P06.05.A Repeated intracranial administration of ipilimumab and nivolumab in patients with recurrent glioblastoma (rGB): A multi-cohort adaptive phase I clinical trial

Background

Perioperative intracerebral (iCE) administration of ipilimumab (IPI) and nivolumab (NIVO) in combination with IV NIVO was shown to be feasible, safe and associated with an encouraging survival benefit (Duerinck et al. JITC 2021). In subsequent cohorts, combination of iCE administration with biweekly intracavitary (iCA, via an Ommaya reservoir) administration of increasing doses of IPI and NIVO was investigated.

Methods

Three cohorts were defined according to resectability and postoperative treatment schedule. Patients (pts) in cohort-A and -C underwent a maximal safe resection, pts in cohort-B stereotactic biopsy only. All pts received iCE administration of 10 mg NIVO and 5 mg IPI at the end of the surgical intervention, after which an OR was implanted and an additional 10mg of NIVO and IPI (1, 5 or 10 mg) was administered iCA in cohort-C. All pts received biweekly postoperative NIVO 10 mg IV and iCA administrations of NIVO (3 dose levels were investigated in cohorts-A and -B: 1, 5, or 10 mg) for up to a maximum of 24w postoperatively. In cohort-C, 10 mg of NIVO was complemented with IPI (1, 5, or 10 mg). NGS and RNA gene expression profiling was performed on all tissue samples.

Results

In total, 44 pts were included (A: n= 16, B: n= 16, C: n= 12 recruitment ongoing). All pts in cohort-A and -B are off study treatment. All pts received the predefined dose of iCE IPI/NIVO and at least one administration of the predefined iCA dose. AE were infrequent and mostly not immune-related. Most common AE were fatigue(n=37), headache(n=25), confusion(n=18) and postoperative fever(n=15). Bacterial colonization of the Ommaya port occurred in 6 pts, subacute neurological deterioration requiring corticosteroids in 8 pts. There were no grade 5 AEs. Median PFS was 13w for cohort-A, 5w in cohort-B and 13w in cohort-C. Median OS is 43weeks in A, 29w in B and is not yet reached in cohort-C after median follow-up of 23w. OS did not differ significantly between study cohorts. OS of pts who underwent surgical resection (cohorts-A and -C) compared favorably to a historical cohort of 469 Belgian patients with rGB (treated in three prospective phase II clinical trials and a large multicenter early acces program for bevacizumab).

Conclusions

iCE followed by repeated iCA administrations of increasing doses of NIVO with/without IPI in rGB is feasible and safe without dose limiting AEs. A potential survival benefit seems restricted to pts amenable to surgical resection.

CTIM-17. INTRA-CRANIAL ADMINISTRATION OF CTLA-4 AND PD-1 IMMUNE CHECKPOINT-INHIBITING MONOCLONAL ANTIBODIES IN RECURRENT GLIOBLASTOMA PATIENTS: A MULTI-COHORT ADAPTIVE PHASE I CLINICAL TRIAL

BACKGROUND: Intracerebral (iCE) administration of nivolumab (NIVO) and ipilimumab (IPI) after resection of recurrent glioblastoma (rGB), followed by repeated intravenous(IV) NIVO was recently shown to be feasible, safe and associated with encouraging survival. Subsequent cohorts were defined to investigate the addition of biweekly intracavitary (iCA) or intrathecal (iTH) NIVO +/- IPI administrations. METHODS Four groups were defined according to rGB resectability and postoperative treatment schedule. Group A and D underwent biopsy, B and C maximal safe resection. All patients received iCE injections of 10 mg/1ml NIVO + 5 mg/1ml IPI at the end of surgery, after which an Ommaya catheter was implanted iCA (A, B and C) or iTH (D). Following surgery, all patients received biweekly IV low-dose NIVO(10mg) combined with iCA/iTH 10 mg NIVO (A and B) + 1, 5 or 10 mg IPI (C and D) for up to 24 weeks. NIVO/IPI concentrations were dosed in the cerebrospinal fluid (CSF). Gene sequencing and RNA gene expression profiling were performed on all tissue samples RESULTS 39pts(27 male; 16 in A, 16 in B, 4 in C, 3 in D; recruitment ongoing in C+D) were enrolled. All patients received the predefined dose of iCE IPI/NIVO. Most frequent AEs were fatigue (n=30), headache (n=19), confusion (n=14), dysphasia (n=13), and fever (n=10). Ommaya infection occurred in 5patients, subacute neurological deterioration requiring corticosteroids in 6patients. There were no G5 AEs. irAEs were infrequent and mild. Median PFS and OS were 5w(95% CI 1-8) and 23w(95% CI 0-53) in A and 13w(95% CI 7-19) and 42w(95% CI 30-54) in B, respectively. >90% of CSF samples had elevated protein levels and lymphocytic pleocytosis. There was no evidence for accumulation of NIVO/IPI in the CSF. CONCLUSION Repeated intracavitary or intrathecal administration of NIVO +/- IPI in rGB is feasible and safe. Favourable survival outcome is seen in patients amenable to surgical resection.