Author(s): C. Butts, H. Anderson, A. Maksymiuk, D. Vergidis, D. Soulières, Y. Cormier, M. Davis, E. Marshall, M. Falk, G. Goss; Cross Cancer Institute, Edmonton, AB, Canada; Vancouver Island Cancer Centre, Victoria, BC, Canada; Cancer Care Manitoba, Winnipeg, MB, Canada; Northwestern Ontario Regional Cancer Centre, Thunder Bay , ON, Canada; CHUM, Montreal, QC, Canada; Université Laval, Quebec, QC, Canada; Nova Scotia Cancer Centre, Halifax, NS, Canada; Clatterbridge Centre for Oncology, Bebington, United Kingdom; Merck KGaA, Darmstadt, Germany; The Ottawa Hospital Cancer Centre, Ottawa, ON, Canada
Background: The BLP25 liposome vaccine (L-BLP25, Stimuvax) is an investigational innovative therapeutic cancer vaccine incorporating immunoadjuvant monophosphoryl lipid A and synthetic MUC1 lipopeptide in a liposomal delivery system. In an open-label phase IIb study in 171 pts with stage IIIB/IV NSCLC randomized to best supportive care (BSC) alone (n=83) or BSC + L-BLP25 (1000 µg lipopeptide) (n=88), L-BLP25 pts received weekly vaccinations for 8 weeks (wks) and could continue maintenance vaccinations every 6 wks from wk 13. Results were encouraging (Butts et al, JCO 2005) and a remarkable number of pts received prolonged treatment (tmt). As a result a global phase III study (START) has been initiated.
Methods: Safety results for 16 pts from the phase IIb study treated for ?2 years with L-BLP25 are reported.
Results: In these 16 pts (median age 57.5 years, ECOG PS: 0 in 5/16 [31%] and 1 in 11/16 [69%]), there were more females (56% vs 44% [9/16 vs 76/171]) and locoregional stage IIIB disease at entry (81% vs 38% [13/16 vs 65/171]) vs the phase IIb study population. Pts received L-BLP25 for 2.0-7.7 years and 10 pts were treated for >5 years. Compliance with tmt was good: almost all (96%) maintenance vaccinations were given every 6 wks according to the tmt schedule. L-BLP25 was well tolerated: the most common tmt-emergent adverse events (TEAEs) were cough (n=12, 75%), fatigue (n=12, 75%), and dyspnea (n=11, 69%). The pattern of TEAEs did not change significantly over time and there was no rise in the incidence of TEAEs with increasing time on tmt. Among the most common TEAEs in years 1, 2, and >2 were nausea (44, 19, and 38%), fatigue (56, 18, and 38%), chest pain (38, 31, and 31%), and cough (38, 25, and 31%). Twelve pts (75%) had tmt-related TEAEs (grade 1/2 in 11/12 pts [92%] and grade 3 in 1/12 [8%]): the most common were injection-site reactions. The occurrence of tmt-related TEAEs decreased with increasing tmt duration. There was no evidence of any TEAEs related to autoimmunity. Analysis of laboratory data did not indicate any long-term renal, liver, or other toxicity.
Conclusions: Long-term use of L-BLP25 was without any identifiable safety issues. In particular, there was no evidence of autoimmune reactions with prolonged use.