Table 2.

Characteristics of studies comparing biological agents with alternative interventions

Study	Participants	Intervention	Control treatment	Length of follow-up	Outcomes
Biological agents vs. epidural steroid injection
Becker et al. [19] Germany, RCT	84 patients with nerve root pain confirmed by imaging for at least 6 weeks; Mean age 54 years; 62 % men	Epidural injection of autologous conditioned serum (Group 1)	Epidural injection of steroid triamcinolone 5 mg or 10 mg + local anaesthetic 1 ml (Groups 2 and 3)	22 weeks	Overall pain intensity (VAS)a; Oswestry Disability Index, adverse effects [Results from groups 2 & 3 combined for the forest plot]
Cohen et al. [26] USA, Germany, RCT	84 patients with nerve root pain confirmed by imaging; mean duration 2.7 months; mean age 42 years; 70 % men	Transforaminal epidural injection etanercept 4 mg	Transforaminal epidural injection of steroid methyl prednisolone 60 mg + local anaesthetic 0.5 ml	6 months (large proportion left study after 1 month)b	Global perceived effect; back and leg pain intensity (NRS); Oswestry Disability Index; reduction in analgesic consumption
Biological agents vs. intravenous steroid
Genevay et al. [29] Switzerland, HCS	20 patients with nerve root pain confirmed by imaging; mean duration 3.2 weeks; Mean age 47 years; 50 % men	Subcutaneous injection of etanercept 25 mg (anti-TNF alpha) ×3	Intravenous injection of methylprednisolone 250 mg ×3	6 weeks	Numbers with a good clinical result (leg pain VAS < 30 or Oswestry Disability Index < 20); back and leg pain intensity (VAS); Oswestry Disability Index; Roland-Morris Questionnaire; number of discectomies

HCS historical cohort study, RCT randomised controlled trial, TNF tumour necrosis factor, VAS visual analogue scale

^aResults extracted from graphs

^bAfter 1 month participants who received no benefit exited the study to pursue other treatments