Metformin may help slow progression, reduce risk of certain cancers
NEW YORK — A medication commonly prescribed for patients with Type 2 diabetes also may play a critical role in patients at risk of developing certain cancers.
In three separate studies published in Cancer Prevention Research, a journal of the American Association for Cancer Research, findings showed how metformin may protect against oral cancer and liver cancer, as well as slow the growth rate of prostate cancer among men prior to prostatectomy.
In the oral cancer study, J. Silvio Gutkind, chief of the Oral and Pharyngeal Cancer Branch of the National Institute of Dental and Craniofacial Research at the National Institutes of Health, and colleagues found that administration of metformin reduced the size and number of carcinogen-induced oral tumoral lesions in mice and significantly reduced the development of squamous cell carcinomas by about 70% to 90%. "We saw strong activity against mTORC1 (mammalian target of rapamycin complex 1), which we know contributes to oral cancers, so this is strong preclinical information that there is a protective effect," Gutkind said.
In a study led by Geoffrey Girnun, an assistant professor in the department of biochemistry and molecular biology at the University of Maryland School of Medicine, found that after he and his colleagues chemically induced liver tumors in mice, the mice taking metformin displayed minimal tumor activity, while the control mice displayed significant tumor growth. Girnun’s team also showed that metformin prevented liver cancer in part by inhibiting lipid synthesis in the liver, a process known to promote cancer. Girnun currently is planning a clinical trial in patients at risk for liver cancer to determine if the chemopreventive qualities observed in mice are confirmed in humans.
"Since many of the effects of the drug take place in the liver, we were surprised when we reviewed the literature that there was no direct evidence for a protective effect of metformin in liver cancer except for a few retrospective epidemiological studies," Girnun said.
Meanwhile, in a mid-stage clinical trial conducted by Anthony Joshua, staff medical oncologist at the Princess Margaret Hospital of the University Health Network in Toronto, and colleagues evaluated 22 men with confirmed prostate cancer who had been assigned up to 500 mg of metformin three times a day prior to undergoing prostatectomy. Patients were assigned metformin for a median duration of 41 days. During that time, none of the men reported "grade-3 adverse events" and all of them underwent prostatectomy with no adverse effect related to use of metformin.
"Although these are preliminary results, metformin appeared to reduce the growth rate of prostate cancer in a proportion of men," Joshua said. "Also, it appeared to reduce one of the main growth pathways that may have contributed to the overall growth of the tumor … "This research builds on the hypothesis that metformin has a role in prostate cancer. Exactly what that role will be will depend on the results of the analysis currently being completed by our study team and others worldwide."
For more information on these studies, visit AACR.org.
Astellas, Vical finalize design for phase-3 cytomegalovirus vaccine trial
SAN DIEGO — Two drug makers have finalized the design of a late-stage clinical trial for a vaccine against a common virus that can cause complications later in life.
Vical and Astellas Pharma announced Monday that they had finalized the general design of a phase-3 trial of TransVax, a vaccine against cytomegalovirus, or CMV, for transplant recipients.
A herpes virus related to the viruses that cause diseases ranging from mononucleosis to chickenpox, CMV infects more than half of all U.S. adults by 40 years old and is more widespread in developing countries. A healthy immune system can protect against the virus, but rarely eliminates the infection, and people with compromised immune systems are at high risk of serious complications. The virus affects 30% to 60% of patients undergoing transplant procedures and can cause transplant rejection, serious illness or death if untreated.
Vical and Astellas will begin recruiting patients who have received hematopoietic stem cell transplants in the second half of this year and will start a phase-2 trial of patients who have received solid organ transplants soon after. Under the two companies’ collaboration, Astellas will make a $10 million milestone payment to Vical.
Super PBM merger approved; NACDS, NCPA file emergency motion to block merger
WASHINGTON — The controversial merger between Express Scripts and Medco was completed Monday morning, according to a press release issued by both Express Scripts and the Federal Trade Commission. However, the merger already is being challenged — the National Association of Chain Drug Stores, the National Community Pharmacists Association and nine retail pharmacies filed a complaint against the proposed merger last week, and on Friday filed an emergency motion to temporarily restrain the consummation of the merger until the outcome of the NACDS/NCPA suit has been determined.
Express Scripts and Medco were issued summonses regarding the NACDS/NCPA case on Monday morning, according to court documents. As many as five state attorneys general have pledged to file similar lawsuits challenging the proposed merger should the FTC not do so, according to several reports.
There also is dissension among the commissioners of the FTC. The FTC’s vote on the motion to close the investigation was 3-1, with commissioner Julie Brill dissenting and issuing a separate statement. Commissioners Thomas Rosch and Edith Ramirez and chairman Jon Leibowitz issued a closing statement on behalf of the commission. The vote on the motion to issue the Statement of the Commission was 3-0-1, with commissioner Brill abstaining.
In its statement, the FTC majority explained that the commission’s investigation "revealed a competitive market for PBM services characterized by numerous, vigorous competitors who are expanding and winning business from traditional market leaders. The acquisition of Medco by Express Scripts will likely not change these dynamics: the merging parties are not particularly close competitors, the market today is not conducive to coordinated interaction and there is little risk of the merged company exercising monopsony power. Under these circumstances, we lack a reason to believe that a violation of Section 7 of the Clayton Act has occurred or is likely to occur by means of Express Scripts’ acquisition of Medco."
"This $29 billion merger — between two of the largest three pharmacy benefit management providers — is a game changer," countered Brill in a separate statement. "I have reason to believe that this merger is, in fact, a merger to duopoly with few efficiencies in a market with high entry barriers — something no court has ever approved. I therefore respectfully submit that the commission should have filed a complaint in federal district court seeking to enjoin the transaction pending a full trial on the merits here at the commission. … Under any definition of the market, this merger will create a highly concentrated market that should be presumed to be likely to enhance market power."