A 45-year-old woman presents with three months of symmetrical pain and stiffness in the small joints of her hands and wrists, worse in the morning for 90 minutes. Examination shows synovitis of MCP and PIP joints bilaterally. Rheumatoid factor and anti-CCP antibodies are positive, and hand X-rays show no erosions. According to Canadian rheumatology guidance, what is the most appropriate initial disease-modifying treatment strategy?