HEALTH-CUBA: New Hope in Fight against Cancer

By Patricia Grogg Reprint | | Print |

Patricia Grogg

HAVANA, Mar 11 2002 (IPS) - Researchers at Cuba’s Centre for Molecular Immunology (CIM) are hard at work on two vaccines and a new drug treatment for cancer, the second cause of death in this Caribbean island nation after heart disease.

The CIM, created in 1991, is the newest in the cluster of government institutes on the west side of Havana involved in cutting-edge medical and biotech research and development.

With the new drug and two new vaccines that “we are currently testing, we aim to make a contribution to the arsenal of treatments already available to fight cancer,” said CIM director of research Rolando Pérez. The project is a joint undertaking between the Cuban government and a Canadian venture capital firm.

Between 13,000 and 15,000 people die of cancer and some 25,000 new cases are registered every year in Cuba, a country of 11 million.

The monoclonal antibody hR3, used in treating skin tumours, is undergoing clinical trials in patients with advanced tumours of the head and neck. Injected into the patient, the antibody is capable of recognising and blocking the Epidermal Growth Factor (EGF) receptor, a protein found in skin tumour cells, said Pérez.

The drug, which is administered intravenously, is used in combination with chemo- or radio-therapy. Trials are currently being carried out in 24 patients in Cuba and 16 in Canada.

Pilot clinical trials began in 1999, and six of the 12 initial patients showed marked improvement, while in two of the other patients, the tumours shrank in size, thus enabling doctors to remove them.

“Normally, radio-therapy has a hard time making tumours disappear in patients with large tumours, but we have observed the contrary with this treatment,” said Marta Osorio, head of experimental chemotherapy at the National Institute of Oncology.

Cuba has already patented the drug in the United States and several European countries, and CIM researchers believe it will be the first of its kind produced by Cuba’s biotech industry.

“There is no registered drug in the world today based on this treatment concept, although a few similar drugs are being researched,” Pérez told the local newspaper Juventud Rebelde.

The CIM is seeking provisional registration in Cuba with the State Centre for the Quality Control of Medicines, which would give the researchers “greater flexibility” in testing the drug, and allow them to expand the trials to other hospitals that offer chemo- and radio-therapy.

“When good results are obtained, provisional registration is sought, and can be granted on condition that the rest of the steps are completed,” Normando Iznaga, CIM head of business affairs and development, told IPS.

The last of the three phases entailed in the clinical trials must be carried out on a broad group of patients, and is the decisive test for obtaining a patent from Cuba’s regulatory agency, before the product can be marketed.

Two vaccines designed to keep cancer from spreading have also shown encouraging results – the EGF vaccine for use against lung cancer, and a vaccine based on ganglioside molecules, for use in cases of melanoma.

But unlike the hR3 antibody, in the case of the vaccines it is not yet possible to speak of effectiveness, said the sources, who explained that not until next year would the researchers be able to apply for the provisional registration that would allow the vaccines to continue moving forward in clinical trials.

The EGF vaccine, which does not prevent cancer but is designed to keep existing tumours from spreading, works by provoking the immune system into making antibodies against EGF, which is a naturally occurring protein that plays an important role in childhood development but apparently has no raison d’etre in adults besides nourishing tumours.

Most lung cancer cells have abundant EGF receptors to which the EGF binds, causing lung cancer cells to multiply.

The question was how to find a way to get the immune system to fight a substance normally found in the body.

The researchers found a way to bind EGF with a bacterial protein, which triggers an immune response to both, thus reducing the concentration of EGF and stopping cancer growth.

Pilot trials being carried out in Cuba, Canada and Britain have demonstrated that the vaccine is safe and has a low level of toxicity, and many of the patients have showed a considerable immune response.

The second vaccine, being tested on advanced breast tumours and melanomas, has also shown positive results, demonstrating that it is immunogenic and tolerated well by patients.

To create the vaccine, ganglioside molecules were extracted from tumourous cells and inserted into the protein complex of the external membrane of the Nisseria meningitis bacteria, which forms the basis for the Cuban vaccine against meningitis B, known as Vamengoc-BC.

“We created something similar to a bacteria, but with tumourous elements, and it has turned out to be quite immunogenic,” said CIM research director Pérez.

Since it was founded in 1991, the CIM has developed 16 different products, including medicine that prevents the rejection of transplant organs.

“We believe we are going to grow quite a bit over the next five years, although we could grow faster” if the four-decades- old U.S. economic embargo against Cuba did not exist, Iznaga, CIM director of business affairs and development, told IPS.

In Iznaga’s view, “transnational corporations do not dare do business with Cuba due to the origin of the product,” no matter how good the drug in question is. Most laboratories are keen to break into the U.S. market for cancer medicine, which accounts for 40 to 50 percent of global business in that field.

So far, only the Vamengoc-BC vaccine against meningitis B, developed by Cuba’s Carlos J. Finlay Institute, has gotten around the embargo.

The first clinical trials that will open the doors of the industrialised world to Cuba’s anti-meningitis vaccine will began a few months from now in Belgium, thanks to a joint marketing agreement signed with the British-U.S. company SmithKline Beecham.