Chief Financial Officer at Biogen
Thank you, Priya, and good morning, everyone. I will provide some highlights of our financial performance for the second quarter and update to our full year 2022 guidance. Please note that all financial comparisons are versus the second quarter of 2021 unless otherwise noted. Total revenue for the second quarter was $2.6 billion, which was a decrease of 7% at actual currency and 5% at constant currency. Non-GAAP diluted earnings per share in the second quarter was $5.25, a decrease of 6%.
Total MS revenue inclusive of OCREVUS royalties was $1.7 billion, a decrease of 4% at actual currency and 3% at constant currency. Global TECFIDERA revenue of $398 million decreased 18% at actual currency and 17% at constant currency. TECFIDERA revenue in the US increased versus the prior quarter. However, this was primarily due to channel dynamics and we do expect TECFIDERA in the US to decline throughout the year of 2022. Outside the US, TECFIDERA was modestly impacted by generic competition in markets such as Canada and Germany. At this point, we are aware of several generic applications that have approved in Europe, and we will be monitoring the situation closely.
Importantly, we were pleased to be granted a new patent in the EU and reserve all rights to assert the patent against infringing but it's possible that it may still be at risk. Global VUMERITY revenue of $137 million increased 51% at actual currency and 52% at constant currency. VUMERITY continued to grow in the US. We are pleased with the trajectory. Outside the US, VUMERITY is now launched in 14 markets. We are currently working with our contract manufacturing suppliers to address potential supply constraints and have therefore delayed any additional country launches. Global TYSABRI revenue of $516 million decreased 2% at actual currency and was flat at constant currency.
In the United States, TYSABRI revenue was negatively impacted by modest volume declines, partially offset by favorable pricing. Outside the US, we were pleased to see continued patient growth. We are aware that regulatory filings for a biosimilar referencing TYSABRI have been submitted to both the FDA and the EMA. We will continue to enforce our IP, but a biosimilar could launch upon approval in the US and EU, which could occur next year. Global Interferon revenue of $350 million was decreased 13% at actual currency and 11% at constant and was impacted by the continued shift from the injectable platform to oral or high efficacy therapies.
Versus the prior quarter, Interferon revenue increased 13% at actual currency and 14% at constant currency, primarily due to seasonality in channel dynamics in the US. Moving to SMA. Global SPINRAZA revenue of $431 million, declined 14% at actual currency and 11% at constant currency. In the US, we're encouraged to see fewer SPINRAZA discontinuations during the quarter. Outside the US, the revenue decline was primarily driven by competition and with the timing of shipments in certain markets, pricing dynamics and negative currency impacts. Global SPINRAZA revenue decreased 9% versus the first quarter of 2022 at actual currency and 8% at constant currency, driven by competition and negative currency impacts outside the US as well as some seasonality dynamics in the US.
Moving to our biosimilars business. Revenue of $194 million declined 4% at actual currency, increased 3% at constant currency. Biosimilars volume increases were more than offset by negative currency impact and pricing pressure. We continue to expect full year biosimilars revenue to decrease versus 2021. We are pleased to have launched BYOOVIZ this quarter in the US, and we recorded some modest initial revenue due to channel stocking.
As a reminder, we expect a gradual launch of BYOOVIZ with more meaningful revenue contribution starting in 2023. Total anti-CD20 revenue of $436 million decreased 1%. Revenue from OCREVUS royalties increased 14%, which was more than offset by continued RITUXAN declines due to biosimilar competition. Now moving on to expenses and the balance sheet. Second quarter non-GAAP R&D expense was $529 million, including $18 million in upfront payments related to operations with MedRhythms and Alectos Therapeutics. This is compared to $585 million in the second quarter of 2021, which included approximately $50 million in upfront payments.
Non-GAAP SG&A was $570 million, including approximately $29 million related to ADUHELM. This is compared to $635 million in the second quarter of 2021. Second quarter collaboration profit sharing was a net expense of $29 million, which includes $58 million of profit sharing expense related to the collaboration with Samsung Bioepis, partially offset by reimbursement of $29 million from Eisai related to commercialization of ADUHELM in the US. Non-GAAP other expense was $79 million, primarily driven by interest expense. GAAP other income was $429 million, which included two items of note.
First, we recorded an approximately $1.5 billion gain on the sale of our equity stake in the Samsung Bioepis joint venture. In addition, we recorded $900 million, plus estimated fees and expenses, related to an agreement in principle to resolve a previously disclosed qui tam litigation relating to conduct prior to 2015. This agreement in principle does not include any admission of liability and is subject to the negotiation of final settlement agreements and documents. We expect to make the payment shortly after the agreements are finalized, which we expect to be as soon as possible and within the next 12 months.
In the second quarter, we generated $737 million in cash flow from operations. Capital expenditures were $37 million. Free cash flow was $700 million. We repurchased 2.4 million shares of the company's common stock during the quarter for $500 million. As of June 30, we ended the quarter with $7.3 billion in debt, $5.9 billion in cash and marketable securities and $1.4 billion in net debt. In July, we repaid our senior notes due September 2022, with an aggregate principal amount of $1 billion.
Of note, as of June 30, we utilized approximately $71 million of work in-process inventory related to lecanemab. We plan to continue building inventory over the coming months and we are also procuring raw materials associated with this production. If the lecanemab Phase 3 study is negative or lecanemab does not receive regulatory approval, we would expect to expense inventory on hand at that time as research and development expense subject to cost sharing with Eisai. Overall, we remain in a very strong financial position with significant cash and financial capacity, including a $1 billion undrawn revolving credit facility to invest in growing the business over the long term.
Let me now turn to our updated full year 2022 guidance. We are increasing our full year revenue guidance from our previous range of $9.7 billion to $10 billion to a range of $9.9 billion to $10.1 billion and increasing our full year non-GAAP diluted EPS guidance from our previous range of $14.25 to $16 to a new range of $15.25 to $16.75. This guidance increase is primarily a result of better-than-expected topline performance and continued cost management.
This guidance assumes that foreign exchange rates, as of July 15, will remain in effect for the remainder of the year, net of hedging activities. Importantly, we are raising our revenue and EPS guidance ranges despite some meaningful currency headwinds which were not included in our guidance at the beginning of the year. Specifically, subsequent to issuing our most recent guidance on May 3, we have experienced a headwind of approximately $55 million to revenue and $0.20 to EPS due to currency fluctuations from April 29 through July 15. This is in addition to a headwind of approximately $120 million to revenue and $0.35 to EPS due to currency fluctuations between January 1 and April 29.
These currency headwinds are primarily due to strengthening of the US dollar relative to other currencies in which we transact. This financial guidance assumes continued declines in RITUXAN revenue due to biosimilar competition as well as continued erosion of TECFIDERA revenue in the US due to generic entry. Further, this guidance reflects a range of scenarios for the impact of TECFIDERA generics in the EU, which is difficult to predict. We are aware of a small number of generics that have launched to date, and we are monitoring the situation. We assume we will utilize a portion of the remaining share repurchase authorization of $2.3 billion throughout the remainder of the year.
Please see our press release for important guidance assumptions. In summary, we continue to execute well across our core business and are pleased to be raising our financial guidance for the year. We remain focused on delivering results and are optimistic about the potential opportunities ahead of us that we believe can create long-term value for shareholders. We will now open the call for questions.