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&lt;p style="MARGIN-TOP: 18px; MARGIN-BOTTOM: 0px"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&lt;b&gt;Note 7. Convertible
Promissory Notes&lt;/b&gt;&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 6px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;On
January&amp;#xA0;23, 2013, Opexa closed a private offering consisting
of convertible notes (the &amp;#x201C;January 2013 Notes&amp;#x201D;) and
warrants to purchase shares of common stock for gross proceeds of
$650,000 of which $100,000 was from a related party (see Note 8).
The January 2013 Notes&amp;#xA0;are scheduled to mature on
January&amp;#xA0;23, 2014 and accrue interest at the rate of
12%&amp;#xA0;per annum, compounded annually. The January 2013 Notes are
convertible into common stock at the option of the investors at a
price of $1.30 per share, subject to certain limitations. The
principal balance plus accrued interest is payable within five
business days of the receipt by Opexa of an aggregate of at least
$7.5 million in proceeds from the sale of its equity securities
and/or as payments from one or more partners or potential partners
in return for granting a license, other rights, or an option to
license or otherwise acquire rights with respect to
Tcelna.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;The January
2013 Notes were analyzed at issuance for a beneficial conversion
feature and Opexa concluded that a beneficial conversion feature
exists. The beneficial conversion feature was measured using the
commitment-date stock price and was determined to be $141,829 of
which $21,820 was attributable to the related party. Opexa also
analyzed the Notes for derivative accounting consideration and
determined that derivative accounting does not apply.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;In connection
with the issuance of the January 2013 Notes, Opexa also issued
Series J warrants to purchase an aggregate of 243,750 shares of
Opexa&amp;#x2019;s common stock (see Note 11), subject to certain
limitations and adjustments.&amp;#xA0;The relative fair value of the
warrant liabilities of $195,969, together with the beneficial
conversion feature of $141,829 were recognized as a debt discount
and are amortized to interest expense in the consolidated
statements of expenses over the term of the January 2013 Notes
using the effective interest method.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;On
February&amp;#xA0;26, 2013, following the receipt of $3.25 million in
gross proceeds during February 2013 from the sale of common stock
and warrants to purchase shares of common stock, and following the
receipt of the upfront payment of $5 million from Merck on
February&amp;#xA0;20, 2013, Opexa paid principal and interest totaling
$567,368 to holders of the January 2013 Notes, of which $100,000
was to a related party, and issued 77,034 shares of common stock to
one holder of the January 2013 Notes who elected to convert the
principal of $100,000.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;During the
quarter ended March&amp;#xA0;31, 2013, the debt discount of $337,798 in
connection with the January 2013 Notes was fully amortized to
interest expense.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;In February
2013, three of the third party holders of the July 2012 Notes
elected to convert their principal amounts of $900,000 into shares
of the Company&amp;#x2019;s Series A convertible preferred stock with
further immediate conversion into 288,229 shares of the
Company&amp;#x2019;s common stock. As of March&amp;#xA0;31, 2013, an
aggregate of $3,185,000 in principal amount of the July 2012 Notes
to third parties and related parties is reported as long term
liabilities in the consolidated balance sheets, of which $630,000
was issued to related parties (see Note 8).&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; MARGIN-BOTTOM: 0px; FONT-SIZE: 1px"&gt;
&amp;#xA0;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 0px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;The following
table provides a summary of the changes in convertible
debt&amp;#x2014;third parties, net of unamortized discount, during the
quarter ended March 31, 2013:&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; FONT-SIZE: 12px"&gt;
&amp;#xA0;&lt;/p&gt;
&lt;table style="BORDER-COLLAPSE: collapse" border="0" cellspacing="0" cellpadding="0" width="68%" align="center"&gt;
&lt;tr&gt;
&lt;td width="85%"&gt;&lt;/td&gt;
&lt;td valign="bottom" width="7%"&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr bgcolor="#CCEEFF"&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Balance at
December&amp;#xA0;31, 2012&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;318,658&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;January 2013 Notes, face
value&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;550,000&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr bgcolor="#CCEEFF"&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Discount on beneficial
conversion feature of January 2013 Notes at issuance&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;(120,009&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;)&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Discount on fair value of
Series J warrant liability at issuance&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;(165,820&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;)&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr bgcolor="#CCEEFF"&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Repayment of
January&amp;#xA0;23, 2013 Notes&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;(450,000&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;)&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Conversion of
January&amp;#xA0;23, 2013 Notes into common stock&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;(100,000&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;)&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr bgcolor="#CCEEFF"&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Conversion of July&amp;#xA0;25,
2012 Notes into common stock&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;(900,000&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;)&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Amortization of debt
discount to interest expense through March&amp;#xA0;31, 2013&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;1,168,581&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr style="FONT-SIZE: 1px"&gt;
&lt;td valign="bottom"&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
&lt;td valign="bottom"&gt;
&lt;p style="BORDER-TOP: #000000 1px solid"&gt;&amp;#xA0;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;
&lt;p style="BORDER-TOP: #000000 1px solid"&gt;&amp;#xA0;&lt;/p&gt;
&lt;/td&gt;
&lt;td&gt;&amp;#xA0;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr bgcolor="#CCEEFF"&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Balance at March&amp;#xA0;31,
2013&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;301,410&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr style="FONT-SIZE: 1px"&gt;
&lt;td valign="bottom"&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
&lt;td valign="bottom"&gt;
&lt;p style="BORDER-TOP: #000000 3px double"&gt;&amp;#xA0;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;
&lt;p style="BORDER-TOP: #000000 3px double"&gt;&amp;#xA0;&lt;/p&gt;
&lt;/td&gt;
&lt;td&gt;&amp;#xA0;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell><Cell FlagID="0" ContextID="eol_PE10315---13S-1-0008_STD_366_20121231_0" UnitID=""><Id>2</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div&gt;
&lt;p style="MARGIN-TOP: 18px; MARGIN-BOTTOM: 0px"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&lt;b&gt;Note 6. Convertible
Promissory Notes&lt;/b&gt;&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 6px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;On
July&amp;#xA0;25, 2012, Opexa issued a total of $4,085,000 in principal
amount of secured convertible promissory notes
(&amp;#x201C;Notes&amp;#x201D;) to third parties and related parties
(collectively, the &amp;#x201C;Noteholders&amp;#x201D;), of which an
aggregate of $630,000 was issued to related parties (See Note
7).&amp;#xA0;The Notes mature on July&amp;#xA0;25, 2014 and accrue interest
at the rate of 12%&amp;#xA0;per annum, compounded annually. Interest is
payable semi-annually on June&amp;#xA0;30 and December&amp;#xA0;31 in
either cash or registered shares of common stock, at Opexa&amp;#x2019;s
election. The Notes are secured by substantially all of
Opexa&amp;#x2019;s assets and are convertible into a new class of
non-voting Series A convertible preferred stock. The Notes can be
converted into Series A convertible preferred stock at the option
of the investors at a price of $100.00 per share, subject to
certain limitations and adjustments. Additionally, Opexa can elect
to convert the Notes into Series A convertible preferred stock if
(i)&amp;#xA0;Opexa&amp;#x2019;s common stock closes at or above $10.00 per
share for 20 consecutive trading days or (ii)&amp;#xA0;Opexa achieves
certain additional funding milestones to continue its clinical
trial program. These milestones include (x)&amp;#xA0;executing a
strategic agreement with a partner or potential partner by which
Opexa will receive a minimum of $5 million to partially fund, or an
option to partner with Opexa for, its Phase II clinical trial for
Tcelna in patients with SPMS and (y)&amp;#xA0;receiving a minimum of
$25 million in additional capital (including the Note offering
proceeds) from any partner, potential partner or any other
source.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;The Series A
convertible preferred stock accrues dividends at the rate of
8%&amp;#xA0;per annum, which are cumulative and payable semi-annually
on June&amp;#xA0;30 and December&amp;#xA0;31 in either cash or registered
shares of common stock at Opexa&amp;#x2019;s election. The Series A
convertible preferred stock has a liquidation preference of $100.00
per share, entitling holders to payment from the assets of the
Company available for distribution to its shareholders before any
payment is made to the holders of the common stock. The Series A
convertible preferred stock participates in any dividends or other
distributions on shares of common stock (other than dividends
payable in shares of common stock) along with the common stock. As
a result of anti-dilution adjustments following the November 2012
sale of shares of Opexa&amp;#x2019;s common stock, the Series A
convertible preferred stock is convertible into shares of the
Company&amp;#x2019;s common stock at a price of $3.12 per share (the
floor price), subject to certain limitations and conditions, and up
to 1,308,236 shares of common stock were issuable if all 12%
convertible secured promissory notes issued in the July 2012
financing and outstanding at December&amp;#xA0;31, 2012 were converted
to Series A convertible preferred stock and such stock is then
converted into common stock. Additionally, Opexa can elect to
convert the Series A convertible preferred stock into common stock
if the Company&amp;#x2019;s common stock closes at or above $16.00 per
share for 20 consecutive trading days. As of December&amp;#xA0;31,
2012, no shares of Series A convertible preferred stock were
currently outstanding. Subsequent to December&amp;#xA0;31, 2012,
$900,000 in principal amount of the notes were converted into
shares of Series A convertible preferred stock and such shares were
then converted into common stock (see Note 14).&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;As part of the
security interest in all of the Company&amp;#x2019;s assets granted to
the Noteholders, $1.0 million of the proceeds is maintained in a
controlled account (see Note 2).&amp;#xA0;Subsequent to
December&amp;#xA0;31, 2012, the restricted cash was reduced to $500,000
(see Note 14). The Noteholders were granted certain registration
rights for the shares of underlying common stock.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;If the Company
does not make the required payments when due, either at maturity,
or at applicable installment payment dates, or if the Company
breaches other terms of the convertible secured notes or related
agreements, the Noteholders could elect to declare all amounts
outstanding, together with accrued and unpaid interest, to be
immediately due and payable. Even if the Company was able to prepay
the full amount in cash, any such repayment could leave the Company
with little or no working capital for its business. If the Company
is unable to repay those amounts, the Noteholders will have a first
claim on Opexa&amp;#x2019;s assets pledged under the convertible secured
notes. If the Noteholders should attempt to foreclose on the
collateral, it is unlikely that there would be any assets remaining
after repayment in full of such secured indebtedness. Any default
under the convertible secured notes and resulting foreclosure would
have a material adverse effect on Opexa&amp;#x2019;s financial condition
and the Company&amp;#x2019;s ability to continue its
operations.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;The Notes were
analyzed at issuance for a beneficial conversion feature and Opexa
concluded that a beneficial conversion feature exists. The
beneficial conversion feature was measured using the
commitment-date stock price and was determined to be $1,497,634, of
which $230,969 was attributable to related parties. This amount was
recorded as a debt discount and is amortized to interest expense in
the consolidated statements of expenses over the term of the Notes.
Opexa also analyzed the Notes for derivative accounting
consideration and determined that derivative accounting does not
apply.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;In connection
with the issuance of the Notes, Opexa also issued Series I warrants
to the Noteholders to initially purchase an aggregate of 957,422
shares of Opexa&amp;#x2019;s common stock at $5.00 per share, subject to
certain limitations and adjustments.&amp;#xA0;The warrants have a
five-year term and are exercisable six months from the date of
issuance, or January&amp;#xA0;25, 2013. As a result of anti-dilution
adjustments, the number of warrant shares for which the Series I
warrants are exercisable increased to an aggregate increase of
1,436,121 shares of Opexa&amp;#x2019;s common stock at an adjusted
exercise price of $2.56 per share, subject to further certain
limitations and adjustments. As a result, Opexa accounted for these
reset provisions in accordance with FASB ASC 815-40, which requires
Opexa to record the warrants as a derivative liability at the grant
date and to record changes in fair value relating to the warrants
at each subsequent balance sheet date (see Note 8).&amp;#xA0;Opexa can
redeem the warrants at $0.01 per share if its common stock closes
at or above $10.00 per share for 20 consecutive trading
days.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;The initial
fair value of the warrant liabilities of $2,314,635, together with
the beneficial conversion feature of $1,497,634 were recognized as
a debt discount and are amortized to interest expense in the
consolidated statements of expenses over the term of the Notes
using the effective interest method.&amp;#xA0;The amortized debt
discount for the year-ended December&amp;#xA0;31, 2012 was $104,032 and
Opexa recognized $552,978 as a derivative gain in the consolidated
statements of expenses due to the change in fair value of the
liability. The unamortized discount as of December&amp;#xA0;31, 2012
amounted to $3,708,237.&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 12px; MARGIN-BOTTOM: 0px; FONT-SIZE: 1px"&gt;
&amp;#xA0;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 0px; TEXT-INDENT: 4%; MARGIN-BOTTOM: 0px"&gt;
&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;The following
table provides a summary of the changes in convertible debt &amp;#x2013;
third parties, net of unamortized discount, during 2012:&lt;/font&gt;&lt;/p&gt;
&lt;p style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; FONT-SIZE: 12px"&gt;
&amp;#xA0;&lt;/p&gt;
&lt;table style="BORDER-COLLAPSE: collapse" border="0" cellspacing="0" cellpadding="0" width="68%" align="center"&gt;
&lt;tr&gt;
&lt;td width="84%"&gt;&lt;/td&gt;
&lt;td valign="bottom" width="9%"&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr bgcolor="#CCEEFF"&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Balance at
December&amp;#xA0;31, 2011&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#x2014;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;July&amp;#xA0;25, 2012 Notes,
face value&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;3,455,000&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr bgcolor="#CCEEFF"&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Discount on beneficial
conversion feature of Notes at issuance&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;(1,266,665&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;)&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Discount on fair value of
Series I warrant liability at issuance&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;(1,957,665&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;)&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr bgcolor="#CCEEFF"&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Amortization of debt
discount to interest expense through December&amp;#xA0;31,
2012&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;87,988&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr style="FONT-SIZE: 1px"&gt;
&lt;td valign="bottom"&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
&lt;td valign="bottom"&gt;
&lt;p style="BORDER-TOP: #000000 1px solid"&gt;&amp;#xA0;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;
&lt;p style="BORDER-TOP: #000000 1px solid"&gt;&amp;#xA0;&lt;/p&gt;
&lt;/td&gt;
&lt;td&gt;&amp;#xA0;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td valign="top"&gt;
&lt;p style="TEXT-INDENT: -1em; MARGIN-LEFT: 1em"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;Balance at
December&amp;#xA0;31, 2012&lt;/font&gt;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font size="1"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;$&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" align="right"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;318,658&lt;/font&gt;&lt;/td&gt;
&lt;td valign="bottom" nowrap="nowrap"&gt;&lt;font style="FONT-FAMILY: Times New Roman" size="2"&gt;&amp;#xA0;&amp;#xA0;&lt;/font&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr style="FONT-SIZE: 1px"&gt;
&lt;td valign="bottom"&gt;&lt;/td&gt;
&lt;td valign="bottom"&gt;&amp;#xA0;&amp;#xA0;&lt;/td&gt;
&lt;td valign="bottom"&gt;
&lt;p style="BORDER-TOP: #000000 3px double"&gt;&amp;#xA0;&lt;/p&gt;
&lt;/td&gt;
&lt;td valign="bottom"&gt;
&lt;p style="BORDER-TOP: #000000 3px double"&gt;&amp;#xA0;&lt;/p&gt;
&lt;/td&gt;
&lt;td&gt;&amp;#xA0;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>The entire disclosure for long-term debt.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef

 -Publisher SEC

 -Name Regulation S-X (SX)

 -Number 210

 -Section 02

 -Paragraph 22

 -Article 5



Reference 2: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 210

 -SubTopic 10

 -Section S99

 -Paragraph 1

 -Subparagraph (SX 210.5-02.22)

 -URI http://asc.fasb.org/extlink&amp;oid=6877327&amp;loc=d3e13212-122682



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