LOS ANGELES, Nov. 23, 2015 /PRNewswire/ — CytRx Corporation (NASDAQ: CYTR), a biopharmaceutical research and development company specializing in oncology, today announced that it has achieved its target enrollment of 28 patients with unresectable glioblastoma multiforme (GBM), a deadly form of brain cancer, in its Phase 2 trial with aldoxorubicin. To date, aldoxorubicin has shown evidence of tumor shrinkage, and overall survival has not yet been reached. Additionally, an advisory board of neuro-oncologists recently met to review the updated Phase 2 results and concluded that aldoxorubicin should be evaluated in combination with Avastin® in what could potentially be a pivotal trial in patients with late-stage GBM.
“The initial findings strongly indicate that aldoxorubicin has significant anti-tumor activity in patients with GBM,” said Morris D. Groves, M.D., Neuro-Oncologist, Texas Oncology-Austin Brain Tumor Center and co-principal investigator of the trial. “Pseudo-progression prevented us from determining the true efficacy of this agent since subjects may have been removed from aldoxorubicin treatment prematurely. Adding Avastin® to aldoxorubicin may increase the uptake of this drug into tumors leading to improved efficacy. ”
The open-label, multisite single-arm trial is investigating the preliminary efficacy and safety of aldoxorubicin in patients whose tumors have progressed following prior treatment with surgery, radiation and temozolomide. Patients to date received from 1 to 20 cycles of either 350 mg/m2 (260 mg/m2 doxorubicin equivalents) (n=6) or 250 mg/m2 (185 mg/m2 doxorubicin equivalents) (n=22) of aldoxorubicin intravenously on Day 1, and every 21 days thereafter until discontinuation. Median overall survival (range: 1 to 16+ months) has not yet been reached. Fifty-seven percent (16 of 28) of patients continue to be followed for survival with six patients still receiving aldoxorubicin treatment. Clear evidence of pseudo-progression was demonstrated in the tumor lesions of at least 4 subjects either after surgical debulking or by Dynamic Susceptibility Contrast MRI. Other subjects demonstrated extensive tumor necrosis on pathology with small amounts of residual tumor. Pseudo-progression refers to post-treatment imaging changes in the tumor where the tumor appears larger compared to the pre-treatment baseline images. These changes can be misleading in that the tumor appears to get worse (true progression), when in fact the changes may be the result of tumor destruction and related swelling around the tumor bed.
Aldoxorubicin was well tolerated at both dose levels, with all adverse events consistent with known doxorubicin toxicities. No subject has had a decrease in their cardiac function. At the 250 mg/m2 dose, the most common grade 3 or 4 adverse events included neutropenia, fatigue, thrombocytopenia and mucositis. All adverse events resolved prior to the subsequent dose of aldoxorubicin. Only four patients have had aldoxorubicin-related serious adverse events and all have been resolved successfully.
An Advisory Board of neuro-oncology experts recently reviewed the data from this trial. They concluded that aldoxorubicin clearly demonstrated anti-tumor activity with a favorable safety profile and that a randomized, comparative pivotal trial combining aldoxorubicin with Avastin® compared to Avastin® in patients who have relapsed after initial therapy was warranted.
“By adding Avastin® to a treatment regimen with aldoxorubicin, we may be able to improve upon the activity of the agents in these very needy patients,” said Daniel Levitt, M.D., Ph.D., CytRx Executive Vice President and Chief Medical Officer. “We plan to develop a protocol for a comparative potential pivotal trial based on the positive feedback from our advisors. We look forward to discussing the protocol with regulatory agencies, like the FDA, once we have the final data from the Phase 2 trial.”
This Phase 2 study follows positive confirmatory results reported in 2013 from a preclinical study in which aldoxorubicin demonstrated statistically significant efficacy (p<.0001) in the treatment of rapidly growing human brain (glioblastoma) cancer in the brains of animals. In that study, animals treated with aldoxorubicin had median survival of more than 63 days, compared with approximately 25 days for animals treated with doxorubicin or saline. In addition, because aldoxorubicin uptake was confined to the tumor in the brain rather than normal brain tissue, the principal investigator concluded that aldoxorubicin has the potential to safely shrink glioblastoma tumors, which could dramatically prolong patient survival.
About Glioblastoma Multiforme
Glioblastoma is the most common and most malignant primary brain tumor in adults and afflicts more than 12,000 new patients in the U.S. annually. The median survival after diagnosis is approximately 14 months, despite patients subsequently receiving surgical resection, radiotherapy and chemotherapy. Limited efficacy of chemotherapeutic agents has been attributed to several contributing factors including insufficient drug delivery to the tumor site through the blood-brain barrier.
The widely used chemotherapeutic agent doxorubicin is delivered systemically and is highly toxic, which limits its dose to a level below its maximum therapeutic benefit. Doxorubicin also is associated with many side effects, especially the potential for damage to heart muscle at cumulative doses greater than 450 mg/m2. Aldoxorubicin combines doxorubicin with a novel single-molecule linker that binds directly and specifically to circulating albumin, the most plentiful protein in the bloodstream. Protein-hungry tumors concentrate albumin, thus increasing the delivery of the linker molecule with the attached doxorubicin to tumor sites. In the acidic environment of the tumor, but not the neutral environment of healthy tissues, doxorubicin is released. This allows for greater doses (3 ½ to 4 times) of doxorubicin to be administered while reducing its toxic side effects. In studies thus far there has been no evidence of clinically significant effects of aldoxorubicin on heart muscle, even at cumulative doses of drug well in excess of 2,000 mg/m2.
About CytRx Corporation
CytRx Corporation is a biopharmaceutical research and development company specializing in oncology. CytRx currently is focused on the clinical development of aldoxorubicin (formerly known as INNO-206), its improved version of the widely used chemotherapeutic agent doxorubicin. CytRx is also seeking to expand its pipeline of oncology candidates at its laboratory facilities in Freiburg,Germany, through its LADR™ (Linker Activated Drug Release) technology platform, a discovery engine designed to leverage CytRx’s expertise in albumin biology and linker technology for the development of a new class of anti-cancer therapies.