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                        CONFIDENTIAL TREATMENT REQUESTED

                           DARK FIBER LEASE AGREEMENT

         THIS DARK FIBER LEASE AGREEMENT (the "AGREEMENT") is made and entered
into as of this 21st day of November, 2001 (the "EFFECTIVE DATE"), by and
between QWEST COMMUNICATIONS CORPORATION, a Delaware corporation ("QWEST"), and
COGENT COMMUNICATIONS, INC., a Delaware corporation ("LESSEE").

                                    RECITALS:

         A. Qwest through ownership or other arrangement possesses the right to
use and operate a fiber optic telecommunications network between various points
in the United States (the "QWEST SYSTEM" or "QWEST NETWORK").

         B. Lessee desires to be granted a lease in certain optical fibers in
particular segments of the Qwest System (the "SEGMENT"), which Segments will
consist of both Lessee Fibers in Rings or Building Laterals (defined below) and
are more particularly described on EXHIBIT A, and Qwest desires to grant Lessee
a lease in such Lessee Fibers in the Segments, upon the terms and conditions set
forth in this Agreement.

         NOW THEREFORE, in consideration of the mutual promises set forth below,
and other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereby agree as follows:

I.       DEFINITIONS

The following capitalized terms shall have the following meanings when used in
this Agreement, unless explicitly stated to the contrary:

         "ACCEPTANCE" or "ACCEPTED" means the Delivery by Qwest and acceptance
by Lessee of a Ring or Building Lateral, as set forth in Section 5.

         "ACCEPTANCE DATE" means the date on which a Ring or Building Lateral is
Accepted pursuant to Section 5.

         "ACCEPTANCE PERIOD" is defined in Section 5.5.

         "AFFILIATE" means any person, which directly or indirectly controls or
is controlled by, or is under common control with a party to this Agreement.

         "ALLOCABLE SHARES" means, for purposes of apportioning responsibility
for costs, the ratio of the number of Lessee Fibers in a relevant Segment to the
total number of Fibers in the same Segment. For example, if Lessee's interest in
the relevant Segment is

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two (2) strands of fiber and there are a total of one hundred (100) strands of
fiber in the relevant Segment, Lessee's Allocable Share is two (2) of one
hundred (100) or two percent (2%).

         "ASSOCIATED PROPERTY" means tangible and intangible property needed for
the use of Lessee's Fibers in a Segment, including but not limited to: (i) the
associated conduit; (ii) Qwest's interests in the Underlying Rights; and (iii)
access to Connecting Points. Associated Property excludes electronic or optronic
equipment.

         "BUILDING LATERAL" means a Segment of Fiber from a building to a Ring
on the Qwest Network.

         "BUILDING LATERAL FEE" is defined in Section 4.2.

         "CONNECTING POINTS" means the mutually agreed upon splice points in
Qwest manholes, handholes, or fiber distribution panels which can be used to
access Lessee's Fibers in the Qwest Network.

         "COSTS" means all actual, direct costs paid or payable in accordance
with the established accounting procedures generally used by Qwest and which it
utilizes in billing third parties for reimbursable projects which costs shall
include the following: (i) internal labor, including wages and salaries, and
benefits, and overhead allocable to such labor costs, and (ii) other direct
costs and out-of-pocket expenses on a pass-through basis (e.g., equipment,
materials, supplies, contract services, etc.).

         "CROSS-CONNECT PANEL" means the piece of equipment designated by Qwest
in a Qwest POP at which Lessee's Fibers are terminated and at which location
Lessee may have access to and interconnect with Lessee's Fibers through use of
Local Distribution Facilities or other facilities acceptable to Qwest.

         "DELIVER" or "DELIVERY" of a Ring or Building Lateral means that the
applicable Lessee Fibers are available for use at the applicable Qwest
demarcation point.

         "DELIVERY DATE" is the date that Qwest Delivers the Lessee Fibers to
Lessee.

         "DISCLOSING PARTY" is defined in Section 17.1 herein.

         "EFFECTIVE DATE" is defined in the first paragraph of this Agreement.

         "EXPECTED DELIVERY DATE" is the date that Qwest expects to Deliver the
Lessee Fibers to Lessee pursuant to an Order.

         "FIBER(S)" means the Qwest strands of optical fiber in the Qwest
System.

         "IMPOSITIONS" means all taxes, fees, levies, imposts, duties, charges,
contributions or withholdings of any nature (including, without limitation,
gross receipts taxes and franchise, license and permit fees), together with any
penalties, fines, or interest thereon arising out of the transactions
contemplated by this Agreement and/or imposed upon

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either party hereto by any federal, state or local government or other public
taxing authority of any country.

         "INSOLVENT" means the occurrence of any of the following events,
whereby either party (i) becomes or is declared insolvent or bankrupt; (ii) is
the subject of any judicial proceedings related to its liquidation, insolvency
or for the appointment of a receiver or similar officer for it; (iii) makes an
assignment for the benefit of all or substantially all of its creditors; or (iv)
enters into an agreement for the composition, extension, or readjustment of all
or substantially all of its obligations.

         "LEASE FEE" is defined in Section 4.1.

         "LESSEE FIBER(S)" means the Fiber in a Segment leased by Qwest to
Lessee for the Lessee Fiber Term, in accordance with this Agreement.

         "LESSEE FIBER TERM" shall mean either a Lessee Ring Fiber Term or a
Lessee Building Lateral Fiber Term.

         "LESSEE RING FIBER TERM" is defined in Section 3.2.

         "LESSEE BUILDING LATERAL FIBER TERM" is defined in Section 3.3.

         "LOCAL DISTRIBUTION FACILITIES" means those telecommunications
transmission facilities that interconnect with the applicable Lessee Fibers at a
Cross-Connect Panel and extend each Segment of the applicable Lessee Fiber to a
location outside of the Qwest POP.

         "ORDER" means an order mutually agreed to between the Parties as set
forth in Section 5 pursuant to which Lessee will lease a Ring or Building
Lateral and/or Qwest will perform construction or splicing work.

         "ORDER DATE" means the date on which Qwest receives an Order under the
procedures established pursuant to Section 5.

         "PLANNED SYSTEM WORK PERIOD" or "PSWP" means a prearranged period of
time reserved for performing certain work on the Qwest Network that may
potentially impact traffic. Generally, this will be restricted to weekends,
avoiding the first and last weekend of each month and high-traffic weekends. The
PSWP shall be agreed upon pursuant to EXHIBIT B.

         "POP" means the Qwest terminal facility (point of presence) where the
Lessee Fibers are delivered to Lessee.

         "PROPRIETARY INFORMATION" is defined in Section 17.1 herein.

         "QWEST NETWORK" or "QWEST SYSTEM" means the fiber optic
telecommunications network operated by Qwest in the United States, including at
the election of Qwest such telecommunications capacity as Qwest may obtain from
another network provider and

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integrate into its own network for purposes of providing services or leased
fibers to Qwest's lessees. Although Qwest possesses telecommunications network
facilities and capacity in locations other than the United States, such network
facilities and capacity are not part of the Qwest Network for purposes of this
Agreement.

         "RECIPIENT PARTY" is defined in Section 17.1 herein.

         "REGULATIONS" are defined in Section 20.1 herein.

         "RENEWAL RESPONSE" is defined in Section 3.4 herein.

         "RENEWAL TERM" is defined in Section 3.4 herein.

         "REQUEST" shall mean a written request by Lessee to Qwest to lease a
Ring or Building Lateral or for Qwest to perform either construction or splicing
work for Lessee.

         "RING" means a continuous loop of local network backbone Fiber in the
Qwest Network.

         "ROUTE MILES" means the length of a Ring, as reasonably determined by
Qwest.

         "SEGMENT" means particular Rings and/or Building Laterals of the Qwest
System leased by Lessee.

         "TERM" is defined in Section 3.1 herein.

         "UNDERLYING RIGHTS" means certain rights of way, licenses,
authorizations, easements, leases, fee interests, franchises and other
agreements necessary for construction and operation of the Qwest Network in
accordance with this Agreement. Underlying Rights shall expressly include, but
not be limited to, Qwest's lease rights in a building location, any applicable
rules to a building, and Qwest's private right of way from the manhole to the
building point of entry at each location.

         "UNDERLYING RIGHTS REQUIREMENTS" means the requirements, restrictions,
and/or limitations on the Fibers listed by Lessee, and safety, operational and
other rules and regulations imposed in connection with the Underlying Rights.

2.       LEASE

         2.1 Subject to the terms and conditions set forth in this Agreement and
upon Qwest's acceptance of an Order, Qwest hereby leases to Lessee, and Lessee
hereby agrees to lease from Qwest the Rings and Building Laterals set forth in
the applicable Order. Qwest further grants, and Lessee accepts, subject to the
terms and conditions in this Agreement, the nonexclusive right of use of any
necessary Associated Property.

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3.       TERM OF AGREEMENT; TERM, RENEWAL AND TERMINATION OF LESSEE FIBER.

         3.1 The term of this Agreement for lease (the "TERM") shall begin on
the Effective Date and shall terminate upon the expiration of the final Lessee
Fiber Term for Lessee Fibers leased under this Agreement.

         3.2 The term of any given Lessee Fibers in a Ring shall begin on the
Acceptance Date for such Ring and shall terminate of the last day of the Two
Hundred and Fortieth (240th) calendar month following such Acceptance Date
(each a "LESSEE RING FIBER TERM").

         3.3 The term of any given Lessee Fibers in a Building Lateral shall
begin on the Acceptance Date for such Building Lateral and shall terminate of
the last day of the Sixtieth (60th) calendar month following such Acceptance
Date (each a "LESSEE BUILDING LATERAL FIBER TERM").

         3.4 Lessee may notify Qwest of Lessee's desire to renew Lessee's
lease to any Ring leased hereunder upon no less than six (6) months notice
before the expiration of the existing Lessee Ring Fiber Term. Within sixty
(60) days of Qwest's receipt of such notification, Qwest shall notify Lessee
whether Qwest, in its reasonable discretion, has approved such request for
renewal and, if applicable, the new term (the "RENEWAL TERM") and the
applicable Lease Fee for such renewal ("RENEWAL RESPONSE"). If Qwest does not
respond to Lessee within sixty (60) days of Qwest's receipt of Lessee's
notification, then the request shall be deemed rejected. Lessee shall notify
Qwest within sixty (60) days of Lessee's receipt of the Renewal Response
whether Lessee desires to renew the applicable Ring subject to the terms in
the Renewal Response. Pricing for Rings during a Renewal Term shall be [*].
The Renewal Response shall take precedence over any additional or different
terms incorporated in Lessee's response to which notice of objection is
hereby given. If Lessee accepts the Renewal Response, then the Lessee Ring
Fiber Term and Lessee Fiber for such Ring shall be amended to incorporate the
terms of such Renewal Response.

         3.5 Lessee shall be granted two (2) sixty (60) month renewals to the
initial Lessee Building Lateral Fiber Term for each Building Lateral (each a
"RENEWAL TERM") upon receipt by Qwest of written notice from Lessee
requesting one or both renewals. Lessee shall provide Qwest with written
notice of Lessee's desire to renew Lessee's lease to any Building Lateral
leased hereunder no less than six (6) months before the expiration of the
existing initial Lessee Fiber Term or the Renewal Term, if applicable. At the
expiration of the second Renewal Term, Lessee may notify Qwest of Lessee's
desire to renew Lessee's lease to the Building Lateral for an additional
sixty (60) month term upon no less than six (6) months notice before the
expiration of the existing Renewal Term. Within sixty (60) days of Qwest's
receipt of such notification, Qwest shall notify Lessee whether Lessee will
be granted the additional Renewal Term. Qwest can either (a) approve Lessee's
request for the additional Renewal Term at no additional cost to Lessee; or
(b) decline to grant the additional Renewal Term to Lessee. If Qwest declines
to grant the additional Renewal Term to Lessee, the lease for the applicable
Building Lateral shall terminate at the expiration of the second Renewal
Term. Upon such termination, Qwest shall use reasonable endeavors to
facilitate Lessee's direct contractual relationship with the owner of the
building location of the Building Lateral and shall use reasonable endeavors
to transfer title of such Building Lateral to Lessee. Lessee shall not have
any rights to perform maintenance of the Building Lateral unless mutually
agreed between the Parties.

         3.6 At the expiration or termination of any applicable Product Order,
the lease of the applicable Lessee Fibers shall immediately terminate unless
renewed pursuant to

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the process set forth in Section 3.4 or 3.5. above, and all rights of Lessee to
use the applicable Associated Property, or any part thereof, shall cease.

         3.7 Lessee may terminate its lease of a Ring after the Acceptance Date
by providing Qwest prior written notice. The termination of the applicable lease
shall be effective upon Lessee's Acceptance of Ring(s) with an equal or greater
Lease Fee than the terminated Ring. Lessee shall be obligated to pay the
terminated Lease Fee until the Acceptance by Lessee of the replacement Ring(s).
Lessee can terminate a lease to a Building Lateral by providing Qwest with
written notice. The termination of Lessee's lease to the applicable Building
Lateral shall be effective sixty (60) days from the date that Qwest received
Lessee written notice of termination. Qwest shall not have any obligation to
refund any of the applicable Building Lateral Fee to Lessee.

4.       CONSIDERATION FOR LESSEE FIBERS

         4.1 In consideration of the lease of each Ring hereunder, Lessee shall
pay to Qwest the stated monthly fee as set forth in EXHIBIT E (Pricing) for such
Ring (the "LEASE FEE") for the term of Lessee Ring Fiber Term for such Ring. The
Lease Fee shall be exclusive of maintenance costs for the Rings. Lessee shall
commence making such payments with respect to each Ring upon the first business
day of the first calendar month commencing [*]. The first Lease Fee payment
shall include payment from the Acceptance Date to the last day of the month
during which the Acceptance Date occurs, as well as payment for the first full
month after the Acceptance Date. The Lease Fee for any partial month shall be
prorated based on the number of days in that month. For the term of each Ring,
Lessee shall also pay to Qwest an annual operation and maintenance charge,
payable monthly, calculated at the rate of [*], which will begin to be applied
to each Ring leased herein on the Acceptance Date thereof, and shall continue
for the Lessee Ring Fiber Term associated with the Ring. The operations and
maintenance fee shall also be prorated based on the number of days in any
partial month.

         4.2 In consideration of the lease of each Building Lateral hereunder,
Lessee shall pay to Qwest [*] (the "BUILDING LATERAL FEE"). For those Building
Laterals not already identified on EXHIBIT A or added to EXHIBIT A subsequent to
the execution of this Agreement, the parties shall determine whether a Building
Lateral [*] in their commercially reasonable judgment. The Building Lateral Fee
shall be exclusive of all maintenance costs for the Building Lateral. Payment of
such Building Lateral Fee will allow Lessee to use of [*] Lessee Fibers in such
Building Lateral. Lessee shall remit payment of [*] of the Building Lateral Fee
to Qwest concurrent with placing the Order for such Building Lateral. Lessee
shall pay Qwest the balance of the Building Lateral Fee no later than
[*]calendar days after Lessee Accepts the Building Lateral for the term of each
Building Lateral. Lessee shall also pay to Qwest an annual operation and
maintenance charge, payable yearly, calculated at the rate of [*] to a connected
Building Lateral, which will begin to be applied to each Building Lateral leased
herein on the Acceptance Date. Lessee shall pay the annual operation and
maintenance charge concurrent with the [*] balance payment upon Acceptance of
the Building Lateral and on each anniversary of the Acceptance Date throughout
the Lessee Building Lateral Fiber Term.

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         4.3 If Lessee fails to make any payment under this Agreement within
five (5) business days of when due, such amount shall accrue interest from the
date such payment is due until paid at a rate of [*] per annum or the maximum
rate provided by law, whichever is less.

         4.4 The Parties agree that in order to receive the pricing set forth in
EXHIBIT E, Lessee must place Orders for [*] Fiber Miles of Ring [*] months of
the Effective Date, and place Orders for [*] Fiber Miles [*] months of the
Effective Date. Qwest shall use commercially reasonable efforts to notify Lessee
if Lessee has not placed Orders for enough Rings in sufficient time to meet the
required minimums. Qwest's failure to notify Lessee shall not be deemed a breach
of this Agreement and shall not effect Lessee's obligation to pay the minimum
Lease Fee as set forth herein. If Lessee fails to place Orders for the minimum
Fiber Mile requirement, then Qwest shall invoice Lessee for the deficiency in
the Fiber Mile requirement at a rate of [*] per month times the number of Fiber
Miles for which Lessee should have placed Orders to meet its minimum
requirements. As Lessee Accepts additional Fiber Miles, Qwest shall reduce the
[*] per month per Fiber Mile charge on a mile for mile basis until Lessee has
met its Fiber Mile minimum requirement. (By way of example, if Lessee has a
deficiency of 50 Fiber Miles and later Accepts an additional 25 Fiber Miles,
Qwest shall reduce the deficiency charge by 25 Fiber Miles)

5.       ORDERS, DELIVERY AND ACCEPTANCE TESTING

         5.1 The initial Rings and Building Laterals available for lease by
Lessee, subject to Qwest's acceptance of such request, shall be set forth on
EXHIBIT A, which may be amended from time to time by Qwest to add (but not to
subtract) Rings or Building Laterals. The list of Rings and Building Laterals
that Lessee has leased from Qwest are set forth in EXHIBITS A1 and A2,
respectively, which exhibits may be amended from time to time to reflect the
actual Rings and Building Laterals so leased. The Parties acknowledge and agree
that any Building Laterals ordered pursuant to this Agreement must connect to a
Qwest Ring. Lessee will, from time to time, request to lease a Segment pursuant
to the terms and conditions herein by providing Qwest with one or more written
Request. Each such Request shall indicate Lessee's proposed Segments, the number
of fibers, and the Qwest metropolitan market(s). Qwest shall respond to Lessee
in writing within fifteen (15) business days of receiving such Request by either
accepting or rejecting such Request in its commercially reasonable judgment. Any
acceptance of a Request by Qwest shall include any specific conditions that may
effect or impact Lessee's use of the Ordered Segment in a material way and the
Expected Delivery Date. If Qwest does not respond to a Request within fifteen
(15) business days, then the Request shall be deemed rejected. Lessee shall
respond to Qwest's response within fifteen (15) business days of receiving such
response. Lessee shall have the option of continuing with the Request subject to
the additional terms stated by Qwest or canceling the Request. [*] The Parties
shall have the right but not the obligation to negotiate the terms of any
Request. Once the Parties have mutually agreed upon the terms of a Request, then
Lessee shall submit a written Order in a form reasonably requested by Qwest. The
Order Date shall be the date on which Qwest receives the written Order.

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         5.2 Qwest shall use commercially reasonable efforts to Deliver any
Segment to Lessee by the estimated Delivery Date mutually agreed to by the
Parties in the Order ("EXPECTED DELIVERY DATE"). If a Ring is not Delivered to
Lessee within [*] days after the Expected Delivery Date, then Lessee may either
terminate the Order for the applicable Ring or the Parties may negotiate a
revised Expected Delivery Date. If a Ring is not Delivered to Lessee within [*]
days after the Expected Delivery Date, then either Party may terminate the
Product Order with no further obligations under the applicable Product Order. If
either Party terminates an Order for a Ring pursuant to this Section, [*]. If a
Building Lateral is not Delivered to Lessee within [*] days after the Expected
Delivery Date, then Qwest shall pro rate the monthly Lease Fee for the Ring on
which the applicable Building Lateral will connect equal to [*] of the Lease Fee
for each day that Qwest is late in delivering the Building Lateral past the
Expected Delivery Date plus [*] days. If a Building Lateral is not Delivered to
Lessee within [*] days after the Expected Delivery Date, then Lessee may either
revise the Expected Delivery Date subject to Qwest's approval or terminate the
Order. In the event that Lessee terminates the Order for a Building Lateral
pursuant to this Section, [*]. The pro rating of the monthly Lease Fee shall
cease upon Qwest's Delivery of the Building Lateral to Lessee.

         5.3 Upon Delivery, the Lessee Fibers shall comply with the technical
specifications set forth in EXHIBIT B hereto. Qwest shall test each Segment in
accordance with the procedures specified in EXHIBIT B to verify that it is
operating in accordance with the technical specifications in EXHIBIT B. Qwest
shall provide Lessee with reasonable advance notice of the date and time of each
applicable acceptance test so that Lessee shall have the right, but not the
obligation, to have a person or persons present to observe the tests. Upon
Lessee's request, Qwest shall promptly provide Lessee with a copy of the test
results.

         5.4 In the event the results of any applicable acceptance test show
that the Lessee Fibers are not operating in accordance with the applicable
technical specifications in EXHIBIT B, Qwest shall promptly take action that is
commercially reasonable to bring the Segment of the Lessee Fibers that is not
operating within the applicable technical specifications into compliance with
such standards. In no event shall the unavailability, incompatibility, delay in
installation, or other impairment of any of Lessee's interconnection facilities
including Lessee's suppliers (E.G., a local access telephone service provider)
be used as a basis for rejecting any portion of the Fibers granted hereunder.

         5.5 Qwest will notify Lessee in writing when any applicable Segment of
the Lessee Fibers has met the technical specifications in EXHIBIT B. Within
twenty (20) days of receipt of such notice ("ACCEPTANCE PERIOD"), Lessee shall
sign and deliver an Acceptance letter to Qwest acknowledging the Delivery of
each Segment of Lessee Fibers in the System Route. By signing the Acceptance
letter, Lessee acknowledges that each Segment of Lessee Fiber listed in the
Acceptance letter complies with the applicable technical specifications. The
date of such signing shall become the Acceptance Date. If Lessee determines that
any Segment of Lessee Fiber does not comply with the technical specifications,
it shall notify Qwest in writing within the Acceptance Period. Such notice shall
specify in detail how the applicable Segment of Lessee Fiber does not conform.
If

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Lessee fails to provide such notice within the Acceptance Period, or if the
notice does not provide reasonable specificity, Lessee is deemed to have
Accepted the applicable leased Fiber Segments on the expiration of the
Acceptance Period, which shall then become the Acceptance Date. [*].

         5.6 If Lessee requests Fibers in a Building Lateral identified on
EXHIBIT A, and such requested Fibers are not available due to unavailability of
Fibers in such Building Lateral, Lessee may submit a Request that Qwest pull an
additional fiber bundle through the existing conduit, or to use another of
Qwest's building conduits, if available ("WORK REQUEST"). The Parties will
follow the Request and Order process set forth above in Section 5.1. If Qwest
accepts the Work Request, then the Parties shall negotiate in good faith the
terms and conditions for such work and any credits for Lessee for the sale or
lease of Fibers from the fiber bundle so installed that are not taken by Lessee.
Qwest shall not be under any obligation to perform such construction work for
Lessee unless set forth in a written Order.

         5.7 Lessee shall at all times be entitled to install fiber optic cable
to any buildings not set forth on EXHIBIT A at its own cost and expense,
provided that Lessee shall comply with applicable standards and parameters set
forth in this Agreement. Lessee may submit a Request that Qwest provide
Connecting Points to such laterals in accordance with EXHIBIT C hereto. The
Parties will follow the Request and Order process set forth above in Section
5.1. If Qwest accepts an Order under this Section, then Qwest shall use
commercially reasonable efforts to provide access to Connecting Points subject
to the terms and conditions set forth in EXHIBIT C hereto. Qwest shall not be
under any obligation to provide Connecting Points unless set forth in a written
Order.

6.       OPERATIONS AND MAINTENANCE

         6.1 The lease of the Lessee Fibers does not provide Lessee with the
right to physically access, encumber or to use the Qwest Network except as
expressly set forth herein. The Lessee Fibers are subject to and provisioned in
accordance with the technical specifications in Sections 1-3 of EXHIBIT B
hereto, which may be modified from time to time subject to the standards and
practices of the industry. Qwest shall provide Lessee with annual notice of any
changes to the technical specifications set forth in EXHIBIT B, but in no event
shall Qwest's failure to provide such notice be deemed an Event of Default.

         6.2 Qwest will use commercially reasonable efforts to operate and
maintain the Lessee Fibers in accordance with the operations and maintenance
specifications and procedures in Section 4 of EXHIBIT B hereto. However, the
operations and maintenance requirements herein do not ensure that the Lessee
Fibers will perform in accordance with the technical specifications in EXHIBIT B
following the Effective Date.

         6.3 This Agreement does not obligate Qwest to supply to Lessee any
optical or electrical equipment, or other facilities, including without
limitation, generators, batteries, air conditioners, fire protection equipment,
monitoring equipment and testing

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equipment, all of which are the sole responsibility of Lessee. Qwest is not
responsible for performing any work other than as specifically set forth in this
Agreement.

7.       PERMITS; UNDERLYING RIGHTS; RELOCATION

         7.1 Qwest has obtained, or will obtain prior to the relevant Effective
Date, the Underlying Rights, at Qwest's sole cost and expense, for the
construction, operation and maintenance of the Lessee Fibers. The lease of the
Fibers is subject and subordinate to the terms of the Underlying Rights,
including, but not limited to, covenants, conditions, restrictions, easements,
reversionary interests, bonds, mortgages and indentures, and other matters,
whether or not of record, and to the rights of tenants and licensees in
possession. The lease of the Fibers is further subject and subordinate to the
prior right of the grantor of the Underlying Rights to use the right of way for
other business activities, including railroad operations, telecommunications
uses, pipeline operations or any other purposes, and to the prior right of Qwest
to use its rights granted under the Underlying Rights. The rights granted herein
are expressly made subject and subordinate to each and every limitation,
restriction or reservation affecting the Underlying Rights. Nothing herein shall
be construed as to be a representation, warranty or covenant of Qwest's right,
title or interest with respect to the right of way or the Underlying Rights.

         7.2 Upon the expiration or other termination of an Underlying Right
that is necessary in order to grant, continue or maintain the Lessee Fibers
hereunder, Qwest shall be responsible either to renew such Underlying Right or
to obtain an alternate right of way at no cost to Lessee. In the event Qwest
loses an Underlying Right during a Lessee Fiber Term or needs such Underlying
Right in order to grant a Renewal Term to Lessee, and Qwest requests assistance
by Lessee in obtaining such Underlying Right, Lessee agrees to use commercially
reasonable efforts to assist Qwest in obtaining such Underlying Right (I.E.,
assisting Qwest in gaining access to a building for which Lessee has obtained
access rights). If at any time during the Term a federal, state or local
government authority or agency seeks to impose any new, material Underlying
Right on the Lessee Fibers above and beyond current charges, Lessee shall be
responsible for paying its Allocable Share of such new charges to Qwest.

         7.3 If Qwest is required to relocate any part of the Qwest Network
during a Lessee Fiber Term, including any of the facilities used or required in
providing the Lessee Fibers, Qwest shall reasonably determine the extent of, the
timing of, and methods to be used for such relocation; provided that any such
relocation shall be constructed and tested in accordance with the specifications
set forth in EXHIBIT B, and incorporate Fiber meeting the specifications of the
original leased Lessee Fiber. Qwest shall bear the costs of such relocation.

         7.4 Qwest shall deliver to Lessee updated as built drawings with
respect to the relocated Segment within ninety (90) days following the
completion of such relocation.

         7.5 In the event of a relocation, Qwest may, at its sole discretion,
route the Lessee Fibers through additional terminal, end link, POP or
regeneration facilities that are not required under this Section 7, in which
case Qwest shall be responsible for all

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additional Costs and expenses associated with those additional, non-required
facilities only.

         7.6 Relocation pursuant to this Section shall not effect the applicable
Lessee Fiber Term.

8.       ACCESS TO QWEST POPS

         8.1 Lessee and its designees (such as local telecommunications
providers) shall have access to each Qwest POP specified in EXHIBIT A (if any
are specified) for the purposes of interconnecting with each granted Segment of
Lessee Fiber. Such access and interconnection shall be subject to the access and
interconnection standards and procedures regularly established by Qwest, as
modified by it from time to time.

9.       USE OF QWEST NETWORK

         9.1 Lessee represents and warrants that the use of the Lessee Fibers by
its customers or end users shall comply with all applicable laws, ordinances,
rules, regulations and restrictions, and will be used for interstate purposes
only.

         9.2 This Agreement grants no right to Lessee to use any element of the
Qwest Network other than the right to use the Lessee Fibers and Associated
Property pursuant to the terms hereof. Qwest shall not cause or permit any of
Lessee's rights under this Agreement or any Lessee equipment connected to any
leased Segment to become subject to any mechanic's, materialmen's, or vendor's
lien, or any similar lien. Lessee shall keep any and all of the Qwest Network,
including the Lessee Fibers, free from any liens, rights or claims of any third
party attributable to Lessee or its use of the Qwest Network.

         9.3 Lessee shall be responsible for the configuration and operation of
Lessee's network using the Lessee Fibers, including the provisioning of all
Local Distribution Facilities, interconnection facilities, network equipment,
testing equipment and procedures, maintenance (other than maintenance of the
Lessee Fibers or any portion of the Qwest Network), and other facilities or
actions necessary to use the Lessee Fibers. Local Distribution Facilities shall
be separately acquired by Lessee and may be provided by a local telephone
company or other third party, and must comply with Qwest's applicable
engineering and operations requirements. Local Distribution Facilities are not
part of the Lessee Fibers, and Lessee's Acceptance of each Segment hereunder may
not be conditioned upon the availability of such Local Distribution Facilities.
Lessee shall conduct all operations and use of the Lessee Fibers in a manner
that does not interfere with the Qwest Network or the use thereof by Qwest or
any other customer of Qwest. Lessee shall comply at all times with Qwest's
operating procedures and interconnection requirements.

         9.4 Lessee shall hold Qwest harmless to Lessee's customers and limit
the liability of Lessee for interruptions, failures, or degradation of service
to the charges received by Lessee for such service.

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         9.5 Lessee and Qwest agree to cooperate and support each other in
complying with any requirements applicable to their respective rights and
obligations in this Agreement imposed by any governmental agency, regulatory
agency or authority.

10.      INDEMNIFICATION

         10.1 Lessee agrees to release, indemnify, defend, protect, hold
harmless Qwest, its employees, officers, directors, agents, shareholders and
Affiliates, from and against, and assumes liability for any third party claim
relating to the following:

               (a) Any injury, loss or damage to any third person, tangible
property or facilities of any third person or entity (including reasonable
attorneys' fees and costs) to the extent arising out of or resulting from
either: (i) the acts or omissions, negligent or otherwise, of Lessee, its
officers, employees, servants, Affiliates, agents, contractors, licensees,
invitees or vendors; or (ii) negligent acts or willful misconduct by Lessee;

               (b) Any claims, liabilities or damages arising out of any
violation by Lessee of any regulation, rule, statute or order of any local,
state or federal governmental agency, court or body in connection with the
use of the Fibers hereunder;

               (c) Any claims, liabilities or damages arising out of any
interference with or infringement of the rights of any third party as a
result of Lessee's use of the leased Fibers hereunder not in accordance with
the provisions of this Agreement; and

               (d) Any claims, liabilities or damages arising out of the use,
resale, sharing or modification of the leased Fibers or any other portion of
the Qwest Network by Lessee and/or its customers or end users.

         10.2 Qwest agrees to release, indemnify, defend, protect, hold
harmless Lessee, its employees, officers, directors, agents, shareholders and
Affiliates, from and against, and assumes liability for any third party claim
relating to the following:

               (a) Any injury, loss or damage to any third person, tangible
property or facilities of any third person or entity (including reasonable
attorneys' fees and costs) to the extent arising out of or resulting from
either: (i) the acts or omissions, negligent or otherwise, of Qwest, its
officers, employees, servants, Affiliates, agents, contractors, licensees,
invitees or vendors; or (ii) negligent acts or willful misconduct by Qwest;

               (b) Any claims, liabilities or damages arising out of any
violation by Qwest of any regulation, rule, statute or order of any local,
state or federal governmental agency, court or body in connection with the
use of the Fibers hereunder; or

               (c) Any claims, liabilities or damages arising out of any
interference with or infringement of the rights of any third party as a
result of Qwest's provisioning of the leased Fibers hereunder not in
accordance with the provisions of this Agreement.

         10.3 Nothing contained herein shall operate as a limitation on either
party's right to bring an action for damages against any third party, such
damages to include, but not be limited to, direct, indirect, special,
consequential or punitive damages, based on any acts or omissions of a third
party that may affect Qwest or Lessee, as the case may be.

11.      LIMITATION OF LIABILITY; DISCLAIMER OF WARRANTIES

         11.1 NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY SPECIAL,
INCIDENTAL, INDIRECT, PUNITIVE, RELIANCE OR CONSEQUENTIAL DAMAGES, WHETHER OR
NOT SUCH DAMAGES WERE FORESEEABLE OR A PARTY WAS NOTIFIED IN ADVANCE OF THE
POSSIBILITY OF SUCH DAMAGES.

         11.2 LESSEE ACKNOWLEDGES THAT, EXCEPT AS SPECIFICALLY SET FORTH IN THIS
AGREEMENT, QWEST MAKES NO WARRANTY REPRESENTATION OR INDEMNITY WITH RESPECT TO
THE LEASED FIBERS, THE QWEST NETWORK, THE ASSOCIATED PROPERTY AND SERVICES, THE
FACILITIES, OR ANY WORK PERFORMED UNDER THIS AGREEMENT, INCLUDING ANY AND ALL
WARRANTIES, IMPLIED OR EXPRESS, OF DESIGN, MERCHANTABILITY, NONINFRINGEMENT OF A
THIRD PARTY'S RIGHTS, OR FITNESS FOR A PARTICULAR PURPOSE OR ARISING FROM A
COURSE OF DEALING, USAGE OR TRADE, AND CUSTOMER HEREBY EXPRESSLY WAIVES AND
DISCLAIMS ALL SUCH WARRANTIES,

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REPRESENTATIONS AND INDEMNITIES. THE WARRANTIES SET FORTH IN THIS AGREEMENT
CONSTITUTE THE ONLY WARRANTIES MADE BY QWEST TO CUSTOMER WITH RESPECT TO THIS
AGREEMENT AND ARE MADE IN LIEU OF ALL OTHER WARRANTIES MADE BY QWEST TO CUSTOMER
WITH RESPECT TO THIS AGREEMENT AND ARE MADE IN LIEU OF ALL OTHER WARRANTIES,
WRITTEN OR ORAL, STATUTORY, EXPRESS OR IMPLIED.

         11.3 IN NO EVENT SHALL EITHER PARTY'S THE CUMULATIVE LIABILITY UNDER
THIS AGREEMENT EXCEED [*] TO THE EXTENT ALLOWED BY LAW.

12.      INSURANCE

         12.1 Lessee shall at all times during the term of this Agreement, at
its own cost and expense, carry and maintain the insurance coverage listed below
with insurers having a minimum "Best's" rating of A VII. Lessee shall require
its subcontractors and agents to maintain the same insurance.

               (a) Commercial General Liability insurance covering claims for
          bodily injury, death, personal injury or property damage (including
          loss of use) occurring or arising out of the license, use or occupancy
          of any premises in connection with this Agreement by Lessee, including
          coverage for premises-operation, products/completed operations and
          contractual liability with respect to the liability assumed by Lessee
          hereunder. The limits of insurance shall not be less than:

               Each Occurrence                       [*]
               a)                                    General Aggregate      [*]

               Products/Completed Operations         [*]
               Personal & Advertising Injury         [*]

               (b) Workers' Compensation insurance with statutory limits as
          required in the state(s) of operation; and providing coverage for any
          employee entering onto any premises in connection with this Agreement,
          even if not required by statute. Employer's Liability or "Stop Gap"
          insurance with limits of not less than [*] each accident.

               (c) Comprehensive Automobile Liability insurance covering the
          ownership, operation and maintenance of all owned, non-owned and hired
          motor vehicles used in connection with this Agreement, with limits of
          at least [*] per occurrence for bodily injury and property damage.

               (d) Any other insurance coverage specifically required of such
          party pursuant to Qwest's right of way agreements with railroads and
          other third parties.

         12.2 The insurance limits required herein may be obtained through any
combination of primary and excess or umbrella liability insurance.
Self-insurance can be

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utilized for a retention of up to [*]. Lessee shall forward to Qwest
certificate(s) of such insurance upon execution of this Agreement and upon any
renewal of such insurance during the Term. The certificate(s) shall provide that
(i) Qwest Communications Corp. (and its participating affiliates) be named as
additional insured as their interest may appear with respects this Agreement;
(ii) at least thirty (30) days prior written notice of cancellation, material
change or exclusion to any required policy shall be given to Qwest; (iii)
coverage is primary and not excess of, or contributory with, any other valid and
collectible insurance purchased or maintained by Qwest.

13.      PAYMENT

         13.1 Other than the monthly payments due pursuant to Section 4 herein,
all other payments due hereunder, if any, shall be due thirty (30) days after
the date of receipt of the invoice by Lessee. If any amount due under this
Agreement is not received by its respective due date, such amount shall accrue
interest as provided in Section 4. All disputes or requests for billing
adjustments must be submitted in writing by the due date and submitted with
payment of all undisputed amounts due. Any amounts which are determined by Qwest
to be in error or not in compliance with Agreement shall be adjusted on the next
month's invoice. Disputes shall not be cause for Lessee to delay payment of the
undisputed balance to Qwest according to the terms outlined in this Section, and
shall be addressed pursuant to Section 21 if not otherwise resolved by the
parties. Invoices submitted to Lessee by Qwest shall conform to Qwest's standard
billing format and content, as modified by Qwest from time to time.

         13.2 Either party may offset any amounts not paid when due from any
amounts that such party owes to the other party under any other agreements
between the parties.

14.      CHARACTERIZATION OF TRANSACTION

         14.1 The parties intend that the lease of the Fibers granted in this
Agreement does not provide Lessee with any ownership or other possessory
interests in any real property, conduit, fiber, or equipment pertaining to the
Associated Property, the Qwest Network, or along the System Route of the Qwest
Network. Further, it is not the intention of the parties to create a loan or
other financing arrangement between the parties.

15.      TAXES, FEES AND OTHER GOVERNMENTAL IMPOSITIONS

         15.1 Qwest is responsible for Impositions with respect to the
construction or operation of the Qwest Network which are (a) imposed or assessed
prior to the Effective Date; or (b) imposed or assessed in exchange for the
approval of the original construction of the Qwest Network.

         15.2 Except as set forth in Section 15.1 herein, each party shall be
responsible for paying any and all Impositions accessed against such party by
any authorized governmental tax authority. The parties agree that they will
cooperate with each other and coordinate their mutual efforts concerning audits,
or other such inquiries, filings,

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reports, etc., as may relate solely to the activities or transactions arising
from or under this Agreement, which originate from an authorized governmental
tax authority.

16.      NOTICE

         16.1 Unless otherwise provided herein, all notices and communications
concerning this Agreement shall be in writing and addressed to the other party
as follows:

         If to Qwest:           Qwest Communications Corporation
                                Attention:  QwestLink PMO Director
                                1670 Broadway, 26th Floor
                                Denver, Colorado 80202
                                Telephone No.:  (303) 992-1400
                                Facsimile No.:  (303) 992-7162

         with a copy to:        Qwest Communications Corporation
                                Attention:  Vice President & General Counsel
                                1801 California, Suite 3800
                                Denver, Colorado  80202
                                Telephone No.:  (303) 992-1400
                                Facsimile No.:  (303) 295-6973

         If to Lessee:          Cogent Communications, Inc.
                                Attention:  CFO
                                1015 31st Street, NW
                                Washington, DC 20007
                                Telephone No.:  (202) 295-4200
                                Facsimile No.:  (202) 338-8798

         with a copy to:        Cogent Communications, Inc.
                                Attention:  Vice President & General Counsel
                                1015 31st Street, NW
                                Washington, DC 20007
                                Telephone No.:  (202) 295-4200
                                Facsimile No.:  (202) 338-8798

or at such other address as either party may designate from time to time in
writing to the other party.

         16.2 Unless otherwise provided herein, notices shall be delivered by
hand, registered or certified U.S. mail (postage prepaid), by commercial
overnight delivery service, or by facsimile. Notices shall be deemed delivered
upon receipt if delivered by hand (if acknowledgment of receipt is obtained),
upon confirmation if delivered by facsimile, one (1) day after delivery if sent
by overnight delivery service, or three (3) days after deposit in the mail when
sent by U.S. mail.

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17.      CONFIDENTIALITY

         17.1 Qwest and Lessee agree that if either party (the "DISCLOSING
PARTY") provides confidential or proprietary, non-public information
("PROPRIETARY INFORMATION") to the other party (the "RECIPIENT PARTY"), such
Proprietary Information shall be held in confidence, and the Recipient Party
shall afford Proprietary Information the same care and protection as it affords
generally to its own confidential and proprietary information (which in any case
shall be not less than reasonable care) in order to avoid disclosure to or
unauthorized use by any third party. This Agreement, including its existence and
all of the terms, conditions and provisions, constitutes Proprietary
Information. All information disclosed by either party to the other in
connection with or pursuant to this Agreement shall also be deemed to be
Proprietary Information, provided that written information is clearly marked in
a conspicuous place as confidential or proprietary, and verbal information is
indicated as being confidential or proprietary when given or promptly confirmed
in writing as such thereafter. All Proprietary Information, unless otherwise
specified in writing, shall remain the property of the Disclosing Party, shall
be used by the Recipient Party only for its intended purpose. All Proprietary
Information, including all copies thereof, shall be returned to the Disclosing
Party or destroyed after the Recipient Party's need for it has expired or upon
the request of the Disclosing Party. Proprietary Information shall not be
reproduced except to the extent necessary to accomplish the purpose and intent
of this Agreement, or as otherwise may be permitted in writing by the Disclosing
Party.

         17.2 The foregoing provisions of Section 17.1 shall not apply to any
Proprietary Information which: (i) becomes publicly available other than through
disclosure by the Recipient Party; (ii) is required to be disclosed by law, rule
or regulation, or by court order; (iii) is independently developed by the
Recipient Party; (iv) becomes available to the Recipient Party without
restriction from a third party; or (v) becomes relevant to the settlement of any
dispute or enforcement of either party's rights under this Agreement in
accordance with its terms and conditions. If any Proprietary Information is
required to be disclosed pursuant to this Section, the party required to make
such disclosure shall immediately inform the other party of the requirements of
such disclosure and take all reasonable protective measures to preserve the
confidentiality of such Proprietary Information as fully as possible in the
context of such permitted disclosure.

         17.3 Notwithstanding Sections 17.1 and 17.2, either party may disclose
Proprietary Information to its employees or agents, its legal, financial, and
accounting advisors, and to its lenders with a need to know such Proprietary
Information, provided that the Disclosing Party notifies any recipient of its
confidential and proprietary nature and obtains, in advance, an agreement in
writing from the recipient to be bound by the non-disclosure obligations of this
Section.

         17.4 The provisions of this Section 17 shall survive for a period of
two (2) years from the date of the expiration or termination of this Agreement.

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18.      DEFAULT

         18.1 A party shall be in default under the Agreement upon the
occurrence of an Event of Default. The defaulting party shall have thirty (30)
days after the non-defaulting party gives written notice of default to the
defaulting party to cure the default (unless the default is cured or waived in
writing by the non-defaulting party within the thirty (30) day period). However,
in such cases where a default cannot be cured within the thirty (30) day period
by the exercise of diligent, commercially reasonable effort, the party in
default must cure the default within ninety (90) days after the non-defaulting
party gives its notice. Notwithstanding the preceding provisions, if the default
is for Lessee's non-payment of any amount due under Section 4 of this Agreement,
the Lessee shall have five (5) days from the date a payment is due to cure the
default, and in cases of such payment default Qwest is not required to send a
written notice of default to Lessee.

         18.2 Events of Default shall mean the following: (i) failure to make
any payment when due; (ii) breach of any material provision not cured within the
applicable cure period; or (iii) either party is or becomes Insolvent.

         18.3 In addition to the specific remedies provided in this Agreement,
upon giving notice of default, the non-defaulting party may: (i) take any action
it determines to be necessary to correct the default; and (ii) pursue any other
legal or equitable remedies it may have under applicable law that are consistent
with the terms of this Agreement.

19.      TERMINATION

         19.1 Qwest may terminate this Agreement upon the failure of Lessee to
cure an Event of Default before the expiration of the applicable cure period, if
any, as required by Section 18. In the event that Qwest terminates this
Agreement due to an uncured Event of Default by Lessee, all monthly Lease Fee
payments for the remainder of the Lessee Fiber Term for such Ring or Building
Lateral shall become immediately due and payable. In the event either party
fails to cure an Event of Default within the applicable cure period, the
aggrieved party may pursue any legal or equitable remedy available to it under
applicable law, subject to the dispute resolution provisions herein.

         19.2 Upon the expiration or termination of this Agreement, all rights
of Lessee to use the Qwest System, the Fibers, the Associated Property or any
part thereof shall cease. Promptly thereupon, Lessee shall remove all of
Lessee's electronics, equipment, and other Lessee property from Qwest facilities
at its sole cost, under Qwest's supervision. Upon termination or expiration of
this Agreement, each party shall return all of the other party's Confidential
Information in its possession or control.

         19.3 The defined terms and the rights and obligations set forth in the
following sections shall survive the termination or expiration of the Agreement:
10 (Indemnification), 11 (Limitation of Liability, Disclaimer of Warranties), 17
(Confidentiality), 21 (Arbitration), 22 (Waiver), 23 (Governing Law), 24 (Rules
of Construction), 26 (Publicity), 28 (No Personal Liability), 30 (No Third
Beneficiaries), 31 (Severability), 33 (Entire Agreement; Amendment).

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20.      FORCE MAJEURE

         20.1 Neither party shall be in default under this Agreement if its
failure to perform is caused by any of the following conditions: act of God;
fire; flood; fiber cut; power outages; material shortages or unavailability or
other delay in delivery not resulting from the responsible party's failure to
timely place orders; lack of or delay in transportation; government codes,
ordinances, laws, rules, regulations, orders approvals or restrictions
(collectively, "REGULATIONS"); war or civil disorder; labor unrest or strike; or
any other cause beyond the commercially reasonable control of the effected
party; provided the condition giving rise to such claim for relief under this
Section was not due to the actions of the party claiming relief under this
Section. The party claiming relief under this Section shall promptly notify the
other in writing of the existence of the event relied upon and the cessation or
termination of that event. For the duration of any valid force majeure event,
the performance of the effected party shall be excused.

21.      ARBITRATION

         21.1 Either party shall notify the other in writing upon the existence
of any dispute pertaining to this Agreement. The parties agree to work in good
faith to resolve the dispute during the thirty (30) day period after the written
notice is delivered. If the parties are unable to reach a settlement of the
dispute within the thirty (30) day period, either party may file a demand for
arbitration in the offices of the American Arbitration Association. The
arbitration shall take place in New York, New York. The arbitration shall be
conducted in accordance with the Commercial Arbitration Rules of the American
Arbitration Association in effect at the time the demand for arbitration is
filed. If the parties are unable to agree on a single arbitrator within thirty
(30) days from the commencement of arbitration, each party shall select an
arbitrator and the two (2) arbitrators shall promptly select a third neutral
arbitrator, the three of whom shall serve as an arbitration panel. The decision
of the arbitrator(s) shall be final and binding upon the parties and shall
include written findings of law and fact. Any award issued by the arbitrator(s)
may be reduced to a judgment and entered in a court of competent jurisdiction.
Each party shall bear its own fees and costs in connection with the arbitration,
except for the fees and expenses of the arbitrator(s), which shall be borne
equally by the parties.

         21.2 The obligation to arbitrate shall not be binding upon any party
with respect to requests for preliminary injunctions, temporary restraining
orders or other similar temporary procedures in a court of competent
jurisdiction to obtain interim relief when deemed necessary by such court to
preserve the status quo or prevent irreparable injury pending resolution by
arbitration of the actual dispute. It is not the intention of the parties that
such injunctive procedures shall be in lieu of, or cause substantial delay to,
any arbitration proceeding commenced under Section 21.1 above.

22.      WAIVER

         22.1 The failure of either party to enforce any provision of this
Agreement, or the waiver of any provision, shall not be construed as a general
waiver or relinquishment

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on its part of any such provision, but the same shall nevertheless be and remain
in full force and effect. A waiver of any provision of this Agreement is only
valid if given in writing executed by an authorized representative of the
waiving party.

23.      GOVERNING LAW

         23.1 This Agreement shall be governed by and construed in accordance
with the domestic laws of the State of New York, without reference to choice of
law principles.

24.      RULES OF CONSTRUCTION

         24.1 The captions or headings in this Agreement are strictly for
convenience and shall not be considered in interpreting this Agreement or as
amplifying or limiting any of its content. Words in this Agreement which import
the singular connotation shall be interpreted as plural, and words which import
the plural connotation shall be interpreted as singular, as the identity of the
parties or objects referred to may require.

         24.2 Unless expressly defined herein, words having well known technical
or trade meanings shall be so construed. All listing of items shall not be taken
to be exclusive, but shall include other items, whether similar or dissimilar to
those listed, as the context reasonably requires.

         24.3 Except as set forth to the contrary herein, any right or remedy of
Lessee or Qwest shall be cumulative and without prejudice to any other right or
remedy, whether contained herein or not.

         24.4 This Agreement has been fully negotiated between and jointly
drafted by the parties, each of whom had full opportunity to consult with
counsel before execution.

         24.5 In the event of a conflict between the provisions of this
Agreement and those of any Exhibit, the provisions of this Agreement shall
prevail and such Exhibit shall be corrected accordingly.

         24.6 All actions, activities, consents, approvals and other
undertakings of the parties in this Agreement shall be performed in a reasonable
and timely manner, it being expressly acknowledged and understood that time is
of the essence in the performance of obligations required to be performed by a
date expressly specified herein. Except as specifically set forth herein, for
the purpose of this Section the normal standards of performance within the
telecommunications industry in the relevant market shall be the measure of
whether a party's performance is reasonable and timely.

25.      REPRESENTATIONS

         25.1     Each party represents that:

               (a) It has the full right and authority to enter into, execute,
          deliver and perform its obligations under this Agreement;

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               (b) This Agreement constitutes a legal, valid and binding
          obligation enforceable against such party in accordance with its
          terms, subject to bankruptcy, insolvency, creditors' rights and
          general equitable principles; and

               (c) At the time of execution, this Agreement does not violate any
          applicable existing state, federal, city or county law.

26.      PUBLICITY, NAME AND MARKS.

         26.1 Notwithstanding the foregoing, no publicity regarding the
existence and/or terms of this Agreement may occur without Qwest's prior express
written consent, and such written consent, if granted, may be granted only by
Qwest's Senior Vice President of Corporate Communications. The content and
timing of any press releases and all other publicity regarding the subject
matter of this Agreement or Lessee's relationship with Qwest, if authorized,
shall be mutually agreed upon by the parties in advance. Notwithstanding
anything to the contrary, Lessee may not make any disclosure to any other person
(other than to those Lessee's representatives or agents who have a need to know
such information and who agree to maintain the confidentiality thereof), or any
public announcement regarding this Agreement or any relation between Lessee and
Qwest, without Qwest's prior written consent, which consent shall not be
unreasonably withheld. In addition, neither Party shall use any trademark,
service mark, brand name, copyright, patent, or any other intellectual property
of the other Party or its respective Affiliates without the other Party's prior
written consent and (a) in the case of Qwest, with the prior written consent of
the Senior Vice President of Corporate Communications; or (b) in the case of
Lessee, with the prior written consent of its General Counsel.

27.      ASSIGNMENT

         27.1 This Agreement shall be binding on each party and its
respective Affiliates, successors, and assigns. Neither party shall assign,
sell or transfer this Agreement or the right to lease the leased Fiber
hereunder, whether by operation of law or otherwise, without the prior
written consent of the other party, which consent shall not be unreasonably
withheld. Notwithstanding the foregoing, an assigning party may assign or
transfer all of its rights and obligations under this Agreement to any
partnership, corporation or other entity which controls, is controlled by, or
is under common control with the assigning party or its parent (control being
defined for such purposes as ownership of at least 50% of the equity
interests in, or the power to direct the management of, the relevant entity)
or to any partnership, corporation or other entity resulting from a merger or
consolidation with the assigning party or its parent, or to any person or
entity which acquires substantially all the assets of the assigning party as
a going concern. Any attempted assignment in violation hereof shall be null
and void.

28.      NO PERSONAL LIABILITY

         28.1 Each action or claim against any party arising under or relating
to this Agreement shall be made only against such party as a corporation, and
any liability relating thereto shall be enforceable only against the corporate
or limited liability

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company assets of such party. No party shall seek to pierce the corporate or
limited liability company veil or otherwise seek to impose any liability
relating to, or arising from, this Agreement against any shareholder, employee,
officer or director of the other party.

29.      RELATIONSHIP OF THE PARTIES

         29.1 The relationship between Lessee and Qwest shall not be that of
partners, agents, or joint venturers. Nothing in this Agreement shall be deemed
to constitute a partnership or agency agreement between the parties for any
purposes, including but not limited to federal income tax purposes. Lessee and
Qwest, in performing any of their obligations hereunder, shall be independent
contractors or independent parties and shall discharge their contractual
obligations at their own risk.

30.      NO THIRD PARTY BENEFICIARIES

         30.1 This Agreement does not provide and is not intended to provide any
third party beneficiaries, including but not limited to Lessee's end users or
customers, with any remedy, claim, reimbursement, cause of action or other right
or privilege.

31.      SEVERABILITY

         31.1 If any term, covenant or condition contained herein shall, to any
extent, be invalid or unenforceable in any respect under the laws governing this
Agreement, the remainder of this Agreement shall not be affected thereby, and
each term, covenant or condition of this Agreement shall be valid and
enforceable to the fullest extent permitted by law.

32.      COUNTERPARTS

         32.1 This Agreement may be executed in one or more counterparts, all of
which taken together shall constitute one and the same instrument.

33.      ENTIRE AGREEMENT; AMENDMENT

         33.1 This Agreement constitutes the entire and final agreement and
understanding between the parties with respect to the subject matter hereof and
supersedes all prior agreements relating to the subject matter hereof, which are
of no further force or effect.

         33.2 The Appendices and Exhibits referred to herein are integral parts
hereof and are made a part of this Agreement.

         33.3 This Agreement may only be modified or supplemented by an
instrument in writing executed by a duly authorized representative of each
party.

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In confirmation of their consent and agreement to the terms and conditions
contained in this Agreement and intending to be legally bound hereby, the
parties have executed this Agreement as of the date first above written.

                            (2)  QWEST COMMUNICATIONS CORPORATION

                  By:__________________________________________
                  Name:  _______________________________________
                  Title:    _______________________________________

                                 (a)  LESSEE:  COGENT
                                 COMMUNICATIONS, INC.

                  By:__________________________________________
                  Name:  _______________________________________
                  Title:    _______________________________________

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List of Exhibits:

o  Exhibit A:     List of Rings and Building Laterals Available in Qwest Network

o  Exhibit A-1:   Description of System Route in Qwest Network for Rings

o  Exhibit A-2:   Description of System Route in Qwest Network for Building
                  Laterals

o  Exhibit B:     Technical Specifications

o  Exhibit C:     Additional Terms and Conditions

o  Exhibit D:     Technical Specifications Lucent Technologies

o  Exhibit E:     Pricing

THIS AGREEMENT INCLUDES METRO FIBERS AND LATERALS AND THUS ALL EXHIBITS ARE
APPLICABLE.

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                                    EXHIBIT A

                     B.           QWEST METRO NETWORK

Austin:
        Metro Networks: CBD, 1, 2, 3, 4, 5
        Approximate total route mileage: 179

Dallas:
        Metro Networks: 1, 2, 3, 4
        Approximate total route mileage: 34

Houston:
        Metro Networks: 1, 2, 3
        Approximate total route mileage: 36

Irvine:
        Metro Networks: 4, 5, 8, 9, 10
        Approximate total route mileage: 187

Los Angeles:
        Metro Networks: 1, 2, 3
        Approximate total route mileage: 8

New York City:
        Metro Network: Financial District
        Approximate total route mileage: 10

Sacremento:
        Metro Networks: CBD
        Approximate total route mileage: 18

San Francisco:
        Metro Networks: 1, 2
        Approximate total route mileage: 18

San Jose:
        Metro Networks: CBD
        Approximate total route mileage: 2

Washington DC:
        Metro Networks: 1, 2, 3, 4, 5, 6, 7, 5H, 6H
        Approximate total route mileage: 256

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                                   EXHIBIT B:

                            TECHNICAL SPECIFICATIONS

1.       STANDARD SPECIFICATIONS FOR FACILITIES

         1.1 Qwest will install conditioned space along the System Route to
house electronic equipment (supplied by Lessee) necessary for the use of the
leased Fibers. Facilities will consist of 30 square feet (up to two rack spaces)
for joint use space, 105 square feet for amplifier/regen sites and up to 250
square feet for POP sites. Facilities space will be caged, with separate,
lockable secured, 24-hour access. Lessee will have access to redundant DC power
provided from a common source backed up by a standby generator. DC power is
available at a one-time fee of $200.00 per ampere. To the extent provided in the
Agreement, any additional space and/or power required may be made available,
with Lessee solely responsible for Qwest's incremental cost. Following are the
general specifications of the buildings and support equipment:

                  (a) Buildings shall be standard production buildings, with
         walls and doors bullet-resistant to 30-06 caliber rounds from 15 feet.
         Walls and ceilings shall be R-19 insulated.

                  (b) Facilities will be equipped with redundant HVAC units.

                  (c) A fire extinguisher will be provided inside Lessee's main
         door. A fire suppression system will be provided for overall fire
         protection coverage.

                  (d) Facilities will have adequate backup generator(s) designed
         to provide power during emergency periods for sufficient time to
         restore prime power. A battery plant capable of handling the load for a
         minimum of four (4) hours to ensure uninterrupted power will be
         installed in the building.

                  (e) Facilities will grounded and equipped with a principal
         ground termination bar. A ground cable will be provided to Lessee
         space, to which the Lessee may attach equipment frame ground wires.

                  (f) The building will be equipped with A/C duplex isolated
         outlets for testing and miscellaneous equipment in accordance with the
         National Electrical Code.

                  (g) The building will have sufficient interior lighting, and
         will be equipped with security-type weatherproof exterior light
         fixtures.

                  (h) Qwest will install properly sized cable racks for DC power
         and fiber distribution in accordance with prototypical drawings. Qwest
         will run properly sized cables from the common DC power plant to the
         Lessee-supplied fuse panel in the Lessee's space. The Lessee is
         responsible for providing fiber connections (e.g., jumpers) from the
         Lessee space to Qwest's fiber distribution panel, whether these
         connections are terminated at the Qwest panel or spliced through to the
         Qwest Network backbone.

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2.       STANDARD CONSTRUCTION SPECIFICATIONS

         2.1      In General.

                  (a) The intent of this document is to outline the
         specifications for construction of a fiber optic cable system. In all
         cases, the standards contained in this document or the standards of the
         federal, state, local or private agency having jurisdiction, whichever
         is stricter, shall be followed.

         2.2      Material.

                  (a) Steel or PVC conduit shall be minimum schedule 40
         wall thickness.

                  (b) Any exposed steel conduit,  brackets or hardware
         (i.e.,  bridge  attachments) shall be hot-dipped galvanized after
         fabrication.

                  (c) Handholes shall have a minimum load rating of H-20
         with sufficient soil cover.

                  (d) Manholes shall have a minimum H-20 loading rating.

                  (e) Buried cable warning tape shall be 3 inches wide and
         display "Warning: Buried Fiber Optic Cable," Qwest, and local and
         emergency One Call "800" numbers repeated every 24 inches.

                  (f) Fiber optic cable shall be single armored, unless
         prohibited by the right-of-way owner, or by codes, laws or regulations.

                  (g) EMS markers will be fabricated in the lids of
         handholes.

         2.3      Minimum Depths.

                  (a) Minimum cover required in the placement of conduit shall
         be 42 inches, except where field conditions dictate otherwise.

                  (b) At locations where conduit crosses other subsurface
         utilities or other structures, the conduit shall be installed to
         provide adequate vertical clearance and the applicable minimum depth
         can be maintained; otherwise the conduit will be installed under the
         existing utility or other structure. If, however, adequate clearance
         cannot be obtained and the conduit must be placed above, the cable
         shall be encased in steel pipe and HDPE conduit.

(c)      In rock, the conduit depth shall be:

                   36"- 42" in HDPE,

                   24"- 36" in HDPE encased in steel,

                   18"- 24" in HDPE or PVC or steel and concrete encased.

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                  (d) PVC or HDPE conduit will be backfilled with 6 inches of
         select materials (padding) in rock areas. MDI Polyurethane channel
         (Fiber-Rockgard by Chempro, Inc. or equivalent) may be used as
         protective cover in lieu of select material padding. .

                  (e) In the case of the use/conversion of existing steel
         pipelines or existing conduit systems, the existing depth shall be
         considered adequate.

         2.4      Buried Cable Warning Tape.

                  (a) All conduits will be installed with buried cable warning
         tape except where existing steel pipelines or existing conduit systems
         are used. The warning tape shall generally be placed directly above the
         conduit.

         2.5      Conduit Construction.

                  (a) Conduits may be placed by means of trenching, plowing,
         jack and bore, push-pull method, or directional bore. Conduits will
         generally be placed on a level grade parallel to the surface, with only
         gradual changes in grade elevation.

                  (b) Steel conduit will be joined with threaded collars or
         welding.

                  (c) Conduit crossings of roads maintained by government bodies
         and railroad crossings will be encased in steel conduit, except where
         the cable is placed with 10 feet or more of cover. In the latter case,
         HDPE is adequate.

                  (d) Conduit placed by the push-pull method (that is, using a
         push rod, followed by pulling conduit) may use HDPE, PVC, or steel
         conduit.

                  (e) All directional bores will use HDPE or steel conduit.

                  (f) All conduits placed on bridges shall have expansion joints
         placed at each structural (bridge) expansion joint or at least every
         300 feet, whichever is the shorter distance. For bridges under 100
         feet, with no bridge expansion joint, no conduit expansion joint is
         required. For bridges greater than 100 feet, at least one conduit
         expansion joint will be placed, even if there is no bridge expansion
         joint.

         2.6      Innerduct Installation.

                  (a) Innerduct(s) shall be installed in all steel conduits.
        No cable will be placed directly in any split/solid steel conduit
        without innerduct.

                  (b) Innerduct(s) shall extend beyond the end of all conduits
        a minimum of 18 inches.

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         2.7      Cable Installation.

                  (a) The fiber optic cable shall be installed using a powered
         pulling winch and hydraulic-powered assist pulling wheels. The maximum
         pulling force to be applied to the fiber optic cable shall be not
         exceed manufactures recommendations.

                  (b) All splices will be contained in a handhole or
         manhole.

         2.8      Cable Markers (Warning Signs).

                  (a) Cable markers shall be installed at sufficient frequency
         to mark the location of the cable. Markers shall be positioned so that
         they can be seen from the location of the cable and generally set
         facing perpendicular to the cable running line.

         2.9      Compliance.

                  (a) All work will be done in accordance with federal, state,
         local and applicable private rules and laws regarding safety and
         environmental issues, including those set forth by OSHA and the EPA. In
         addition, all work and the resulting fiber system will comply with the
         current requirements of all governing entities (FCC, NEC, DEC, and
         other national, state, and local codes).

         2.10     Drawings.

                  (a) Drawings will contain a minimum of the following:

                           1) Information showing the location of running line,
                  relative to permanent landmarks, including but not limited to,
                  railroad mileposts, boundary crossings and utility crossings.

                           2) Splice locations

                           3) Manhole and handhole locations

                           4) Conduit information (type, length, expansion
                  joints, etc.)

                           5) Cable information (manufacturer, type of fiber,
                  type of cable, fiber assignments, and final cable lengths)

                           6) Notation of all deviations from specifications
                  (depth, etc.)

                           7) Right-of-way detail (type, centerline distances,
                  boundaries, waterways, and road crossings, known utilities
                  and obstacles)

                           8) Cable marker locations and stationing

                           9) Regeneration locations. Construction of facilities
                  will be documented on the sitework/facility drawings and
                  maintained in a file at the facility.

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                  (b) Drawings will be updated with actual field data during
         and after construction.

                  (c) Drawings will be provided within 90 days after acceptance,
         in both hard copy and electronic format (Auto-CAD Release 13.0 or
         later). Updates to the drawings will be provided within 90 days of
         completion of change, like a relocation project.

         2.11     Deviations From Specifications.

                  (a) Qwest may deviate from these specifications, when
         field conditions dictate.

3.0      FIBER CABLE SPLICING, TESTING AND ACCEPTANCE PROCEDURES

         3.1 All splices will be performed with an industry-accepted fusion
splicing machine. Testing will be documented on diskettes in laser precision
format and on trace analysis sheets reflecting bi-directional losses by fiber
and installed span loss by fiber. One copy of trace diskettes and three copies
of trace analysis sheets will be submitted. All testing will be performed at
1550 nm.

         3.2 During initial uni-directional OTDR testing, a general indicator of
the quality of each splice will be an objective loss of 0.15 dB or less. If,
after three attempts, Qwest is not able to produce a loss value of less than
0.15 dB, then 0.25 dB will become the objective. If, after two additional
attempts, a value of less than 0.25 is not achievable, then the splice will be
marked as "Out-of -Spec" (OOS) on a field data sheet. The parties recognize that
uni-directional OTDR test data is not an acceptance/rejection criterion.

         3.3 The installed span loss (span shall be FDP to FDP) shall be a
bi-directional average of 0.25 dB/km or less, as calculated using an
industry-accepted optical loss test set at 1550 nm. The installed span loss
includes the inherent attenuation of the glass, the backbone splice losses, the
pigtail splice losses, the inherent loss in the pigtails, and the connector
losses.

         3.4 Optical Return Loss (ORL) will be recorded on the testing
documentation, for information only.

         3.5 The entire fiber optic cable system shall be properly protected
from foreign voltage and grounded with an industry-accepted system. The current
systems in use by Qwest are the ACT 4400-150 and the Norscan 2745 SGU.

         3.6 The fibers shall be terminated to the FDP with Ultra FC-PC
connectors, unless another type of connector is specified.

4.       OPERATIONS AND MAINTENANCE SPECIFICATIONS AND PROCEDURES

         4.1 For the purposes of this Section 4, any party responsible for
providing maintenance of the Qwest Network hereunder shall be referred to herein
as the "Service Provider." The Party receiving maintenance services from the
Service Provider hereunder shall be referred to herein as the "Service
Recipient". All other capitalized terms not otherwise

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defined herein shall have their respective meanings as set forth in the
Agreement of which this Exhibit forms a part.

         4.2      Maintenance.

                  (a) Scheduled Maintenance. Routine maintenance and repair of
         the leased Fibers described in this section ("SCHEDULED MAINTENANCE")
         shall be performed by or under the direction of Service Provider, at
         Service Provider's reasonable discretion or at Service Recipient's
         request. Scheduled Maintenance of a leased Fiber Segment shall commence
         when Lessee executes an acceptance letter of that Segment. Scheduled
         Maintenance shall include the following activities:

                           (1) Patrol of System Route on a regularly scheduled
                  basis, which will be weekly unless hyrail access is necessary,
                  in which case, it will be quarterly;

                           (2) Maintenance  of a  "Call-Before-You-Dig" program
                  and all  required and related cable locates;

                           (3) Maintenance of sign posts along the System Route
                  right-of-way with the number of the local
                  "Call-Before-You-Dig" organization and the "800" number for
                  Qwest's "Call-Before-You-Dig" program; and

                           (4) Assignment of fiber maintenance technicians to
                  locations along the System Route at approximately 100-mile
                  intervals dependent upon terrain and accessibility.

                  (b) Unscheduled Maintenance. Non-routine maintenance and
         repair of the leased Fibers which is not included as Scheduled
         Maintenance ("UNSCHEDULED MAINTENANCE"), shall be performed by or under
         the direction of Service Provider. Unscheduled Maintenance of a leased
         Fiber Segment shall commence when Lessee executes an acceptance letter
         of that Segment. Unscheduled Maintenance shall consist of:

                           (1) "Emergency Unscheduled Maintenance" in response
                  to an alarm identification by Service Provider's Operations
                  Center, notification by Service Recipient or notification by
                  any third party of any failure, interruption or impairment in
                  the operation of the leased Fibers, or any event imminently
                  likely to cause the failure, interruption or impairment in the
                  operation of the leased Fibers.

                           (2) "Non-Emergency Unscheduled Maintenance" in
                  response to any potential service-affecting situation to
                  prevent any failure, interruption or impairment in the
                  operation of the Qwest System.

                  (c) Service Recipient shall immediately report the need for
         Unscheduled Maintenance to Service Provider in accordance with
         procedures promulgated by Service Provider from time-to-time. Service
         Provider will log the time of Service Recipient's report, verify the
         problem and dispatch personnel immediately to take corrective action.

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         4.3      Operations Center.

                  (a) Service Provider shall operate and maintain an Operations
         Center ("OC") staffed twenty-four (24) hours a day, seven (7) days a
         week by trained and qualified personnel. Service Provider's maintenance
         employees shall be available for dispatch twenty-four (24) hours a day,
         seven (7) days a week. Service Provider shall have its first
         maintenance employee at the site requiring Emergency Unscheduled
         Maintenance activity within two (2) hours after the time Service
         Provider becomes aware of an event requiring Emergency Unscheduled
         Maintenance, unless delayed by circumstances beyond the reasonable
         control of Service Provider. Service Provider shall maintain a
         toll-free telephone number to contact personnel at the OC. Service
         Provider's OC personnel shall dispatch maintenance and repair personnel
         along the system to handle and repair problems detected in the leased
         Fibers, (i) through the Service Recipient's remote surveillance
         equipment and upon notification by Service Recipient to Service
         Provider, or (ii) upon notification by a third party.

         4.4.     Cooperation and Coordination.

                  (a) SERVICE RECIPIENT shall utilize an Operations Escalation
         List, as updated from time to time, to report and seek immediate
         initial redress of exceptions noted in the performance of Service
         Provider in meeting maintenance service objectives.

                  (b) SERVICE RECIPIENT will, as necessary, arrange for
         unescorted access for Service Provider to all leased Fiber sites in the
         System Route, subject to applicable contractual, underlying real
         property and other third-party limitations and restrictions.

                  (c) In performing its services hereunder, Service Provider
         shall take reasonable care to prevent impairment to the signal
         continuity and performance of the leased Fibers. The precautions to be
         taken by Service Provider shall include notifications to Service
         Recipient. In addition, Service Provider shall reasonably cooperate
         with Service Recipient in sharing information and analyzing the
         disturbances regarding the cable and/or fibers. In the event that any
         Scheduled or Unscheduled Maintenance hereunder requires a traffic roll
         or reconfiguration involving cable, fiber, electronic equipment, or
         regeneration or other facilities of the Service Recipient, then Service
         Recipient shall, at Service Provider's reasonable request, make such
         personnel of Service Recipient available as may be necessary in order
         to accomplish such maintenance, which personnel shall coordinate and
         cooperate with Service Provider in performing such maintenance as
         required of Service Provider hereunder.

                  (d) Service Provider shall notify Service Recipient at least
         ten (10) business days prior to the date in connection with any PSWP of
         any Scheduled Maintenance and as soon as possible after becoming aware
         of the need for Unscheduled Maintenance. Service Recipient shall have
         the right to be present during the performance of any Scheduled
         Maintenance or Unscheduled Maintenance so long as this requirement does
         not interfere with Service Provider's ability to perform its
         obligations under this Agreement. In the event that Scheduled
         Maintenance is canceled or delayed for whatever reason as previously
         notified, Service Provider shall notify Service Recipient at Service

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         Provider's earliest opportunity, and will comply with the provisions of
         the previous sentence to reschedule any delayed activity.

         4.5      Facilities.

                  (a) Service Provider shall maintain the Qwest System in a
         manner which will permit Service Recipient's use the leased Fibers and
         the Associated Property in accordance with the terms and conditions of
         this Agreement.

                  (b) Except to the extent otherwise expressly provided in this
         Agreement, Service Recipient will be solely responsible for providing
         and paying for any and all maintenance of all electronic, optronic and
         other equipment, materials and facilities used by Service Recipient in
         connection with the operation of the leased Fibers, none of which is
         included in the maintenance services to be provided hereunder.

         4.6      Cable/Fibers.

                  (a) Service Provider shall perform appropriate Scheduled
         Maintenance on the cable contained in the System Route in accordance
         with Service Provider's then current preventative maintenance
         procedures as agreed to by Service Recipient, which shall not
         substantially deviate from standard industry practice.

                  (b) Service Provider shall have qualified representatives on
         site any time Service Provider has reasonable advance knowledge that
         another person or entity is engaging in construction activities or
         otherwise digging within five (5) feet of the cable.

                  (c) Service Provider shall maintain sufficient capability to
         teleconference with Service Recipient during an Emergency Unscheduled
         Maintenance in order to provide regular communications during the
         repair process. When correcting or repairing cable discontinuity or
         damage, including but not limited to in the event of Emergency
         Unscheduled Maintenance, Service Provider shall use reasonable efforts
         to repair traffic-affecting discontinuity within four (4) hours after
         the Service Provider maintenance employee's arrival at the problem
         site. In order to accomplish such objective, it is acknowledged that
         the repairs so effected may be temporary in nature. In such event,
         within twenty-four (24) hours after completion of any such Emergency
         Unscheduled Maintenance, Service Provider shall commence its planning
         for permanent repair, and thereafter promptly shall notify Service
         Recipient of such plans, and shall implement such permanent repair
         within an appropriate time thereafter. Restoration of open fibers on
         fiber strands not immediately required for service shall be completed
         on a mutually agreed-upon schedule. If the fiber is required for
         immediate service, the repair shall be scheduled for the next available
         Planned Service Work Period (PSWP).

                  (d) In performing repairs, Service Provider shall comply with
         the splicing specifications as set forth in Section 3 of this Exhibit.
         Service Provider shall provide to Service Recipient any modifications
         to these specifications as may be necessary or appropriate in any
         particular instance for Service Recipient's approval, which approval
         shall not be unreasonably withheld.

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                  (e) Service Provider's representatives that are responsible
         for initial restoration of a cut cable shall carry on their vehicles
         the typically appropriate equipment that would enable a temporary
         splice, with the objective of restoring operating capability in as
         little time as possible. Service Provider shall maintain and supply an
         inventory of spare cable in storage facilities supplied and maintained
         by Service Provider at strategic locations to facilitate timely
         restoration.

         4.7      Planned Service Work Period (PSWP).

                  (a) Scheduled Maintenance which is reasonably expected to
         produce any signal discontinuity must be coordinated between the
         parties. Generally, this work should be scheduled after midnight and
         before 6:00 a.m. local time. Major system work, such as fiber rolls and
         hot cuts, will be scheduled for PSWP weekends. A calendar showing
         approved PSWP will be agreed upon in the last quarter of every year for
         the year to come. The intent is to avoid jeopardy work on the first and
         last weekends of the month and high-traffic holidays.

         4.8      Restoration.

                  (a) Service Provider shall respond to any interruption of
         service or a failure of the leased Fibers to operate in accordance with
         the specifications set forth in this Exhibit (in any event, an
         "OUTAGE") as quickly as possible (allowing for delays caused by
         circumstances beyond the reasonable control of Service Provider) in
         accordance with the procedures set forth herein. Outage shall expressly
         exclude any Scheduled Maintenance.

                  (b) When restoring a cut cable in the System Route, the
         parties agree to work together to restore all traffic as quickly as
         possible. Service Provider, promptly upon arriving on the site of the
         cut, shall determine the course of action to be taken to restore the
         cable and shall begin restoration efforts. Service Provider shall
         splice fibers tube by tube or ribbon by ribbon or fiber bundle by fiber
         bundle, rotating between tubes or ribbons operated by the separate
         Interest Holders, including Service Recipient, in accordance with the
         following described priority and rotation mechanics; provided that, lit
         fibers in all buffer tubes or ribbons or fiber bundles shall have
         priority over any dark fibers in order to allow transmission systems to
         come back on line; and provided further that, Service Provider will
         continue such restoration efforts until all lit fibers in all buffer
         tubes or ribbons are spliced and all traffic restored. For the purpose
         of this Exhibit, the term "INTEREST HOLDER" means any party who owns or
         has a right to use fibers on the System Route. In general, priority
         among Interest Holders affected by a cut shall be determined on a
         rotating restoration-by-restoration and Segment-by-Segment basis, to
         provide fair and equitable restoration priority to all Interest
         Holders, subject only to such restoration priority to which Qwest is
         contractually obligated prior to the date of the Agreement. Service
         Provider shall use all reasonable efforts to implement a Qwest
         Network-wide rotation mechanism on a Segment-by-Segment basis so that
         the initial rotation order of the Interest Holders in each Segment is
         varied (from earlier to later in the order), such that as restorations
         occur, each Interest Holder has approximately equivalent rotation order
         positions across the Qwest Network. Additional participants in

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         the Qwest Network that become Interest Holders after the date hereof
         shall be added to the restoration rotation mechanism.

                  (c) The goal of emergency restoration splicing shall be to
         restore service as quickly as possible. This may require the use of
         some type of mechanical splice, such as the "3M Fiber Lock" to complete
         the temporary restoration. Permanent restorations will take place as
         soon as possible after the temporary splice is complete.

         4.9      Subcontracting.

                  (a) Service Provider may subcontract any of the maintenance
         services hereunder; provided that Service Provider shall require the
         subcontractor(s) to perform in accordance with the requirement and
         procedures set forth herein. The use of any such subcontractor shall
         not relieve Service Provider of any of its obligations hereunder.

         4.10     Fees and Costs.

                  (a) Scheduled Maintenance Fees. The fees payable for any and
         all Scheduled Maintenance hereunder shall be determined in accordance
         with the following provisions. During any time after Lessee signs an
         acceptance letter for any leased Fiber Segment, but subject to Section
         4.11 below, Qwest shall be the Service Provider and provide Scheduled
         Maintenance at a cost of [*] per route mile per year, subject to
         the CPI adjustment described below (the "QWEST FIXED FEE") and
         Unscheduled Maintenance as provided this Section.

                           (1) A quarter of the first such Scheduled Maintenance
                  Fee with respect to each Segment will be due and payable
                  thirty (30) days after Lessee signs an acceptance letter with
                  respect to such leased Fiber Segment. Thereafter, one quarter
                  of such fee shall be due quarterly. All fees shall be paid by
                  Service Recipient within thirty (30) days of receipt of
                  invoice therefore. The Qwest Fixed Fee, if applicable, may be
                  adjusted annually, in Qwest's sole discretion, beginning with
                  the first anniversary date of the execution date of this
                  Agreement, for increases in the United States Bureau of Labor
                  Statistics, CPI-U All Services Index (unadjusted), as
                  originally published. Said adjustment shall be hereinafter
                  referred to as "CPI-U ADJUSTMENT". Such fee, as adjusted by
                  the CPI-U Adjustment, shall be equal to the product of the fee
                  specified herein multiplied by the fraction (i) whose
                  numerator is the CPI-U All Services for March of the previous
                  calendar year for which the adjustment to the fee is being
                  made, and (ii) whose denominator is the CPI-U All Services for
                  March of the preceding year. The adjusted fee shall remain in
                  effect until the next annual fee is due, when a new adjusted
                  fee fixed pursuant to this provision shall become effective.
                  In no event shall the amount of the fee as adjusted pursuant
                  to this provision be less than the amount of fee in effect for
                  the immediately-preceding year. The parties agree that the
                  Index for March 1995 is defined as 151.4. In the event that
                  the Bureau of Labor Statistics (or any successor organization)
                  changes the current base of the CPI-U from 1982-84 = 100, the
                  calculation of a fee under this provision shall be adjusted to
                  ensure that Qwest receives the same amount as it

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                  would have had, had the base not been changed. In the event
                  the Bureau of Labor Statistics (or any successor organization)
                  no longer publishes the CPI-U, Qwest may, subject to Service
                  Recipient's agreement (which shall not be unreasonably
                  withheld), designate the statistical index it deems most
                  appropriate for collocation of adjustments to a fee and, from
                  the date the CPI-U ceased to be published, such index shall
                  be used to make adjustments in a fee under this provision.

                  (b) Unscheduled Maintenance Fees. If the aggregate amount of
         the Costs of Unscheduled Maintenance required as a result of any single
         event or multiple, closely-related events is less than [*], such Costs
         shall be borne by Service Provider. For any other Unscheduled
         Maintenance, the Costs thereof shall be allocated among the various
         Interest Holders in the conduit, cable an/or fibers affected thereby
         as follows: (i) Costs of Unscheduled Maintenance solely to or
         affecting a conduit or cable which houses fibers of a single Interest
         Holder shall be borne 100% by such Interest Holder; (ii) Costs of
         Unscheduled Maintenance to or affecting a conduit which houses
         multiple innerduct conduits, not including such Costs attributable to
         the repair or replacement of fiber therein, shall be borne
         proportionately by the Interest Holds in each of the affected
         innerduct conduits based on the ratio that such affected conduit bears
         to the total number of affected innerduct conduits, and (iii) Costs of
         Unscheduled Maintenance attributable to the repair or replacement of
         fiber, including the acquisition, installation, inspection, testing and
         splicing thereof, shall be borne proportionately by the Interest
         Holders in the affected fiber, based on the ratio that the number of
         affected fibers subject to the interest of each such Interest Holder
         bears to the total number of affected fibers. All such Costs which are
         allocated to Service Recipient pursuant to the foregoing provisions
         shall be the responsibility of and paid by Service Recipient within
         thirty (30) days after its receipt from Service Provider of an invoice
         therefore.

         4.11     Term.

                  (a) Service Provider's obligation to perform maintenance on
         the relevant portion of the Qwest System shall be for an initial term
         expiring June 30, 2006, and unless a different Service Provider is
         selected by the Interest Holders under a mutually agreed selection
         process, then Qwest shall be the Service Provider. Thereafter, Qwest
         shall have no obligation to provide Scheduled or Unscheduled
         Maintenance hereunder, but shall be entitled to participate in any
         process selected by the Interest Holders as a potential Service
         Provider.

                                       B-11

[*] Indicates confidential treatment requested.

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                                   EXHIBIT C:

                                   (i) ADDITIONAL TERMS AND CONDITIONS

The following provisions shall be a part of the Agreement only if Qwest has
specifically designated in EXHIBIT A hereto that any Segment the leased Fibers
in the System Route is part of a Qwest metropolitan dark fiber optic
telecommunications network. The additional provisions of this Exhibit apply only
to that portion of the leased Fibers that are contained within in a
Qwest-designated metropolitan dark fiber optic telecommunication network. The
provisions of this Exhibit do not apply to any other leased Fiber Segments,
including, but not limited to long haul or local access Segments.

1.       ADDITIONAL DOCUMENTATION

         1.1 Qwest shall provide Lessee with the following documentation within
ninety (90) days of the applicable Acceptance Date

                  (a) Technical specifications of the fiber cable and associated
splices and other equipment placed in the Qwest Network along the System Route
relevant to the Leased Fibers;

                  (b) a copy of the test results of the Leased Fibers

                  (c) System route drawings

2.       CONNECTING POINTS

         2.1 Qwest shall provide Lessee with access to the Lessee Fibers at the
Connecting Points set forth in an Order. All connections shall be performed by
Qwest, in accordance with Qwest's applicable specifications and operating
procedures.

         2.2 Subject to all applicable Underlying Rights Requirements, Qwest
shall provide Lessee with reasonable access to the Connecting Points set forth
in an Order, but only if accompanied by a Qwest representative(s) in accordance
with Qwest's standard operating procedures. Lessee shall pay Qwest's Costs for
providing such representative(s).

         2.3 Neither Qwest nor Lessee shall have any limitations on the types of
electronics or technologies employed to use the Leased Fiber; however, Lessee's
electronics or technologies must comply with Qwest safety procedures and shall
not interfere with the Qwest Network.

         2.4 In placing a Request, Lessee shall submit the Request for any
connection at least ninety (90) days in advance of the date needed by Lessee.
The Parties must agree to an Order before provisioning may begin. Upon Qwest
approval, any construction work will be restricted to a Planned System Work
Period, unless otherwise agreed to in writing. The [*] of such additional
connections will fully be paid by Lessee. Lessee shall pay Qwest's Costs for
each additional connection within thirty (30) days of the date of Qwest's
invoice and as provided in Section 4 of the Agreement. It is the responsibility
of Lessee to obtain all governmental and

                                       C-1

[*] Indicates confidential treatment requested.

<Page>
                                                                  EXECUTION COPY

other approvals and consents necessary for the delivery of the leased Fibers to
any additional Connecting Point.

3.       LIMITED PASS-THROUGH FIBER WARRANTY

         3.1 Beginning on the Effective Date, and ending twelve (12) months
thereafter, Qwest warrants that, except for those items that are supplied or
specified by Lessee, at the time of Delivery the Lessee Fibers complies with the
specifications set forth in EXHIBIT D. If within twelve (12) months following
the Effective Date, the Lessee Fibers do not meet the warranty described above,
Lessee shall notify Qwest in writing. Upon receipt of written notice from
Lessee, Qwest will inspect the subject leased Fiber to confirm any alleged
defect(s) and take commercially reasonable steps to correct such defects.

         3.2 Qwest will pass through to Lessee all manufacturers' warranties
that pertain to the leased Fibers to the extent that they are transferable.
Qwest's liability to Lessee under the manufacturers' warranty shall not exceed
the terms, conditions and scope of the manufacturer's warranty and shall not
exceed the terms and conditions of the Agreement. In addition to the limitation
of liability set forth in Section 11 of the Agreement, in no event shall Qwest
be liable to Lessee for any direct, exemplary, special, consequential or
punitive damages, including but not limited to, lost profits or the cost of
providing alternative service.

         3.3 Lessee's sole and exclusive remedy for breach of the warranty
mentioned in the preceding paragraph shall be repair and/or replacement of the
portions of the Lessee Fibers found to be defective, but only if such repairs
and/or replacement are approved by the manufacturer of the fiber pursuant to the
manufacturer's warranty.

                                       C-2

[*] Indicates confidential treatment requested.

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                                                                  EXECUTION COPY

                                   EXHIBIT D:

                                      (ii) FIBER SPECIFICATIONS

                                       [*]

                   [12 pages describing fiber specifications]

                                       D-1

[*] Indicates confidential treatment requested.

<Page>
                                                                  EXECUTION COPY

                                    EXHIBIT E

                                     PRICING

                                       [*]

                           [1 page describing pricing]Prepared by MERRILL CORPORATION

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Exhibit 4.5    
  

THIS
WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE LAWS, AND NO INTEREST THEREIN MAY BE SOLD,
DISTRIBUTED, ASSIGNED, OFFERED, PLEDGED OR OTHERWISE TRANSFERRED UNLESS THERE IS AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT AND APPLICABLE STATE SECURITIES LAWS COVERING ANY SUCH TRANSACTION,
OR SUCH TRANSACTION IS EXEMPT FROM THE REGISTRATION REQUIREMENTS OF SUCH ACT AND LAWS, SUCH COMPLIANCE, AT THE OPTION OF THE CORPORATION, TO BE EVIDENCED BY AN OPINION OF THE WARRANT HOLDER'S COUNSEL,
IN FORM ACCEPTABLE TO THE CORPORATION, THAT NO VIOLATION OF SUCH REGISTRATION PROVISIONS WOULD RESULT FROM ANY PROPOSED TRANSFER OR ASSIGNMENT. 

	 	 	 	 	Warrant to Purchase
	Date: February 12, 2001	 	 	 	24,000 Shares

COMMON STOCK PURCHASE WARRANT

Axonyx Inc.  

    THIS CERTIFIES that for good and valuable consideration received, SCO Financial Group LLC or a registered assignee (the "Holder") is entitled, upon the terms
and subject to the conditions hereinafter set forth, to acquire from Axonyx Inc., a Nevada corporation (the "Corporation") up to 24,000 fully paid and nonassessable shares of common stock, par
value $0.001, of the Corporation ("Warrant Stock") at a purchase price per share (the "Exercise Price") of $6.81 (the "Warrant"). 

	1.
	Term of Warrant. 

    Subject
to the terms and conditions set forth herein, this Warrant shall be exercisable, in whole or in part, at any time on or after the date hereof and at or prior to
11:59 p.m., Eastern Standard Time, on February 11, 2006 (the "Expiration Time"). 

	2.
	Method of Exercise; Payment. 

    A) Cash Exercise. The purchase rights represented by this Warrant may be exercised by the Holder, in whole or in part,
at any time or from time to time, by the surrender of this Warrant (with the notice of exercise form attached hereto as Exhibit A duly executed)
at the principal office of the Company, and by the payment to the Company, by certified, cashier's or other check acceptable to the Company, of an amount equal to the aggregate Exercise Price of the
shares being purchased. 

    B)  Net Issue Exercise. In lieu of exercising this Warrant, the Holder may elect to receive, without the payment by the
Holder of any additional consideration, shares equal to the value of this Warrant (or the portion thereof being cancelled) by surrender of this Warrant at the principal office of the Company together
with notice of such election, in which event the Company shall issue to the Holder a number of shares of the Company's Common Stock computed using the following formula: 

	 	X =	Y (A-B)
 A

	 

Where:

X = the
number of shares of Common Stock to be issued to the Holder. 

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Y = the number of shares of Common Stock purchasable under this Warrant, or if only a portion of this Warrant is being exercised, the number of shares of Common Stock represented by the
portion of the Warrant being exercised. 

A = the
fair market value of one share of the Company's Common Stock at the time the net issue exercise election is made. 

B = the
Exercise Price (as adjusted to the date of such calculation). 

    C)  Fair Market Value. For purposes of this Section 1, the fair market value of the Company's Common Stock shall
mean: if the Company's Common Stock is traded on a securities exchange, the average of the closing price each day over the thirty consecutive day period ending three days before the date on which the
fair market value of the securities is being determined; if the Company's Common Stock is actively traded over-the counter, the average of the closing bid and asked prices quoted on the
NASDAQ system (or similar system) each day over the thirty consecutive day period ending three days before the date on which the fair market value of the securities is being determined; or if at any
time the Company's Common Stock is not listed on any securities exchange or quoted in the NASDAQ System or the over-the-counter market, then as determined by the board of
directors of the Company in good faith. 

	3.
	Issuance of Shares; No Fractional Shares of Scrip. 

    Certificates
for shares purchased hereunder shall be delivered to the Holder hereof by the Corporation's transfer agent at the Corporation's expense within a reasonable time after the
date on which this Warrant shall have been exercised in accordance with the terms hereof. Each certificate so delivered shall be in such denominations as may be requested by the Holder hereof and
shall be registered in the name of such Holder or, subject to applicable laws, such other name as shall be requested by the Holder. If, upon exercise of this Warrant, fewer than all of the shares of
Warrant Stock evidenced by this Warrant are purchased prior to the Expiration Time, one or more new warrants substantially in the form of, and on the terms in, this Warrant will be issued for the
remaining number of shares of Warrant Stock not purchased upon exercise of this Warrant. The Corporation hereby represents and warrants that all shares of Warrant Stock which may be issued upon the
exercise of this Warrant will, upon such exercise, be duly and validly authorized and issued, fully paid and nonassessable and free from all taxes, liens and charges in respect of the issuance thereof
(other than liens or charges created by or imposed upon the Holder of the Warrant Stock). The Corporation agrees that the shares so issued shall be and will be deemed to be issued to such Holder as
the record owner of such shares as of the close of business on the date on which this Warrant shall have been surrendered for exercise in accordance with the terms hereof. No fractional shares or
scrip representing fractional shares shall be issued upon the exercise of this Warrant. With respect to any fraction of a share called for upon the exercise of this Warrant, an amount equal to such
fraction multiplied by the then current price at which each share may be purchased hereunder shall be paid in cash to the Holder of this Warrant. 

	4.
	Lock Up, Registration Rights. 

    Pursuant
to the terms of the Registration Rights Agreement signed in conjunction with this Warrant, certain piggy-back registration rights apply to the Warrant Stock with
regard to any registration statement filed by the Corporation. The Corporation may, at the request of an underwriter, if any, limit or exclude such Warrant Stock from a registration statement in
connection with a public offering, or impose on each Holder a so-called "lock up" period in connection with a public offering, which lock-up period will not exceed
12 months from the effective date of the registration statement for such public offering. In addition, the Company may exclude the Warrant Stock from registration statements filed pursuant to
an acquisition, merger or under Form S-8, and, if such registration statement includes registrable securities of certain selling stockholders who purchased such registrable 

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securities in a previous private placement, the Company may exclude the Warrant Stock from such registration statement. See the Registration Rights Agreement for a full description of the
piggy-back registration rights applicable to the Warrant Stock and the limitations on such rights. 

	5.
	Charges, Taxes and Expenses. 

    Issuance
of certificates for shares of Warrant Stock upon the exercise of this Warrant shall be made without charge to the Holder hereof for any issue or transfer tax or other
incidental expense in respect of the issuance of such certificate, all of which taxes and expenses shall be paid by the Corporation, and such certificates shall be issued in the name of the Holder of
this Warrant or in such name or names as may be directed by the Holder of this Warrant; provided, however, that in the event certificates for shares of Warrant Stock are to be issued in a name other
than the name of the Holder of this Warrant, this Warrant when surrendered for exercise shall be accompanied by an Assignment Form to be provided by the Company duly executed by the Holder hereof. 

	6.
	No Rights as Shareholders. 

    This
Warrant does not entitle the Holder hereof to any voting rights or other rights as a shareholder of the Corporation prior to the exercise hereof. 

	7.
	Exchange and Registry of Warrant. 

    This
Warrant is exchangeable, upon the surrender hereof by the registered Holder at the above mentioned office or agency of the Corporation, for a new Warrant of like tenor and dated
as of such exchange. The Corporation shall maintain at the above-mentioned office or agency a registry showing the name and address of the registered Holder of this Warrant. This Warrant may be
surrendered for exchange, transfer or exercise, in accordance with its terms, at such office or agency of the Corporation, and the Corporation shall be entitled to rely in all respects, prior to
written notice to the contrary, upon such registry. 

	8.
	Loss, Theft, Destruction or Mutilation of Warrant. 

    Upon
receipt by the Corporation of evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Warrant and in case of loss, theft or destruction of
indemnity or security reasonably satisfactory to it, and upon reimbursement to the Corporation of all reasonable expenses incidental thereto, and upon surrender and cancellation of this Warrant, if
mutilated, the Corporation will make and deliver a new Warrant of like tenor and dated as of such cancellation, in lieu of this Warrant. 

	9.
	Saturdays, Sundays and Holidays. 

    If
the last or appointed day for the taking of any action or the expiration of any right required or granted herein shall be a Saturday or a Sunday or that is a legal holiday, then
such action may be taken or such right may be exercised on the next succeeding day not a Saturday, Sunday or legal holiday. 

	10.
	Merger, Sale of Assets, Etc. 

    If
at any time the Corporation proposes to merge or consolidate with or into any other corporation, effect any reorganization, or sell or convey all or substantially all of its assets
to any other entity, then, as a condition of such reorganization, consolidation, merger, sale or conveyance, the Corporation or its successor, as the case may be, shall enter into a supplemental
agreement to make lawful and adequate provision whereby the Holder shall have the right to receive, upon exercise of the Warrant, the kind and amount of equity securities which would have been
received upon such reorganization, consolidation, merger, sale or conveyance by a Holder of a number of shares of common stock equal to the number of shares issuable upon exercise of the Warrant
immediately prior to such reorganization, consolidation, merger, sale or conveyance. If the property to be received upon 

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such reorganization, consolidation, merger, sale or conveyance is not equity securities, the Corporation shall give the Holder of this Warrant ten (10) business days prior written notice of the
proposed effective date of such transaction, and if this Warrant has not been exercised by or on the effective date of such transaction, it shall terminate. 

	11.
	Subdivision, Combination, Reclassification, Conversion, Etc. 

    If
the Corporation at any time shall by subdivision, combination, reclassification of securities or otherwise, change the Warrant Stock into the same or a different number of
securities of any class or classes, this Warrant shall thereafter entitle the Holder to acquire such number and kind of securities as would have been issuable in respect of the Warrant Stock (or other
securities which were subject to the purchase rights under this Warrant immediately prior to such subdivision, combination, reclassification or other change) as the result of such change if this
Warrant had been exercised in full for cash immediately prior to such change. The Exercise Price hereunder shall be adjusted if and to the extent necessary to reflect such change. If the Warrant Stock
or other securities issuable upon exercise hereof are subdivided or combined into a greater or smaller number of shares of such security, the number of shares issuable hereunder shall be
proportionately increased or decreased, as the case may be, and the Exercise Price shall be proportionately reduced or increased, as the case may be, in both cases according to the ratio which the
total number of shares of such security to be outstanding immediately after such event bears to the total number of shares of such security outstanding immediately prior to such event. The Corporation
shall give the Holder prompt written notice of any change in the type of securities issuable hereunder, any adjustment of the Exercise Price for the securities issuable hereunder, and any increase or
decrease in the number of shares issuable hereunder. 

	12.
	Transferability; Compliance with Securities Laws. 

    (a) This
Warrant may not be transferred or assigned in whole or in part without compliance with all applicable federal and state securities laws by the transferor and
transferee (including the delivery of investment representation letters and legal opinions reasonably satisfactory to the Corporation, if requested by the Corporation). Subject to such restrictions,
prior to the Expiration Time, this Warrant and all rights hereunder are transferable by the Holder hereof, in whole or in part, at the office or agency of the Corporation referred to in
Section 2 hereof. Any such transfer shall be made in person or by the Holder's duly authorized attorney, upon surrender of this Warrant together with the Assignment Form attached hereto
properly endorsed. 

    (b) The
Holder of this Warrant, by acceptance hereof, acknowledges that this Warrant and the Warrant Stock issuable upon exercise hereof are being acquired solely for
the Holder's own account and not as a nominee for any other party, and for investment, and that the Holder will not offer, sell or otherwise dispose of this Warrant or any shares of Warrant Stock to
be issued upon exercise hereof except under circumstances that will not result in a violation of the Securities Act of 1933, as amended, or any state securities laws. Upon exercise of this Warrant,
the Holder shall, if requested by the Corporation, confirm in writing, in a form satisfactory to the Corporation, that the shares of Warrant Stock so purchased are being acquired solely for Holder's
own account and not as a nominee for any other party, for investment, and not with a view toward distribution or resale. 

    (c) The
Warrant Stock has not been and will not be registered under the Securities Act of 1933, as amended, and this Warrant may not be exercised except by
(i) the original purchaser of this Warrant from the Corporation or (ii) an "accredited investor" as defined in Rule 501(a) under the Securities Act of 1933, as amended. Each
certificate representing the Warrant Stock or other securities issued in respect of the Warrant Stock upon any stock split, stock dividend, recapitalization, merger, consolidation or similar event,
shall be stamped or otherwise imprinted 

4

 

with a legend substantially in the following form (in addition to any legend required under applicable securities laws): 

THE
SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF, AND HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED. SUCH SHARES MAY NOT BE SOLD OR TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR UNLESS THE SALE OR TRANSFER IS EXEMPT FROM THE REGISTRATION AND PROSPECTUS
DELIVERY REQUIREMENTS OF SAID ACT. 

	13.
	Representations and Warranties. 

    The
Corporation hereby represents and warrants to the Holder hereof that: 

    (a) during
the period this Warrant is outstanding, the Corporation will reserve from its authorized and unissued common stock a sufficient number of shares to provide
for the issuance of Warrant Stock upon the exercise of this Warrant; 

    (b) the
issuance of this Warrant shall constitute full authority to the Corporation's officers who are charged with the duty of executing stock certificates to execute
and issue the necessary certificates for the shares of Warrant Stock issuable upon exercise of this Warrant; 

    (c) the
Corporation has all requisite legal and corporate power to execute and deliver this Warrant, to sell and issue the Warrant Stock hereunder, and to carry out and
perform its obligations under the terms of this Warrant; and 

    (d) all
corporate action on the part of the Corporation, its directors and stockholders necessary for the authorization, execution, delivery and performance of this
Warrant by the Corporation, the authorization, sale, issuance and delivery of the Warrant Stock, the grant of registration rights as provided herein and the performance of the Corporation's
obligations hereunder has been taken; 

    (e) the
Warrant Stock, when issued in compliance with the provisions of this Warrant and the Corporation's Articles of Incorporation (as they may be amended from time
to time), will be validly issued, fully paid and nonassessable, and free of all taxes, liens or encumbrances with respect to the issue thereof, and will be issued in compliance with all applicable
federal and state securities laws; and 

    (d) the
issuance of the Warrant Stock will not be subject to any preemptive rights, rights of first refusal or similar rights. 

	14.
	Corporation Good Faith. 

    The
Corporation will not, by amendment of its Articles of Incorporation or through any reorganization, recapitalization, transfer of assets, consolidation, merger, dissolution,
issuance or sale of securities or any other action, avoid or seek to avoid the observance or performance of any of the terms to be observed or performed hereunder by the Corporation, but will at all
times in good faith assist in the carrying out of all the provisions of this Warrant and in the taking of all such action as may be necessary or appropriate in order to protect the rights of the
Holder of the Warrant against impairment. 

	15.
	Governing Law. 

    This
Warrant shall be governed by and construed in accordance with the laws of the State of New York. 

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    IN WITNESS WHEREOF, the Corporation has caused this Warrant to be executed by its duly authorized officers. 

Dated:

	 AXONYX INC.	 	 
	

 	
 	

 	
 	

 
	By:	 	 	 	 
	 	 	
 Marvin S. Hausman, M.D. President & CEO	 	 

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Exhibit 4.5

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