Inhibition of PSA flare in prostate cancer patients by administration of flutamide for 2 weeks before initiation of treatment with slow-releasing LH-RH agonist

Molecular Hybrid Design, Synthesis, In Vitro Cytotoxicity, In Silico ADME and Molecular Docking Studies of New Benzoate Ester-Linked Arylsulfonyl Hydrazones

In this paper, we present the synthesis and characterization of two known sulfonyl hydrazides (1 and 2) and their new sulfonyl hydrazone derivatives (9-20), as well as in vitro and in silico investigations of their cytotoxic properties against human lung (A549) and human breast (MCF-7) cancer cell lines. The target compounds (9-20) obtained in high yields were synthesized for the first time by a multi-step reaction, and their structures were confirmed by elemental analysis and various spectral techniques, including FT-IR, 1H-, and 13C-NMR. The antiproliferative profiles of these compounds (1, 2, and 9-20) in this study were determined at concentrations of 200, 100, 50, and 25 µM against selected cancer cell lines for 72 h using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. Except for compounds 1 and 2, other compounds (9-20) demonstrated cytotoxic activity at concentrations lower than 200 µM. The newly synthesized compounds (9-20) demonstrated antiproliferative activities at a micromolar level, with IC50 values in the range of 29.59-176.70 μM for the A549 cell line and 27.70-170.30 μM for the MCF-7 cell line. Among these compounds, compound 15 (IC50 = 29.59 μM against A549 cell line and IC50 = 27.70 μM against MCF-7 cell line) showed the highest cytotoxic activity against these two cancer cell lines compared to the reference drug cisplatin (IC50 = 22.42 μM against A549 cell line and IC50 = 18.01 μM against MCF-7 cell line). From docking simulations, to establish a plausible binding mode of compounds, we noticed that compound 15 demonstrated the highest affinity (-6.8508 kcal/mol) for estrogen receptor-beta (ERbeta) compared to others, suggesting promising ERbeta binding potential. Most compounds followed Lipinski's rule of five, with acceptable logP values. Additionally, all had mixed gastrointestinal absorption and limited blood-brain barrier permeability. Overall, our study proposed new sulfonyl hydrazones as a potential class of anticancer agents.

Prognostic role of early PSA drop in castration resistant prostate cancer patients treated with abiraterone acetate or enzalutamide

BACKGROUND

Previous studies demonstrated a predictive value of prostate-specific antigen (PSA) kinetics for treatment outcome. Our retrospective study evaluates the prognostic role of early PSA drop in metastatic castration resistant prostate cancer (mCRPC) patients receiving abiraterone acetate (AA) or enzalutamide (E).

METHODS

All mCRPC patients treated with AA or E at the San Luigi Hospital in Orbassano between 2010 and 2018 and at the Ordine Mauriziano Hospital in Turin between 2014 and 2018 were included in this retrospective study. Only patients with an early PSA (measured 28-60 days after the beginning of the treatment) were included in the analysis. Patients were divided in early responders and non-early responders according to early PSA response (drop≥50% from baseline). Univariate and multivariate analyses for progression free survival (PFS) and overall survival (OS) were performed.

RESULTS

Of 144 patients with early PSA value, 61 (42.4%) patients received E (docetaxel-naïve 42, post-docetaxel 19) and 83 (57.6%) received AA (docetaxel-naïve 44, post-docetaxel 39). Seventy-five (52.1%) patients achieved early PSA drop. In docetaxel-naïve setting (N.=86), median PFS was 14.9 (with early PSA drop) vs. 8.8 months (without early PSA drop, P=0.001). In post-docetaxel setting (N.=58) median PFS was 11.9 vs. 4.5 months (P<0.001). Globally, median PFS was 14.9 vs. 6.3 months in patients with and without early PSA drop, respectively (P<0.001). In docetaxel-naïve setting, patients with early PSA drop had a median OS of 39.5 vs. 18.8 months (P=0.12). In post-docetaxel setting median OS was 29.6 vs. 10.7 months (P=0.01). Comprehensively, median OS was 31.9 vs. 16.3 (P=0.002) in patients with and without early PSA drop, respectively. At multivariate analysis, early PSA drop confirmed an independent association with PFS (HR 0.21; 95% CI: 0.12-0.38, P<0.001) and OS (HR 0.25; 95% CI: 0.12-0.50, P<0.001).

CONCLUSIONS

mCRPC patients treated with AA or E, in docetaxel-naïve or post-docetaxel setting, with early PSA drop had significantly better OS and PFS.

Patterns of Bicalutamide Use in Prostate Cancer Treatment: A U.S. Real-World Analysis Using the SEER-Medicare Database

INTRODUCTION

Bicalutamide (BIC), a non-steroidal anti-androgen, is FDA-indicated for use in combination with a luteinizing hormone-releasing hormone (LHRH) analog for treatment of Stage D2 metastatic carcinoma of the prostate. Lack of consensus exists regarding the clinical benefit of BIC use, either alone or combined use of BIC with an LHRH analog or antagonist (combined androgen blockade or CAB), versus treatment with androgen deprivation therapy (ADT) alone.

METHODS

The SEER-Medicare database was used to identify prostate cancer patients aged ≥ 66 years diagnosed between 2007 and 2011 and who filled at least one prescription for BIC. Duration of BIC treatment was assessed in relation to ADT use; either alone (monotherapy), as part of CAB only, and as part of CAB followed by monotherapy. Additionally, we assessed use of BIC during or outside a potential testosterone flare prevention period (initiation within 2 months of an LHRH agonist).

RESULTS

A total of 7521 prostate cancer patients who filled a prescription for BIC were identified. Eighteen percent of the cohort used BIC alone, over half the patients (54%) used BIC as part of CAB and 27% used BIC as part of CAB followed by monotherapy. Among men treated with BIC as part of CAB, 58% received BIC only within the potential flare period.

CONCLUSIONS

Although there is no FDA indication for BIC use as monotherapy, > 44% of patients in this study used BIC alone or as part of CAB followed by monotherapy. Further research is necessary to understand the outcomes of BIC utilization in these settings, particularly compared with newer second-generation anti-androgens.

FUNDING

Medivation LLC, a Pfizer company, and Astellas, Pharma, Inc.

Multidirectional Efficacy of Biologically Active Nitro Compounds Included in Medicines

The current concept in searching for new bioactive products, including mainly original active substances with potential application in pharmacy and medicine, is based on compounds with a previously determined structure, well-known properties, and biological activity profile. Nowadays, many commonly used drugs originated from natural sources. Moreover, some natural materials have become the source of leading structures for processing further chemical modifications. Many organic compounds with great therapeutic significance have the nitro group in their structure. Very often, nitro compounds are active substances in many well-known preparations belonging to different groups of medicines that are classified according to their pharmacological potencies. Moreover, the nitro group is part of the chemical structure of veterinary drugs. In this review, we describe many bioactive substances with the nitro group, divided into ten categories, including substances with exciting activity and that are currently undergoing clinical trials.

Early abiraterone acetate treatment is beneficial in Japanese castration-resistant prostate cancer after failure of primary combined androgen blockade

Background

Development of novel agents targeting the androgen axis has led to improved overall survival in castration-resistant prostate cancer (CRPC). This study aimed to investigate the optimal timing of treatment with one such agent, abiraterone acetate (AA), in Japanese patients.

Materials and methods

Between July 2014 and February 2016, 106 CRPC patients were administered AA in Nagoya City University Hospital, Nagoya, Japan and in four affiliated hospitals following failure of primary combined androgen blockade (CAB). Of these, records of 69 patients treated before chemotherapy were retrospectively analyzed. Patients were divided into two AA treatment groups: (1) first- or second-line after diagnosis of CRPC, designated the Early Group, and (2) third-line onwards, designated the Deferred Group. Prostate-specific antigen (PSA) response rate, ≥ 50% PSA decline rate with treatment, progression-free survival (PFS), and overall survival (OS) were compared between the two groups. National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0 was used to classify adverse events.

Results

In 24 patients in the Early Group and 45 patients in the Deferred Group, no significant differences in baseline parameters were observed between groups. PSA response rate, ≥ 50% PSA decline rate and PFS (but not OS) were significantly better in the Early Group than in the Deferred Group. Serum aspartate aminotransferase/alanine aminotransferase elevations were the most common Grade 3 treatment-related toxicities, and were clinically manageable. In subgroup analyses of the Early Group, comparison of first-line AA with second-line AA after flutamide treatment showed no changes in PSA response rate, PFS, or OS.

Conclusion

This study suggests improved favorable outcomes of first- or second-line AA treatment in Japanese chemotherapy-naïve CRPC patients after failed CAB; statistical confirmation of such improvement was evident for PFS, but not OS. In addition, early AA treatment exhibited an acceptable safety profile.

Risk of Testosterone Flare in the Era of the Saturation Model: One More Historical Myth

CONTEXT

When luteinizing hormone-releasing hormone (LHRH) agonists were introduced in the 1980s, it was universally believed that the initial transient rise in serum testosterone (T), termed T flare, caused rapid prostate cancer (PCa) growth and led to disease progression, complications, and death. It became routine to offer antiandrogens (AAs) to prevent these risks. However, over the last decade, it has become recognized that androgens have a finite ability to stimulate PCa growth (the saturation model), providing a theoretical challenge to the risks of T flare.

OBJECTIVE

To review evidence for the risks associated with T flare from a modern perspective, specifically prostate-specific antigen (PSA) flare, disease progression, and spinal cord compression.

EVIDENCE ACQUISITION

An Ovid Medline database search was conducted to identify articles related to "testosterone flare", "disease flare", and "PSA flare" associated with LHRH agonists. The literature review included papers published from May 1, 1980 through May 1, 2016. Key search terms included, luteinizing hormone-releasing hormone, gonadotropin-releasing hormone, and antiandrogens.

EVIDENCE SYNTHESIS

Initial administration of LHRH agonists uniformly results in peak increases in serum T by 40-100% on days 2-3, returning to baseline by days 7-8, after which T declines to castrate levels by approximately 2-3 wk. Of six LHRH agonist studies reporting PSA during the period of T flare, five showed no significant rise in PSA despite the presence of advanced disease with mean baseline PSA as high as ≥500ng/ml. Evidence for disease flare was limited to one report of greater bone pain with LHRH agonists alone versus LHRH agonists with AAs. Three other RCTs reported no disease flare. Rates of spinal cord compression were no greater for LHRH agonists alone compared with castration or estrogen treatment. We identified no studies of men treated with LHRH agonists versus placebo/no treatment to assess the effects of LHRH agonists compared with the natural history of advanced PCa.

CONCLUSIONS

Although T flare has been considered risky for 30 yr, a modern review of the evidence collected primarily in the 1980s and 1990s fails to support this view. Specifically, T flare does not appear to be associated with significantly increased PSA, disease progression, or adverse events, even in men with widely metastatic disease. These results are consistent with the saturation model, first introduced in 2006. There seems little value in adding AA to LHRH agonists, except possibly for men with extensive vertebral metastases and serum T concentrations well below the saturation point of approximately 250ng/dl (8.7nmol/l).

PATIENT SUMMARY

A review of the literature reveals no evidence for increased risks associated with testosterone flare from the initiation of luteinizing hormone-releasing hormone (LHRH) agonists. This appears to be an unsupported belief from an earlier era when our understanding of testosterone's relationship to prostate cancer was less sophisticated. Except in rare instances, there appears to be no need to use an androgen blocker when beginning treatment with LHRH agonists.

Degarelix monotherapy compared with luteinizing hormone-releasing hormone (LHRH) agonists plus anti-androgen flare protection in advanced prostate cancer: an analysis of two randomized controlled trials

OBJECTIVES

The objective of this study was to assess differences in efficacy outcomes between luteinizing hormone-releasing hormone (LHRH) agonist plus antiandrogen (AA) flare protection and monotherapy with the gonadotrophin-releasing hormone antagonist degarelix in patients with prostate cancer.

METHODS

Data from 1455 patients were pooled from two prospective, phase III randomized 1-year clinical trials of degarelix versus LHRH agonist with or without AA. The AA bicalutamide was administered at the investigator's discretion. Adjusted hazard ratios (HRs) were calculated using a Cox proportional hazards regression model and a conditional logistic regression model was used for a case-control analysis of odds ratios (ORs).

RESULTS

Patients received degarelix monotherapy (n = 972) or LHRH agonist (n = 483) of whom 57 also received AA. Overall, prostate-specific antigen progression-free survival (PSA PFS) was improved with degarelix versus LHRH agonist + AA (Cox proportional hazards regression model-adjusted HR for PSA PFS failure was 0.56 [95% confidence interval (CI) 0.33-0.97, p = 0.038]). To compensate for a higher proportion of patients with metastases, Gleason score 7-10, and PSA >20 ng/ml in the LHRH agonist + AA group, a case-control analysis using a conditional logistic regression model was utilized. This resulted in an OR for PSA PFS of 0.42 (95% CI 0.20-0.89; p = 0.023) in the overall population, and 0.35 (95% CI 0.13-0.96; p = 0.042) in patients with PSA >50 ng/ml at baseline, when treated with degarelix versus LHRH agonists + AA. There were a small number of deaths, 1.9% with degarelix and 7% with LHRH agonists + AA (case-control analysis OR = 0.37; p = 0.085).

CONCLUSIONS

Degarelix monotherapy produced a more favorable effect on PSA PFS outcomes than a LHRH agonist + AA flare protection therapy in patients with prostate cancer when a case-control analysis was used to compensate for differences between treatment groups.

Molecular and biochemical effects of a kola nut extract on androgen receptor-mediated pathways

The low incidence of prostate cancer in Asians has been attributed to chemopreventative properties of certain chemicals found in their diet. This study characterized the androgenic and chemopreventative properties of the Jamaican bush tea “Bizzy,” using androgen receptor positive and negative cell lines. Exposure of prostate cells to Biz-2 resulted in a growth inhibition (GI₅₀) of 15 ppm in LNCaP cells and 3.6 ppm in DU145 cells. Biz-2 elicited a 2-fold increase in the mRNA of the anti-apoptotic gene Bcl2, with a 10-fold increase in that of the proapoptotic gene Bax. We observed a 2.4- to 7.5-fold change in apoptotic cells in both cell lines. Biz-2 at 10 ppm elicited a time- and dose-dependent stimulation of both the protein and mRNA levels of several androgen-regulated genes. Biz-2 caused a 36% decrease in PSA secretion and a significant increase in PSA mRNA. The relative binding affinity (IC₅₀) of Biz-2 for AR was 2- to 5-fold lower than that of the synthetic androgen R1881. Biz-2 was found to be a specific ligand for the AR in that the natural ligand, DHT, and the anti-androgen, flutamide, displaced Biz-2 bound to AR and inhibited Biz-2-induced transcription and PSA secretion. This study provided evidence that Biz-2 extract possesses the ability to modulate prostate cancer cell biology in an AR-dependent manner.

PSA surge/flare-up in patients with castration-refractory prostate cancer during the initial phase of chemotherapy

BACKGROUND

Docetaxel-based chemotherapy has shown great promise for the treatment of CRPC and is considered the current standard of care. PSA is mainly used as marker to monitor the treatment response. Several articles were published reporting an initial PSA surge/flare-up after starting chemotherapy. The cause and the impact of this phenomenon are discussed controversially. The intention of this review is to define the significance of initial PSA surge/flare-up and to increase awareness to this phenomenon in the urological community.

MATERIALS AND METHODS

A comprehensive literature search was performed in different data bases using various key words. Relevant articles and references between 1999 and 2009 were reviewed and analyzed for data on the association between chemotherapy and initial PSA surge/flare.

RESULTS

The incidence of a PSA surge/flare-up ranges according to the reported studies between 7.6% and 13.6%. A PSA surge/flare-up was reported up to 404% from baseline PSA level followed by PSA response. The median duration of a PSA surge/flare-up is 2-3 weeks and can last up to 6-8 weeks. However, the occurrence of a PSA surge/flare-up did not impact outcome and survival negatively compared to patients with an immediate PSA response.

CONCLUSIONS

A considerable portion of CRPC patients experience an initial PSA surge/flare-up under systemic chemotherapy. The definitions used for PSA surge/flare-up differ slightly in the literature. This issue needs to be solved since it might impact defining treatment response. As a PSA surge/flare-up did not impact outcome and survival negatively, chemotherapy should be continued according to the literature addressing specifically the phenomenon of a PSA surge/flare-up for a minimum of 8 weeks or 3 rounds of a 3-weekly cycle chemotherapy regimen before further decisions are made about efficacy. However, Scher et al. recommended a 12-week period drug exposure based on their results on PSA progression-free survival and overall survival. This dilemma needs to be addressed in further data analysis in order to establish a general rule regarding when to stop chemotherapy. Physicians should be aware of this effect to avoid inadequate early discontinuation of chemotherapy. The underlying mechanisms of a PSA surge/flare-up are still elusive and need further clarification.

Indirect androgen doping by oestrogen blockade in sports

Androgens can increase muscular mass and strength and remain the most frequently abused and widely available drugs used in sports doping. Banning the administration of natural or synthetic androgens has led to a variety of strategies to circumvent the ban of the most effective ergogenic agents for power sports. Among these, a variety of indirect androgen doping strategies aiming to produce a sustained rise in endogenous testosterone have been utilized. These include oestrogen blockade by drugs that act as oestrogen receptor antagonists (antioestrogen) or aromatase inhibitors. The physiological and pharmacological basis for the effects of oestrogen blockade in men, but not women, are reviewed.

Impact of PSA flare-up in patients with hormone-refractory prostate cancer undergoing chemotherapy

OBJECTIVES

The intention of this study is to describe the impact and underlying potential basis of the prostate-specific antigen (PSA) flare-up phenomenon in patients with hormone-refractory prostate cancer (HRPC) treated with docetaxel-based chemotherapy.

METHODS

We retrospectively identified 74 consecutive patients who received docetaxel/estramustine-based chemotherapy at our institution. Patients were evaluated based on modified criteria from the Prostate-Specific Antigen Working Group regarding survival and toxicity. Additionally, two androgen receptor mutations derived from patients with advanced disease were analyzed for promiscuous transactivation activity.

RESULTS

The 74 patients were stratified into four groups: response, partial response, flare-up-initial PSA elevation, and progression. Median survival in the flare-up group (n=8) was 20 months and did not differ from the response group (p=0.564). The flare-up group showed a maximum PSA elevation from baseline between 3.4 and 28.3% (between three and six weeks) followed by PSA decline >or=50% from the baseline level in seven of the eight patients. The androgen receptor mutations AR(877) and AR(715) displayed a 37.5- and 5.2-fold increase in transactivation activity by progesterone and a 12.6- and 5.4-fold increase by estrogen compared to the AR(WT), respectively.

CONCLUSIONS

A considerable portion of HRPC patients experience an initial PSA flare-up under systemic chemotherapy. In this study, occurrence of flare-up phenomenon did not impact survival. Chemotherapy should be continued a minimum of six weeks before removing patients from a docetaxel-based regimen. We showed evidence that co-medication with dexamethasone/prednisolone and/or estramustine itself can induce an initial PSA flare-up via androgen receptor mutations.

Etude randomisée multicentrique comparant la castration médicale par triptoréline à la castration chirurgicale dans le traitement du cancer de la prostate localement avancé ou métastatique

OBJECTIVE

To report the results of a trial comparing the efficacy of triptorelin and surgical castration in the treatment of locally advanced or metastatic prostate cancer.

MATERIALS AND METHODS

80 patients with previously untreated locally advanced or metastatic prostate cancer prostate cancer were included in a one-year multicentre, randomized, prospective, open-label therapeutic trial. Patients either received a monthly injection of triptorelin (group 1; n = 40), or were treated by pulpectomy (group 2; n = 40). Patients were reviewed every 3 months, then every 6 months.

RESULTS

The mean age of the patients was 71.22 +/- 8.25 years. At 1 month, 38 patients were castrated (plasma testosterone < 0.5 mg/ml) in the pulpectomy group versus 35 in the triptorelin group. The mean follow-up was 38.8 +/- 26 months in the triptorelin group and 36.3 +/- 25 months in the pulpectomy group. On multivariate analysis, age, impaired performance status and PAP level (> 3.2 ng/ml) were predictive factors of a poor outcome. The median survival was 37.5 +/- 9 months in the triptorelin group and 33 +/- 3 months in the pulpectomy group. At 3 years, no significant difference in specific survival was observed between the 2 groups. At 8 years of follow-up, 63 patients had died.

CONCLUSION

This study demonstrates an equivalent specific survival between patients treated by triptorelin or surgical castration. Castration is rapidly obtained with triptorelin (< 2 months) and is maintained over time throughout the duration of treatment.

Clinical significance of a prostate-specific antigen flare phenomenon in patients with hormone-refractory prostate cancer receiving docetaxel

Docetaxel has shown promise for the treatment of hormone-refractory prostate cancer and has become the standard of care. The flare phenomenon is a known entity in androgen-deprivation therapy of advanced prostate cancer and it has also been described in palliative chemotherapy of hormone-refractory prostate cancer. The aim of this study was to evaluate the clinical impact of a prostate-specific antigen flare phenomenon in docetaxel-treated hormone-refractory prostate cancer patients. From December 2002 to August 2005, we treated 44 patients with hormone-refractory prostate cancer applying docetaxel-based regimens. Prostate-specific antigen levels were determined before therapy and weekly thereafter. Patients were divided into three groups: response (group 1), progression (group 2) and flare (group 3). Flare was defined as initially rising prostate-specific antigen under therapy, dropping thereafter to values below baseline. The groups were compared for overall survival by Kaplan-Meier analysis. We observed a prostate-specific antigen flare phenomenon in eight (18%) of 44 evaluable patients; 24 (54.5%) patients were primary responders and 12 (27.3%) experienced progressive disease. In group 3, prostate-specific antigen levels rose to 107-180% from baseline and then dropped to 21-68%. Kaplan-Meier analysis showed significantly better overall median survival for groups 1 (18 months, P=0.0005) and 3 (19 months, P=0.006) than for group 2 (7 months). Survival in groups 1 and 3 was comparable. Grade 3 and 4 toxicity was below 5% and equally distributed between the 3 groups. In our limited patient cohort, prostate-specific antigen flare phenomenon does not seem to be a clinically relevant issue in terms of overall survival. Thus, an initial rise of prostate-specific antigen under docetaxel therapy in hormone-refractory prostate cancer does not indicate therapeutic failure and should not lead to early withdrawal from therapy in the absence of clinical signs of progression.

Complete response, as determined by prostate-specific antigen level, to chlormadinone acetate withdrawal persisting longer than 2 years in patients with advanced prostate cancer: Two case reports

Antiandrogen withdrawal syndrome (AWS) is a well-established phenomenon in prostate cancer. However, responses to AWS are usually of limited duration, and a complete response (CR) is extremely rare. We present two patients who exhibited a chemical CR for more than 2 years after the discontinuation of steroidal antiandrogen chlormadinone acetate use. Whether patients who respond to antiandrogen withdrawal include a group of patients with a better prognosis remains uncertain. However, considering that the usual survival period of patients with hormone-resistant prostate cancer is approximately 12 months, both of the patients reported here, who are present in excellent physical condition, exhibiting an improved quality of life, and attending their hospital as outpatients, obviously acquired a prolonged survival because of AWS.

Pain flare following external beam radiotherapy and meaningful change in pain scores in the treatment of bone metastases

BACKGROUND AND PURPOSE

To examine the incidence of pain flare following external beam radiotherapy and to determine what constitutes a meaningful change in pain scores in the treatment of bone metastases.

PATIENTS AND METHODS

Patients with bone metastases treated with external beam radiotherapy were asked to score their pain on a scale of 0-10 before the treatment (baseline), daily during the treatment and for 10 days after completion of external beam radiation. Pain flare was defined as a two-point increase from baseline pain in the pain scale of 0-10 with no decrease in analgesic intake or a 25% increase in analgesic intake employing daily oral morphine equivalent with no decrease in pain score. To distinguish pain flare from progression of pain, we required the pain score and analgesic intake to return back to baseline levels after the increase/flare. They were also asked to indicate if their pain changed during that time compared to pre-treatment level. The change in pain score was compared with patient perception.

RESULTS

Eighty-eight patients were evaluated in this study. There were 49 male and 39 female patients with the median age of 70 years. Twelve of 88 patients (14%) had pain flare on day 1. The overall incidence of pain flare during the study period ranged from 2 to 16%. A total of 797 pain scorings were obtained. Patients perceived an improvement in pain when their self-reported pain score decreased by at least two points.

CONCLUSIONS

Our study confirms the occurrence of pain flare following the external beam radiotherapy in the treatment of bone metastases. Further studies are required to predict who are at risk for flare. Appropriate measures can be taken to alleviate the pain flare. The finding in the meaningful change in pain scores supports the investigator-defined partial response used in some clinical trials.