizon. The base case analysis compared FOV with the 9vHPV vaccine with routine GNV (coverage rate 70%) for the prevention of HPV-related diseases. Compared with a FOV approach, routine GNV with the 9vHPV vaccine is predicted to provide greater reductions in cumulative HPV-related disease incidence and mortality, as well as lower HPV-related treatment costs. In the base case analysis, the ICER was $248,354 per QALY for routine GNV. As compared with FOV, routine GNV fell below the cost-effectiveness ceiling of $382,046/year for Hong Kong. These results highlight the potential value of a routine GNV program with the 9vHPV vaccine among 12-year-olds in Hong Kong to reduce the public health and economic burden of HPV-related diseases.

A multicenter evaluation of the Technoscreen ADAMTS13 activity semi-quantitative screening test for thrombotic thrombocytopenic purpura diagnosis and exclusion.

INTRODUCTION: Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially fatal microangiopathy, with an untreated mortality rate of around 90%. TTP is caused by severe deficiency in ADAMTS13, which results in accumulation of ultra large von Willebrand factor multimers, triggering a consumptive thrombocytopenia, microangiopathic hemolytic anemia and end-organ dysfunction and damage. Demonstration of severe ADAMTS13 deficiency is diagnostic for TTP, but long turnaround times for quantitative activity testing often necessitates empirical plasma exchange and/or caplacizumab treatment. METHODS: Multisite (n = 4) assessment of the Technoscreen ADAMTS13 activity assay (semi-quantitative flow through screening assay) for diagnosis/exclusion of TTP compared to current standard practice of quantitative assays (ELISA or chemiluminescence AcuStar). RESULTS: A total of 128 patient samples were analyzed, with quantitative ADAMTS13 values ranging from 0% to 150%. The Technoscreen assay demonstrated high sensitivity and negative predictive value (NPV) for ADAMTS13 deficiency, but low specificity and positive predictive value (PPV), especially with one lot of reagent. Good inter-observer reliability was demonstrated. Excluding one possibly compromised batch and other test failures, results of 80 samples yielded sensitivity of 100% (95% CI = 84-100), specificity of 90% (80-95), PPV 77% (58-89) and NPV 100% (93-100). CONCLUSION: The Technoscreen assay appears to be a reliable screening test for ADAMTS13 activity to exclude TTP in routine clinical practice. However, the assay falsely identified ADAMTS13 deficiency in many cases, partially batch related, which mandates confirmation with a quantitative assay, as well as initial assessment of kits as 'fit for purpose' prior to use for patient testing.

A cell-based functional assay that accurately links genotype to phenotype in familial HLH.

Familial forms of the severe immunoregulatory disease hemophagocytic lymphohistiocytosis (HLH) arise from biallelic mutations in the PRF1, UNC13D, STXBP2, and STX11 genes. Early and accurate diagnosis of the disease is important to determine the most appropriate treatment option, including potentially curative stem cell transplantation. The diagnosis of familial HLH (FHL) is traditionally based on finding biallelic mutations in patients with HLH symptoms and reduced natural killer (NK)-cell cytotoxicity. However, patients often have a low NK-cell count or receive immunosuppressive therapies that may render the NK-cell cytotoxicity assay unreliable. Furthermore, to fully understand the nature of a disease it is critical to directly assess the effect of mutations on cellular function; this will help to avoid instances in which carriers of innocuous mutations may be recommended for invasive procedures including transplantation. To overcome this diagnostic problem, we have developed a rapid and robust method that takes advantage of the functional equivalence of the human and mouse orthologues of PRF1, UNC13D, STX11, and STXBP2 proteins. By knocking out endogenous mouse genes in CD8+ T cells and simultaneously replacing them with their mutated human orthologues, we can accurately assess the effect of mutations on cell function. The wide dynamic range of this novel system allowed us to understand the basis of, otherwise cryptic, cases of FHL or HLH and, in some instances, to demonstrate that previously reported mutations are unlikely to cause FHL. This novel approach provides valuable new information to enable more accurate diagnosis and treatment of patients with HLH or FHL who inherit mutations of undetermined pathogenicity.

Immune thrombocytopenia and COVID-19 vaccination: Outcomes and comparisons to prepandemic patients.

Background: Immune thrombocytopenia (ITP) has been reported following COVID-19 vaccination. After index case fatalities, there was concern among patients both with and without a prior history of ITP in Australia. Objectives: To describe treatment outcomes of ITP after COVID-19 vaccination and compare relapsed vs historical pre-COVID-19 ITP cohorts. Methods: We collected ITP cases in Australia within 6 weeks of receiving any COVID-19 vaccination as part of primary vaccination (up to October 17, 2021). Second, we reviewed platelet charts in a historical ITP cohort to determine whether platelet variability was distinct from relapsed ITP after vaccination. Results: We report on 50 patients (37 de novo, 13 relapsed ITP) vaccinated from March 22, 2021, to October 17, 2021. Although there was 1 fatality, bleeding was otherwise mostly minor: (70% WHO bleeding grade <2). De novo ITP was more likely after AstraZeneca ChAdOx1 nCoV-19 (89%) than Pfizer BNT162b2 (11%). Most patients responded quickly (median, 4 days; complete response, 40 of 45 [89%]). In the historical cohort, only 6 of 47 patients exhibited platelet variability (>50% decrease and platelets <100 × 109/L), but median platelet nadir was significantly higher than vaccination relapse (27 vs 6 × 109/L, P =.005). Conclusion: ITP was more frequently reported after AstraZeneca ChAdOx1 nCoV-19 than Pfizer BNT162b2 vaccination. Standard ITP treatments remain highly effective for de novo and relapsed ITP (96%). Although thrombocytopenia can be severe after vaccination, bleeding is usually mild. Despite some sampling bias, our data do not support a change in treatment strategies for patients with ITP after vaccination.

Consensus guidelines for the management of adult immune thrombocytopenia in Australia and New Zealand.

INTRODUCTION: The absence of high quality evidence for basic clinical dilemmas in immune thrombocytopenic purpura (ITP) underlines the need for contemporary guidelines relevant to the local treatment context. ITP is diagnosed by exclusions, with a hallmark laboratory finding of isolated thrombocytopenia. MAIN RECOMMENDATIONS: Bleeding, family and medication histories and a review of historical investigations are required to gauge the bleeding risk and possible hereditary syndromes. Beyond the platelet count, the decision to treat is affected by individual bleeding risk, disease stage, side effects of treatment, concomitant medications, and patient preference. Treatment is aimed at achieving a platelet count > 20 × 109 /L, and avoidance of severe bleeding. Steroids are the standard first line treatment, with either 6-week courses of tapering prednisone or repeated courses of high dose dexamethasone providing equivalent efficacy. Intravenous immunoglobulin can be used periprocedurally or as first line therapy in combination with steroids. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: There is no consensus on choice of second line treatments. Options with the most robust evidence include splenectomy, rituximab and thrombopoietin receptor agonists. Other therapies include azathioprine, mycophenolate mofetil, dapsone and vinca alkaloids. Given that up to one-third of patients achieve a satisfactory haemostatic response, splenectomy should be delayed for at least 12 months if possible. In life-threatening bleeding, we recommend platelet transfusions to achieve haemostasis, along with intravenous immunoglobulin and high dose steroids.

The impact and cost-effectiveness of 9-valent human papillomavirus vaccine in adolescent females in Hong Kong.

INTRODUCTION: In Hong Kong (HK), a single-cohort vaccination program for 10-12-year-old girls with the 9-valent human papillomavirus (HPV) vaccine (9vHPV; types 6/11/16/18/31/33/45/52/58) has been launched. This study assessed the public health impact and cost-effectiveness of implementing routine 9vHPV vaccination (12-year-olds) with or without catch-up 9vHPV vaccination (13-18-year-olds) in HK. METHODS: The health impact and costs of implementing routine 9vHPV vaccination with or without catch-up vaccination over a 100-year time horizon were evaluated using a validated HPV-type transmission dynamic model adapted to the HK population; analyses were performed from a healthcare payer perspective. Routine vaccination (12-year-old girls) and catch-up vaccination (13-18 years) assumed vaccine coverage rates of 70% (base case) and 30%, respectively. The model also assumed herd immunity, lifelong vaccine protection, a discount rate of 3%, and a cost per dose of HK dollars (HKD) 858 [United States dollars (USD) 110] and HKD 1390 (USD 179) for the 2-valent HPV (2vHPV) and 9vHPV vaccines, respectively. HPV disease-related incidence and the incremental cost-effectiveness ratio (ICER) per quality-adjusted-life-year (QALY) were estimated. Cost-effectiveness was determined at a ceiling threshold of HK dollars (HKD) 382,046 (USD 49,142) or 1.0 times the gross domestic product per capita of HK. RESULTS: Compared with routine 9vHPV alone, routine plus catch-up 9vHPV is projected to reduce cervical cancer incidence by 3.4%. Routine plus catch-up 9vHPV will also reduce genital warts incident cases for males/females by 2.6%/5.4%. The incremental cost-effectiveness ratios were HKD 29,911 (USD 3847)/quality-adjusted life-year (QALY) for routine plus catch-up 9vHPV versus routine 9vHPV alone and HKD 25,524 (USD 3283)/QALY for routine 9vHPV alone versus screening only. Sensitivity analyses indicated that routine plus catch-up 9vHPV compared with routine 9vHPV alone remained cost-effective at coverage rates of 30% and 90%. CONCLUSIONS: This analysis predicts that the current HK vaccination strategy can be considered cost-effective and will provide maximum health benefit. These results support addition of the routine 9vHPV vaccine with or without catch-up 9vHPV vaccination to the regional vaccination program in HK.

A multicenter laboratory assessment of a new automated chemiluminescent assay for ADAMTS13 activity.

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially fatal disorder caused by ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) deficiency. Prompt identification/exclusion of TTP can thus be facilitated by rapid ADAMTS13 testing. The most commonly utilized (enzyme-linked immunosorbent assay [ELISA]-based) assay takes several hours to perform and so does not generally permit rapid testing. OBJECTIVES: To evaluate the utility of a new automated test for ADAMTS13 activity, the HemosIL AcuStar ADAMTS13 Activity assay, based on chemiluminescence and able to be performed on an ACL AcuStar instrument within 33 minutes. PATIENTS/METHODS: This multicenter (n = 8) assessment included testing of more than 700 test samples, with similar numbers of prospective (n = 348) and retrospective (n = 385) samples. The main comparator was the Technozym ADAMTS13 Activity ELISA. We also assessed comparative performance for detection of ADAMTS13 inhibitors using a Bethesda assay. RESULTS: Overall, the chemiluminescent assay yielded similar results to the comparator ELISA, albeit with slight negative bias. ADAMTS13 inhibitor detection was also comparable, albeit with slight positive bias with the AcuStar assay. Assay precision was similar with both assays, and we also verified assay normal reference ranges. CONCLUSIONS: The HemosIL AcuStar ADAMTS13 Activity assay provided results rapidly, which were largely comparable with the Technozym ADAMTS13 Activity ELISA assay, albeit lower on average. Conversely, inhibitor levels tended to be identified at a higher level on average. Thus, the HemosIL AcuStar ADAMTS13 Activity assay provides a fast and accurate means to quantitate plasma levels of ADAMTS13 for TTP/ADAMTS13 identification/exclusion, and potentially also for other applications.

Cost-Utility of All-Oral Direct-Acting Antiviral Regimens for the Treatment of Genotype 1 Chronic Hepatitis C Virus-Infected Patients in Hong Kong.

BACKGROUND: Direct-acting antivirals (DAAs) are entering the hepatitis C virus (HCV) treatment landscape in Hong Kong, prompting the need for cost-effectiveness evaluations of these interventions to enable optimal use of healthcare resources. AIMS: This study aimed to compare the cost-effectiveness of DAAs to standard-of-care pegylated interferon plus ribavirin (RBV) in treatment-naïve patients without significant liver fibrosis and to compare different DAAs in patients who are treatment-experienced and/or have advanced liver disease. METHODS: A Markov model was constructed to evaluate cost-effectiveness over a lifetime time horizon from the payer perspective. The target population was treatment-naïve and treatment-experienced HCV genotype 1 patients, stratified by degree of liver fibrosis. The model consists of 16 health states encompassing METAVIR fibrosis score (F0-F4), treatment success or failure, decompensated cirrhosis, hepatocellular carcinoma, liver transplant, and liver-related death. The proportions of patients achieving sustained virologic response were obtained from clinical trials. Other inputs were obtained from published and local data. The primary outcome was incremental cost-utility ratio for each DAA versus pegylated interferon + ribavirin and among different DAAs. RESULTS: In treatment-naïve F0-2 HCV patients, all DAAs were cost-effective in genotype 1a and daclatasvir + asunaprevir, elbasvir/grazoprevir, ledipasvir/sofosbuvir, and glecaprevir/pibrentasvir were cost-effective compared to pegylated interferon + ribavirin in genotype 1b. In genotypes 1a and 1b, treatment-experienced patients, and F3-4 patients, elbasvir/grazoprevir was the least costly DAA and economically dominant over most other DAAs. CONCLUSIONS: DAAs can be a cost-effective option for the treatment of genotype 1 HCV patients in Hong Kong, and elbasvir/grazoprevir is cost-effective.

A life-threatening case of pregnancy-related atypical Haemolytic uremic syndrome and successful treatment with Eculizumab.

BACKGROUND: Pregnancy-related Atypical Haemolytic Uremic Syndrome (P-aHUS) is a rare condition affecting genetically predisposed women during pregnancy. It is often difficult to diagnose and has a significant impact on maternal and foetal outcomes. It is characterised by microangiopathic haemolytic anaemia and kidney injury from thrombotic microangiopathy. CASE PRESENTATION: A 27-year-old female of Lebanese descent presented at 36 weeks' gestation with foetal death in-utero (FDIU) with placental abruption on a background of previously normal antenatal visits. She was coagulopathic and anaemic with anuric acute kidney injury, requiring emergency Caesarean section, intubation and dialysis. Her coagulopathy rapidly resolved, however, her anaemia and renal dysfunction persisted. A diagnosis of P-aHUS was made, and she was empirically treated with Eculizumab. Her ADAMTS13 level was normal, effectively excluding thrombotic thrombocytopenic purpura. Within 2 weeks of treatment her haematological parameters improved, and her renal function began to recover and within 2 months she became dialysis independent. CONCLUSION: This case highlights the challenges of a timely diagnosis of P-aHUS from other pregnancy-related diseases. Although our patient is dialysis-independent, her risk of relapse remains high with subsequent pregnancies. Currently we are awaiting her genetic sequencing to complete her assessment for underlying mutations and are determining the safest approach to a future planned pregnancy.

Cost-effectiveness of letermovir as cytomegalovirus prophylaxis in adult recipients of allogeneic hematopoietic stem cell transplantation in Hong Kong.

BACKGROUND: The cost-effectiveness of letermovir as cytomegalovirus (CMV) prophylaxis in adult seropositive patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT), compared with the conventional strategy of preemptive treatment, has not been evaluated in Asia. METHODS: A decision analytical model, simulating the clinical progression of CMV infection on a lifetime horizon, was developed to compare prophylactic strategy with letermovir with preemptive therapy alone as anti-CMV strategies. Prophylaxis comprised administering letermovir for 14 weeks, with clinical outcomes measured at 24 weeks, followed by preemptive therapy if CMV infection occurred. This approach was modeled on outcomes of the letermovir phase 3 clinical study. The model enumerated the cost of letermovir prophylaxis, quality-adjusted life years (QALYs), and incremental cost per QALYs gained with prophylaxis. The opposite arm involved regular monitoring and preemptive therapy for CMV reactivation. Real-world costs from the adult HSCT center at Queen Mary Hospital, Hong Kong, were adopted for analysis. Costs and clinical benefits, expressed as QALYs, were discounted at 3% per year. RESULTS: Letermovir prophylaxis compared with preemptive therapy only would lead to an increase of life-year and QALYs at increased costs. Incremental cost-effectiveness analysis showed that letermovir prophylaxis had an associated cost of HKD 193,580 for each life-year gained, and HKD 234,675 for each QALY gained. Probabilistic sensitivity analysis showed that the majority of incremental cost-effectiveness ratio fell below the cost-effectiveness threshold of HKD 382,046 (one gross domestic product per capita) per QALY gained. CONCLUSIONS: Letermovir prophylaxis would be cost-effective for preventing CMV infection in adult seropositive allogeneic HSCT recipients in Hong Kong.

Baseline characteristics of patients with atypical haemolytic uraemic syndrome (aHUS): The Australian cohort in a global aHUS registry.

AIMS: To describe the baseline characteristics and treatment of Australian patients diagnosed with atypical haemolytic uraemic syndrome (aHUS) reported to the Global aHUS Registry. METHODS: Descriptive analysis of the Australian cohort with aHUS (n = 106) was undertaken for demographics, disease characteristics and prior treatment with eculizumab; comparing with the global cohort (n = 1688) for certain pre-specified disease characteristics. RESULTS: In Australia, almost two-thirds of patients diagnosed with aHUS were female and over 80% of patients were Caucasians, with similar proportions reported in the global cohort. Less than 6% of patients in the Australia and global cohorts were reported to have a history of autoimmune disease (4% vs 2%, respectively; P = .21) or cancer (5% vs 5%, respectively; P = .93), conditions that have been associated with secondary HUS. In the Australian cohort, 26% had received a kidney transplant and 68% of patients had received eculizumab. Kidneys were the most common organ involvement, followed by gastrointestinal tract (26%) and cardiovascular system (19%), with 35% of patients reported to have had at least two organs involved within 6 months prior to baseline visit or entry into the registry. Complement factor H was the most common pathogenic complement gene variant in the Australian patients. CONCLUSION: Data from the aHUS registry confirms and defines region-specific disease characteristics among a selected group of Australian children and adults with aHUS reported to the registry. Ongoing and more inclusive data will provide further information about temporal trends and treatment outcomes, representing a unique opportunity for clinicians and researchers to further develop knowledge surrounding this rare disease.

Cost Effectiveness of PD-L1-Based Test-and-Treat Strategy with Pembrolizumab as the First-Line Treatment for Metastatic NSCLC in Hong Kong.

BACKGROUND: Pembrolizumab, a monoclonal antibody against programmed death ligand 1 (PD-L1), is approved by several regulatory agencies for first-line treatment of metastatic non-small-cell lung cancer (NSCLC) with a PD-L1 tumor proportion score (TPS) ≥ 50% and no epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase genomic tumor aberrations. This study was conducted from the perspective of the Hospital Authority in Hong Kong and aimed to evaluate the cost effectiveness of a biomarker (PD-L1) test-and-treat strategy (BTS), in which patients with a TPS ≥ 50% received pembrolizumab and other patients received platinum doublet chemotherapy versus all patients receiving platinum doublet chemotherapy. METHODS: The model used a partitioned survival approach to estimate the incremental cost-effectiveness ratio (ICER) expressed as the cost per quality-adjusted life-year (QALY) gained. The clinical efficacy, utility and safety data were derived from the KN024 trial. Costs and health outcomes were projected over a 10-year time horizon and discounted at 3% per year. Costs for drug acquisition, PD-L1 testing, drug administration and disease management were used. Sensitivity analyses were conducted to evaluate the robustness of results. RESULTS: The BTS approach led to an increase of 0.29 QALYs at an additional cost of Hong Kong dollars (HK$) 249,077 (US$31,933) compared with platinum doublet chemotherapy, resulting in an ICER of HK$865,189 (US$110,922) per QALY gained. This is lower than the World Health Organization cost-effectiveness threshold of three times the 2016 gross domestic product (GDP) per capita for Hong Kong of HK$1017,819 (US$130,490). Probabilistic sensitivity analyses showed a 59.4% chance that the ICER would be below this threshold. CONCLUSION: First-line treatment with pembrolizumab in a BTS to identify patients with NSCLC with PD-L1 TPS ≥ 50% can be considered cost effective in Hong Kong compared with platinum doublet chemotherapy based on a three-times GDP per capita threshold. However, local data on clinical efficacy and safety were not available to estimate overall survival (OS) and progression-free survival (PFS) specific to patients with NSCLC in Hong Kong. Further, uncertainty is inherent in the survival projections/extrapolation of PFS and OS beyond the trial period, and future research may help to further inform these parameters.

Pregnancy-induced atypical haemolytic uremic syndrome: A new era with eculizumab.

Pregnancy is a well-recognised trigger of atypical haemolytic syndrome (P-aHUS) and often occurs in the post-partum period. Similar to atypical haemolytic uremic syndrome, it carries a poor prognosis with high morbidity particularly in the form of renal failure. Early recognition and intervention is crucial in its management particularly with the recent availability of eculizumab, a humanized monoclonal antibody to complement component C5, which has demonstrated drastic improvement in prognosis. The issue, however, is arriving at a timely diagnosis given the considerable amount of overlap in the clinical and biochemical manifestation of P-aHUS, HELLP syndrome (haemolysis, elevated liver enzyme and low platelet count) and other hypertensive disorders of pregnancy. We present a case report and literature review that highlights the clinical conundrum of arriving at the diagnosis. We also highlight the importance of early management of P-aHUS with eculizumab and its impact on improving morbidity.

Parallel synthesis and biological evaluation of 837 analogues of procaspase-activating compound 1 (PAC-1).

Procaspase-Activating Compound 1 (PAC-1) is an ortho-hydroxy N-acyl hydrazone that enhances the enzymatic activity of procaspase-3 in vitro and induces apoptosis in cancer cells. An analogue of PAC-1, called S-PAC-1, was evaluated in a veterinary clinical trial in pet dogs with lymphoma and found to have considerable potential as an anticancer agent. With the goal of identifying more potent compounds in this promising class of experimental therapeutics, a combinatorial library based on PAC-1 was created, and the compounds were evaluated for their ability to induce death of cancer cells in culture. For library construction, 31 hydrazides were condensed in parallel with 27 aldehydes to create 837 PAC-1 analogues, with an average purity of 91%. The compounds were evaluated for their ability to induce apoptosis in cancer cells, and through this work, six compounds were discovered to be substantially more potent than PAC-1 and S-PAC-1. These six hits were further evaluated for their ability to relieve zinc-mediated inhibition of procaspase-3 in vitro. In general, the newly identified hit compounds are two- to four-fold more potent than PAC-1 and S-PAC-1 in cell culture, and thus have promise as experimental therapeutics for treatment of the many cancers that have elevated expression levels of procaspase-3.