Ronald de wit

Dr. Ronald de wit


Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 December 2022 in Annals of Oncology
Verified
Journal Article
Open access
ABA.V. Balar
A.V. Balar
DCD.E. Castellano
D.E. Castellano
PGP. Grivas
P. Grivas
DVD.J. Vaughn
D.J. Vaughn
TPT. Powles
T. Powles
POP.H. O’dOnnell
P.H. O’dOnnell
Immune checkpoint inhibitors are a standard therapy in metastatic urothelial carcinoma (UC). Long-term follow-up is necessary to confirm durability of response and identify further safety concerns. In KEYNOTE-045, patients with metastatic UC that progressed on platinum-containing chemotherapy were randomly assigned 1:1 to receive pembrolizumab or investigator's choice of paclitaxel, docetaxel, or vinflunine. Primary endpoints were progression-free survival per RECIST version 1.1 by blinded independent central review (BICR) and overall survival. In KEYNOTE-052, cisplatin-ineligible patients with metastatic UC received first-line pembrolizumab. The primary endpoint was objective response rate per RECIST version 1.1 by BICR. A total of 542 patients (pembrolizumab, n = 270; chemotherapy, n = 272) were randomly assigned in KEYNOTE-045. The median follow-up was 62.9 months (range 58.6-70.9 months; data cut-off 1 October 2020). At 48 months, overall survival rates were 16.7% for pembrolizumab and 10.1% for chemotherapy; progression-free survival rates were 9.5% and 2.7%, respectively. The median duration of response (DOR) was 29.7 months (range 1.6+ to 60.5+ months) for pembrolizumab and 4.4 months (range 1.4+ to 63.1+ months) for chemotherapy; 36-month DOR rates were 44.4% and 28.3%, respectively. A total of 370 patients were enrolled in KEYNOTE-052. The median follow-up was 56.3 months (range 51.2-65.3 months; data cut-off 26 September 2020). The confirmed objective response rate was 28.9% (95% confidence interval 24.3-33.8), and the median DOR was 33.4 months (range 1.4+ to 60.7+ months); the 36-month DOR rate was 44.8%. Most treatment-related adverse events for pembrolizumab in either study were grade 1 or 2 and manageable, which is consistent with prior reports. With ∼5 years of follow-up, pembrolizumab monotherapy continued to demonstrate durable efficacy with no new safety signals in patients with platinum-resistant metastatic UC and as first-line therapy in cisplatin-ineligible patients. With ClinicalTrials.gov NCT02256436 (KEYNOTE-045); https://clinicaltrials.gov/ct2/show/NCT02256436 and NCT02335424 (KEYNOTE-052); https://clinicaltrials.gov/ct2/show/NCT02335424.

15 November 2003 in Journal of Clinical Oncology
Verified
Journal Article
Closed access
Ronald de witRonald de wit
Ronald de wit
JHJ. Herrstedt
J. Herrstedt
BRBernardo Rapoport
Bernardo Rapoport
ACA.D. Carides
A.D. Carides
GCG. Carides
G. Carides
KHK.J. Horgan
K.J. Horgan
Purpose: This analysis evaluated whether the antiemetic efficacy of the NK1 receptor antagonist aprepitant (EMEND™, Merck, Whitehouse Station, NJ) plus standard antiemetics could be sustained for up to six cycles of cisplatin-based chemotherapy. Patients and Methods: Patients receiving cisplatin ≥ 70 mg/m2 were blindly assigned to receive one of the following three regimens: (1) aprepitant 375 mg 1 hour before cisplatin on day 1 and aprepitant 250 mg on days 2 to 5 (n = 35); (2) aprepitant 125 mg before cisplatin and aprepitant 80 mg on days 2 to 5 (n = 81); or (3) placebo before cisplatin on days 2 to 5 (n = 86). All groups received ondansetron 32 mg and dexamethasone 20 mg before cisplatin, and dexamethasone 8 mg on days 2 to 5. The primary end point was complete response (no emesis and no rescue therapy) over 5 days following cisplatin in up to six cycles. A cumulative probability analysis using a model for transitional probabilities was used to analyze the data. The aprepitant 375/250-mg regimen was discontinued early in light of new pharmacokinetic data. Results: In the first cycle, 64% of patients in the aprepitant group and 49% in the standard therapy group had a complete response. Thereafter, complete response rates for the aprepitant group were still 59% by cycle 6, but decreased to 34% by cycle 6 for the standard therapy group. Reasons for discontinuation were similar across treatment groups. Conclusion: Compared with patients who received standard therapy, those who received only the aprepitant regimen had better and more sustained protection against chemotherapy-induced nausea and vomiting over multiple cycles.

1 September 2017 in European Urology
Verified
Journal Article
Closed access
MRMaud Rijnders
Maud Rijnders
Ronald de witRonald de wit
Ronald de wit
JBJoost L. Boormans
Joost L. Boormans
MLMartijn P.J. Lolkema
Martijn P.J. Lolkema
AVAstrid A.M. van der Veldt
Astrid A.M. van der Veldt

10 March 2012 in Journal of Clinical Oncology
Verified
Journal Article
Open access
Ronald de witRonald de wit
Ronald de wit
ISIwona Skoneczna
Iwona Skoneczna
GDGedske Daugaard
Gedske Daugaard
MSMaria De Santis
Maria De Santis
AGAugust Garin
August Garin
LCLaurence Collette
Laurence Collette
Purpose: To compare the efficacy of four cycles of paclitaxel–bleomycin, etoposide, and cisplatin (T-BEP) to four cycles of bleomycin, etoposide, and cisplatin (BEP) in previously untreated patients with intermediate-prognosis germ-cell cancer (GCC). Patients and Methods: Patients were randomly assigned to receive either T-BEP or standard BEP. Patients assigned to the T-BEP group received paclitaxel 175 mg/m2 in a 3-hour infusion. Patients who were administered T-BEP received primary granulocyte colony-stimulating factor (G-CSF) prophylaxis. The study was designed as a randomized open-label phase II/III study. To show a 10% improvement in 3-year progression-free survival (PFS), the study aimed to recruit 498 patients but closed with 337 patients as a result of slow accrual. Results: Accrual was from November 1998 to April 2009. A total of 169patients were administered BEP, and 168 patients were administered T-BEP. Thirteen patients in both arms were ineligible, mainly as a result of a good prognosis of GCC (eight patients administered BEP; six patients administered T-BEP) or a poor prognosis of GCC (one patient administered BEP; four patients administered T-BEP). PFS at 3 years (intent to treat) was 79.4% in the T-BEP group versus 71.1% in the BEP group (hazard ratio [HR], 0.73; CI, 0.47 to 1.13; P [log-rank test] = 0.153). PFS at 3 years in all eligible patients was 82.7% versus 70.1%, respectively (HR, 0.60; CI: 0.37 to 0.97) and was statistically significant (P = 0.03). Overall survival was not statistically different. Conclusion: T-BEP administered with G-CSF seems to be a safe and effective treatment regimen for patients with intermediate-prognosis GCC. However, the study recruited a smaller-than-planned number of patients and included 7.7% ineligible patients. The primary analysis of the trial could not demonstrate statistical superiority of T-BEP for PFS. When ineligible patients were excluded, the analysis of all eligible patients demonstrated a 12% superior 3-year PFS with T-BEP, which was statistically significant.

1 February 2004 in European Journal of Cancer
Verified
Journal Article
Closed access
Ronald de witRonald de wit
Ronald de wit
JHJ. Herrstedt
J. Herrstedt
BRB. Rapoport
B. Rapoport
ACA.D. Carides
A.D. Carides
JGJ. Guoguang-Ma
J. Guoguang-Ma
KHK.J. Horgan
K.J. Horgan

10 December 2006 in Journal of Clinical Oncology
Verified
Journal Article
Closed access
Ronald de witRonald de wit
Ronald de wit
KFKarim Fizazi
Karim Fizazi
During the last two decades, definitive primary treatments and surveillance with definitive treatment deferred until relapse have demonstrated 98% to 99% cure rates in patients with stage I testis cancer, and these options have obtained firm positions in standard management. The development of optimal management strategies in various countries were at least partly guided by available surgical expertise in retroperitoneal lymph node dissection in the United States, and easy access to reference hospitals in densely populated countries in Western Europe that facilitated close surveillance programs; hence, treatment preferences differ on the two sides of the Atlantic. The success of both approaches is highly dependent on the skills of the practitioner, particularly of surgery and of scrutinized surveillance. As a result, local expertise and familiarity with a chosen modality has strengthened over the years, and investigators have been reluctant to embark on randomized trials designed to compare one modality with another. Such expertise with one particular technique, with the other approach being less familiar territory, has created controversy, because both physicians and patients seek evidence-based data coming from randomized clinical trials on which to make management decisions. Moreover, the reduced risk of relapse resulting from the use of radiotherapy or carboplatin in stage I seminoma and of cisplatin-based chemotherapy in stage I nonseminoma must be balanced against the potential long-term adverse effects in this population of patients with a normal life expectancy. The purpose of this review is to present the currently available data and discuss the merits and the disadvantages of the various approaches, yielding to the possible conclusion that all options appear to be equal in terms of efficacy, but that modality-associated adverse effects differ.