SAN DIEGO—Results of a pilot study suggest an experimental molecule can increase hemoglobin levels in patients with hematologic malignancies who are suffering from anemia.
The molecule, lexaptepid pegol (NOX-H94), is a pegylated L-stereoisomer RNA aptamer that binds and neutralizes hepcidin.
In this phase 2 study, 5 of 12 patients who received lexaptepid pegol experienced a hemoglobin increase of 1 g/dL or greater and qualified as responders.
Researchers presented these results at the AACR Annual Meeting 2014 as abstract 3847. The study was supported by NOXXON Pharma AG, the Berlin, Germany-based company developing lexaptepid pegol.
“Our concept is to treat anemia by inhibiting the activity of hepcidin,” said study investigator Kai Riecke, MD, of NOXXON Pharma.
“Hepcidin regulates iron in the blood. The problem is that, in quite a few tumors, hepcidin reduces iron in the circulation, and, over a long period of time, that leads to iron-restricted anemia.”
So Dr Riecke and his colleagues tested their antihepcidin molecule, lexaptepid pegol, in anemic cancer patients. The team enrolled patients with hemoglobin levels less than 10 g/dL who had been diagnosed with multiple myeloma, chronic lymphocytic leukemia, Hodgkin lymphoma, or non-Hodgkin lymphoma.
The patients had a median age of 64 years (range, 35-77). At baseline, the mean hemoglobin was 9.5 ± 0.2 g/dL, the mean serum ferritin was 1067 ± 297 μg/L, the mean serum iron was 34 ± 6 μg/dL, and the mean transferrin saturation was 16.7 ± 3.4%.
The patients received twice-weekly intravenous infusions of lexaptepid pegol for 4 weeks, and the researchers observed patients for 1 month after treatment. Patients were not allowed to receive erythropoiesis-stimulating agents or iron products during the study period.
The results showed increases in hemoglobin of 1 g/dL or greater, which qualified as a response, in 5 of the 12 patients (42%). Three patients achieved a response within 2 weeks of treatment initiation. All 5 patients maintained the increase in hemoglobin throughout the follow-up period.
There was no clear difference in response among the different malignancies, Dr Reike said. But he also noted that, as the study included a small number of patients, it wasn’t really possible for the researchers to make a fair comparison.
In addition to increasing hemoglobin levels, lexaptepid pegol decreased the mean serum ferritin from 1067 μg/L to 815 μg/L in the entire cohort of patients (P=0.014) and from 772 μg/L to 462 μg/L in responders (but this was not significant).
Reticulocyte hemoglobin increased from 22.7 pg to 24.9 pg (P=0.019) in responding patients, but there was no increase in non-responders. (Data for this measurement were only available for 3 of the responders—but all 7 of the non-responders—due to differences in measurement capabilities at the different research sites).
“During the treatment, we saw a very nice increase in reticulocyte hemoglobin, which shows, in these patients, the red blood cells were able to take up iron and build up more hemoglobin,” Dr Riecke said.
The researchers also observed an increase in the mean reticulocyte index in responding patients, from 0.9 to 1.2, although the increase was not significant.
“So this shows that, not only do you have an increase in hemoglobin within each reticulocyte, but you have an increase in the number of reticulocytes—something that we didn’t really expect in the beginning,” Dr Riecke said. “And this may be a sign that the efficacy of erythropoiesis is improved.”
Additionally, responding patients experienced a decrease in soluble transferrin receptor levels, from 10.0 mg/L to 8.6 mg/L, although this was not significant. Soluble transferrin receptor levels remained unchanged in non-responders. (Data for this measurement were only available for 3 of the responders and 4 of the non-responders.)
“The decrease in soluble transferrin receptor levels is a sign that, in the beginning, the cells were very iron-hungry, and then their hunger was satisfied—at least to a certain extent—during the treatment with our drug,” Dr Reike said. “This is a sign that, by reducing hepcidin, more iron is being released into the circulation, and this iron can effectively be used for erythropoiesis.”
Dr Reike added that, although the researchers did observe some adverse effects in the patients, none of these could be clearly attributed to lexaptepid pegol.
Some of the patients did have low blood pressure shortly after treatment, but that may have been influenced by factors other than treatment, he said. Furthermore, in the phase 1 study of lexaptepid pegol in healthy subjects, the only adverse effect that occurred in the treatment arm (and not in the placebo arm) was headache.
Based on these results, NOXXON is now planning—and recruiting for—a study of lexaptepid pegol in dialysis patients.
