The market for pain therapies in seven leading markets will grow at an annual rate of 1.8% over the next 15 years, surpassing $49 billion by 2026, say new forecasts.

The loss of sales due to the generic entry of blockbuster pain therapies over the next several years will be offset by uptake of branded and emerging agents in current drug classes such as Johnson & Johnson(J&J)/Gruenenthal's Nucynta ER/Palexia SR (tapentadol extended-release), MAP Pharmaceuticals/Allergan's Levadex (orally-inhaled dihydroergotamine) and opioid reformulations, says the study, from Decision Resources.

Growth in these markets - France, Germany, Italy, Spain, UK and US - will be driven primarily by the launch of the first biologic pain therapies, Pfizer's tanezumab and J&J/Takeda's fulranumab, beginning in 2016, it adds.

Sales of these two anti-nerve growth factor (NGF) monoclonal antibodies (MAbs) will account for 19% of sales in the total pain market in 2026, approaching the market share of drug classes that currently earn the greatest share of the pain market - the opioid analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs), says the report. Despite safety concerns that will constrain the number of patients suffering from chronic pain who will receive anti-NGF MAbs, the impressive efficacy, premium pricing and large target populations - which includes severe osteoarthritis pain - will lead to these agents generating blockbuster sales surpassing $9 billion, it forecasts.

Decision Resources also anticipates that novel subtype-selective ion channel modulators will enter the pain market beginning in 2018 and account for nearly $1 billon in sales across the seven major markets by 2026.

"Thought leaders we interviewed are enthusiastic regarding the clinical potential of these agents, in particular those targeting Nav1.7 sodium channels," said commented Decision Resources analyst Alana Simorellis.

"Teva/Xenon Pharmaceuticals' XEN-402 - a topical Nav1.7 antagonist - is likely to achieve significant uptake in peripheral neuropathic pain patients as an adjunct therapy to currently-used oral medications such as antidepressants and antiepileptics, owing to a well-validated molecular target and minimal systemic exposure, which facilitates polypharmacy. Additionally, several other companies such as Pfizer and Convergence Pharmaceuticals are developing oral agents that selectively block promising ion channel targets, which we continue to follow with interest," she added.

The report also finds that opioid analgesics and NSAIDs will remain entrenched in the treatment algorithm for pain and will comprise at least 45% of total sales in the pain market over the next 15 years. The major-market class sales of opioid analgesics, NSAIDs, antiepileptics and local anaesthetics will remain stable over the forecast period, as emerging agents in these classes replace sales lost to the generic entry of current branded therapies, it adds.

- Meantime, Decision Resources also forecasts that sales of acute pain drugs in these seven major markets will reach $17.4 billion in 2021.

Similar to the chronic pain market, opioid analgesics and NSAIDs continue to hold leading market status in the acute pain space; in 2011, their combined sales made up well over half of the total major-market sales in acute pain, a trend that will continue through 2021, forecasts Andrea Buurma, an analyst with the firm.

Looking at variations in drug use across the seven markets, the study finds that the most significant difference between physician prescribing trends in the US compared with Europe and Japan is the more liberal use of strong opioid analgesics for the treatment of acute pain in the US. In contrast, European physicians are more likely to prescribe the dual-acting opioid analgesic tramadol to a greater percentage of their acute pain patients than their colleagues in the US and Japan, while Japanese physicians more frequently rely on NSAIDs and Pfizer/Astellas' COX-2 inhibitor Celebrex (celecoxib) to treat acute pain.