Sibylle Loibl, MD, PhD
Nab-paclitaxel (Abraxane) provides more benefits than paclitaxel for certain subsets of patients with breast cancer, according to results of the GeparSEpto trial.
The study investigated whether weekly nab-paclitaxel could increase the proportion of patients achieving pathological complete response (PCR) compared with weekly solvent-based paclitaxel, both followed by epirubicin (Ellence) plus cyclophosphamide as neoadjuvant treatment.
“This could be demonstrated overall, but we were curious to see how that would play out in the subgroups of luminal patients, triple negative breast cancer patients, and HER2-positive with or without hormone receptor (HR) expression,” said Sibylle Loibl, MD, PhD.
In an interview with OncLive
, Loibl, co-chair of the German Breast Group (GBG) and associate professor at the University of Frankfurt, discusses the most recent subanalysis of the GeparSepto trial, potential combinations with nab-paclitaxel, and a separate set of data looking at patients with breast cancer who are also pregnant.
OncLive: Can you tell us a little about the subanalysis of the GeparSepto trial?
: The GeparSepto study was investigating if the exchange of nab-paclitaxel instead of paclitaxel followed in both arms by epirubicin would lead to an increased PCR rate. This could be demonstrated overall, but we were curious to see how that would play out in the subgroups of luminal patients, triple negative breast cancer patients, and HER2-positive with or without hormone receptor (HR) expression. The patients with HER2-positive disease received, in addition to the chemotherapy, pertuzumab (Perjeta) plus trastuzumab (Herceptin) from the very beginning for the whole 24 weeks and continued afterward with trastuzumab for up to 1 year.
We have seen that in the HER2-positive cohort, the PCR rate was much higher. We achieved a PCR rate of almost 75% in the HR-negative HER2-positive cohort. There was a difference in favor of nab-paclitaxel, but it was not statistically significant. In that group, the HER2 treatment is probably more important than the chemotherapy schedule. What we also found, and this has already ben seen in previous studies, is that the definition of the PCR is more important in the HER2-positive cohort than the triple negative cohort.
The second results were about the toxicity, because there have not been so many data in the neoadjuvant setting using the 2 antibodies. In fact, this is the largest cohort using the 2 antibodies in the neoadjuvant setting and using 24 chemotherapy regimen. In TRYPHAENA, the chemotherapy was 18 weeks. We found the PCR rates were comparable to that of the TRYPHAENA trial when pertuzumab was added to trastuzumab, and the toxicity was also comparable to that. Especially the rate of diarrhea is to be noted, so up to 10% of the patients had greater than grade 2 diarrhea, which seems to be noteworthy.
Are there any next steps or other analyses of this trial that are important?
We're currently conducting the rate of peripheral sensory neuropathy, and how that has evolved after patients have completed their treatment. We have seen a higher rate with peripheral sensory neuropathy with paclitaxel compared to nab-paclitaxel, but we can also see that the neuropathy is decreasing around 1 year after the treatment, and the rate then of grades 2 and higher is equivalent between paclitaxel and nab-paclitaxel. Grade 3 and 4 is a little more tricky because the neuropathy stays a little longer.