Data from Monotherapy study
- Phase 1, first-in-human, dose-escalation, safety study. Between January 2016 and September 2017, we enrolled twenty-nine patients into six cohorts, or groups, in the dose-escalation phase of our Phase 1 trial. Twenty-four of the patients received at least two prior chemotherapy regimens. No drug-related serious adverse events occurred during the first four cohorts. In cohort five, serious adverse events (klebsiella sepsis with metabolic acidosis in one patient, renal and hepatic toxicity in one patient, and mesenteric vein thrombosis with metabolic acidosis in one patient) were observed in three of the ten patients, two of whom exhibited progressive disease at the end of their first cycle of treatment and were determined by the DSMB to be DLTs. Consistent with the study protocol, the DSMB recommended continuation of the study by expansion of cohort 4, one level below that at which DLTs were observed. Four patients were enrolled in this expansion cohort. One patient developed focal pancreatitis at the site of the primary tumor after 2.3 months, but SBP-101 was considered well tolerated below dose level five. The most common drug related adverse events were nausea, vomiting, diarrhea, injection site pain and abdominal pain, which were mostly mild, grades 1 or 2, and are symptoms common in patients with pancreatic cancer. No drug-related bone marrow toxicity or peripheral neuropathy was observed at any dose level.
- In addition to being evaluated for safety, 23 of the 29 patients were evaluable for preliminary signals of efficacy prior to or at the eight-week conclusion of their first cycle of treatment using the RECIST, the current standard for evaluating changes in the size of tumors. Eight of the 23 patients (35%) had SD and 15 of 24 (65%) had PD. It should be noted that of the 15 patients with PD, six came from cohorts one and two and are considered to have received less than potentially therapeutic doses of SBP-101. We also noted that 28 of the 29 patients had follow-up blood tests measuring the Tumor Marker CA 19-9 associated with pancreatic ductal adenocarcinoma. Eleven of these patients (39%) had reductions in the CA 19-9 levels, as measured at least once after the baseline assessment. Seven of the remaining 17 patients who showed no reduction in CA 19-9 came from cohorts one and two.
- By cohort, stable disease occurred in two patients in cohort 3, two patients in cohort 4 and four patients in cohort 5. The best response outcomes and best median survival were observed in the group of patients who received total cumulative doses of approximately 6 mg/kg (cohort three). Two of four patients (50%) showed SD at week eight. Median survival in this group was 5.9 months, with two patients surviving 8 and 10 months, respectively. By total cumulative dose received, five of twelve patients (42%) who received total cumulative doses between 2.5 mg/kg and 8.0 mg/kg had reductions in the CA19-9 levels, as measured at least once after the baseline assessment. Nine of these patients (67%) exceeded three months of OS, three patients (25%) exceeded nine months of OS and two patients (17%) exceeded one year of OS and were still alive at the end of the study.