SecProbe.io

September 6, 2013

Via E -mail
Kim D. Blickenstaff
President and Chief Executive Officer
Tandem Diabetes Care, Inc.
11045 Roselle Street
San Diego, CA  92121

Re: Tandem Diabetes Care, Inc.
Draft Registration Statement on Form S-1
Submitted August 12, 2013
  CIK No. 1438133

Dear Mr. Blickenstaff :

We have reviewed your draft registration statement  and have the following comments.  In
some of our comments, we may ask you to provide us with information so we may better
understand your disclosure.

Please respond to this letter by providing the requested information and either submitting
an amended draft registration statement or  publicly  filing your registration statement on
EDGAR.  If you do not believe our comments apply to your facts and circumst ances or do not
believe an amendment is appropriate, please tell us why in your response.

After reviewing the information you provide in response to these  comments  and your
amended draft registration statement or filed registration statement,  we may have additional
comments.

Artwork

1. Please note that you may include text in your artwork only to the extent necessary to
explain briefly the visuals in the presentation.  Text such as “touch simplicity,”
“advanced technology,” and “ manufacturing excellence” does not appear necessary to
explain the visuals .  Additionally, it is unclear why the visuals and accompanying text in
the right column on the third page of your graphics is necessary.  Please revise
accordingly.

2. We note that the third page of the front graphics and on the back prospectus cover page
include products that you do not design, develop or sell or that are currently in
development.  Given the prominence of the artwork, it is inappropriate to include
products that you do not sell or  that are in development, have not been approved by

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 2

 regulatory agencies, and may never generate revenue in such a prominent manner. Please
revise.

Market and Industry Data and Forecasts, page ii

3. We note your statement that forecasts are “particularly li kely to be inaccurate.”  It is
unclear why you believe it is appropriate to include such information in a registration
statement.  Please remove this language disclaiming responsibility for your disclosure
and remove any forecast that is likely to be inacc urate.

Prospectus Summary, page 1

4. Please revise the italicized introductory paragraph to clarify that the Summary discusses
all material aspects of the offering.  Refer to Item 503(a) of Regulation S -K.

Overview, page 1

5. We note your disclosure highlig hting sales  in the year ended December 31, 2012 and six -
month period ended June 30, 2013 .  Please balance your disclosure by highlighting your
net losses in these periods.   Also disclose the accumulated deficit as of June 30, 2013.

6. In the first paragrap h, please revise to clarify what you mean by “Micro -Delivery
Technology .” In the fourth paragraph, please briefly explain the significance of your
pump being one of the first cleared under the FDA’s Infusion Pump Improvement
Initiative.  Finally, in the fi fth paragraph, please revise to disclose the basis for your
belief that you have an opportunity to “rapidly” increase sales.

7. We note your statement in the third paragraph here and in the third paragraph on page 2
regarding the size of the target market.  Please revise to identify the source of this data.

8. Please provide us support for your statement in the fifth paragraph that a significant
number of customers have converted from multiple daily injection to t:sli m for their
insulin therapy, and tell us, with a view toward disclosure, what percentage of your
customers converted.

The Market, page 2

9. We note the inclusion of third -party data in the prospectus, such as the market data from
The International Diabet es Federation, the National Diabetes Information Clearinghouse,
JDRF and others.  Please provide us with copies of the sources of this data, clearly
marking the relevant sections of the reports that support the data you have included in the
prospectus and the page number of your prospectus where such data has been used. Also
tell us whether the data was commissioned for use in connection with the registration
statement.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 3

 10. Please tell us how you calculated the 7% “annual increase in pump use” as disclosed on
page 2, including any assumptions used.  Also tell us whether the rate calculated takes
into account patients who return to insulin injections or otherwise stop using the pump.

Our Solution, page 3

11. We note your disclosure here and elsewhere concerning use of the “science of human
factors” to guide your product development process.  Please revise to explain how your
approach is “fundamentally different from the traditional medical device development
process.”

12. Please provide us objective, independent support for your statements here  and in  your
Business section regarding the superior or unique design and performance of your insulin
pump.  By means of nonexclusive example, we note  your statement s that t:slim is the
“slimmest and smallest durable  insulin pump on the market ” and that it is “capable of
delivering the smallest increment of insulin to users of any pump currently available.”

Implications of being an Emerging Growth Company, page 5

13. Please  supplementally provide us with copies of all written communications, as defined
in Rule 405 under the Securities Act, that you , or anyone authorized to do so on your
behalf , present to potential investors in reliance on Section 5(d) of the Securities Act,
whether or not they retain copies of the communications.   Similarly, please
supplementally provide us with any research reports about you that are published or
distributed in reliance upon Section 2(a)(3) of the Securities Act of 1933 added by
Section 105 (a) of the Jumpstart Our Business Startups Act by any broker or dealer that is
participating or will participate in your offering.

Risk Factors, page 10

14. We note your risk factor beginning on page 10 combining the risks relating to reliance on
a sole product and the risks relating to market acceptance of your product.  Please revise
to provide separate risk factor disclosure for each of these distinct risks .  Please also add
risk factor disclosure that discusses the risks relating to market adoption of your insulin
pump  as compared to traditional injection therapy , separate from a discussion of risks
relating to adoption of your pump technology compared with established pump
technology.  Also a dd appropriate risk factor disclosure of the risks associated with the
relatively short life span of the t:slim product, or tell us why you do not believe such
disclosure is required.

Our financial performance..., p age 32

15. With a view toward disclosure, please explain the basis for your belief that the t:slim
product is not subject to the 2.3% annual excise tax  on medical devices .

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 4

Use of Proceeds, page 41

16. Please refer to Regulation S -K, Item 504 and revise to dis close the approximate dollar
amount of proceeds intended for each stated purpose.

Capitalization, page 43

17. Please revise to  remove  cash and cash equivalents from the table on page 43 since this is
not a component of capitalization for purposes of this disclosure .

Management’s Discussion and Analysis, starting on page 48

Comparison of Six Months…, page 50

18. Please revise to disclose what portion of your revenues was derived from pump -related
supplies and accessories .  Please also disclos e whether your margins for pump -related
supplies an d accessories materially differ  from your t:slim margins.

Liquidity and Capital Resources, page 52

19. Please revise to disclose your estimated working capital needs and capital expenditures
over the next year and discuss plans to fund your liquidity requirements.

Contractual Obligations and Commitments, page 55

20. We note your disclosure prior to the table that s ubsequent to fiscal year end, you entered
into the term loan agreement with Capital Royalty Partners.  Please revise to quantify,
either with the statement prior to the table , by footnote to the table or otherwise, the
payments due to Capital Royalty Partn ers for the periods presented in the table.

Critical Accounting Policies and Management Estimates and Assumptions

Stock Based Compensation, pages 57 -61

21. We reference the discussion on pages 57 -60 of the use of third -party valuation specialists
for the valuation of capitalized intellectual property, common stock and option grants .
Please tell us the extent of the reliance that that  you placed on the work of  the third party
specialists . In that regard, please tell us how  you consid ered Qu estion 141.02 of  the
Comp liance and Dis closure Interpretations on  Securities Act Sections, whi ch can be
found at http://www.sec.gov/divisions/corpfin/guidance/sasinterp.htm.

22. Please tell us whether you have had any preliminary pricing discussions with your
underwriters.  If so, please tell us about the substance of those discussions and whether
they were considered in determining the estimated fair value of your common stock.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 5

23. After pricing information is available, please revise to provide a specific discussion of
each significant factor contributing to significant difference s between the estimated fair
value of your stock and the estimated IPO price (or pricing range) for the 12 months prior
to the IPO .  Please note that we are deferring final evaluation of share -based
compensation until the estimated offering price is specified, and we may have further
comments in that regard when you file an amendment containing that information.

24. Please explain how you determined the estimated fair value of $15 per share in January
2012 through July 2012.  We note that the convertible preferred stock issuances were at a
significantly lower price.  In addition, further clarify the reason that the estima ted fair
value per common share was lowered to $2.96 in March 2013. Please explain the specific
developments and circumstances that resulted in a significantly lower valuation.

25. Please disclose how you considered the convertible preferred stock issuances in fiscal
2012 and 2013 in the valuation of your common shares.  We note that the preferred
issuances were at $4.40 per share in fiscal 2012 and 2013 and that the estimated value of
common shares during this period from page 61 was significantly different. We also note
that preferred shares convert to an equal number of common shares.

Our Solution, page 67

26. In an appropriate section of your document, please balance your disclosure regarding the
advantages of your technology with any material challenges of the technology.  In this
regard, we note the disadvantages section of the table on page 64 is provided as
comparison between injections and pumps generally, and is not specific to your
technology compared with traditional injection therapy or other insulin pumps.

Sales and Marketing, page 75

27. We note your disclosure on page F -10 indicating that you have cus tomers that accounted
for greater than 10% of your revenues.  Please revise your disclosure to identify these
customers.  Refer to Regulation S -K, Item 101(c)(1)(vii).

Third -Party Reimbursement, page 77

28. We note your disclosure on page 77 indicating that your products are described by
existing codes for Medicare reimbursement and your disclosure on page 11 that many
third -party payors look to CMS coverage determinations when setting their own coverage
policies.  Accordingly, please expand your disclosure to address existing CMS
reimbursement coverage for insulin pumps and disposable cartridges and discuss any
trends related to CMS reimbursement policies.

29. We refer to your disclosure on page 4 concerning you r intent to add third -party payors
and your disclosure on page 12 indicating that traditional insulin pump suppliers enjoy

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 6

 competitive advantages because they have established relationships with healthcare
providers and third -party payors.  Accordingly, pl ease expand your discussion of third -
party reimbursement to compare the size of your third -party payor coverage relative to
that of your competitors’.  Also, we note that your disclosure on page 70 indicates that
there are “areas where you have concentrate d (y)our initial sales.”  Accordingly, please
expand your disclosure, as applicable, to identify geographic regions, market segments or
other areas where you have concentrated your initial sales efforts .

Research and Development, page 78

30. Please expand y our discussion of the agreements with DexCom and JDRF to describe
more fully the payment provisions of the agreement s.  For instance, describe and quantify
the milestone payments and clarify whether the license s provide  for royalty payments .  If
so, please  quantify.  Finally, please clarify the intellectual property status of any products
jointly developed with JDRF.

Clinical Advisory Board, page 79

31. Please expand your disclosure to clarify how members of the board are compensated.

Intellectual Property, page 79

32. We note your risk factor disclosure on page 25 indicating that two U.S. patents and
various other pending patents are particularly important to the pumping mechanism and
therefore the functionality of your products.  Please revise your d isclosure on page 79 to
specifically identify the particular patents and patents pending referenced in the risk
factor.

33. Please expand the third paragraph of this section to identify the entity or person with
whom you entered into the agreements mentione d here and specify the technology and
products to which these agreements relate. Also disclose the royalty rate for any
sublicenses that you may enter into that will be payable under the agreement, and clarify
whether you have entered into any sublicenses .

FDA’s Pre -Market Clearance and Approval Requirements, page 80

34. Please revise your disclosure in the second paragraph under this subheading to clarify the
classification of the t:slim  and t:connect products for which you received FDA clearance.
Further identify the classification of the t:flex device for which you plan to submit a
510(k) application and the joint t:slim/DexCom product for which you plan to submit a
PMA application, as  noted on page 81.

Kim D. Blickenstaff
Tandem Diabetes Care, Inc.
September 6, 2013
Page 7

Board of Directors, page 92

35. We note your risk factor disclosure on page 32 indicating that following the offering your
executive officers, directors and 5% holders may be able to determine the outcome of all
maters submitted to shareholders.  To the extent that you will satisfy the c riteria
necessary to elect treatment as a “controlled company” pursuant to NASDAQ listing
rules, please revise your disclosure to discuss how this exemption could impact your
corporate governance.

Market Comparisons, page 98

36. Please expand your disclosu re to identify the companies within the peer group you
reference.

Equity -Based Awards, page 99

37. Please expand your narrative disclosure to discuss any grants of awards to named
executive officers after December 31, 2012.

Description of Capital Stock, page 111

38. Your disclosure may not be qualified by reference to state law. Please revise accordingly.

Shares Eligible for Future Sale, page 118

39. Please quantify the number of shares outstanding after the completion of the offering that
will be subject to the lockup agreements and/or Rule 144 restrictions.

Financial Statements

40. Please update the financial statements when requ