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.

OS5.4 Characteristics of adult diffuse H3K27M-mutant gliomas at recurrence

BACKGROUND

Adult diffuse H3K27M-mutant gliomas are rare and associated with a poor prognosis but could benefit in the next future from specific therapeutic strategies. In this context, the aim of the present study was to describe the characteristics of these tumors at recurrence.

MATERIAL AND METHODS

We retrospectively analyzed the characteristics of a series of 27 adult diffuse H3K27M-mutant gliomas at recurrence

RESULTS

Median age at diagnosis was 37 years. Initial treatment consisted of temozolomide radiochemotherapy (n=17, 62%), radiotherapy alone (n=1, 4%), chemotherapy alone (n=4, 15%), wait and see (n=1, 4%) and palliative care (n=4, 15%). Median PFS and median OS were 11 and 22 months in the whole series and 15 and 29 months in the patients who were treated with temozolomide radiochemotherapy. The pattern of recurrence could be analyzed in 19 patients. Ten patients (50%) demonstrated a local recurrence, five patients a local and distant recurrence (25%), two patients only a distant recurrence (10%) and two patients a leptomeningeal progression (10%). At recurrence, 15 patients received an oncological treatment that consisted of an alkylating chemotherapy (n=5), a bevacizumab based chemotherapy regimen (n=9) and of radiotherapy (n=1). Median PFS and OS after first recurrence in these patients were 6 and 14 months, respectively. An activating FGFR1 mutation was identified in 4 out of the 9 patients in whom it was assessed.

CONCLUSION

At recurrence, adult diffuse H3K27M-mutant gliomas are associated with a high rate of distant locations. A subset of patients harbor targetable FGFR1 activating mutations.

P14.13 Incidence of pseudoprogression in high-grade IDH-mutant gliomas

BACKGROUND

Pseudoprogression (PsP) is a well-known concern in IDH-wildtype glioblastomas. The aim of the present study was to describe its incidence in high-grade IDH-mutant gliomas.

MATERIAL AND METHODS

We retrospectively analyzed the characteristics of a consecutive series of high-grade IDH-mutant gliomas treated with radiotherapy (RT) with or without chemotherapy between March 2009 and September 2017. PsP was defined as a new enhanced lesion that occurred after RT and subsequently disappeared or remained stable during follow-up for a least 6 months.

RESULTS

The study population consisted of 38 anaplastic IDH-mutant and 1p/19q codeleted oligodendrogliomas, 34 IDH-mutant anaplastic astrocytomas and 18 IDH-mutant glioblastomas. Treatment consisted of radiotherapy alone (n=8, 9%), radiotherapy and PCV chemotherapy (n=63, 70%) and temozolomide radiochemotherapy (n=19, 21%). After a median follow-up of 3.5 years (range 1–8 years), 24 patients (28%) presented a PsP that occurred after a median delay of 10 months after radiotherapy (2 to 32 months). PsP was more frequent in patients treated with RT+PCV than in those treated with RT+TMZ (34% vs 10%, p=0.05). During the first two years after RT completion, 19 patients (21%) presented a PsP and 15 patients (17%) a true progression. At last follow-up, 1 patient (4%) in the PsP group had died compared to 10 patients (16%) in the group of patients without PsP.

CONCLUSION

PsP is a frequent issue in IDH-mutant high-grade gliomas. Its timing of onset is delayed compared to the timing of PsP onset reported in IDH-wildtype glioblastomas. The association between the use of PCV chemotherapy and PsP requires validation in an independent series.

P04.18 Management of diffuse gliomas using hypnosis-aided awake surgery: oncological and functional preliminary results in a series of 16 cases

BACKGROUND

Awake resection of diffuse gliomas aims to find a tailored onco-functional balance for each patient. Hypnosis represents an innovative technique able to optimize the comfort and well-being of the patient during such procedures. The aim of the present study is to analyse the oncological and functional outcome in a cohort of patients operated on with hypnosis-aided awake surgery.

MATERIAL AND METHODS

All consecutive adult patients that underwent hypnosis-aided resection for a diffuse glioma between January 2018 and January 2019 were recorded. Neurological and cognitive status were assessed preoperatively and at 3 months postoperatively. Extent of tumor resection was quantified by a radiologist on magnetic resonance imaging.

RESULTS

Sixteen patients (6 males and 10 females), with a mean age of 39 years, were included. Gliomas were revealed by epileptic seizures (62.5%), motor deficit (6.25%) or incidentally discovered (31.25%) and were either located in the right hemisphere (50%) or in the left hemisphere (50%), with a mean initial volume of 42 mL. Histologically, there were six grade II-astrocytomas, three grade III-astrocytomas, five grade II-oligodendroglioma, one grade III-oligodendroglioma and one ganglioglioma. Under HAS, the awake-time after the anaesthesia drugs stop was short, because low doses of drugs were required thanks to the hypnotic state. All patients were able to reliably performed the different tests until functional subcortical limits were reached. Postoperative magnetic resonance imaging showed complete resection in 8 cases (50%), subtotal resection in 2 cases (12.5%) and partial resection in 6 cases (37.5%), with a mean resection rate of 84.6%. At 3 months after surgery, there was only a new motor deficit (6.25%). The language and neuropsychological assessments were improved in 7 patients (43.75%), stable in 7 patients (43.75%) and deteriorated in some tests in 2 patients (12.5%). After surgery, no patient reported negative emotion concerning the awake glioma resection and all patient declared being ready for a second awake resection in the future, if indicated.

CONCLUSION

According to these preliminary results, hypnosis-aided awake resection of diffuse gliomas appears to be safe and effective from an onco-functional viewpoint and parallelly contributes to decrease intra-operative pain, anxiety and major discomfort.