Is HTA unfairly limiting access to treatments for rare disorders?

August 4th, 2015

What are the consequences for patients when methods for Health Technology Assessment (HTA) are too rigid?

Interesting new research suggests that the burden of proof required by Canada’s health technology assessment (HTA) process for new drugs is too rigid and unfairly excludes many treatments for rare disorders from public drug insurance coverage.

The study was authored by pharmacoepidemiologist Dr. Nigel Rawson, Ph.D. It was published at Canadian Health Policy the online journal of Canadian Health Policy Institute (CHPI).

Dr. Rawson argues that the evidence requirements to prove cost-effectiveness are unrealistic for drugs treating very small patient populations. Canada’s drug reimbursement process requires large randomized clinical trials to provide evidence for clinical efficacy and places less emphasis on studies using surrogate outcomes or based on observational data.

Randomized trials of drugs for rare disorders with sufficient statistical power over a reasonable period of time are difficult, if not impossible, to perform due to small numbers of potential participants. The result is that most drugs for rare disorders are rejected for public insurance coverage.

Dr. Rawson reviewed public reimbursement recommendations published between May 27, 2004 and March 31, 2015 by the Common Drug Review (CDR) of the Canadian Agency for Drugs and Health Technologies (CADTH). He found that the CDR’s negative recommendation rate was comparatively much higher for drugs that treat rare disorders than it was for other drugs. The data showed that 65.5 percent of drugs that treat rare disorders were given a negative recommendation by the CDR compared with 47.6 percent overall for all types of drugs.

The findings shed new light on what some have called the politicization of drug coverage decisions. The study notes that with the burden of proof being almost impossible to overcome, patients suffering from rare disorders are often left as a last resort to lobby governments to cover new drugs rejected by the HTA process. Dr. Rawson argues that “patient group advocacy is essential if sufferers of rare disorders, who for some diseases may number less than 100 spread across Canada and thus comprise only a small group of voters, are to stand any chance at influencing politicians and bureaucrats.”