2015: A year of taking on disease — and winning

Eveline Gan (eveline [at] mediacorp.com.sg) looks at five medical game changers — from gene-editing to novel vaccines — that have opened up a new world of possibilities.
 

‘Cut and paste” gene-editing technology

Imagine a world where deadly diseases no longer kill and human embryos can be customised so that they result in perfect babies. That possibility may become a reality with CRISPR-Cas9, a new gene-editing technology heralded as the 2015 Breakthrough of the Year by Science magazine.

Developed based on how bacteria fend off viruses, CRISPR allows scientists to selectively trim off and replace DNA to recreate the desired outcome.

Associate Professor Toh Han Chong, deputy director of the National Cancer Centre Singapore (NCCS), said the novel biotechnology is “exciting and frightening at the same time”. In the area of cancer, for example, it can be used to study cancer biology in a more sophisticated way and potentially design even better treatments.

Already, the technology has sparked ethical concerns, with the first attempt at human embryo DNA manipulation. In April, Chinese researchers reportedly used CRISPR to modify genes responsible for the blood disorder beta-thalassemia on human embryos.

Harnessing the immune system to fight cancer

Researchers looking for a cure for cancer, which is currently the No 1 killer in Singapore, may be one step closer to their goal with a new class of cancer treatment known as immunotherapy.

In the process of destroying cancer cells, current conventional cancer treatments, such as chemotherapy, tend to also affect normal surrounding cells. Immunotherapy, however, harnesses the body’s own defence system to attack rogue cells.

For patients, especially those with advanced cancers, the new treatment heralds an exciting milestone.

“This year, immunotherapy using an antibody (anti-pd1) to activate T-cells to fight cancer saw another FDA (United States Food and Drug Administration) approval for the second line treatment of advanced lung cancer and also for the treatment of advanced kidney cancer.

Experts predict more approvals in other cancers in the near future,” said Assoc Prof Toh.

Earlier this year, the NCCS launched a first-in-human clinical trial of a novel cancer vaccine targeting top cancers in Singapore, adding to existing clinical trials exploring immunotherapy worldwide. Cancer vaccines stimulate the body’s immune cells to attack specific protein on cancer cells.

Packaged in the common cold virus, the cancer vaccine used in the NCCS trial encodes one of the most common proteins MUC-1 that is expressed on many cancers, including ovarian, breast, prostate, colon, pancreas and lung cancer, but not on normal cells. To date, 12 patients have been treated using the cancer vaccine with no significant side effects, said Assoc Prof Toh.

First vaccine against dengue

Despite the prevalence of dengue around the world, there has not been a tried-and-tested drug or vaccine for the mosquito-borne disease until this year. About 20 years in the making, the world’s first dengue vaccine was approved in the Philippines last week.

The dengue virus has four serotypes which theoretically means a person can get up to four episodes of infections, said Associate Professor David Lye, senior consultant at Tan Tock Seng Hospital’s Institute of Infectious Diseases and Epidemiology.

In children aged nine to 16 years, the new vaccine was found to reduce dengue from all four serotypes in two-thirds of the study participants, according to findings published in The New England Journal of Medicine on July 27. It also prevented eight out of 10 hospitalisations.

However, Assoc Prof Lye said adoption of the vaccine in Singapore requires further study given differences between the local population and the vaccine’s study population. More than 40,000 volunteers across 15 countries in Asia and Latin America participated in the clinical trial.

He explained: “In countries where the vaccine was tested, children are exposed to dengue very early in childhood. In Singapore, our children have less exposure to dengue and, as a result, many of our adults are still at risk of the infection. More importantly for dengue serotype 2, which is common in Singapore, the vaccine effectiveness was found to be around 30 to 40 per cent.”

Restoring fertility using frozen ovarian tissue cryopreservation

For the first time in Asia, a team from the National University Hospital (NUH) Women’s Centre and the National University Cancer Institute, Singapore helped a 32-year-old cancer survivor naturally conceive and deliver a baby using implanted ovarian tissue in May.

Diagnosed with a rare soft tissue cancer at the age of 26 in 2009, Mdm Siti Nurjannah’s (picture) success story offers hope to young women struggling with early loss of ovarian function, for instance, while undergoing cancer treatment.

Mdm Siti’s ovarian tissue was preserved using a method called ovarian tissue cryopreservation before she underwent chemotherapy. After recovering from her illness, the preserved tissue was re-implanted and she eventually had a healthy baby.

Worldwide, only 20 other babies have reportedly been conceived naturally and born following ovarian tissue cryopreservation.

Last year, a woman in her late 20s reportedly gave birth to a baby boy after Belgium doctors transplanted her ovarian tissue, which was removed and frozen at the age of 13 before she underwent chemotherapy.

The success case, published in a June 2015 report in Human Reproduction, marks the first in the world using ovarian tissue removed before puberty.

Telehealth set to change healthcare

As the population ages and the number of chronic illnesses rises, telehealth services are expected to pick up pace in the coming years.

Several hospitals and healthcare centres here have jumped on the tech bandwagon in recent years, making it possible for patients to be monitored by healthcare professionals without leaving their homes.

In January, a telehealth monitoring service at the National University Health System (NUHS) was officially launched for chronically ill patients with hypertension, heart failure and poorly controlled diabetes, allowing them to be monitored at home using a simple elder-friendly set-up.

Associate Professor James Yip, chief medical information officer at NUHS, shared that the service has helped pick up the diagnosis of new hypertension in 30 per cent of patients who have borderline blood pressures, and improved control blood pressure readings in 80 per cent of patients.

Patients who have been discharged with heart attacks, heart failure and poorly controlled diabetes have also benefitted from the system.

It captures changes in blood pressure, weight and sugar control, expediting care before their scheduled appointments.