KS02.4.A Olaparib in Recurrent IDH-mutant High-Grade Glioma (OLAGLI)

BACKGROUND

There is a need to develop new treatments in IDH-mutant high-grade gliomas recurring after radiotherapy and chemotherapy. Based on preclinical studies showing that IDH-mutant tumors could be vulnerable to PARP inhibition we launched a phase II study to test the efficacy of olaparib (Lynparza) monotherapy in this population.

METHODS

Adults with recurrent high-grade IDH-mutant gliomas after radiotherapy and at least one line of alkylating chemotherapy (PCV or TMZ), KPS > 60, normal organ function were enrolled. The primary endpoint was 6 months PFS according to RANO criteria. Patients were treated with olaparib 300 mg twice daily. We used a single-stage Fleming design with p0 = 30%, p1 = 50%, a type I unilateral error rate of 5% and a power of 80%.

RESULTS

35 patients with recurrent IDH-mutant gliomas (IDH1R132H-mutant n = 32, other IDH mutation n = 3, 1p/19 codeleted n = 16, 1p/19q non-codeleted n = 14) were enrolled (malignantly transformed low-grade gliomas n = 21, anaplastic gliomas n = 8, glioblastomas n = 6). Median time since diagnosis was 7.4 years (1–22 years), median time since radiotherapy was 2.8 years (0.6–18 years), median number of previous chemotherapy lines was 2 (1–5). With a median follow-up of 11 months, 30 patients had stopped treatment due to tumor progression and 2 patients were still on treatment 16 to 18 months after treatment start. At 6 months, 11/35 patients were progression-free (31 %). According to RANO criteria, based on local investigator analysis, 2 patients (5%) had a partial response and 14 patients a stable disease (37%) with a median duration of response of 9 months (4–18+). Median PFS and OS were 2.3 and 15.9 months and were similar in 1p/19q codeleted and non-codeleted patients. A grade 3 olaparib-related adverse event was observed in 5 patients (14%, lymphopenia n = 3, fatigue n = 2, diarrhea n = 1) and a grade 2 in 15 patients (43%), most frequently consisting in fatigue (23%), gastrointestinal disorders (20%) and lymphopenia (20%). No patient definitively stopped olaparib due to side effects.

CONCLUSIONS

In this heavily pre-treated population of recurrent IDH-mutant gliomas, olaparib monotherapy was well tolerated and resulted in some activity supporting its evaluation in association with alkylating chemotherapy in recurrent IDH-mutant gliomas in future studies.

P14.24 Bevacizumab treatment in atypical disseminated choroid plexus papilloma in adult patients

BACKGROUND

Choroid plexus tumours represent less than 1% of brain tumours. Low-grade papilloma may be treated with gross total surgical resection, while in disseminated progressive atypical choroid plexus papilloma (APP), there is no standard treatment: various chemotherapy regimens have been reported. Since this tumour is characterized by a rich vascular component, antiangiogenic therapy is an attractive treatment. The use of Bevacizumab has already been reported in three patients. Authors expand this experience with 5 further patients diagnosed with progressive APP treated with bevacizumab.

MATERIAL AND METHODS

Patients were recruited through the weekly Adolescent Young Adult French web conference. They have been treated with bevacizumab 10 mg/kg by intravenous injection each 2 to 3 weeks. Their clinical status and radiological response are reported: Karnofsky Index (KI), Pain Scale (PS) and RANO criteria were used.

RESULTS

All our patients had a progressive disease prior to bevacizumab. Pt 1: 41 years old; APP with cranio-spinal dissemination; Previous treatments: local and cranio-spinal irradiation in 2012 and in 2014; surgery: complete and partial resection in 2010, 2014, and VP shunt in 2018; Bevacizumab: total of 33 cures in 18 months. Result: radiological and clinical stabilization. Pt 2: 58 years old; APP with cranio-spinal dissemination; Previous treatments: surgery: VP shunt and gross total resection, in 2006; VP shunt, in 2011. Bevacizumab: total of 4 cures, in 2 months. Result: radiological and clinical stabilization. Pt 3: 34 years old; APP with cranio-spinal dissemination; Previous treatments: surgery: gross total resection, in 1992, and shunt in 2008. Bevacizumab: total of 21 cures, in 21 months. Result: radiological and clinical stabilization. Pt 4: 63 years old; APP with cranio-spinal dissemination; Previous treatments: surgery: surgical resection and VP shunt in 2013; chemotherapy: temozolomide. Bevacizumab: 29 months (still treated). Result: radiological and clinical stabilization. Pt 5: 62 years old; APP with cranio-spinal dissemination; Previous treatments: surgery: gross total resection in 1999 and VP shunt in 2009; chemotherapy: Carboplatin Vespesid. Bevacizumab: 23 cures, in 14 months. Result: radiological stabilization and clinical amelioration.

CONCLUSION

Despite their previous worsening disease, all patients obtained a stabilization or amelioration of their IK and PS under bevacizumab. Bevacizumab should be evaluated in a multicentric trial as standard therapy for disseminated metastasized progressive choroid plexus tumours.

Obesity and chemotherapy administration: between empiric and mathematic method review

Introduction: Obesity is a major risk factor for chronic disease and cancer development. Therapeutic management of obese patients with cancer is a real challenge for physician because of the alteration of antineoplastic pharmacokinetics parameters in this population. In routine clinical practices, chemotherapy doses in obese patients are arbitrarily capped or adjusted to an ideal weight to minimize excessive toxicities. Material and methods: The main goal of this review is to describe the current state of knowledge concerning the correlation between the adjustment of BSA (capping or ideal weight) and the rates of global toxicities and survival outcomes in obese patients under chemotherapy in different types of cancer. We searched in the Medline database (via PubMed) in order to identify all publications of literature reviews whose subject chemotherapy dosing in obese population. Results: Only a single study was pointing toward increased of global toxicities of full weight dosing. Furthermore, some studies suggests that the practice of limiting doses in overweight and obese patients may negatively influence the quality of care and outcomes in a constantly increasing population. Conclusion: This review highlights the lack of prospective studies focusing on chemotherapy methods of administration in obese patients. At this time, there is no prospective study comparing capping and full weight dose chemotherapy administration in obese patient population.

[Radiotherapy phase I trials' methodology: Features]

In clinical research, biostatistical methods allow the rigorous analysis of data collection and should be defined from the trial design to obtain the appropriate experimental approach. Thus, if the main purpose of phase I is to determine the dose to use during phase II, methodology should be finely adjusted to experimental treatment(s). Today, the methodology for chemotherapy and targeted therapy is well known. For radiotherapy and chemoradiotherapy phase I trials, the primary endpoint must reflect both effectiveness and potential treatment toxicities. Methodology should probably be complex to limit failures in the following phases. However, there are very few data about methodology design in the literature. The present study focuses on these particular trials and their characteristics. It should help to raise existing methodological patterns shortcomings in order to propose new and better-suited designs.

[Carcinomatous meningitis: The radiation therapist's point of view]

Carcinomatous meningitis complicates 5 to 10% of cancers, essentially with breast cancers, lung cancers and melanomas. The incidence probably increased because of therapeutic advances in oncology. Treatment is based on external beam radiotherapy, systemic treatment, intrathecal chemotherapy and supportive care. The aim of this work was to review data on external radiation therapy and carcinomatous meningitis. There are few evidences on the subject, but it is a major topic of interest. A whole brain radiation therapy is indicated in case of brain metastases or clinical encephalitis. Focal radiation therapy is recommended on symptomatic, bulky or obstructive sites. The dose depends on performance status (20 to 40 Gy in five to 20 fractions), volume to treat and available techniques (classic fractionation or hypofractionation via stereotactic radiosurgery). The objective of radiation therapy is to improve quality of life. Association with systemic therapy improves overall survival. Administration of sequential intrathecal chemotherapy may also improve overall survival, but induces more toxicity. The use of new radiotherapy techniques and development of radiosensitizing molecules in patients with good performance status could improve survival in this frequent complication of cancer.