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Firwana, Belal

https://orcid.org/0000-0002-3060-5751

Mayo Clinic

Heartland Cancer Research

Citations 26

Cabozantinib in high-grade neuroendocrine neoplasms.
Trikalinos, Nikolaos, Firwana, Belal, Reimers, Melissa A., Mehan, Paul, Rohatgi, Anjali , Pressey, Olive, Waldron, Nicholas, Wu, Shuang , Tan, Benjamin , Suresh, Rama , Pedersen, Katrina S. , Firwana, Belal , Reimers, Melissa A. , Liu, Jingxia

Journal of Clinical Oncology | May 27, 2026 | Volume: 44 | Issue: 16_suppl | Pages: 4183-4183

10.1200/jco.2026.44.16_suppl.4183 Get It

4183 Background: High grade neuroendocrine neoplasms (HG-NENs) are treated with platinum doublets mirroring guidelines for small cell lung cancer (SCLC) but recurrences are common and salvage options are limited in efficacy. Cabozantinib (CABO), an inhibitor of VEGFR, MET, and TAM kinases (TYRO3, AXL, and MER) was approved by the FDA for treatment of well differentiated (WD) NENs of both pancreatic and extrapancreatic origins based on the CABINET study (Chan, NEJM 2025). However, its efficacy in the whole spectrum of HG-NEN patients including poorly differentiated disease (PDD) has not been prospectively explored. Methods: This was a single institution, Phase II study of CABO in patients with HG-NENs who had progressed on at least one prior treatment. Key inclusion/exclusion criteria were NENs of any origin except SCLC, high grade by Ki-67 of > 20% or histology consensus, ECOG of < = 1, appropriate hematological parameters and no history of bleeding or active cardiac disease. CABO was given orally starting at 60 mg po daily in 3-week cycles. The primary endpoint of this study was overall response rate (ORR). Secondary endpoints included progression free survival (PFS) and overall survival (OS). A Simon optimal 2-stage design tested the null hypothesis that the true ORR is < = 1% at the type I error rate of 5%, resulting in projected enrollment of up to 32 total patients. Toxicities were graded according to CTCAE v5.0 and response was evaluated according to RECIST v1. Results: All patients have been accrued, with 4/32 patients still on treatment. Median age at diagnosis was 62 years and male to female ratio was 1.46. Origin of tumor was GI in 68.8% of the cases, the rest being thoracic (6.3%), prostate (6.3%) cervical (6.3%) head/neck (3.1%) and unknown (9.4%). Median Ki-67 was 55%, 11 patients had Ki-67 > 70%. Histology was WD-HG in 40% of patients and PDD in 60%. Two patients had mixed PDD/other components (MiNEN). Median PFS in evaluable patients was 4.01 months [95% CI 1.61 to 9.30] and mOS was 9.89 mo [95% CI 6.73 to 18.96]. Three patients so far (9.3%) have had partial response as best response (PDD-colon, WD-pancreas and PDD-cervical) while 19/32 (59.4%) patients have had stable disease as best response so far (disease control rate 68.8%). Five (15.6%) patients have received more than 10 treatment cycles. The three longest treated patients had WD-pancreas (23 and 17 cycles) and PDD-unknown (12 cycles). One patient had eventual resection of a metastatic site and is currently without evidence of disease. Three patients withdrew from the trial because of toxicities (shortness of breath, GI bleeding, thromboembolism). Twenty-six patients have expired. Conclusions: CABO monotherapy showed efficacy in some HG-NEN patients with not just WD but also the very aggressive PDD histology. No new side effects to the ones previously described for this agent were noted. Supported by Exelixis and a Siteman investment program grant. Clinical trial information: NCT04412629 .
The Role of Systemic Therapy in Resectable Colorectal Liver Metastases: Systematic Review and Network Meta-Analysis
Sonbol, Mohamad Bassam , Pathak, Surabhi , Firwana, Belal , Botrus, Gehan , Almader‐Douglas, Diana , Ahn, Daniel H. , Starr, Jason S. , Jones, Jeremy , Stucky, Chee‐Chee , Smoot, Rory L. , Bekaii‐Saab, Tanios , Almader-Douglas, Diana, Riaz, Irbaz Bin , Smoot, Rory L , Sonbol, Mohamad B , Bekaii-Saab, Tanios S , Jones, Jeremy C , Siddiqi, Rabbia , Usón, Pedro Luiz Serrano , Borad, Mitesh J.

The Oncologist | September 27, 2022 | Volume: 27 | Issue: 12 | Pages: 1034-1040

10.1093/oncolo/oyac212 Get It

Abstract Background Despite multiple randomized trials, the role of perioperative chemotherapy in colorectal cancer liver metastasis (CRLM) is still under debate. In this systematic review and network meta-analysis (NMA), we aim to evaluate the efficacy of perioperative systemic therapies for patients with CRLM. Methods We searched various databases for abstracts and full-text articles published from database inception through May 2021.We included randomized controlled trials (RCTs) comparing the addition of perioperative (post, pre, or both) systemic therapies to surgery alone in patients with CRLM. The outcomes were compared according to the chemotherapy regimen using a random effects model. Outcomes of interest included disease-free survival (DFS) and overall survival (OS). Results Seven RCTs with a total of 1504 patients with CRLM were included. Six studies included post-operative treatment and one evaluated perioperative (pre- and postoperative) therapy. Fluoropyrimidine-based chemotherapy was the most used systemic therapy. NMA showed benefit of adding perioperative therapy to surgery in terms of DFS (HR 0.73, 95% CI 0.63 to 0.84). However, these findings did not translate into a statistically significant OS benefit (HR 0.88, 95% CI 0.74 to 1.05). NMA did not show any advantage of one regimen over another including oxaliplatin or irinotecan. Conclusions This systematic review and NMA of 7 RCTs found that the addition of perioperative systemic treatment for resectable CRLM could improve disease-free survival but not overall survival. Based on the findings, addition of perioperative treatment in resectable CRLM should be individualized weighing the risks and benefits.
An online academic writing and publishing skills course: Help Syrians find their voice
Sabouni, Ammar , Chaar, Abdelkader , Bdaiwi, Yamama , Masrani, Abdulrahman , Abolaban, Heba, Alahdab, Fares , Firwana, Belal , Moujahed, Ahmad Al, Al‐Moujahed, Ahmad , Alahdab, Fares

Avicenna Journal of Medicine | August 16, 2021 | Volume: 07 | Issue: 03 | Pages: 103-109

10.4103/ajm.ajm_204_16 Get It

Abstract Purpose: A group of Arab-American physicians and researchers in the United States organized a blended online course in academic writing and publishing in medicine targeting medical students and physicians in war-torn Syria. This was an effort to address one of the reasons behind the poor quantity and quality of scientific research papers in Syria and the Arab region. In this paper, we report on the design, conduct, and outcome of this course and attempt to evaluate its effectiveness. Methods: The educational intervention was a 2-month blended online course. We administered a questionnaire to assess satisfaction and self-reported improvement in knowledge, confidence, and skills of academic writing and publishing. Results: The course succeeded in reaching more than 2588 physicians and medical students from the region; 159 of them completed most of the course. Eighty-three percent of the participants felt that they were confident enough to write an academic paper after the course and 95% felt the learning objectives were achieved with an average student satisfaction of 8.4 out of 10. Conclusion: Physicians in Syria and neighboring countries are in need of training to become an active part of the global scientific community and to document and communicate the crisis their countries are going through from a medical perspective. Low-cost online educational initiatives help respond, at least partially, to those needs.
How to read a published clinical trial: a practical guide for clinicians
Firwana, Belal , Murad, Mohammad Hassan, Sonbol, Mohamad Bassam , Hilal, Talal , Murad, M. Hassan

Avicenna Journal of Medicine | April 1, 2020 | Volume: 10 | Issue: 02 | Pages: 68-75

10.4103/ajm.ajm_186_19 Get It

AbstractOver the last 5 years, there have been more than 140 new drug approvals in the field of Oncology alone, all based on newly published clinical trials. These approvals have led to an ongoing change in clinical practice, offering new therapeutic options for patients. Therefore, it is important for healthcare providers to be able to appraise a clinical trial and determine its validity, understand its results, and be able to apply such results to their patients. In this guide, we provide a simplified approach tailored to practicing clinicians and trainees. The same concepts and principles apply to other medical specialties.
Chronic Lymphocytic Leukemia-Associated Chromosomal Abnormalities and Risk of Secondary Malignancies
Hampel, Paul J. , Firwana, Belal , Wang, Zhen , Shad, Yasar, Aluri, Lata, Naidzionak, Uladzislau, Doll, Donald C., Raza, Shahzad

Blood | October 11, 2019 | Volume: 124 | Issue: 21 | Pages: 5636-5636

10.1182/blood.v124.21.5636.5636 Get It

Abstract Introduction: Incidence of secondary malignant neoplasm in patients with chronic lymphocytic leukemia (CLL) is already established. Genetic predisposition has been considered to be a possible contributory factor for the preponderance of second cancers in this population. In the present study, we examined the frequency, characteristics, and clinical outcomes of secondary malignancies in patients with CLL based on their Interphase fluorescence in situ hybridization (FISH) panel. Methods: We reviewed the medical records of consecutive patients with CLL observed or treated at Ellis Fischel Cancer Center during the period from 2007-2014. We collected demographic data, CLL Rai stage, treatment history, Interphase fluorescence in situ hybridization (FISH) panel results and the presence of a secondary malignancy (skin cancers, solid tumors and hematologic malignancy excluding CLL transformation).Our aim was to investigate the association between secondary malignancy and chromosomal abnormalities and other risk factors using Chi2test for categorical variables and Wilcoxon rank-sum test for continuous variables. Cox proportional hazard models and logistic regression models were used to evaluate risk factors of developing secondary malignancy and overall survival. Results: We identified 142 CLL patients who were either observed (n=62) or had a history of treatment (n=80) for CLL. 67% were male and 33% were female. 85% of patients were Caucasians, 10% African Americans, and 5% other. Familial CLL was present in 6% of cases. 51% of patients were non-smokers. 5% of patients had cancers preceding the diagnosis of CLL (non-melanoma skin cancers=3, melanoma=1, Hodgkin's lymphoma=1, Prostate=2). 28% of patients developed secondary malignancies after the diagnosis of CLL; among them non-melanoma skin cancers were the most common (78%), followed by cutaneous melanoma (9.5%) and papillary thyroid cancer (4.7%). Other malignancies included lung (2.3%), kidney (2.3%), prostate (2.3%) and ocular melanoma (2.3%). 12% patients had aggressive non-melanoma recurrent skin cancers that require multiple treatments along-with systemic therapy for progressive CLL. CLL-FISH panel at diagnosis was available in 98 patients. Among these patients,13q deletion was present in 45%. Within the 13q deletion group, secondary malignancy was noted in 50% during a median follow up of 7 years. All cases of papillary thyroid cancers were also present in 13q deletion. In contrast, 11q deletion was detected in 15% and trisomy 12 in 18% of patients with incidence of secondary malignancy 40% and 10%, respectively. No solid malignancy other than skin was identified in the 11q deletion and trisomy 12 groups. 17p deletion was present in 5% of cases and 60% of 17p deletion cases had secondary cancers (skin 80%). Normal FISH panel was present in 17% cases and 20% of normal FISH had secondary malignancy (solid 10%, skin 10%). The median overall survival time is 6 years for the entire cohort (IRQ: 3-9 years). Secondary malignancy was associated with worse overall survival (OS) (HR=0.57, 95% CI:0.33-0.98, p=0.04) compare to patients who did not have secondary malignancy. The risk of secondary malignancy is increased in patients with advanced age (OR=1.05, 95% CI:1.00-1.10, p=0.04) and in those who were treated with alkylating agent for CLL OR=6.62, 95% CI:2.08-21.03, p=0.001. However, there were no significant difference on risk of developing secondary malignancy based on specific chromosomal FISH result, Rai stage, smoking, family history and gender. Conclusion: Secondary malignancies are frequent in patients with detectable chromosome abnormality on FISH panel. However, the increased risk of secondary malignancy does not correlate with specific cytogenetic abnormality. Non melanoma skin cancers are exceedingly common in CLL patients and carries aggressive couse in progressive CLL patients. Larger studies are required to identify subtype of CLL based on integrated mutational and cytogenetic subgroup that are at increased risk of specific secondary malignancies. Disclosures No relevant conflicts of interest to declare.
Efficacy of First-Line CLL Treatments in Comparison to Chlorambucil: A Network Meta-Analysis
Firwana, Belal , Ravilla, Rahul , Raval, Mihir, Hao, Lin, Veeraputhiran, Muthu, Makhoul, Issam , Sasapu, Appalanaidu , Sonbol, Mohamad Bassam , Atrash, Shebli , Hao, Lin, Jethava, Yogesh S.

Blood | October 11, 2019 | Volume: 128 | Issue: 22 | Pages: 5594-5594

10.1182/blood.v128.22.5594.5594 Get It

Abstract Background: In the past several years, biology of CLL is being unleashed which had led to discovery of novel treatments, including ofatumumab and obinutuzumab, CD20 monoclonal antibodies (mAb), and ibrutinib, a Bruton tyrosine kinase inhibitor, which exhibited a paradigm shift in CLL. Available clinical trials provided direct comparison with chlorambucil, with no head-to-head trials to compare them. We conducted a network meta-analysis (NMA) to summarize the evidence on first-line treatments of CLL. Methods: We included randomized controlled trials (RCTs) that evaluated the efficacy of ofatumumab, obinutuzumab, ibrutinib, rituximab, bendamustin or alemtuzumab, in patients with previously untreated CLL. Efficacy outcome measures included progression-free survival (PFS) at 18 months and best overall response rate (ORR), which consists of both complete and partial response rates. Bayesian NMA method was used to conduct this NMA that pools evidence from direct and indirect comparisons to facilitate simultaneous inference regarding all treatments used. Results: Five trials were identified, enrolling 2,113 newly diagnosed CLL patients with a median age ranging from 60 to 73. NMA demonstrated superiority of obinutuzumab plus chlorambucil over other mAb combinations and ibrutinib, and had the highest probability of achieving PFS at 18 months when compared to ibrutinib with risk ratio (RR) of 2.41 (credible interval [CrI] 0.89 to 5.29) and ofatumumab plus chlorambucil with RR of 7.11 (CrI 3.31 to 13.8). Table-1 depicts the results of NMA for PFS at 18 months. It also had the highest probability of achieving ORR, followed by ibrutinib ranking the second. Conclusion: Obinutuzumab plus chlorambucil has higher probability of achieving efficacy compared to other mAb combinations or ibrutinib, in terms of better ORR and better PFS rates, followed by ibrutinib. The certainty in the evidence is low because of indirectness, which is a limitation in this NMA, however our results parallel the evidence based practice. Although no head to head clinical trials compared first-line treatments for CLL, our NMA showed that obinutuzumab plus chlorambucil and ibrutinib had better efficacy profile. NMA is not a substitute for well conducted RCTs investigating direct comparisons. Abbreviations: CrI, credible intervals; PFS, progression free survival. *Treatments are ranked according to their probability of achieving comparative effectiveness. Disclosures No relevant conflicts of interest to declare.
Long Term Outcomes of First Line Tyrosine Kinase Inhibitors for Chronic Phase Chronic Myeloid Leukemia: A Mixed-Treatment Comparison
Firwana, Belal , Diab, Maria , Hasan, Rim, Yousef, Ibraheem , Garipalli, Archana, Al‐Kali, Aref , Doll, Donald C., Sonbol, Mohamad Bassam , Raza, Shahzad

Blood | October 10, 2019 | Volume: 124 | Issue: 21 | Pages: 3146-3146

10.1182/blood.v124.21.3146.3146 Get It

Abstract Background: Tyrosine kinase inhibitors (TKI) are associated with marked improvements in molecular response and survival compared with previous therapies for patients with chronic myelogenous leukemia (CML) in chronic phase (CP). We previously reported efficacy and safety of TKI at 12-month follow-up (Firwana et. al.JCO. 2014; 32(15_suppl): 7054). Here, we summarize the evidence of TKI efficacy and safety of TKI, comparing them directly and in-directly, in the mature follow-up for patients with newly diagnosed CP-CML. Methods: We included randomized controlled trials (RCTs) evaluating TKI in adults with newly diagnosed CP-CML. TKI (imatinib, dasatinib and nilotinib) were included if used as an initial treatment. Studies on bosutinib were excluded as it is only approved in the US for the treatment of CP-CML after failure of initial therapy. Studies that included patients with accelerated- or blast-phase CML, intolerant or resistant patients to first-line treatment, those on IFN-α, older agents or stem cell transplantation were excluded. Main outcomes are efficacy, represented by major molecular response (MMR, ≤ 0.1% BCR-ABLIS) and deeper molecular responses (MR4.5, ≤ 0.0032%IS), survival, represented by overall survival (OS) and progression free survival (PFS), and safety represented by medication discontinuation rate due to adverse events. Latest period of reporting outcome data were considered. As available trials provides direct comparison with imatinib, with no head-to-head trials to compare other TKI, we conducted a mixed treatment comparison (MTC) analysis which pools evidence from direct and indirect comparisons to facilitate simultaneous inference regarding all treatments. Bayesian mixed-treatment comparison method was used to rank TKI in terms of effectiveness. Results: Four landmark trials reported in 15 published articles and conference abstracts were identified involving 1647 patients with CP-CML. Follow-up times ranged from 3 months to 6 years. Table-1 depicts the results of MTC for imatinib, dasatinib and nilotinib. MTC analysis demonstrated superiority of both nilotinib and dasatinib over imatinib in terms of efficacy and safety. Nilotinib ranked first in efficacy with better improvement in MMR and MR4.5 at 48-month follow-up despite its different regimens, followed by dasatinib. Dasatinib has the highest medication discontinuation rate due to adverse events or drug-related toxicity. Among TKI, nilotinib was found to have the best survival profile; however, it was statistically nonsignificant. Conclusion: Both nilotinib and dasatinib are associated with significantly better efficacy and safety profiles compared to imatinib. At 48-month follow-up period, nilotinib ranked first to achieve MMR and MR4.5, with lower discontinuation rate due to adverse events. This analysis shows that new generation TKI are not only showing faster response, but also maintaining a more potent one through longer follow up period. It is important to note out that MTC is not a substitute for well conducted RCTs investigating direct comparisons. Table-1: Results of mixed treatment comparison for imatinib, dasatinib and nilotinib using fixed-effect Bayesian method. Comparison Mean risk difference (95% CrI) compared to from reference standard (Imatinib) Rank* MMR MR 4.5 PFS OS Discontinuation due to adverse events 48 months 48 months 36 months 48 months 48 months Imatinib Reference Reference Reference Reference Reference 4 Dasatinib 0.62 (0.26 to 1.01) 0.32 (-0.05 to 0.69) 0.21 (-0.43 to 0.85) 0.17 (-0.49 to 0.83) 0.59 (-0.05 to 1.25) 3 Nilotinib 300 0.92 (0.56 to 1.28) 0.81 (0.45 to 1.18) 1.02 (0.24 to 1.86) 0.19 (-0.51 to 0.89) -0.11 (-0.66 to 0.43) 1 Nilotinib 400 0.76 (0.41 to 1.12) 0.68 (0.31 to 1.05) 0.05 (-0.57 to 0.65) 0.81 (0.01 to 1.67) 0.30 (-0.20 to 0.81) 2 *Reported rank is valid for all outcomes, except for PFS and OS, where Nilotinib 400 ranks #1 and Nilotinib 300 ranks #2. Also, for rate of medication discontinuation due to adverse events, Dasatinib has the highest rate for discontinuation, followed by Nilotinib, both doses. Abbreviations: CrI, credible intervals; MMR, major molecular response, BCR-ABLIS ≤ 0.1%; MR4, deeper molecular responses, BCR-ABLIS ≤ 0.0032%; PFS, progression free survival; OS, overall survival. Disclosures No relevant conflicts of interest to declare.
A Systematic Review and Network Meta-Analysis of Regorafenib and TAS-102 in Refractory Metastatic Colorectal Cancer
Sonbol, Mohamad Bassam , Benkhadra, Raed, Firwana, Belal , Walden, Daniel J., Mody, Kabir , Murad, M. Hassan , Ahn, Daniel H. , Bekaii‐Saab, Tanios , Walden, Daniel , Hubbard, Joleen M. , Murad, M Hassan , Sonbol, Mohamad B , Bekaii-Saab, Tanios S , Wang, Zhen

The Oncologist | June 4, 2019 | Volume: 24 | Issue: 9 | Pages: 1174-1179

10.1634/theoncologist.2019-0189 Get It

Abstract Background Regorafenib at different dosing strategies and TAS-102 are treatment options for refractory metastatic colorectal cancer (mCRC). We aimed to evaluate the comparative effectiveness evidence supporting these different strategies. Materials and Methods We searched different databases for randomized controlled trials evaluating TAS-102 or regorafenib in patients with refractory mCRC who failed prior oxaliplatin, irinotecan, and fluoropyrimidine. Outcomes of interest included overall survival (OS) and progression-free survival (PFS). The overall effect was pooled using the DerSimonian random effects model. We conducted network meta-analysis based on White's multivariate meta-regression to pool evidence from direct and indirect comparisons. Results Six trials at low risk of bias (2,445 patients) were included. Direct comparisons showed that Rego 160 and TAS-102 as monotherapy were superior to best-supportive care (BSC) in terms of PFS (Rego 160: hazard ratio [HR], 0.4; 95% confidence ratio [CI], 0.26–0.63; TAS-102: HR, 0.46 CI, 0.40–0.52) and OS (Rego 160: HR, 0.67; CI, 0.48–0.93; TAS-102: HR, 0.67; CI, 0.57–0.80). Network analysis showed no statistically difference in PFS or OS between Rego 160 and TAS-102. Rego 80+ was superior to BSC in terms of OS (HR, 0.44; CI, 0.23–0.84) and PFS (HR, 0.37; CI, 0.21–0.66). Rego 80+ was associated with statistically nonsignificant improvement in OS and PFS compared with TAS-102 and Rego 160. Conclusion Regorafenib 160 and TAS-102 appear to have similar efficacy. Rego 80+ is shown to be superior to BSC. A trend for improved OS was observed with Rego 80+ versus Rego 160 or TAS 102. Implications for Practice Regorafenib at a dose of 160 mg and TAS-102 appear to have similar efficacy in patients with refractory metastatic colorectal cancer. Regorafenib with a dose escalation strategy is superior to best-supportive care. Given its tolerability and the observed trend in survival benefit compared with regorafenib 160, dose escalation strategy of regorafenib (80+) may be the preferred option in this setting.
The role of maintenance strategy in metastatic colorectal cancer (mCRC): A systematic review and meta-analysis.
Mountjoy, Luke , Firwana, Belal , Almader‐Douglas, Diana , Mody, Kabir , Ahn, Daniel H. , Sonbol, Mohamad Bassam , Hubbard, Joleen M. , Borad, Mitesh J. , Murad, M. Hassan , Bekaii‐Saab, Tanios

Journal of Clinical Oncology | May 27, 2019 | Volume: 37 | Issue: 15_suppl | Pages: 3524-3524

10.1200/jco.2019.37.15_suppl.3524 Get It

3524 Background: In mCRC, induction combination chemotherapy with targeted agents is considered the mainstay of treatment. This is typically followed by maintenance therapy vs. observation which had been examined in various trials. However, it remains unclear how best optimize maintenance strategy. We aim to evaluate comparative effectiveness to support best maintenance strategy. Methods: We searched PubMed, Embase, and Cochrane CENTRAL for randomized controlled trials (RCT) evaluating different maintenance strategies in previously untreated mCRC patients (pts): observation (obs), bevacizumab (bev), fluoropyrimidine (FP), FP+bev, or continuing induction regimen (CTX). Outcomes of interest included OS and PFS. The overall effect was pooled using the DerSimonian random effects model. We conducted network meta-analysis based on White’s multivariate meta-regression to pool evidence from direct and indirect comparisons. Agents were ranked using surface under the cumulative ranking (SUCRA) probabilities. Higher SUCRA scores correspond to greater efficacy. Results: Twelve trials at low risk of bias (5540 pts) were included. Network meta-analysis shows no benefit of CTX over obs in terms of PFS (HR 0.7; 95% CI 0.46-1.09) and OS (HR 0.95; 95% CI 0.85-1.07). Compared to obs, maintenance therapy shows PFS benefit (HR 0.58; 95% CI 0.43-0.77) with only a trend in OS (HR 0.91; 95% CI 0.83-1.009). All maintenance strategies (FP, FP+bev, and bev) show significant improvement in PFS over obs. On SUCRA analysis, maintenance treatment (FP or FP+bev) has the highest likelihood of achieving better PFS (67.1% for FP and 99.8% for FP+bev) and OS (81.3% for FP and 73.2% for FP+bev). Conclusions: A maintenance strategy with at least a FP with or without the addition of bevacizumab is preferred. However, given the lack of a clear OS benefit, obs is an acceptable alternative. Optimal maintenance strategies should be dependent on factors including patient preferences, cost and toxicities. [Table: see text]