1151P - Biochemical and radiological efficacy of systmic lanreotide therapy of patients with advanced, unresectable, non-metastatic paraganglioma/pheochromocytoma (PPGL) sporadic and hereditary

Background

Case series study of 17 pts. with unresectable, non-metastatic paraganglioma/ pheochromocytoma (PPGL) spontaneous or germline mutations treated with standard dose lanreotide Autogel every 4 weeks.

Methods

The primary endpoints: the tumor growth rate (TGR) based on RECIST 1.1, the second- biochemical response in secretory tumors by evaluation of fractionated metoxycatecholmin every 3m. Calculation of TGR and differences in secretion of metoxycaecholamin and response to lanreotide therapy based on PFS was performed with KM estimator.

Results

Mean age 45.3 +/-16.5, male/female ratio 5/12, sporadic/hereditary 4/13 subjects (PGL1=11, PGL3=1; PGL4=1). Before strat of lanreotide in secretory tumors metoxy 4.1xULN (IQR 2.9-11.8), during -increase to 14.6 (IQR 5.6-20.4) [p=0.02], in non-secretory initially 1.0 vs 1.1 during the therapy n.s. TGR per year evaluated in all subjects, as initial follow-up 0.08 (IQR 0.1-0.4) vs. time of lanreotide therapy 0.04 (IQR 0.01-0.1) (Wilcoxon p<0.001). The significant differences in initial TGR per year and during lanreotide therapy noted in secretory tumors TGR=0.3 (0.01-0.5) vs. 0.1 (0.04-0.12) [p=0.02]; hereditary tumors 0.08 (0.04-0.28) vs. 0.02 (0.01.06) p=0.02, in multpile lesions 0.15 (0.06-0.48) vs. 0.05 (0.02-0.012), also in female 0.15 (0.06-0.39) vs. 0.02 (0.01-0.1) [p=0.01]. PFS in all subjects 42.9 months (IQR 22.9-n.r.), there was significant difference in selected groups: sporadic vs. hereditary tumors PFS=31.0 months (13.5-45.5) vs. n.r. (23.3-n.r.) [T.Cox-Mantel p=0.04] and also secretory vs. non secretory PFS=24.3 months (16.3-32.3) vs. 59.0 (43.0-n.r.) [p=0.01].

Conclusions

Lanreotide autogel therapy is effcient in reducing TGR in all subjects. TGR reduction is seen in a group of secretory tumors, hereditary syndromes and also female and multiple lesions. Lanreotide did not block over-secretion of metoxycatecholamines in secretory tumours, most of the subjects developed metabolic further progression. There are differences in PFS comparing sporadic vs. hereditary and secretory vs non-secretory indicating different biology of these tumours.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.