Abstract 3481: Pharmacokinetics of alofanib and biomarker analysis in patients with advanced gastric cancer: A phase 1b study

• Published in: Cancer research (Chicago, Ill.) Ill.), 2022-06, Vol.82 (12_Supplement), p.3481-3481
• Main Authors: Raskin, Grigory, Kazey, Vasily, Gorbacheva, Svetlana, Nikiforova, Aiyyna, Statsenko, Galina, Artamonova, Elena, Vladimirova, Liubov, Besova, Natalia, Mochalova, Anastasia, Rykov, Ivan, Moiseyenko, Vladimir, Utyashev, Igor, Iugai, Sergei, Dragun, Nadezhda, Reznikov, Dmitry, Gavrilova, Evgenia, Tjulandin, Sergei, Tsimafeyeu, Ilya
• Format: Article
• Language: English
• ISSN: 1538-7445; 1538-7445
• DOI: 10.1158/1538-7445.AM2022-3481

Alofanib is a potent, small molecule, allosteric inhibitor that binds to the non-active extracellular site of IIIc and IIIb FGFR2 isoforms. Phase 1b clinical study (RPT835GC1B) met its primary endpoints and recommended phase 2 dose was described early. Here, we present pharmacokinetics (PK) and results of biomarker analysis. Alofanib was administered daily intravenously for 5-days followed by a 2-day interval (rest). There were five dose levels using a 3 + 3 design. 21 patients have been enrolled in the study. Patients were Caucasian (100%), predominantly male (71%), 67% had 2 and more metastatic sites, including liver (43%) and bone (14.3%) metastases, 19% had ECOG PS 2, and were heavily pretreated (86% had previous 3 and more lines of therapy). The PK and biomarker analysis set included 18 patients. FGFR2 amplification was accessed by FISH with ZytoLight SPEC FGFR2/CEN 10 Dual Color Probe and FGFR2 expression was accessed by IHC with antibody 1G3 (Abcam (ab 5820). Table summarizes PK data. The geometric mean values of Cmax, AUC0-t, T1/2, Vd increased and CL, Kel decreased approximately dose-proportionally after single dosing, similar to previous preclinical studies. The decrease in the mean value of the Vd for a dose of 350 mg/m2 may be associated with a significant increase in AUC0-t. No correlations between PK values and objective response rate (n=2; 9.5%), progression-free (median 3.63 months (95% CI, 1.58 - 5.68) and overall (median 7.0 months (3.82 - 10.18) survival as well as in patients with liver metastases were found (all P>0.1). A positive FGFR2 IHC expression was observed in all tumor cells and a weak positive reaction in normal epithelium. FGFR2 amplification was confirmed by FISH in 1 (5.6%) patient.Alofanib PK in a gastric patient population is well characterized, supporting the use of a once-daily 350 mg/m2 dose. In further studies, the evaluation of FGFR2 amplification seems to be important. Cohort 1 Cohort 2 Cohort 3 Cohort 4 Cohort 5 50 mg/m2 100 mg/m2 165 mg/m2 250 mg/m2 350 mg/m2 Cmax, mcg/ml (CV%) 21.4 (32.3) 23.7 (18.4) 44.7 (15.5) 72.8 (64.3) 145.9 (42.7) AUC0-t, mcg*h/ml (CV%) 2.3 (31.9) 6.6 (14.2) 13.3 (49.9) 23.8 (8.7) 74.0 (57.5) Vd, ml/m2 (CV%) 4006.1 (28.3) 4907.5 (14.7) 5676.8 (26.6) 6686.7 (11) 3823.0 (63.8) CL, ml/h/m2 (SD) 19609.5 (7740) 14028.2 (1990) 11910.5 (8740) 10011.0 (827) 4183.0 (2420) Kel, 1/h (CV%) 4.9 (15.3) 2.9 (2.8) 2.1 (41.2) 1.5 (3.8) 1.1 (47.0) T1/2, h (SD) 0.1 (0.024) 0.2 (0.01) 0.3 (0.118) 0.5 (0.0171)