We've added 45 OCE clients this year, bringing our total number of clients to 125.
Revenue for the third quarter came in at $2,786 million, which was $11 million above the high end of our guidance range.
Third quarter adjusted EBITDA was $604 million with a $22 million beat versus the high end of our guidance range.
Third quarter adjusted diluted earnings per share was $1.63 reflecting the EBITDA drop-through because the below the line items essentially netted out to zero.
Third quarter R&DS contracted backlog, including pass-throughs, grew 18.5% year-over-year to $21.7 billion as of September 30th, 2020.
The contracted net book-to-bill ratio, including pass-throughs, was 1.71 for the third quarter of 2020 and 1.42 excluding pass-throughs.
The LTM contracted book-to-bill ratio at September 30 was 1.55, including pass-throughs and 1.45, excluding pass-throughs.
Third quarter revenue of $2,786 million grew 0.6% reported and was flat at constant currency.
Revenue for the first nine months of the year was $8,061 million which was down 1.6% reported and 1.2% at constant currency.
Technology & Analytics Solutions revenue of $1,207 million grew 10.2% reported and 9.2% at constant currency.
Year-to-date Tech & Analytics Solutions revenue was $3,433 million, up 4.9% reported and 5.6% at constant currency.
In R&D Solutions third quarter revenue of $1,400 million was down 4.5% at actual FX rate and 5.1% at constant currency.
Excluding the impact of pass-throughs, R&D Solutions third quarter revenue grew 2.6%.
Year-to-date revenue of $4,076 million was down 5.6% at actual FX rate and 5.4% at constant currency.
Contract Sales & Medical Solutions revenue of $179 million was down 13.9% year-over-year reported and 14.4% on a constant currency basis in the third quarter.
Year-to-date revenue was $552 million, down 8.6% at actual FX rates and 8.3% at constant currency.
Now moving down to P&L, adjusted EBITDA was $604 million for the third quarter, which represented growth of 1.9%.
Year-to-date adjusted EBITDA was $1,649 million.
Third quarter GAAP net income was $101 million and GAAP diluted earnings per share was $0.52.
Year-to-date GAAP net income was $160 million and GAAP diluted earnings per share was $0.82.
Adjusted net income was $318 million for the quarter and $841 million year-to-date.
Our adjusted diluted earnings per share grew 1.9% in the third quarter to $1.63.
Year-to-date adjusted diluted earnings per share was $4.32.
Consequent on the robust booking activity that Ari talked about, our backlog grew 18.5% year-over-year to close at $21.7 billion and we expect $5.8 billion of this backlog to convert to revenue over the next 12 months, which is an increase of over $400 million versus where we were at June 30th.
At September 30th, cash and cash equivalents totaled $1.5 billion and debt was $12.3 billion, resulting in net debt of $10.9 billion.
Due to our strong EBITDA and cash flow in the quarter, our net leverage ratio at September 30th was 4.7 times trailing 12-month adjusted EBITDA, which was down a tad [Phonetic] from where we were at June 30th.
Cash flow from operations was $574 million in the third quarter, up 74% over last year.
Capital expenditures were $157 million and that resulted in free cash flow of $417 million.
For the first nine months of the year, free cash flow was $769 million, which is about double the same period last year.
Underlying demand is robust and cash flow is as well and we have a very solid liquidity position closing the quarter with an undrawn revolver of almost -- undrawn revolver and almost $1.5 billion of cash in the balance sheet.
And as a result of all this, we lifted our suspension on share repurchase program and we're expecting to opportunistically resume share repurchase activity.
And as a reminder, we currently have about $1 billion of share repurchase authorization remaining under the program.
We now expect 2020 revenue for the full year to be between $11,100 million and $11,250 million, which is an increase of $125 million over our prior guidance at the midpoint of the range.
For profit we now expect full-year adjusted EBITDA to be between $2,335 million and $2,360 million, which represents a $27 million increase over our prior guidance at the midpoint of the range.
And adjusted diluted EPS, we are expecting to be between $6.25 and $6.35, which is an increase of $0.10 over our prior guidance at the midpoint of the range.
This full-year guidance implies fourth quarter revenue of $3,040 million to $3,190 million, representing growth of 5% to 10.2%.
For fourth quarter profit, we expect adjusted EBITDA to be between $685 million and $710 million, representing growth of 6.7% to 10.6% and adjusted diluted earnings per share to be between $1.93 and $2.03, or growth of 10.9% to 16.7%.
For the full year 2021, we expect revenue in the range of $12,300 million to $12,600 million.
This represents growth of 10.1% to 12.8% versus the midpoint of our 2020 guide.
We expect adjusted EBITDA to be in the range of $2,725 million to $2,800 million, representing growth of 16.1% to 19.3% compared to the midpoint of our 2020 guidance.
And finally, we expect adjusted earnings per share to be in the range of $7.65 to $7.95, which would represent growth of 21.4% to 26.2% compared to the midpoint of our 2020 guidance.
The adjusted diluted earnings per share guidance assumes interest expense of approximately $420 million, operational depreciation and amortization of about $400 million and other below the line expense items such as minority interest of approximately $50 million and also the continuation of our share repurchase activity.

Summary:
Third quarter adjusted diluted earnings per share was $1.63 reflecting the EBITDA drop-through because the below the line items essentially netted out to zero.
Third quarter GAAP net income was $101 million and GAAP diluted earnings per share was $0.52.
Our adjusted diluted earnings per share grew 1.9% in the third quarter to $1.63.
And as a result of all this, we lifted our suspension on share repurchase program and we're expecting to opportunistically resume share repurchase activity.
We now expect 2020 revenue for the full year to be between $11,100 million and $11,250 million, which is an increase of $125 million over our prior guidance at the midpoint of the range.
And adjusted diluted EPS, we are expecting to be between $6.25 and $6.35, which is an increase of $0.10 over our prior guidance at the midpoint of the range.
For the full year 2021, we expect revenue in the range of $12,300 million to $12,600 million.
And finally, we expect adjusted earnings per share to be in the range of $7.65 to $7.95, which would represent growth of 21.4% to 26.2% compared to the midpoint of our 2020 guidance.