British drugs giant AstraZeneca's risk profile is increasing as it invests in research and development (R&D), future growth and operational efficiency, even as patent expiries place pressure on its near-term sales and profits.Hence, ratings agency Fitch has downgraded its rating on the company's long-term debt by one notch, to A+, albeit with a 'stable' outlook.The firm is achieving progress in reviving the fortunes of its late stage pipeline but is nevertheless in a transitional period during which the volatility of its cash-flow will increase, the credit analysts wrote.The stable outlook reflects the likelihood that its improving pipeline will allow it to return to growth from 2017.Nevertheless, year-to-date the company has already spent about $5bn on acquisitions and further investment is expected to allow it to meet its 2023 revenue target of above $45bn.As well, "some of AstraZeneca's chosen areas of R&D are subject to growing competition, particularly in the field of oncology, respiratory and cardio-metabolism," the agency said in a statement.Shares of AstraZeneca ended the Friday session higher by 0.64% to 4,741p.